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I-hydrogen sulfide (H2S) inemiphumela eminingi yomzimba kanye neyezifo emzimbeni womuntu. I-Sodium hydrosulfide (NaHS) isetshenziswa kabanzi njengethuluzi lezokwelapha ukuhlola imiphumela ye-H2S ekuhlolweni kwezinto eziphilayo. Nakuba ukulahlekelwa yi-H2S ezixazululweni ze-NaHS kuthatha imizuzu embalwa kuphela, izixazululo ze-NaHS zisetshenziswe njengezakhi zomnikelo ze-H2S emanzini okuphuza kwezinye izifundo zezilwane. Lolu cwaningo luhlole ukuthi amanzi okuphuza ane-NaHS concentration engu-30 μM elungiselelwe emabhodleleni egundane/igundane angahlala eqinile okungenani amahora angu-12-24, njengoba kusikiselwa abanye ababhali. Lungisa ikhambi le-NaHS (30 μM) emanzini okuphuza bese ulithululela ngokushesha emabhodleleni amanzi egundane/igundane. Amasampula aqoqwe kusukela esicongweni nangaphakathi kwebhodlela lamanzi emahoreni angu-0, 1, 2, 3, 4, 5, 6, 12 kanye nama-24 ukuze kulinganiswe okuqukethwe kwe-sulfide kusetshenziswa indlela eluhlaza okwesibhakabhaka ye-methylene. Ngaphezu kwalokho, amagundane amaduna nabesifazane ajovwa nge-NaHS (30 μM) amasonto amabili kanti amazinga e-serum sulfide ayelinganiswa njalo ngemva kwesonto lokuqala kanye nasekupheleni kwesonto lesibili. Isixazululo se-NaHS esisampuleni esitholwe esiqongweni sebhodlela lamanzi sasingazinzi; sehle ngo-72% kanye no-75% ngemva kwamahora angu-12 no-24, ngokulandelana. Emasampuleni atholwe ngaphakathi kwamabhodlela amanzi, ukwehla kwe-NaHS kwakungabonakali phakathi kwamahora ama-2; nokho, kwehle ngo-47% kanye no-72% ngemva kwamahora angu-12 no-24, ngokulandelana. I-NaHS imjovo ayizange ithinte izinga le-serum sulfide lamagundane amaduna nabesifazane. Ekuphetheni, izixazululo ze-NaHS ezilungiselelwe ngamanzi okuphuza akufanele zisetshenziselwe ukunikela nge-H2S ngoba isixazululo asizinzi. Le ndlela yokuphatha izoveza izilwane enanini elingajwayelekile futhi elincane kunelilindelekile le-NaHS.
I-hydrogen sulfide (H2S) ibilokhu isetshenziswa njengobuthi kusukela ngo-1700; noma kunjalo, indima yayo engaba khona njenge-molecule ye-biosignaling endogenous yachazwa ngu-Abe noKimura ngo-1996. Eminyakeni engamashumi amathathu edlule, imisebenzi eminingi ye-H2S ezinhlelweni ezahlukene zabantu iye yacaciswa, okwaholela ekuqapheleni ukuthi ama-molecule anikela nge-H2S angaba nezicelo zezokwelapha ekwelapheni noma ekuphatheni izifo ezithile; bheka uChirino et al. ukuze uthole isibuyekezo samuva.
I-Sodium hydrosulfide (NaHS) isetshenziswe kabanzi njengethuluzi lezokwelapha ukuhlola imiphumela ye-H2S ezifundweni eziningi zamasiko eseli kanye nezilwane5,6,7,8. Kodwa-ke, i-NaHS ayiyona i-H2S donor efanelekile ngoba iguqulwa ngokushesha ibe yisisombululo se-H2S/HS-in, ingcoliswa kalula yi-polysulfides, futhi i-oxidized futhi i-volatilized kalula4,9. Ezivivinyweni eziningi zebhayoloji, i-NaHS incibilikiswa emanzini, okuholela ekuguqukeni okungenamsebenzi kanye nokulahlekelwa yi-H2S10,11,12, ukujikijelwa okuzenzakalelayo kwe-H2S11,12,13, kanye ne-photolysis14. I-Sulfide esixazululweni sokuqala ilahleka ngokushesha kakhulu ngenxa yokujikijelwa kwe-H2S11. Esitsheni esivulekile, isigamu sempilo (t1/2) se-H2S cishe imizuzu emi-5, futhi ukuhlushwa kwayo kwehla cishe ngo-13% ngomzuzu10. Nakuba ukulahleka kwe-hydrogen sulfide ezixazululweni ze-NaHS kuthatha imizuzu embalwa kuphela, ezinye izifundo zezilwane zisebenzise izixazululo ze-NaHS njengomthombo we-hydrogen sulfide emanzini okuphuza amasonto angu-1-21, zithatha indawo yesixazululo esiqukethe i-NaHS njalo emahoreni angu-12-24. 15,16,17,18,19,20,21,22,23,24,25,26 Lo mkhuba awuhambisani nezimiso zocwaningo lwesayensi, njengoba imithamo yemithi kufanele isekelwe ekusetshenzisweni kwayo kwezinye izinhlobo, ikakhulukazi abantu.27
Ucwaningo lwangaphambi kokwelashwa kwezokwelapha nge-biomedicine luhlose ukuthuthukisa ikhwalithi yemiphumela yokunakekelwa kweziguli noma yokwelashwa. Kodwa-ke, imiphumela yezifundo eziningi zezilwane ayikahunyushwa kubantu28,29,30. Esinye sezizathu zalokhu kwehluleka kokuhumusha ukunganakwa kwekhwalithi yezindlela zezifundo zezilwane30. Ngakho-ke, inhloso yalolu cwaningo kwakuwukuphenya ukuthi izixazululo ze-NaHS ezingama-30 μM ezilungiselelwe emabhodleleni amanzi egundane/egundane zingahlala zizinzile emanzini okuphuza amahora ayi-12-24, njengoba kushiwo noma kuphakanyiswe kwezinye izifundo.
