Effect of matrix metalloproteinase-9 on aquaporin-4 expression in astrocytes after hypoxia and glucose deprivation and its regulatory mechanism / 中华行为医学与脑科学杂志

ABSTRACT

Objective To investigate the effects and regulating mechanisms of matrix metalloproteinase 9 (MMP-9) gene silencing on aquaporin 4(AQP4) expression in astrocytes induced by oxygen-glucose deprivation.Methods Cerebral cortical astrocytes from 2 days newborn SD rats were undergone the primary culture.The ischemic cell model was established by oxygen-glucose deprivation.This experiment were divided into control group,negative control group and MMP-9 gene silencing group.The leakage rate of lactated dehydrogenase (LDH)was detected by chromatoptometry.The MMP-9 gene silencing was carried out by Lentivirus transfection.Real-time fluorescence quantitative PCR and Western blot were used to detect the expression levels of AQP4 and MMP-9.The expressions of PKA,PKC,PKG and CaMK Ⅱ were determined by Western blot.Results Compared with control group,LDH leakage rate was significantly higher in astrocytes induced by oxygen-glucose deprivation(t=13.35,P＜0.01).The expression of MMP-9 mRNA in astrocytes in MMP-9 gene silencing group(0.412±0.297) decreased significantly compared with that in negative control group(1.118 ± 0.240) (t =-4.964,P＜ 0.05).The expression of AQP4 mRNA in astrocytes in MMP-9 gene silencing group(1.002±0.082) decreased significantly compared with that in negative control group(1.442±0.066) (t=-9.886,P＜0.01).The expression of AQP4 protein in astrocytes in MMP-9 gene silencing group(0.643±0.036)decreased significantly compared with that in negative control group(1.000± 0.069)(t=-11.073,P＜0.01).The expression of PKC protein in astrocytes in MMP-9 gene silencing group (0.198±0.110)decreased significantly compared with that in negative control group (0.980± 0.232) (t =-7.218,P＜0.01).The expressions of PKA(t=0.875),PKG(t=0.818) and CaMK Ⅱ (t=0.933) protein had no statistically significant difference between negative control group and MMP-9 gene silencing group(all P＞0.05).Conclusion The permeability of astrocytes is increased by oxygen-glucose deprivation.Gene silencing MMP-9 could induce expression of AQP4 mRNA and protein decreased,and MMP-9 may regulate AQP4 expression by regulating PKC activity.