SIRT1 Pathway Protects Mitochondrial Functional Recovery And Reduces Neurocyte Apoptosis After Intracerebral Hemorrhage In Rats

BackgroudCerebral hemorrhage(intracerebral hemorrhage,ICH)is a common cerebrovascular disease with high mortality and high disability.It is also the most common type of cerebrovascular disease in china.While a great many reserves have been put into clinical and simple investigations involving ICH,no pleasing pharmacologic therapies have been discovered for clinical use,mostly because of a deficiency in understanding the undiscovered mechanisms of post-ICH brain injury.Recent years,studies have shown that the energy metabolism disorder around the hematoma may play an important role in the secondary injury of cerebral hemorrhage.After cerebral hemorrhage,the supply of energy metabolism is interrupted,which leads to energy metabolism disorder and lack of energy substance.As mitochondria are the sites of aerobic respiration and generally are the major energy production center in eukaryotes,its structure and function is closely related to energy metabolism disorder caused by cerebral hemorrhage,and mitochondrial dysfunction can also induce mitochondrial related apoptosis.Thus,mitochondrial dysfunction and mitochondrial related apoptosis induced by ICH may be an important pathogenic mechanism of cerebral hemorrhage,and it also may be an important target for the treatment of cerebral hemorrhage.More and more studies have shown that Silent information 1(SIRT1)is involved in the repair of mitochondrial dysfunction varies diseases.And it also has a neuroprotective effect in a variety of neurodegenerative diseases.However,the protective effect of SIRT1 on the secondary injury of intracerebral hemorrhage in rats and its possible mechanisms are still unclear.ObjectiveSilent information regulator 1(SIRT1)exerts neuroprotective properties in many neurodegenerative diseases.The goal of this evaluation was to examine the impact of SIRT1 on ICH injuries and its potential mechanisms.Methods(1)ICH was induced by autologous arterial blood(60 ul)flow into rats' brains.And rats were given an insertion of SRT1720(5 mg/kg,i.p.)each day before they were killed at 48 h after ICH.To observe the protective effects of SIRT1 on ICH,neurological deficit scores,brain water content,hemorrhagic lesion morphological alterations,mitochondrial morphology,mitochondrial ATP and mitochondrial DNA were evaluated.Real-time PCR and Western Blot were used to examine the expression of SIRT1 after intracerebral hemorrhage in rats,and the effect of SRIT1720 on SIRT1.At the same time,the expression of AMPK and p-AMPK was detected by Western Blot(2)Western Blot was used to examine the expression of PGC-1?,mitochondrial electron transport chain proteins and apoptotic related proteins.Immunoprecipitation(IP)was used to examine deacetylation of PGC-1?.(3)Building one negative siRNA and three siRNA of PGC-1?,si RNA was injected intracerebroventricularly 24 h before ICH.SRT1720 was administered after ICH.Real-time PCR and Western Blot were used to test the knockdown efficiency.Mitochondrial electron transport chain proteins and mitochondria-dependent apoptotic proteins were also measured by Western Blot.(3)Building one negative siRNA and three siRNA of SIRT1,siRNA was injected intracerebroventricularly 24 h before ICH.Real-time-PCR and Western Blot were used to test the knockdown efficiency.After SIRT1 knockdown,neurological deficit scores,brain water content,hemorrhagic lesion morphological alterations,mitochondrial morphology,mitochondrial ATP and mitochondrial DNA were evaluated.And we use Western Blot to further detect the expression of mitochondrial electron transport chain proteins and apoptotic related proteins.ResultsRats at 48 h following severe shock exhibited increased mortality,behavioral deficits,and brain water content.Moreover,severe shock induced mitochondrial dysfunction and neurocyte apoptosis characterized by mitochondrial swelling,reduced ATP levels,decreased deacetylation of peroxisome proliferator initiated receptor gamma and coactivator 1 alpha(PGC-1?),mitochondrial electron transport chain proteins,and increased apoptotic related proteins.Additionally,following ICH,activation of SIRT1 with SRT1720 decreased mortality,behavioral deficits,brain water content,and restored mitochondrial biogenesis in rats without any significant differences of phosphorylated AMP-activated protein kinase(pAMPK).Activation of SIRT1 with SRT1720 also restored mitochondrial electron transport chain proteins and decreased apoptotic related proteins in ICH.However,they would be reversed after treatment with PGC-1? siRNA.To further explore the protective effects of SIRT1 on ICH,siRNAs were used to knockdown SIRT1.Therapy with SIRT1 siRNA substantially further increased mortality,behavioral deficits,brain water content,mitochondrial dysfunction and neurocyte apoptosis after ICH.ConclusionThe results suggest that activation of SIRT1 speeded up the recuperation of mitochondrial protein extraction and function by improving mitochondrial biogenesis(MB),and also reduced neruotyte apoptosis following ICH.We also hypothesized that SIRT1 protects rats from ICH injuries may via the PGC-1? mitochondrial pathway.These might all would offer a new therapeutic hypothesis for the care of ICH injuries.