Zonke izivivinyo kulolu cwaningo zenziwe ngokuhambisana neziqondiso ezishicilelwe zokunakekelwa nokusetshenziswa kwezilwane zaselabhorethri e-Iran31. Yonke imibiko yokuhlolwa kulolu cwaningo iphinde yalandela iziqondiso ze-ARRIVE32. IKomidi Lokuziphatha le-Institute of Endocrine Sciences, iShahid Beheshti University of Medical Sciences, livumile zonke izinqubo zokuhlola kulolu cwaningo.
I-Zinc acetate dihydrate (CAS: 5970-45-6) kanye ne-anhydrous ferric chloride (CAS: 7705-08-0) ithengwe eBiochem, eChemopahrama (Cosne-sur-Loire, eFrance). I-Sodium hydrosulfide hydrate (CAS: 207683-19-0) kanye ne-N,N-dimethyl-p-phenylenediamine (DMPD) (CAS: 535-47-0) ithengwe eSigma-Aldrich (St. Louis, MO, e-USA). I-Isoflurane ithengwe ePiramal (eBethlehem, e-PA, e-USA). I-Hydrochloric acid (HCl) ithengwe eMerck (eDarmstadt, eJalimane).
Lungisa isixazululo se-NaHS (30 μM) emanzini okuphuza bese usithela ngokushesha emabhodleleni amanzi egundane/egundane. Lokhu kuhlushwa kukhethwe ngokusekelwe ezincwadini eziningi ezisebenzisa i-NaHS njengomthombo we-H2S; bheka isigaba sengxoxo. I-NaHS iyi-molecule enamanzi angaqukatha amanani ahlukahlukene amanzi anomswakama (okungukuthi, i-NaHS•xH2O); ngokusho komkhiqizi, iphesenti le-NaHS elisetshenziswe ocwaningweni lwethu lalingu-70.7% (okungukuthi, i-NaHS•1.3 H2O), futhi sacabangela leli nani ekubaleni kwethu, lapho sisebenzise khona isisindo sama-molecule esingu-56.06 g/mol, okuyisisindo sama-molecule se-NaHS engenamanzi. Amanzi anomswakama (abizwa nangokuthi amanzi okukhanyisa) ama-molecule amanzi akha isakhiwo sama-crystalline33. Ama-hydrate anezakhiwo ezihlukile zomzimba nezokushisa uma kuqhathaniswa nama-anhydrate34.
Ngaphambi kokufaka i-NaHS emanzini okuphuza, kala i-pH kanye nokushisa kwesinyibilikisi. Thela ngokushesha isisombululo se-NaHS ebhodleleni lamanzi legundane/legundane ekhejini lesilwane. Amasampula aqoqwe kusukela esiqongweni nangaphakathi kwebhodlela lamanzi emahoreni angu-0, 1, 2, 3, 4, 5, 6, 12, kanye nama-24 ukuze kulinganiswe okuqukethwe yi-sulfide. Ukulinganiswa kwe-sulfide kwathathwa ngokushesha ngemva kokuthatha isampula ngayinye. Sithole amasampula esiqongweni sethubhu ngoba ezinye izifundo zikhombisile ukuthi usayizi omncane wembobo yethubhu lamanzi unganciphisa ukuhwamuka kwe-H2S15,19. Le nkinga ibonakala isebenza nasesixazululweni esisebhodleleni. Kodwa-ke, lokhu kwakungenjalo ngesisombululo esisentanyeni yebhodlela lamanzi, esasinezinga eliphezulu lokuhwamuka futhi sasizishisa ngokuzenzakalelayo; empeleni, izilwane zaphuza la manzi kuqala.
Kusetshenziswe amagundane e-Wistar angamaduna nawesifazane ocwaningweni. Amagundane agcinwa ezindlini ze-polypropylene (amagundane angu-2-3 ngendlini ngayinye) ngaphansi kwezimo ezijwayelekile (izinga lokushisa elingu-21-26 °C, umswakama ongu-32-40%) kanye nokukhanya amahora angu-12 (7 ekuseni kuya ku-7 ntambama) kanye namahora angu-12 obumnyama (7 ntambama kuya ku-7 ekuseni). Amagundane ayenokufinyelela mahhala emanzini ompompi futhi ondliwe nge-standard chow (Khorak Dam Pars Company, eTehran, e-Iran). Amagundane alingana nobudala (izinyanga ezingu-6) amasikazi (n=10, isisindo somzimba: 190–230 g) kanye namaduna (n=10, isisindo somzimba: 320–370 g) ahlukaniswe ngokungahleliwe abe amaqembu aphathwayo kanye nama-NaHS (30 μM) (n=5 ngeqembu ngalinye). Ukuze sithole usayizi wesampula, sisebenzise indlela ye-KISS (Keep It Simple, Stupid), ehlanganisa ulwazi lwangaphambilini kanye nokuhlaziywa kwamandla35. Siqale senza ucwaningo lokuhlola emagundwini amathathu futhi sathola izinga elimaphakathi le-sulfide serum kanye nokuphambuka okujwayelekile (8.1 ± 0.81 μM). Ngemuva kwalokho, sicabangela amandla angu-80% futhi sicabangela izinga lokubaluleka elingu-5% elinhlangothi zombili, sathola usayizi wesampula wokuqala (n = 5 ngokusekelwe ezincwadini zangaphambilini) ohambisana nosayizi womphumela ojwayelekile ongu-2.02 ngenani elichazwe kusengaphambili eliphakanyiswe yi-Festing yokubala usayizi wesampula wezilwane zokuhlola35. Ngemva kokuphindaphinda leli nani nge-SD (2.02 × 0.81), usayizi womphumela otholakalayo obikezelwe (1.6 μM) wawungu-20%, okwamukelekayo. Lokhu kusho ukuthi i-n = 5/iqembu lanele ukuthola ushintsho olumaphakathi lwama-20% phakathi kwamaqembu. Amagundane ahlukaniswe ngokungahleliwe abe amaqembu alawulwayo kanye nalawa aphathwe yi-NaSH kusetshenziswa umsebenzi ongahleliwe wesofthiwe ye-Excel 36 (Isithombe Esingeziwe 1). Ukuhlola kwenziwa ezingeni lomphumela, futhi abacwaningi abenza izilinganiso ze-biochemical babengazi ngezabelo zeqembu.
