Effects of kadsurenin mixture on platelet-activating factor and arachidonic acid metabolism in focal reversible ischemic brain area

Objective To study the relationship between platelet activating factor(PAF) and arachidonic acid and observe the effects of PAF receptor antagonists kadsurenin mixture,kadsurenone,ginkgolide B on PAF and TXA 2 after focal cerebral ischemia reperfusion in rats.Methods Focal cerebral ischemia was induced by inserting a nylon suture into the right intracranial segment of internal carotid artery from external carotid artery to block the origin of middle cerebral artery. For reperfusion,the suture was pulled out to restore the blood flow to the ischemic brain.Senile Wistar rats were randomly devided into twelve groups:sham operated control group,simple ischemia for 90 min group,3 h,6 h,12 h,18 h,24 h,36 h,48 h reperfusion groups,and kadsurenin mixture,kadsurenone,ginkgolide B treated groups.In sham operated rats,the thread was inserted only 9 millimeter.Radioimmunoassay was applied to evaluate the PAF and TXB 2 (stable metabolite of TXA 2) levels in rat ischemic brain tissue.Results Compared with the sham operated control group,a great increase in the PAF concentrations in simple ischemia and 3 h,6 h,12 h,18 h reperfusion groups were observed.In contrast,the marked increase in the TXB 2 level was present after 3 h of reperfusion.The peak levels of PAF and TXB 2 were observed at 12 h and 18 h reperfusion,retuned to basal values at 24 h and 36 h respectively.However,pretreatment with three PAF receptor antagonists as mentioned above significantly alleviated the increase in PAF and TXB 2 levels at 12 h reperfusion.Conclusions It was considered that increase in TXA 2 might be closely related to PAF,which is involved in the progress of ischemic neuropathological damages.Two natural PAF receptorantagonists can reduce the elevation of PAF and TXA 2 and correct the disorder of arachidonic acid after cerebral ischemic reperfusion.