Study On The Protective Effect Of Tongxinluo On The Brain Of Rats With Acute Cerebral Infarction And Its Related Mechanism

1.BackgroundGlobally,cerebrovascular disease affecting nearly 15 million people each year,a huge burden to society.In China,now cerebrovascular disease mortality rate has more than cardiovascular disease,becoming the second leading cause of death after cancer.Therefore,the treatment of cerebrovascular disease will have a huge impact on the world’s health.Acute cerebral infarction belonging to Western ischemic cerebrovascular disease category,due to the cerebral blood disorder so that local cerebral ischemia and hypoxia caused by softening necrosis.The acute phase of the disease is fingered from the onset to a week later.It comes to more complex pathophysiological mechanisms,including excitotoxicity,ionic homeostasis damage,oxygen free radicals,inflammation,blood-brain barrier damage and apoptosis mechanisms.Cell death after cerebral ischemia is divided into two forms:necrotic and apoptosis.With the study of pathophysiological mechanisms of cerebral ischemia deepening,brain microvascular endothelial cell apoptosis involved in the role of ischemic cerebrovascular disease are more and more attention.Acute cerebral infarction included infarction in the center and ischemic penumbra in the around.Cells in the infarct mainly necrosis and ischemic penumbra cells mainly apoptosis.Recent studies have shown that VEGF has a protective effect on blood vessels.Our previous experiments have found that TXL superfine stable expression of VEGF and it can help inhibit the development of inflammation and accelerate the repair process.The role of VEGF in the nervous system is made,including phosphatidylinositol kinase(PI3K)-dependent activation of the serine/threonine kinase Akt(also known as PKB),anti-apoptotic pathways mediated.Studies suggest that PI3K/Akt signaling pathway plays a very important role in the pathogenesis of ischemic cerebrovascular disease.Bad is a pro-apoptotic member of the Bcl-2 family,who play an important role in the regulation of cell survival and apoptosis.However it’s rarely reported that whether tongxinluo can inhibit apoptosis in brain tissue and play a protective role in the brain.This study aims to establish the rat middle cerebral artery occlusion model and apply specific inhibitor LY294002 to block PI3K/Akt pathway.Further studies on the change of PI3K,phosphorylated AKT,Bad brain in the brain microvascular endothelial cells of rats with acute cerebral infarction.To investigate the regulation of PI3K/Akt/Bad signaling pathways and intervention of Tongxinluo superfine in acute cerebral infarction.2.Objective1)To verify the protective effect of Tongxinluo in rats with acute cerebral infarction;2)To clarify the mechanism of the anti-apoptotic effect of Tongxinluo through the PI3K/Akt pathway;3.MethodsRat MCAO model established by suture method,The rats were divided into sham group(Sham group),model group(Model group),DBT group(DBT group),TXL group(TXL group),TXL + inhibitor LY294002 group(TXL + LY294002 group).Each with two time points,respectively,after cerebral ischemia 1 and 3 days.Rats of TXL group and TXL +LY294002 group are gavaged with tongxinluo according to 0.8g/(kg · d).Rats of DBT group are gavaged with DBT according to 0.28mL/(kg·d).Sham group and model group were given an equal volume of saline.To gavage in each group after 6 h,and then repeat at the same point of time daily.1)Methods of neurological function is used to observe recovery of neurological function in rats;2)Methods of TTC staining is used to compute infarct volume ratio in order to evaluate the extent of damage to brain tissue in rats;3)Methods of HE staining is used to observe the general morphology of rat brain tissue in light microscopy;4)Methods of TUNEL staining is used to detect the degree of apoptosis in brain tissue;5)Methods of IHC and Western blot were used to observe the expression of PI3K,Akt,Bad,and other related proteins in rat brain;6)To observe the effects of Chinese medicine Tongxinluo superfine on the above link.4.Result1)Nerve function score results showed that rats with cerebral ischemic injury can lead to neurological disorders.TXL can improve neurological function and make impaired nerve function better.Its role may be blocked by the inhibitor of PI3K/Akt pathway.2)TTC and HE results showed that TXL can reduce the brain damage of focal ischemia in rats.3)TUNEL results showed that TXL can decrease apoptosis of cerebral ischemia penumbra of rats with acute cerebral infarction,thereby reducing brain damage.Its role may be blocked by the inhibitor of PI3K/Akt pathway.4)IHC results showed that TXL can increase the expression of PI3K and p-Akt of penumbra to a certain extent,and can inhibit the expression of the pro-apoptotic protein Bad of the PI3K/Akt pathway downstream.Its role may be blocked by the inhibitor of PI3K/Akt pathway.5)WB results showed that TXL can increase the expression of PI3K and p-Akt of penumbra and inhibit the expression of Bad of microvascular endothelial cells of Cerebral ischemia penumbra.Its role may be blocked by the inhibitor of PI3K/Akt pathway.5.Conclusion1)Rats after acute cerebral ischemic brain tissue was significantly impaired.TXL can promote neurological and morphology recovery of rats with acute cerebral infarction.2)TXL promotes Akt phosphorylation by activating PI3K/Akt signaling pathway,thereby inhibiting the expression of Bad of pro-apoptotic protein.Thus the degree of apoptosis of brain microvascular endothelial cells reduce.Therefore tongxinluo play a protective role in the brain.