Abstract: OBJECTIVE:To investigate effect of icariin on apoptosis in hippocampal neurons cultured in high glucose,and the possible mechanism behind the action.METHODS:Hippocampus was obtained from newborn 24 h Sprague-Dawley rats and then primarily cultured.Then hippocampal neurons were divided into normal control group,high glucose group,icariin group,icariin + protein kinase B(Akt) inhibitor group and Akt agonist group.After each group was cultured in different conditioned medium for 72 h,we detected the apoptosis of neurons with flow cytometry,and the expression of Akt,p-Akt,B-cell lymphoma-2(Bcl-2) and Bcl-2 associated X protein(Bax) with western blot.RESULTS:Compared with the normal control group,the apoptosis rate of hippocampal neurons increased significantly(P < 0.01),and p-Akt/Aktand Bcl-2/Bax decreased significantly(P < 0.01) in high glucose group.Compared with the high glucose group,the apoptosis rate of hippocampal neurons decreased significantly(P < 0.01),and p-Akt/Akt and Bcl-2/Bax increased significantly(P < 0.05)in icariin group and Akt agonist group.Compared with the icariin + Akt inhibitor group,the apoptosis rate of hippocampal neurons decreased significantly(P < 0.01),and p-Akt/Akt and Bcl-2/Bax increased significantly(P < 0.01) in icariin group.CONCLUSION:Icariin could reduce the apoptosis of neurons cultured in high glucose,which may be achieved by increasing the phosphorylation of Akt protein in Akt signal pathway,then increasing the expression of Bcl-2 and inhibiting the expression of Bax.

Key words: Icariin, Protein kinase B, High glucose, Hippocampal neurons, Apoptosis