Ubururu bwa methylene mu bushakashatsi ku mpanuka y'imiyoboro y'amaraso yo mu bwonko no ku kugabanuka kw'amaraso abugeramo: icyo uburyo butatu bw'igerageza bwerekana koko

Umutsi uzibye, uturemangingo twahinzwe muri laboratwari tukamburwa ibidutunga, n'imbeba ifite imiyoboro y'amaraso yo mu ijosi yagabanyijwe ubugari bishobora kumvikana nk'uburyo butatu bw'igerageza rimwe. Si ko biri. Buri buryo bushaka igisubizo cy'ikibazo gitandukanye, kandi ubururu bwa methylene butanga igisubizo gitandukanye muri buri bumwe. Kubwitiranya bituma ubushakashatsi busa n'ubuvuguruzanya. Kubutandukanya bigaragaza ishusho yumvikana, igenwa ahanini n'igihe umuti utangiwe.

Iryo tandukaniro ni ryo rigamijwe muri iri suzuma. Uburyo butatu ni impanuka itunguranye y'imiyoboro y'amaraso yibasira agace kamwe k'ubwonko, kwambura uturemangingo twahinzwe muri laboratwari ogisijeni na glucose hanyuma tukongera guhabwa ogisijeni, n'igabanuka ry'amaraso agera mu bwonko rimara ibyumweru. Uburyo bw'imikorere bushobora kubihuza bureba mitokondiriya, ariko ibisubizo biratandukanye kuko imiterere y'imikorere y'ingufu mu turemangingo itandukanye.

Uburyo butatu bw'igerageza busubiza ibibazo bitandukanye

Impanuka itunguranye y'imiyoboro y'amaraso yibasira agace kamwe k'ubwonko mu mbeba akenshi iterwa no kuziba umutsi wo hagati ujyana amaraso mu bwonko, bikitwa MCAO mu mpine. Uku kuziba kumeze nk'uguterwa n'amaraso yavuriyemo kurema agace ko hagati kabura amaraso, gakikijwe na penumbra: ingirangingo ziri mu kaga ariko zishobora kurokorwa amaraso aramutse yongeye kuzigeramo. Ikibazo hano ni ukumenya niba uburyo bwo gutabara bugabanya umuvuduko wo kwaguka kw'agace kapfuye kubera kubura amaraso, cyangwa bugakomeza imikorere mu gihe amaraso yongeye kuhagera.

Kwambura uturemangingo ogisijeni na glucose, byitwa OGD mu mpine, bikorwa ku rugero rutandukanye cyane. Uturemangingo tw'ubwonko twahinzwe muri laboratwari dushyirwa ahantu hafi ya nta ogisijeni iri, nta glucose, hanyuma tugasubizwa mu ruvange rusanzwe rudutunga. Nta maraso yavuriye mu mutsi ahari, nta yindi miyoboro ishobora kunyuzamo amaraso, nta muvuduko w'amaraso, kandi nta sisitemu y'ubudahangarwa. Ikibazo kireba uturemangingo gusa: bigendekera bite guhumeka kwatwo, ATP, no gukomeza kubaho igihe ibikenerwa mu gukora ingufu bishize hanyuma bikagaruka?

Mu kugerageza igabanuka ry'amaraso agera mu bwonko rimara igihe kirekire, imiyoboro ibiri ya carotid mu mbeba irazibwa burundu; ubu buryo bwitwa 2VO. Amaraso agera mu gice cy'imbere cy'ubwonko aragabanuka kandi akomeza kuba make mu gihe cy'ibyumweru. Nta gace kamwe gahita gapfa kubera kubura amaraso, kandi nta kongera kuhageza amaraso byihutirwa. Ikibazo ni ukumenya niba gufasha imikorere y'ingufu mu gihe cy'ibyumweru birinda imiyoboro y'amaraso, mitokondiriya, n'ubushobozi bwo kwibuka igihe amaraso akomeza kuba make.

Bityo, kwiyongera k'ubushobozi bwo kwibuka nyuma y'ukwezi kumwe k'ubuvuzi mu buryo bwa 2VO nta cyo kuvuga mu buryo butaziguye ku kurokora ubwonko bw'umuntu mu gihe cyo gukuramo amaraso yavuriye mu mutsi byihutirwa. Iri tandukaniro ni ingenzi kuko incamake nyinshi zitanga icyizere zirirengagiza.

