Effect of matrix metalloproteinase-9 on aquaporin-4 expression in astrocytes after hypoxia and glucose deprivation and its regulatory mechanism

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 CaMKⅡ 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 0.05). 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. Key words: Gene silencing; Matrix metalloproteinase 9; Aquaporin-4; Astrocyte; Oxygen-glucose deprivation