Amaqembu e-NaHS abo bobabili ubulili aphathwa ngesisombululo se-NaHS esingu-30 μM esilungiselelwe emanzini okuphuza amasonto ama-2; Isixazululo esisha sanikezwa njalo emahoreni angama-24, lapho kwakulinganiswa khona isisindo somzimba. Amasampula egazi aqoqwa eziqongweni zomsila wawo wonke amagundane ngaphansi kwe-isoflurane anesthesia njalo ngosuku olulodwa ekupheleni kwesonto lokuqala nelesibili. Amasampula egazi afakwa ku-centrifuge ku-3000 g imizuzu eyi-10, i-serum yahlukaniswa futhi yagcinwa ku--80°C ukuze kulinganiswe i-serum urea, i-creatinine (Cr), kanye ne-total sulfide. I-Serum urea yanqunywa ngendlela ye-enzymatic urea, kanti i-serum creatinine yanqunywa ngendlela ye-photometric Jaffe kusetshenziswa ama-kit atholakala kwezentengiselwano (Man Company, Tehran, Iran) kanye ne-automatic analyzer (Selectra E, inombolo ye-serial 0-2124, The Netherlands). Ama-coefficients angaphakathi naphakathi kwe-interassay of variation ye-urea kanye ne-Cr ayengaphansi kuka-2.5%.
Indlela ye-methylene blue (MB) isetshenziselwa ukukala i-sulfide iyonke emanzini okuphuza kanye ne-serum equkethe i-NaHS; i-MB iyindlela evame ukusetshenziswa kakhulu yokulinganisa i-sulfide ezixazululweni eziningi kanye namasampula ebhayoloji11,37. Indlela ye-MB ingasetshenziswa ukulinganisa i-sulfide pool iyonke38 kanye nokulinganisa ama-sulfide angaphili ngendlela ye-H2S, HS- kanye ne-S2 esigabeni samanzi39. Kule ndlela, i-sulfur ifakwa njenge-zinc sulfide (ZnS) lapho kukhona i-zinc acetate11,38. I-Zinc acetate precipitation iyindlela esetshenziswa kakhulu yokuhlukanisa ama-sulfide kwamanye ama-chromophores11. I-ZnS yaphinde yancibilikiswa kusetshenziswa i-HCl11 ngaphansi kwezimo ezinamandla ze-acidic. I-sulfide isabela ne-DMPD ngesilinganiso se-stoichiometric esingu-1:2 ekuphenduleni okubangelwa yi-ferric chloride (i-Fe3+ isebenza njenge-oxidizing agent) ukwakha i-dye MB, etholakala nge-spectrophotometrically ku-670 nm40,41. Umkhawulo wokutholwa kwendlela ye-MB cishe u-1 μM11.
Kulolu cwaningo, i-100 μL yesampula ngayinye (isisombululo noma i-serum) yengezwe epayipini; kwabe sekufakwa i-200 μL ye-zinc acetate (1% w/v emanzini acwengekile), i-100 μL ye-DMPD (20 mM ku-7.2 M HCl), kanye ne-133 μL ye-FeCl3 (30 mM ku-1.2 M HCl). Ingxube yafakwa ku-37°C ebumnyameni imizuzu engama-30. Isixazululo safakwa ku-centrifuge ku-10,000 g imizuzu eyi-10, kanti ukumuncwa kwe-supernatant kwafundwa ku-670 nm kusetshenziswa i-microplate reader (BioTek, MQX2000R2, Winooski, VT, USA). Amazinga e-sulfide anqunywa kusetshenziswa i-calibration curve ye-NaHS (0–100 μM) ku-ddH2O (Isithombe Esingeziwe 2). Zonke izixazululo ezisetshenziswe ekulinganisweni zalungiswa kabusha. Ama-coefficients angaphakathi naphakathi kokulinganisa kwe-sulfide ayengu-2.8% no-3.4%, ngokulandelana. Siphinde sanquma inani eliphelele le-sulfide elitholwe emanzini okuphuza aqukethe i-sodium thiosulfate kanye namasampula e-serum sisebenzisa indlela yesampula eqinile42. Ukutholwa kwamanzi okuphuza aqukethe i-sodium thiosulfate kanye namasampula e-serum kwakungu-91 ± 1.1% (n = 6) kanye no-93 ± 2.4% (n = 6), ngokulandelana.