Impanuka itunguranye y'imiyoboro y'amaraso yo mu bwonko: kurinda igihe amaraso agarutse, gutinza kwangirika iyo atagarutse

Igisubizo gisobanutse kurusha ibindi mu magerageza y'impanuka itunguranye gituruka kuri MCAO y'igihe gito ikurikirwa no kongera kuhageza amaraso. Imitsi y'imbeba yazibwe mu gihe cy'iminota 60, hanyuma zihabwa ubururu bwa methylene mu ngano ntoya binyuze mu mutsi, guhera igihe amaraso yongeye gutembera; izindi ngano zatanzwe nyuma y'amasaha 3 no ku munsi wa 2. Amashusho ya MRI yerekanye ko agace kangiritse mu itsinda ryahawe uruvange rutwara umuti ariko rutarimo umuti w'igerageza kagutse hafi 19 ku ijana kugeza ku munsi wa 2, mu gihe ako mu itsinda ryahawe umuti kagabanutse hafi 17 ku ijana. Uduce twapfuye kubera kubura amaraso ku iherezo twari duto hafi 30 ku ijana, kandi amanota y'imikorere y'ubwonko n'imyakura yari meza kurushaho ku minsi ya 2 na 7. Amashusho yagaragaje ko ingirangingo zo mu gace ko hagati n'izo muri penumbra zarokotse kurushaho. Ubushakashatsi bwagutse ku kurinda ubwonko n'imyakura bushyira uku kurinda gutangirana no kugaruka kw'amaraso hamwe n'ibyasanzwe mu ibura ry'amaraso rigera ku bwonko bwose no mu gukomereka.

Ishusho irahinduka iyo umutsi ukomeza kuba uzibye. Mu igerageza rya MCAO ihoraho, ubururu bwa methylene bwatanzwe mu gihe amaraso yari akibuze bwagabanyije umuvuduko wo kwaguka kw'agace kangiritse kagaragara mu mashusho apima ikwirakwira ry'amazi mu ngirangingo, kandi bumara igihe gito bwongerera igihe itandukaniro hagati y'agace kagaragaza amaraso make n'agace kagaragaza iryo hinduka ry'ikwirakwira ry'amazi. Amaraso yo muri ako gace yatembaga neza ho gato, ariko ubunini bwa nyuma bw'agace kapfuye kubera kubura amaraso nyuma y'amasaha 24 ntibwari butandukanye ku buryo bugaragara mu mibare. Bwatindije kwangirika kw'ingirangingo zari mu kaga, ariko ntibwasimbuye gufungura umutsi.

Ubushakashatsi bwa gatatu ku mpanuka itunguranye bwongeraho ibisobanuro ku mikorere n'itandukaniro rishingiye ku ngano y'umuti. Ingano imwe y'umuti yatewe mu cyuho cy'inda ako kanya nyuma yo kuziba umutsi yagaragaje igabanuka rinini kurusha ayandi ry'agace kapfuye kubera kubura amaraso, hafi 50 ku ijana, ku ngano yo hagati ya 5 mg/kg aho kuba kuri 1 cyangwa 10 mg/kg, hamwe n'amanota meza kurushaho mu bushobozi bwo kumva no kugenda. Abanditsi babihuje no kubungabunga imiterere ya mitokondiriya no kwiyongera kwa mitophagy, ari ukuvanaho mitokondiriya zangiritse mu buryo bwihariye. Ingano, inzira umuti unyuzwamo, n'igihe utangirwa rero bifite akamaro, kandi imibare ya mg/kg yo mu mbeba si ingano yo kuvura impanuka y'imiyoboro y'amaraso yo mu bwonko mu bantu.

