The Neuroprotection Of Pre-treatment With Atorvastatin In PMCAO Model Rat And Possible Mechanism

Objective:Stroke has been one of the most threat diseases to human being with high mortality,morbidity and recurrence rate,and the strategy of prevention is very important.The experimental basis of neuroprotective effect of atorvastatin as a prophylactic agent for ischemic stroke is not sufficient.We treat rat with oral atorvastatin at different dose and different duration before experimental permanent middle cerebral artery occlusion,to investigate the neuroprotection of pre-treatment of statins in experimental ischemic stroke and its possible mechanisms.Methods:1.SD rats were pretreated with oral atorvastatin at different dose(high-dose8.4mg/kg·d^-1,low-dose 2.1mg/kg·d^-1)and different duration（long-term 28 days,short-term 7 days）before permanent middle cerebral artery occlusion.2.Mortality rate 24h after pMCAO was observed in each group.The behavioral score of surviving rats and the proportion of brain volume in rats were determined by TTC.3.Immunohistochemistry,PCR and Western blots were used to detect the expression of inflammation-related factors TLR₄ and NF-κB,vascular endothelial growth factor（VEGF）and apoptosis-related factor caspase-3.TUNEL was used to detect the apoptosis of neuron in ischemic penumbra.4.The levels of VEGF,Ang-1 and Ang-2 in the serum and the levels of IL-10 and IL-17 in the brain after infarction were detected by ELISA.5.The gut microbiota of SD rats in each group was detected by DNA sequencing.Results:1.Pretreatment of atorvastatin reduced the mortality rate of pMCAO rats especially pretreatment of high dose atorvastatin which also improved the neurological function score.Compared with the same dose of long-term atorvastatin pretreatment,short-term pretreatment reduced the proportion of infarcts.2.Short-term pretreatment with atorvastatin significantly increased serum VEGF levels in SD rats,especially short-term pretreatment with low-dose atorvastatin.In short-term pretreatment groups,low-dose atorvastatin significantly increased serum Ang-1level and reduced serum Ang-2 level,while high-dose atorvastatin significantly increased serum Ang-2 level in SD rats.3.High-dose atorvastatin pretreatment significantly reduced the expression of TLR₄and NF-κB in ischemic penumbra 24h after pMCAO.The expression of VEGF in ischemic penumbra of pMCAO rats at 24h was increased,and the expression of caspase-3and apoptotic of neuron was reduced in atorvastatin pretreatment groups,especially in short-term and low-dose group.4.Atorvastatin pretreatment significantly reduced the level of IL-17 and raised the level of IL-10 in the brain of pMCAO rats at 24 hours.Atorvastatin pretreatment altered the gut microbiota of rats,and the frequency of Clostridium in high-dose groups and low-dose long-term group significantly increased.Conclusions:1.Atorvastatin pretreatment dose-dependently reduced 24-hour mortality in pMCAO model rats and its mechanism may be related to the decreased expression of TLR₄ and NF-κB.2.In normal SD rats,short-term administration of high-dose atorvastatin may be conducive to the initiation of angiogenesis;short-term administration of low-dose atorvastatin may be conducive to maintaining vascular stability.3.The short-term atorvastatin pretreatment showed better neuroprotective effect than long-term atorvastatin.The possible reasons may be related to the increased expression of VEGF in serum and brain,the reduced expression of caspase-3 and the reduced apoptotic of neuron in the ischemic penumbra produced by the short-term atorvastatin pretreatment.4.Pretreatment with atorvastatin reduced the inflammatory response in pMCAO model rats,which may be related to the effect of atorvastatin on gut microbiota.