Ukuhlaziywa kwezibalo kwenziwe kusetshenziswa isofthiwe ye-GraphPad Prism version 8.0.2 ye-Windows (GraphPad Software, San Diego, CA, USA, www.graphpad.com). Kusetshenziswe ukuhlolwa kwe-t okubhangqiwe ukuqhathanisa izinga lokushisa kanye ne-pH yamanzi okuphuza ngaphambi nangemva kokufakwa kwe-NaHS. Ukulahleka kwe-H2S esixazululweni esiqukethe i-NaHS kubalwe njengokwehla kwephesenti kusukela ekuthathweni kokuqala, futhi ukuze kuhlolwe ukuthi ukulahleka kwakubalulekile ngokwezibalo, senze i-ANOVA ephindaphindwayo yendlela eyodwa elandelwa ukuhlolwa kokuqhathanisa okuningi kukaDunnett. Isisindo somzimba, i-serum urea, i-serum creatinine, kanye ne-serum sulfide iyonke ngokuhamba kwesikhathi kwaqhathaniswa phakathi kwamagundane alawulwayo kanye nalawa aphethwe yi-NaHS obulili obuhlukene kusetshenziswa i-ANOVA exutshwe ngezindlela ezimbili (phakathi-ngaphakathi) elandelwa ukuhlolwa kwe-Bonferroni post hoc. Amanani e-P anemisila emibili < 0.05 abhekwa njengabalulekile ngokwezibalo.
I-pH yamanzi okuphuza yayingu-7.60 ± 0.01 ngaphambi kokufakwa kwe-NaHS kanye no-7.71 ± 0.03 ngemva kokufakwa kwe-NaHS (n = 13, p = 0.0029). Izinga lokushisa lamanzi okuphuza lalingu-26.5 ± 0.2 futhi lehla laya ku-26.2 ± 0.2 ngemva kokufakwa kwe-NaHS (n = 13, p = 0.0128). Lungisa isisombululo se-NaHS esingu-30 μM emanzini okuphuza bese usigcina ebhodleleni lamanzi. Isixazululo se-NaHS asizinzile futhi ukuhlushwa kwaso kwehla ngokuhamba kwesikhathi. Lapho kuthathwa isampula entanyeni yebhodlela lamanzi, kwabonakala ukwehla okukhulu (68.0%) phakathi nehora lokuqala, kanti okuqukethwe kwe-NaHS esixazululweni kwehle ngo-72% kanye no-75% ngemva kwamahora angu-12 kanye no-24, ngokulandelana. Emasampeleni atholwe emabhodleleni amanzi, ukwehla kwe-NaHS kwakungabonakali kuze kube amahora ama-2, kodwa ngemva kwamahora angu-12 kanye no-24 kwehle ngo-47% kanye no-72%, ngokulandelana. Le datha ikhombisa ukuthi iphesenti le-NaHS esixazululweni esingu-30 μM esilungiselelwe emanzini okuphuza sehle safinyelela cishe ingxenye eyodwa kwezine yenani lokuqala ngemva kwamahora angu-24, kungakhathaliseki indawo yokuthatha isampula (Isithombe 1).
Ukuqina kwesisombululo se-NaHS (30 μM) emanzini okuphuza emabhodleleni egundane/egundane. Ngemva kokulungiswa kwesisombululo, amasampula athathwe esicongweni nangaphakathi kwebhodlela lamanzi. Imininingwane yethulwa njengesilinganiso ± SD (n = 6/iqembu). * kanye no-#, P < 0.05 uma kuqhathaniswa nesikhathi 0. Isithombe sebhodlela lamanzi sibonisa isicongo (esinokuvulwa) kanye nomzimba webhodlela. Umthamo wesicongo cishe u-740 μL.
Ukuhlushwa kwe-NaHS esixazululweni esisanda kulungiswa esingu-30 μM kwakungu-30.3 ± 0.4 μM (ububanzi: 28.7–31.9 μM, n = 12). Kodwa-ke, ngemva kwamahora angu-24, ukuhlushwa kwe-NaHS kwehle kwaba inani eliphansi (isilinganiso: 3.0 ± 0.6 μM). Njengoba kuboniswe kuMfanekiso 2, ukuhlushwa kwe-NaHS lapho amagundane abonakala khona kwakungaguquki phakathi nesikhathi socwaningo.
Isisindo somzimba samagundane esifazane sanda kakhulu ngokuhamba kwesikhathi (kusukela ku-205.2 ± 5.2 g kuya ku-213.8 ± 7.0 g eqenjini lokulawula kanye naku-204.0 ± 8.6 g kuya ku-211.8 ± 7.5 g eqenjini elashwa nge-NaHS); noma kunjalo, ukwelashwa nge-NaHS akuzange kube nomthelela esisindweni somzimba (Isithombe 3). Isisindo somzimba samagundane esilisa sanda kakhulu ngokuhamba kwesikhathi (kusukela ku-338.6 ± 8.3 g kuya ku-352.4 ± 6.0 g eqenjini lokulawula kanye naku-352.4 ± 5.9 g kuya ku-363.2 ± 4.3 g eqenjini elashwa nge-NaHS); noma kunjalo, ukwelashwa nge-NaHS akuzange kube nomthelela esisindweni somzimba (Isithombe 3).
Izinguquko esisindweni somzimba kumagundane esifazane nabesilisa ngemva kokunikezwa i-NaHS (30 μM). Idatha yethulwa njenge-± SEM ephakathi futhi yaqhathaniswa kusetshenziswa ukuhlaziywa okuxubile (ngaphakathi-phakathi) kokuhlukahluka ngokuhlolwa kwe-Bonferroni post hoc. n = 5 yobulili ngabunye eqenjini ngalinye.