Uturemangingo twahinzwe muri laboratwari: umuti umwe urafasha cyangwa ukangiza bitewe n'igihe ugerera ku turemangingo

Igerageza ku turemangingo twa astrocyte ni ryo ryigisha byinshi kandi ni na ryo rikunze gusubirwamo nabi kurusha ayandi. Uturemangingo twa astrocyte twakuwe mu gishishwa cy'ubwonko bw'imbeba twamaze amasaha 6 twambuwe cyane ibidutunga, kuri ogisijeni ingana na 0.1 ku ijana, mu ruvange rutarimo glucose, pyruvate, cyangwa serumu. Byakurikiwe n'amasaha 24 two kongera kuduhereza ogisijeni, ibikenerwa mu gukora ingufu byasubijweho. Hafi kimwe cya kabiri cy'uturemangingo cyarapfuye, bituma igerageza rishobora kugaragaza ingaruka nziza cyangwa mbi.

Iyo ubururu bwa methylene bwabaga buhari mu cyiciro cyo kwambura uturemangingo ibidutunga, umubare w'utwarokokaga waragabanukaga aho kwiyongera. Iyo bwatangwaga mu gihe cyo kongera gutanga ogisijeni aho kuba mbere, ubukana buto bupimwa muri micromolar bwongereye ubushobozi bw'uturemangingo bwo kubaho, ikoreshwa rya ogisijeni, iyinjizwa rya glucose, n'ikorwa rya ATP. Mu bihe bisanzwe, ubwo bukana nyine bwongereye iyinjizwa rya glucose hafi 89 ku ijana kuri 0.1 micromolar na hafi 200 ku ijana kuri 1 micromolar. Glycogen n'imikorere ya hexokinase byarabungabunzwe nyuma yo kwangirika, kandi nta kwiyongera kwa superoxide kwapimwe.

Imikorere yabyo iroroha kuyumva iyo ugereranyije n'imashini itanga amashanyarazi y'ingoboka. Ubururu bwa methylene bukora nk'ubundi buryo bwo gutwara elegitoroni, bukakira ibitanga ubushobozi bwo kugabanya okisidasiyo bukabigeza kuri cytochrome c na complexe IV. Ibyo bifasha elegitoroni gukomeza gutembera no gukora ATP, bikagabanya elegitoroni zisohokera mu byiciro bibanza aho gukurikira inzira yazo. Mu gihe uturemangingo twambuwe cyane ibidutunga, uko gukangura imikorere kuba ikibazo kuko kongera ibikenewe mu gukora ingufu kandi ogisijeni na glucose hafi ya bitakiriho, bikaba byatuma ibyari bisigaye bishira vuba kurushaho. Iyo ibikenerwa mu gukora ingufu bigarutse, uwo mwihariko uba ingirakamaro kuko ufasha mitokondiriya zangiritse gukoresha neza ogisijeni na glucose byagarutse. Ni na yo mpamvu ibisobanuro ku kwimura elegitoroni muri mitokondiriya bigomba kujyana n'imiterere y'igihe uturemangingo twambuwe ibidutunga.

Icyitonderwa kimwe: iri hame ry'igihe umuti utangirwa rireba ubwo buryo bwo gutegura astrocyte. Ubundi bushakashatsi ku turemangingo bwakoresheje ubwoko butandukanye bwatwo, kubwambura ibidutunga ku rwego ruto kurushaho, n'ubukana bw'umuti buri hasi, bwabonye ko umuti warindaga uturemangingo n'iyo twawuhabwaga mu gihe cyo kwamburwa ibidutunga. Ubwoko bw'uturemangingo, ogisijeni isigaye, ubukana bw'umuti, n'uburyo igerageza rikorwa ni byo bigena niba ingaruka ziba nziza cyangwa mbi.

Amaraso make igihe kirekire: kwibuka, cytochrome oxidase, n'imiyoboro y'amaraso mu gihe cy'ibyumweru

Amagerageza y'igihe kirekire yakoresheje umuti mu ngano ntoya buri munsi mu gihe cy'ibyumweru, aho kuba ingano imwe itangwa yose icyarimwe mu gihe cy'ubutabazi bwihutirwa. Mu bushakashatsi bwa mbere, imbeba zari zifite imiyoboro ya carotid yazibwe burundu zahawe 4 mg/kg buri munsi mu gihe cy'ukwezi kumwe. Umuti watangwaga nyuma ya buri mwitozo wa buri munsi kugira ngo ugamije gushimangira ibyizwe aho kuzamura ubushobozi bw'ako kanya. Inyamaswa zari zafungiwe imiyoboro zigiye buhoro imirimo yo gutandukanya ibyo zibona, kandi zitwara nabi kurushaho ku kizamini gikomeye cyo kwibuka; ariko ubushobozi bwo koga, imikorere y'ingingo, no kumenya impumuro ntibyahindutse. Umuti watangwaga buri munsi wagabanyije intege nke mu kwiga no kwibuka utahinduye imyitwarire rusange yo kugenda.

