Effects of Hyperlipidemia on the Expressions of MMP-9 and COX-2 in Brain Tissues of Focal Cerebral Ischemia Reperfusion Rat Model

Aim: To investigate the expressions of cyclooxygenase-2(COX-2) and matrix metalloproteinase-9 (MMP-9) after focal cerebral ischemia reperfusion(I/R) injury in hyperlipidemic(HL) rats and the effects of hyperlipidemia after focal cerebral ischemia reperfusion injury rat. Methods: 35 wistar rats were randomly divided into two groups: non-hyperlipidemia group and hyperlipidemia group. After the hyperlipidemic rats were made, they were randomly divided into three group: sham-operated group, non-hyperlipidemia ischemia reperfuion group(nI/R), and hyperlipidemic ischemia reperfusion group(hI/R). A middle cerebral artery occlusion model(MCAO) in rats was performed with Longa's method. The latter two were further divided into three subgroups according to reperfusion time interval of 12 h, 24 h, and 48 h after brain ischemia, 5 rats in each subgroup. Immunohistochemical staining were used to measure the expressions of MMP-9 and COX-2 in the brain tissue. HE staining were used to observe pathomorphological changes. Results: The expressions of MMP-9 and COX-2 in brain tissues of nI/R group and hI/R group were higher than in the sham-operated group(P0.01). In the same IR time subgroup, the expressions of MMP-9 and COX-2 in hIR group were more than in nIR group(P0.01). The expression of MMP-9 was positively correlated with the expression of COX-2. Conclusion: The expressions of MMP-9 and COX-2 are upgraded in ischemical reperfusion injury. Hyperlipidemia probably aggravate the ischemical reperfusion injury by increasing the expressions of MMP-9 and COX-2.