Effect Of Shugan Tongqiao On The Expression Of Matrix Metalloproteinases And Aquaporin In Experimental Glaucoma

Objective:To study the mechanism of the traditional Chinese medicine prescription' s protection of the optic nerve by studying the effect of TQMMIV on the expression of matrix metalloprotein 9(MMP-9)and aquaporins 4(AQP4)in the retina of ocular hypertension rat model.Methods:Ocular hypertension model was used by injecting compound Carbomer to anterior chamber of the eyes of 323 SD rats(8-12 weeks' old,200±12.09g,half male half female).According to body weight,17rats were randomly chosen as blank controls.Remaining rats were divided into 3 groups:1 week's ocular hypertension group(OC1),2 weeks' ocular hypertension group(OC2)and 3 weeks' ocular hypertension group(OC3).Each group was further divided into 6 subgroups:TQMMIV low dose subgroup,medium dose subgroup,high dose subgroup,control subgroup(VitB1,VitB12 i.g administration),model subgroup 1 and model subgroup 2(saline i.g administration).Rats in model subgroup 1 were sacrificed before the administration of TQMMIV,while the other rats were sacrificed after 2 weeks' administration of TQMMIV.Immunohistochemistry and western blot were used to investigate the expression of AQP4 and MMP-9.Results:1.Immunohistochemistry and immunoblotting results of MMP-9 expression:MMP-9 expression was down-regulated in the absence on ocular hypertension,while it was up-regulated and returned to normal level under hypertension condition.No significant difference was found in OC3 group,indicating MMP-9 expression was significantly decreased after 3 weeks'ocular hypertension.Across the groups,MMP-9 expression was low when the retina was normal.However,it was up-regulated during ocular hypertension and reached the peak at the end of first week.MMP-9 expression was gradually decreased,remained high for an extended period of time and returned to normal level until the fourth week.MMP-9 expression after the TQMMIV treatment:in OC1 group,TQMMIV treatment significantly slowed down the decrease of MMP-9 expression in high dose subgroup,which was not significant in medium dose and control subgroup.In OC2 group,MMP-9 expression in high dose,medium dose and control subgroup was higher than that in model subgroup 2.MMP-9 expression was significantly up-regulated in high dose subgroup and higher than that in model subgroup 1 and low dose subgroup.In OC3 group,high dose treatment significantly increased MMP-9 expression,while the increase in other subgroups was not statistically significant.Across the groups,all 3 doses could increase MMP-9 expression while high dose was most effective.2.Immunohistochemistry and immunoblotting results of AQP4 expression:AQP4 expression was low in blank group,up-regulated in ocular hypertension(model subgroup 1)and gradually decreased as the ocular hypertension prolonged(model subgroup 2).Across groups,AQP4 expression was low when the retina was normal.However,it was up-regulated during ocular hypertension and reached the peak at the end of first week.AQP4 expression was gradually decreased,remained high for an extended period and returned to normal level until the fourth week.MMP-9 expression after the TQMMIV treatment:within each group,no significant difference was found between treated subgroups and model subgroup 2.In OC2 group,AQP4 expression in TQMMIV high dose subgroup was higher than it in control subgroup.In OC3 group,AQP4 expression in low dose and control subgroup was up-regulated.The comparison between groups showed the treatment failed to suppress AQP4 expression.The up-regulation of AQP4 expression was highest in TQMMIV high dose subgroup in OC2 group when compared with OC1 and OC3 group.Conclusion:TQMMIV can up-regulate MMP-9 expression,ameliorate retinopathy caused by ocular hypertension,reverse the degeneration of cells,reduce the apoptosis of retinal ganglion cells in ocular hypertension,promote the regeneration of nerves and protect the optic nerves.The mechanism behind may be related to the disruption of MMP-9's natural inhibitors,the alteration of gene transcription rate and the activation of MMP-9's zymogen activity.TQMMIV can not down-regulate AQP4 expression.