Abstract:Objective To investigate the effect of heat shock protein 22 (HSP22) on oxidized low density lipoprotein (ox-LDL)-induced human brain microvascular endothelial cells (HBMEC) and its molecular mechanism. Methods HBEMC cells were cultured in medium containing different concentrations (0,20,40,80 or 160 μg/ml) of ox-LDL.The protein and mRNA expressions of HSP22 and endothelial nitric oxide synthase (eNOS) in HBEMC cells were detected by Western blot and Real-time PCR,respectively;the levels of TNF-α,IL-6 and IL-1β were respectively detected by ELISA,and the levels of NO was detected by Griess method.After knockdown or over-expression of HSP22 in HBMEC cells cultured in medium containing 80 μg/ml ox-LDL,the contents of TNF-α,IL-6,IL-1β,NO and expression of eNOS mRNA and protein were detected by ELISA,Griess Real-time PCR and Western blot,respectively. Results Ox-LDL promoted the expression of HSP22 in HBMEC cells (P<0.05),induced the release of TNF-α,IL-6 and IL-1β and inhibited the synthesis of NO and expression of eNOS mRNA with concentration-dependent manner(all P<0.05).In HBMEC cells cultured in medium containing 80 μg/ml ox-LDL,the levels of TNF-α,IL-6 and IL-1β significantly increased and NO synthesis decreased and eNOS mRNA expression was down-regulated(all P<0.05) after knockdown of HSP22,however,the opposite results appeared after overexpression of HSP22 in HBMEC cells. Conclusion Ox-LDL could induce functional damage of HBMEC cells,and HSP22 could protect HBMEC cells by inhibiting TNF-α,IL-6,IL-1β secretion and NO synthesis and promoting the expression of eNOS.