Ukuhlushwa kwe-serum urea kanye ne-creatine phosphate kwakufana ekulawuleni kanye nasezimpukuni eziphathwe nge-NaSH kulo lonke ucwaningo. Ngaphezu kwalokho, ukwelashwa kwe-NaSH akuzange kuthinte ukuhlushwa kwe-serum urea kanye ne-creatinechrome (Ithebula 1).
Ukuhlushwa kwe-serum total sulfide okuyisisekelo kwakuqhathaniswa phakathi kwamagundane abesilisa aphathwe nge-NaHS (8.1 ± 0.5 μM vs. 9.3 ± 0.2 μM) kanye namagundane abesifazane (9.1 ± 1.0 μM vs. 6.1 ± 1.1 μM). Ukuphathwa kwe-NaHS izinsuku ezingu-14 akuzange kube nomthelela emazingeni e-serum total sulfide kumagundane abesilisa noma abesifazane (Isithombe 4).
Izinguquko ekugxilweni kwe-serum total sulfide kumagundane abesilisa nabesifazane ngemuva kokuphathwa kwe-NaHS (30 μM). Idatha yethulwa njenge-± SEM ephakathi futhi yaqhathaniswa kusetshenziswa ukuhlaziywa okuxubile (ngaphakathi-ngaphakathi) kokuhlukahluka ngokuhlolwa kwe-Bonferroni post hoc. Ubulili ngabunye, n = 5/iqembu.
Isiphetho esiyinhloko salolu cwaningo ukuthi amanzi okuphuza aqukethe i-NaHS awazinzile: cishe ingxenye yesine kuphela yokuqukethwe kwe-sulfide kokuqala okungatholakala emahoreni angama-24 ngemuva kokuthatha isampula kusukela esicongweni nangaphakathi kwamabhodlela amanzi egundane/igundane. Ngaphezu kwalokho, amagundane athola amazinga e-NaHS angazinzile ngenxa yokulahlekelwa yi-H2S esixazululweni se-NaHS, futhi ukwengezwa kwe-NaHS emanzini okuphuza akuzange kuthinte isisindo somzimba, i-serum urea kanye ne-creatine chromium, noma i-serum sulfide iyonke.
Kulesi sifundo, izinga lokulahlekelwa yi-H2S kusuka kuzixazululo ze-NaHS ezingama-30 μM ezilungiselelwe emanzini okuphuza lalicishe libe ngu-3% ngehora. Esixazululweni esihlanganisiwe (i-sodium sulfide eyi-100 μM ku-10 mM PBS, pH 7.4), ukuhlushwa kwe-sulfide kubikwa ukuthi kwehle ngo-7% ngokuhamba kwesikhathi ngaphezu kwamahora angu-811. Ngaphambilini sivikele ukuphathwa kwe-NaHS ngaphakathi kwesisu ngokubika ukuthi izinga lokulahlekelwa yi-sulfide kusuka kusixazululo se-NaHS esingu-54 μM emanzini okuphuza lalicishe libe ngu-2.3% ngehora (4%/ihora emahoreni angu-12 okuqala kanye no-1.4%/ihora emahoreni angu-12 okugcina ngemuva kokulungiswa)8. Izifundo zangaphambilini43 zithole ukulahlekelwa okuqhubekayo kwe-H2S kusuka kuzixazululo ze-NaHS, ikakhulukazi ngenxa yokuguquguquka kanye nokushiswa. Ngisho nangaphandle kokwengezwa kwama-bubbles, i-sulfide esixazululweni sesitoko ilahleka ngokushesha ngenxa yokuguquguquka kwe-H2S11. Izifundo zikhombisile ukuthi ngesikhathi senqubo yokuncibilikisa, ethatha cishe imizuzwana engama-30-60, cishe u-5-10% we-H2S uyalahleka ngenxa yokuhwamuka6. Ukuze kuvinjelwe ukuhwamuka kwe-H2S esixazululweni, abacwaningi bathathe izinyathelo eziningana, okuhlanganisa nokuxubha kancane isixazululo12, ukumboza isixazululo sesitoko ngefilimu yepulasitiki6, nokunciphisa ukuvezwa kwesisombululo emoyeni, njengoba izinga lokuhwamuka kwe-H2S lincike esibonakalayo somoya-uketshezi.13 Ukushiswa okuzenzakalelayo kwe-H2S kwenzeka ikakhulukazi ngenxa yama-ion ensimbi aguqukayo, ikakhulukazi insimbi ye-ferric, okuyizinto ezingcolile emanzini.13 Ukushiswa kwe-H2S kuphumela ekwakhekeni kwama-polysulfide (ama-athomu esibabule axhunywe yizibopho ze-covalent)11. Ukuze kugwenywe ukushiswa kwayo, izixazululo eziqukethe i-H2S zilungiswa ezinyibilikisini ezingenawo umoya-mpilo44,45 bese zihlanzwa nge-argon noma i-nitrogen imizuzu engama-20-30 ukuqinisekisa ukushiswa komoya-mpilo.11,12,37,44,45,46 I-Diethylenetriaminepentaacetic acid (DTPA) iyi-metal chelator (10-4 M) evimbela ukushiswa kwe-HS- ezixazululweni ze-aerobic. Uma ingekho i-DTPA, izinga lokushiswa kwe-HS- licishe libe ngu-50% cishe emahoreni ama-3 ku-25°C37,47. Ngaphezu kwalokho, njengoba ukushiswa kwe-1e-sulfide kuqhutshwa ukukhanya kwe-ultraviolet, isixazululo kufanele sigcinwe eqhweni futhi sivikelwe ekukhanyeni11.
