The Experimental Study Of Mitochondrial Protection After Subarachnoid Hemorrhage In Mice With SB203580Inhibitor

Objective:Subarachnoid hemorrhage (SAH) is a important disease with highly morbidity and morality. The main cause of death that has been divided into early brain injury (EBI) and cerebral vasospasm (CVS). It has long been recognized that CVS is the most important events in SAH and determing the prognosis of SAH, but target of CVS in treatment has not been found to improve the curative effect of the SAH. Recently,Many studies have found that EBI period after SAH that can activate P38proteasome system (p38mitogen-activated protein kinase,MAPK),which process not only regulates the structure and function of mitochondria, but also inducing cell death by means of mitochondrial apoptosis pathway. Therefore, The EBI period after SAH may provide an optimal time window for treatment of SAH by the inhibition of p38protease activation system, which prevent more serious complication after SAH.Methods:Using physiological saline establish sham model; Using OxyHb to establish SAH model; Using the SB203850(p38inhibitor) or DMSO liquid after30min when the SAH group model was established successfully,then produces each group of p38inhibitors and DMSO. After that, determing each time point (3H,6h,12h,24h,72h) hemorrhage cerebral cortex p38, ATP, Cyt c, nNOS, LDH levels and neural cell apoptosis changes.Results:The positive expression of p38was not detected in the sham group; Only which was expressed at either12h or24h of the both the SAH and DMSO group;12h, decreased24h expression, Whereas the positive expression of the group of p38inhibitors was significant difference compared with the sham group and SAH group (or DMSO group)(P<0.0001).Depolarization of the mitochondrial membrane potential in the SAH group was dramatically inceased after3h, reached the peak after6h, but12h began to decline, which is significant difference compared with the sham group (P<0.0001).However, The depolarization of the mitochondrial membrane potential was decreased which was statistically significant among the SAH group, DMSO group apart from3h time point (P=0.3856)and group of p38inhibitor.The content of ATP in the SAH group was decreased significantly after6h, and after12h was decreased significantly; The content of ATP in the group of p38inhibitor began to rise after3h, which began to reached a higher level after72h. there was an significant difference at the3h and72h time point between the group of p38inhibit and SAH group (P=0.0012, P=0.0001).There was a more stable level of the positive expression of Cyt c in the sham group; however, which was increased at all time points in the SAH group, that there was significant difference compared with the sham group (P<0.0087). However, the positive expression of Cyt c in the group of p38inhibitor showed a moderate level, which was compared with the sham group that was not statistically significant (P>0.0851).The expression of nNOS at all time points of the SAH group (except the SAH after72h) was increased significantly. Which was statistical significance compared with the sham group (P<0.0001), especially between3h andl2h period after SAH. however, The expression of nNOS at each time point of the group of p38inhibitor showed a moderate level, that was not statistically significant comparing with the sham group (P>0.0962).The activity of LDH in the SAH group which became the more longer, the more higher. then reached a highest level after72h in SAH which suggested more and more heavy. however, the group of p38inhibitor seemed a stable level.The more number of neuronal apoptosis in the SAH group along with time prolonging, The more positive expression. The number of TUNEL positive cells which was reduced among the p38group at different time points (except3h) and SAH group or DMSO group at the same time point, seeming a significant difference, P<0.0001).Conclusion:the p38inhibitor restrained p38expression in cerebral cortex after SAH, which bring into play neuroprotection through the reduction of mitochondrial membrane potential, increase the content of ATP, inhibition of Cyt c release to the cytoplasm and cell apoptosis.