The Effect And Significance Of Picroside Ⅱ On The Expression Of COX-2 Following Cerebral Ischemic Injury In Rats

Objective To explore the neuroprotective effect and mechanism of picroside Ⅱ on expression of COX-2 after cerebral ischemia injury in rats.Methods The focal cerebral ischemic models were established by inserting a monofilament threads into middle cerebral artery occlusion(MCAO) in 140 Wistar rats.All rats were randomly divided into control group, model group, picroside group, LPS group and U0126 group, which group contained 6h, 12 h and 24 h subgroup. The neurobehavioral function was evaluated by modified neurological severity score points(m NSS) test. The apoptotic cells were counted by TUNEL assay. The expression of cyclooxygenase(COX-2) in cortex were determined by the immunohistochemistry(IHC)and Western Blot(WB). Real time PCR was used to measure the level of COX-2 m RNA.Results The neurological behavioral malfunction appeared in all rats with MCAO. In model group, the neurobehavioral function score, apoptotic cell index, the expression of COX2 and the level of COX-2 m RNA increased significantly than those in control group.The peak of COX-2 m RNA level arrived at 12 h, ahead of COX-2 protein expression. In treatment and U0126 group, the neurological behavioral function was improved, the number of apoptotic cells and the expression of COX-2 decreased significantly than those in model group. In LPS group, at 6h the COX-2 expressions were much higher than those in model group, later the damage was recovered slightly.Conclusion Picroside Ⅱ could down-regulates expression of COX-2 to protect the neuron from the apoptosis and inflammation after MCAO in rats.