Njengoba kuboniswe kuMfanekiso 5, i-NaHS iyahlukana ibe yi-Na+ kanye ne-HS-6 uma incibilikiswa emanzini; lokhu kuhlukana kunqunywa yi-pK1 yokusabela, okuncike ekushiseni: i-pK1 = 3.122 + 1132/T, lapho i-T isukela ku-5 kuya ku-30°C futhi ilinganiswa ngamadigri i-Kelvin (K), i-K = °C + 273.1548. I-HS- ine-pK2 ephezulu (pK2 = 19), ngakho-ke ku-pH < 96.49, i-S2- ayakhiwa noma yakhiwe ngamanani amancane kakhulu. Ngokuphambene nalokho, i-HS- isebenza njengesisekelo futhi yamukela i-H+ kusuka ku-molecule ye-H2O, kanti i-H2O isebenza njenge-asidi futhi iguqulwa ibe yi-H2S kanye ne-OH-.
Ukwakheka kwegesi ye-H2S encibilikisiwe kusisombululo se-NaHS (30 µM). aq, isixazululo samanzi; g, igesi; l, uketshezi. Zonke izibalo zicabanga ukuthi amanzi i-pH = 7.0 kanye nokushisa kwamanzi = 20 °C. Kwenziwe nge-BioRender.com.
Naphezu kobufakazi bokuthi izixazululo ze-NaHS azizinzile, izifundo eziningana zezilwane zisebenzise izixazululo ze-NaHS emanzini okuphuza njengenhlanganisela yabanikeli be-H2S15,16,17,18,19,20,21,22,23,24,25,26 ngezikhathi zokungenelela ezisukela emasontweni angu-1 kuya kwangu-21 (Ithebula 2). Phakathi nalezi zifundo, isixazululo se-NaHS sasivuselelwa njalo emahoreni ayi-12, 15, 17, 18, 24, 25 noma amahora angama-24, 19, 20, 21, 22, 23. Imiphumela yethu ibonise ukuthi amagundane abhekene nokugxila kwezidakamizwa okungazinzile ngenxa yokulahlekelwa yi-H2S esixazululweni se-NaHS, futhi okuqukethwe yi-NaHS emanzini okuphuza amagundane kwashintsha kakhulu emahoreni ayi-12 noma angama-24 (bheka Umfanekiso 2). Izifundo ezimbili zalezi zibike ukuthi amazinga e-H2S emanzini ahlala eqinile phakathi kwamahora angama-24 namahora angama-22 noma ukuthi ukulahleka kwe-H2S okungu-2–3% kuphela okubonwe phakathi kwamahora ayi-12 namahora ayi-15, kodwa azizange zinikeze idatha esekelayo noma imininingwane yokulinganisa. Izifundo ezimbili zibonise ukuthi ububanzi obuncane bamabhodlela amanzi bunganciphisa ukuhwamuka kwe-H2S15,19. Kodwa-ke, imiphumela yethu ibonise ukuthi lokhu kungase kulibazise ukulahleka kwe-H2S ebhodleleni lamanzi ngamahora ama-2 kunokuba kube ngamahora ayi-12–24. Zombili izifundo ziphawula ukuthi sicabanga ukuthi izinga le-NaHS emanzini okuphuza alishintshanga ngoba asibonanga ushintsho lombala emanzini; ngakho-ke, ukushiswa kwe-H2S ngomoya kwakungabonakali19,20. Ngokumangazayo, le ndlela eqondene nomuntu ngamunye ihlola ukuzinza kwe-NaHS emanzini kunokulinganisa ushintsho ekugxilweni kwayo ngokuhamba kwesikhathi.
Ukulahleka kwe-H2S kusisombululo se-NaHS kuhlobene ne-pH kanye nokushisa. Njengoba kuphawuliwe ocwaningweni lwethu, ukuncibilikisa i-NaHS emanzini kuphumela ekwakhekeni kwesisombululo se-alkaline50. Lapho i-NaHS incibilikiswa emanzini, ukwakheka kwegesi ye-H2S encibilikisiwe kuncike enanini le-pH6. Uma i-pH yesisombululo iphansi, kulapho inani le-NaHS elikhona njengama-molecule egesi ye-H2S liba likhulu futhi i-sulfide eningi ilahleka esixazululweni samanzi11. Azikho kulezi zifundo ezibike i-pH yamanzi okuphuza asetshenziswa njengesixazululi se-NaHS. Ngokwezincomo ze-WHO, ezamukelwa amazwe amaningi, i-pH yamanzi okuphuza kufanele ibe sebangeni eliphakathi kuka-6.5–8.551. Kulolu hlu lwe-pH, izinga lokushiswa kwe-H2S okuzenzakalelayo likhuphuka cishe ngokuphindwe kayishumi13. Ukuncibilikisa i-NaHS emanzini kulolu hlu lwe-pH kuzoholela ekugxilweni kwegesi ye-H2S encibilikisiwe okungu-1 kuya ku-22.5 μM, okugcizelela ukubaluleka kokuqapha i-pH yamanzi ngaphambi kokuncibilikisa i-NaHS. Ngaphezu kwalokho, ububanzi bokushisa obubikwe ocwaningweni olungenhla (18–26 °C) buzoholela ekushintsheni kokuhlushwa kwegesi ye-H2S encibilikisiwe esixazululweni esingaba ngu-10%, njengoba izinguquko zokushisa zishintsha i-pK1, futhi izinguquko ezincane ku-pK1 zingaba nomthelela omkhulu ekuhlushweni kwegesi ye-H2S encibilikisiwe48. Ngaphezu kwalokho, isikhathi eside sezinye izifundo (izinyanga ezi-5)22, lapho kulindeleke khona ukuguquguquka okukhulu kokushisa, nakho kuyayibhebhethekisa le nkinga.