Ubushakashatsi bwakurikiyeho bwapimye cytochrome oxidase, ari yo complexe IV ya mitokondiriya, mu duce 44 tw'ubwonko nyuma ya gahunda imwe y'ukwezi kumwe. Kuziba imiyoboro byagabanyije imikorere y'iyi anzime mu gishishwa cy'ubwonko gitunganya ibyo amaso abona, mu gice cy'imbere cy'igishishwa cy'ubwonko, no muri cortex ya perirhinal, ndetse no muri hippocampus na amygdala. Byanagabanyije imikorere ihujwe hagati y'igishishwa gitunganya ibyo amaso abona na hippocampus. Umuti wabungabunze imikorere y'anzime muri utwo duce kandi ukomeza isano hagati y'imikorere y'ingufu muri two; imikorere yabungabunzwe yajyanaga n'ubushobozi bwiza kurushaho bwo gukora imirimo. Izo sano zisobanura imikorere ihujwe y'anzime zigira uruhare mu gukora ingufu, si ibipimo bitaziguye by'imikoranire y'uduce tw'ubwonko bw'umuntu. Ibi ni ibintu amasuzuma y'ubushakashatsi ku mikorere y'ingufu mu bwonko afasha gusobanukirwa neza.

Ubundi bushakashatsi bwihariye bwamaze icyumweru kimwe bwakoresheje 2 mg/kg buri munsi, bwongeraho ikibuza inzira y'imikorere kugira ngo busuzume uko umuti ukora. Umuti watumye amaraso atembera mu bwonko ava kuri hafi 60 agera kuri hafi 100 mL kuri 100 g ku munota, kandi ubucucike bw'imiyoboro y'amaraso muri hippocampus buva kuri hafi 15.1 bugera kuri 23 ku ijana. Ibyo byiyongereye byombi byagabanutse igice igihe inzira ya PI3K/Akt ifasha uturemangingo kubaho yabuzwaga gukora, kandi Akt yongeweho phosphate yariyongereye igihe umuti watangwaga. Ibyagaragaye ku gutembera kw'amaraso, ubucucike bw'imiyoboro, urubibi rutandukanya amaraso n'ubwonko, n'uturemangingo tw'imyakura byerekeza ku kurinda ubwonko n'imiyoboro yabwo bifitanye isano n'ubutumwa bwa PI3K/Akt, aho kuba ingaruka ku mikorere y'ingufu gusa.

Impamvu nta na kimwe muri ibi kingana n'ubuvuzi bwihutirwa bw'impanuka y'imiyoboro y'amaraso yo mu bwonko

Kuba ibintu bigenzurwa muri laboratwari ni byo bituma ibi bisubizo bidashobora kwimurirwa mu buvuzi mu buryo butaziguye. Uturemangingo twahinzwe muri laboratwari ntidufite amaraso yavuriye mu mutsi cyangwa uburyo umuti winjira, ukwirakwira, uhindurwa, ugasohoka mu mubiri. Uburyo bwa 2VO ni amaraso make agera ku bwonko muri rusange igihe kirekire, si ikintu gitunguranye kiziba umutsi w'agace kamwe kigakora penumbra imaze iminota mike gusa. Ndetse na MCAO yo mu mbeba ikoresha inyamaswa zikiri nto kandi zifite ubuzima bwiza, ikinya, kuziba imitsi mu buryo bumwe, n'umuti utangwa mu bihe byagenwe neza. Ibyo bitandukanye n'abarwayi bakuze bafite amaraso yavuriye mu mitsi mu buryo butandukanye, imitsi yakomeye kandi yagabanyutse kubera ibiyirundamo, umuvuduko w'amaraso ukabije, diyabete, n'igihe indwara yatangiriye kitazwi.

