Abstract: Objective: To modify Ganodermalucidum polysaccharides(GLP) with sulfate and observe the protective effect of Ganodermalucidum polysaccharide sulfate (GLPS) on the cerebral ischemia reperfusion injury in the rats,and to investigate its mechanism.Methods: GLP was modified by sulfation to obtain GLPS. A total of 100 SD rats were randomly divided into sham operation group, model group, GLP group (40mg·kg^-1·d^-1), GLPS group (40mg·kg^-1·d^-1) and nimodipine group (1mg·kg^-1·d^-1).The cerebral ischemia reperfusion models were established by middle cerebral artery occlusion method in the rats. The neurologic deficit score and the content of water in brain tissue of the rats with cerebral ischemia reperfusion injury were detected and the activities of superoxide dismutase(SOD) and the levels of malondialdehyde (MDA) were detected. The levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB),tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1) and interleukin-6 (IL-6) in the brain tissue homogenate were detected by ELISA. Western blotting method was used to detect the protein expression levels of HSP70 and p-Akt in the brain tissue of the rats.Results: Compared with model group, the neurological function scores of the rats in GLP group and GLPS group were decreased(P<0.01),the water contents in brain tissue were decreased(P<0.05), the SOD activities were increased and the MDA levels were decreased(P<0.05), and the levels of NF-κB, TNF-α, IL-1 and IL-6 were decreased(P<0.05);the effect in GLPS group was significantly better than that in GLP group(P<0.05). The results of Western blotting method showed that the p-Akt protein expression levels in the brain tissue of the rats in GLP and GLPS groups were increased compared with model group (P<0.05); compared with model group, the HSP-70 protein expression level in the brain tissue of the rats in GLPS group was increased(P<0.01),but the effect in GLP group was not obvious.Conclusion: Sulfation can significantly improve the protective effect of GLP on the cerebral ischemia reperfusion injury in the rats and its mechanism may be related to regulating the HSP70/PI3K/Akt signaling pathway and inhibiting the inflammatory reaction damage to the nerve cells of reperfusion.

Key words: cerebral ischemia reperfusion injury, Ganodermalucidum polysaccharide, signaling pathway, sulfation