Zonke izifundo ngaphandle kweyodwa21 zisebenzise isisombululo se-NaHS esingu-30 μM emanzini okuphuza. Ukuze kuchazwe umthamo osetshenzisiwe (okungukuthi 30 μM), abanye ababhali baveze ukuthi i-NaHS esigabeni samanzi ikhiqiza ukuhlushwa okufanayo kwegesi ye-H2S nokuthi ububanzi bokuphila be-H2S buyi-10 kuya ku-100 μM, ngakho-ke lo mthamo ungaphakathi kobubanzi bokuphila15,16. Abanye bachaze ukuthi i-NaHS engu-30 μM ingagcina izinga le-H2S le-plasma ngaphakathi kobubanzi bokuphila, okungukuthi 5–300 μM19,20. Sicabangela ukuhlushwa kwe-NaHS emanzini angu-30 μM (pH = 7.0, T = 20 °C), okwasetshenziswa kwezinye izifundo ukutadisha imiphumela ye-H2S. Singabala ukuthi ukuhlushwa kwegesi ye-H2S encibilikisiwe kungu-14.7 μM, okungaba ngu-50% wokuhlushwa kwe-NaHS kokuqala. Leli nani lifana nenani elibalwe abanye ababhali ngaphansi kwezimo ezifanayo13,48.
Esifundweni sethu, ukuphathwa kwe-NaHS akuzange kushintshe isisindo somzimba; lo mphumela uhambisana nemiphumela yezinye izifundo kumagundane esilisa22,23 kanye namagundane esilisa18; Kodwa-ke, izifundo ezimbili zibike ukuthi i-NaSH ibuyisele isisindo somzimba esinciphile kumagundane ancishisiwe24,26, kanti ezinye izifundo azizange zibike umphumela wokuphathwa kwe-NaSH esisisindo somzimba15,16,17,19,20,21,25. Ngaphezu kwalokho, esifundweni sethu, ukuphathwa kwe-NaSH akuzange kuthinte amazinga e-serum urea kanye ne-creatine chromium, okuhambisana nemiphumela yomunye umbiko25.
Ucwaningo luthole ukuthi ukwengezwa kwe-NaHS emanzini okuphuza amasonto ama-2 akuzange kuthinte amazinga e-serum sulfide ephelele kumagundane abesilisa nabesifazane. Lokhu okutholakele kuhambisana nemiphumela kaSen et al. (16): Amaviki ayi-8 okwelashwa nge-30 μM NaHS emanzini okuphuza awazange athinte amazinga e-plasma sulfide kumagundane alawulayo; noma kunjalo, babike ukuthi lokhu kungenelela kubuyisele amazinga e-H2S anciphile ku-plasma yamagundane ancishisiwe. ULi et al. (22) babike nokuthi ukwelashwa nge-30 μM NaHS emanzini okuphuza izinyanga ezi-5 kwandise amazinga e-plasma free sulfide kumagundane asebekhulile cishe ngo-26%. Ezinye izifundo azizange zibike izinguquko ku-sulfide ejikelezayo ngemuva kokwengezwa kwe-NaHS emanzini okuphuza.
Izifundo eziyisikhombisa zibikwe kusetshenziswa i-Sigma NaHS15,16,19,20,21,22,23 kodwa azizange zinikeze imininingwane eyengeziwe ngamanzi okumunca, kanti izifundo ezinhlanu azizange zikhulume ngomthombo we-NaHS osetshenziswe ezindleleni zazo zokulungiselela17,18,24,25,26. I-NaHS iyi-molecule enamanzi futhi okuqukethwe kwayo kwamanzi okumunca kungahluka, okuthinta inani le-NaHS elidingekayo ukulungiselela isixazululo se-molarity ethile. Isibonelo, okuqukethwe kwe-NaHS esifundweni sethu kwakuyi-NaHS•1.3 H2O. Ngakho-ke, amazinga e-NaHS angempela kulezi zifundo angase abe ngaphansi kunalawo abikiwe.