Nta gerageza ryatangajwe, ryakorewe ku bantu bagabanyijwe mu matsinda ku buryo bwa tombola, ryemeje ubururu bwa methylene nk'ubuvuzi bwihutirwa bw'impanuka itunguranye y'imiyoboro y'amaraso yo mu bwonko iterwa no kubura amaraso. Ubushakashatsi ku mashusho y'ubwonko bw'abantu rimwe na rimwe buvugwa bwitabiriwe n'abantu bakuru 26 bafite ubuzima bwiza, atari abarwayi b'iyo mpanuka. Ingano imwe y'umuti banyoye yahinduye ibimenyetso byo mu bwonko bifitanye isano n'imirimo bakoraga, hamwe n'iyiyongera rito mu bushobozi bwo kugarura ibyo bibuka. Ibyo byerekana igikorwa mu bwonko, ntibyerekana ubushobozi bwo kuvura iyo mpanuka. Ahubwo amabwiriza y'ubutabazi bwihutirwa agezweho yibanda ku kugarura amaraso vuba hakoreshejwe umuti ushonga amaraso yavuriye mu mutsi, utangwa unyuze mu mutsi ku barwayi bemerewe kuwuhabwa, no kuyakuramo ku barwayi bafite kuziba kw'imiyoboro minini ibereye ubwo buryo. Inzira zisanzwe z'ubutabazi bwihutirwa bw'iyo mpanuka ni zo zonyine zifite gihamya. Gukeka ko umuntu afite impanuka y'imiyoboro y'amaraso yo mu bwonko ntibigomba na rimwe gutinza ubutabazi kugira ngo ahabwe ubururu bwa methylene. Imipaka ifatika yo kugereranya ingano z'umuti zakoreshejwe mbere y'amagerageza ku bantu isobanura impamvu gahunda zo mu mbeba zidashobora gufatwa nka gahunda z'ubuvuzi bw'abantu.

Ibijyanye n'umutekano birushaho gushimangira uwo mupaka. Ubururu bwa methylene butangwa mu mutsi bufite umuburo ukomeye uri mu gasanduku ku ngaruka zikomeye cyangwa zica z'ihungabana riterwa na serotonine iyo buvanze n'imiti igira icyo ihindura kuri serotonine, harimo SSRIs, SNRIs, n'imiti ibuza MAO gukora. Abantu benshi bageze mu myaka ikunze kubamo iyi mpanuka bafata iyo miti. Ntibwemerewe guhabwa abafite ibura rya G6PD kubera ibyago byo gusenyuka kw'uturemangingo dutukura tw'amaraso. Bunabuza ubutumwa bwa nitric oxide gukora, bikongera ukurwanya gutembera kw'amaraso mu mitsi n'umuvuduko wayo mu bihe bimwe; bityo ntibukwiye kuvugwa gusa nk'umuti wongera amaraso agera mu bwonko. Gahunda yemewe ya 1 mg/kg itangwa mu mutsi ku ndwara ya methemoglobinemia itari iy'umurage si gahunda yo kuvura impanuka y'imiyoboro y'amaraso yo mu bwonko.

Incamake y'ukuri ifite aho igarukira, ariko ibyo ivuga birahari. Mu gihe amaraso yongeraga kugera mu gace k'ubwonko kari kayabuze by'igihe gito, ubururu bwa methylene mu ngano ntoya bwagabanyije uko kwangirika kwakuraga mu mbeba. Iyo umutsi wabaga uzibye burundu, bwatindije ariko ntibwabuza gupfa kw'ingirangingo kubera kubura amaraso. Muri astrocyte, bwangije uturemangingo mu gihe twambuwe cyane ibidutunga, ariko buradufasha igihe ogisijeni yongeye gutangwa. Mu gihe amaraso agera mu bwonko yagabanutse igihe kirekire, bwabungabunze cytochrome oxidase, imiyoboro y'amaraso, n'ubushobozi bwo kwibuka mu gihe cy'ibyumweru. Umutwazi umwe, imiterere itatu, ibisubizo bitatu.