Protective effect of Yulangsan polysaccharide on focal cerebral ischemia/reperfusion injury in rats and its underlying mechanism

Objectives: To study the focal cerebral ischemia/reperfusion (I/R) injury induced by a middle cerebral artery occlusion (MCAO), and the effects of Yulangsan (YLS) polysaccharide on this injury. Methods: This study took place in the Pharmacology Research Laboratory at Guangxi Medical University, China, between March and May 2007. Two hundred and forty rats were randomly divided into I/R group, sham-operated group, high-, medium-, and low-dose of YLS polysaccharide groups, and nimodipine (Nim) group. The animals were intragastrically administered with drugs for 7 days. An operation was performed to induce an MCAO model in the rats. Reperfusion was started after 2 hours of MCAO. The influences of YLS polysaccharide on the neurological score, the brain water content, the infarct volume, the activities of super oxide dismutase (SOD) and nitric oxide synthase (NOS), the contents of malondialdehyde (MDA) and nitric oxide (NO), the expressions of B-cell lymphoma/leukemia-2 (Bcl-2) and Bcl-2-associated X protein (Bax) in brain tissue were investigated; the morphological changes of rat cerebral cortical neurons were observed. Results: Compared with the I/R group, YLS polysaccharide reduced the neurological score, the rain water content, the infract volume, MDA and NO contents, the NOS activity, and the expression of Bax, and increased SOD activity, and the expression of Bcl-2 in the brain tissue, and neuronal edema was reduced. Conclusion: The YLS polysaccharide has a protective effect on cerebral ischemia/reperfusion injury; the mechanism may be related to attenuating free radicals, and increasing the Bcl-2/Bax ratio.