“Inhlanganisela enjalo ehlala isikhathi esifushane ingaba kanjani nomphumela ohlala isikhathi eside kangaka?” UPozgay et al.21 babuze lo mbuzo lapho behlola imiphumela ye-NaHS ku-colitis emagundwini. Bathemba ukuthi izifundo zesikhathi esizayo zizokwazi ukuphendula lo mbuzo futhi baqagela ukuthi izixazululo ze-NaHS zingase ziqukathe ama-polysulfide azinzile ngaphezu kwe-H2S nama-disulfide axhumanisa umphumela we-NaHS21. Okunye okungenzeka ukuthi amazinga aphansi kakhulu e-NaHS asele esixazululweni nawo angaba nomphumela omuhle. Eqinisweni, u-Olson et al. banikeze ubufakazi bokuthi amazinga e-micromolar e-H2S egazini awawona awemvelo futhi kufanele abe sebangeni le-nanomolar noma angabi khona nhlobo13. I-H2S ingasebenza nge-protein sulfation, ukuguqulwa okuguqulwayo ngemva kokuhumusha okuthinta umsebenzi, ukuzinza, kanye nendawo yamaprotheni amaningi52,53,54. Eqinisweni, ngaphansi kwezimo zomzimba, cishe u-10% kuya ku-25% wamaprotheni amaningi esibindi a-sulfylated53. Zombili izifundo ziyavuma ukubhujiswa okusheshayo kwe-NaHS19,23 kodwa ngokumangalisayo zithi “silawule ukugcwala kwe-NaHS emanzini okuphuza ngokuwashintsha nsuku zonke.”23 Ucwaningo olulodwa ngephutha luthi “i-NaHS ingumnikeli ojwayelekile we-H2S futhi ivame ukusetshenziswa emitholampilo ukufaka esikhundleni se-H2S uqobo.”18
Ingxoxo engenhla ikhombisa ukuthi i-NaHS ilahleka esixazululweni ngenxa yokuguquguquka, ukushiswa kwe-oxidation kanye ne-photolysis, ngakho-ke kwenziwa ezinye iziphakamiso zokunciphisa ukulahleka kwe-H2S esixazululweni. Okokuqala, ukushiswa kwe-H2S kuncike ku-interface yegesi-uketshezi13 kanye ne-pH yesisombululo11; ngakho-ke, ukuze kuncishiswe ukulahleka kokushiswa kwe-evaporative, intamo yebhodlela lamanzi ingenziwa ibe ncane ngangokunokwenzeka njengoba kuchaziwe ngaphambilini15,19, futhi i-pH yamanzi ingalungiswa ibe umkhawulo ophezulu owamukelekayo (okungukuthi, 6.5–8.551) ukuze kuncishiswe ukulahleka kokushiswa kwe-evaporative11. Okwesibili, ukushiswa kwe-oxidation okuzenzakalelayo kwe-H2S kwenzeka ngenxa yemiphumela ye-oxygen kanye nokuba khona kwama-ion ensimbi aguqukayo emanzini okuphuza13, ngakho-ke ukushiswa kwe-oxygen emanzini okuphuza nge-argon noma i-nitrogen44,45 kanye nokusetshenziswa kwama-chelators ensimbi37,47 kunganciphisa ukushiswa kwe-sulfide. Okwesithathu, ukuvimbela ukushiswa kwe-photo-liquid kwe-H2S, amabhodlela amanzi angasongwa nge-aluminium foil; Lo mkhuba usebenza nasezintweni ezizwela ukukhanya njenge-streptozotocin55. Okokugcina, usawoti we-sulfide ongaphili (i-NaHS, i-Na2S, kanye ne-CaS) unganikezwa nge-gavage kunokuba uncibilikiswe emanzini okuphuza njengoba kubikwe ngaphambilini56,57,58; izifundo zibonise ukuthi i-sodium sulfide enemisebe enikezwa nge-gavage kumagundane imuncwa kahle futhi isatshalaliswa cishe kuzo zonke izicubu59. Kuze kube manje, izifundo eziningi zinikeze usawoti we-sulfide ongaphili ngaphakathi kwesisu; nokho, le ndlela ayivamile ukusetshenziswa ezindaweni zezokwelapha60. Ngakolunye uhlangothi, indlela yomlomo iyindlela evame kakhulu futhi ekhethwayo yokuphatha kubantu61. Ngakho-ke, sincoma ukuhlola imiphumela yabanikeli be-H2S kumagundane nge-gavage yomlomo.
Umkhawulo ukuthi silinganise i-sulfide kusisombululo samanzi kanye ne-serum sisebenzisa indlela ye-MB. Izindlela zokulinganisa i-sulfide zifaka phakathi i-iodine titration, i-spectrophotometry, indlela ye-electrochemical (i-potentiometry, i-amperometry, indlela ye-coulometric kanye nendlela ye-amperometric) kanye ne-chromatography (i-gas chromatography kanye ne-high-performance liquid chromatography), phakathi kwazo indlela evame ukusetshenziswa kakhulu yi-MB spectrophotometric method62. Umkhawulo wendlela ye-MB yokulinganisa i-H2S kumasampula ebhayoloji ukuthi ilinganisa wonke ama-compound aqukethe i-sulfur hhayi i-H2S63 yamahhala ngoba yenziwa ngaphansi kwezimo ze-acidic, okuholela ekukhishweni kwe-sulfur emthonjeni webhayoloji64. Kodwa-ke, ngokusho kwe-American Public Health Association, i-MB iyindlela ejwayelekile yokulinganisa i-sulfide emanzini65. Ngakho-ke, lo mkhawulo awuthinti imiphumela yethu eyinhloko ekungazinzini kwezixazululo eziqukethe i-NaHS. Ngaphezu kwalokho, ocwaningweni lwethu, ukubuyiselwa kwezilinganiso ze-sulfide kumasampula amanzi kanye ne-serum aqukethe i-NaHS kwakungu-91% no-93%, ngokulandelana. Lezi zindinganiso zihambisana namabanga abikiwe ngaphambilini (77–92)66, okubonisa ukunemba okwamukelwayo kokuhlaziya42. Kubalulekile ukuqaphela ukuthi sisebenzise amagundane amaduna nabesifazane ngokuhambisana neziqondiso ze-National Institutes of Health (NIH) ukuze sigweme ukuthembela ngokweqile ezifundweni zezilwane zamaduna kuphela ezifundweni zangaphambi kokwelashwa67 kanye nokufaka amagundane amaduna nabesifazane noma nini lapho kungenzeka68. Leli phuzu ligcizelelwe ngabanye69,70,71.
Ekuphetheni, imiphumela yalolu cwaningo ikhombisa ukuthi izixazululo ze-NaHS ezilungiselelwe ngamanzi okuphuza azikwazi ukusetshenziselwa ukukhiqiza i-H2S ngenxa yokungazinzi kwazo. Le ndlela yokuphatha izoveza izilwane emazingeni angazinzile futhi aphansi kunalindelekile e-NaHS; ngakho-ke, okutholakele kungase kungasebenzi kubantu.
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