The Change Of MMP-2 And TIMP-2 In Choroid Of Guinea Pigs Myopia And Preliminary Study About Its Mechanism

Objective:To study the change of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-2(TIMP-2) in choroid of guinea pigs form-deprivation myopia eyes and take RA(retinoic acid) peribulbar injection to investigate its possible influencing factor.Methods:Part One:30 3-week-old tri-color guinea pigs were randomly divided into group A and B,group A as a control group was averagely devided into A1 and A2,fed respectively 14d and 21d without treatment;as right eye covered group,group B was divided into group B1 (covered 14d),B2(covered 21d) and B3(covered 14d followed by de-covering 7d),left eyes as self-control.At fixed-time,diopter and axis oculi were detected,and use immunohistochemical method,to study the change of expression level about MMP-2 and TIMP-2 in choroid.Part Two: 12 3-week-old tri-color guinea pigs as group C was randomly divided into group C1 and C2,at he beginning of the experiment,RA(retinoic acid) peribulbar injection was performed on right eyes in group C1 while group C2 were just injected with DMSO(cosolvent solution),both groups were fed 21d,left eyes as self-control.At fixed-time,the change of diopter and axis oculi were observed,and study the expression level of MMP-2 and TIMP-2 with immunohistochemical method.Result.First:Group B1 formed myopia with extended axis oculi after 14d-covering,the expression of MMP-2 in the choroid was higher significantly than group A1.Group B2 formed myopia with extended axis oculi after 21d-covering,the expression of MMP-2 in the choroid was higher significantly than group A2 and B1.Group B3 had lighter myopia and less axis oculi than group B1 and B2,while the expression of MMP-2 in the choroid was lower too.above differences were significant statistically(P＜0.01),but the change of TIMP-2 was not statistically significant in the same time(P＞0.05);Second:Group C1 formed myopia with extended axis oculi after 21d-RA peribulbar injection,the expression of MMP-2 in the choroid was higher significantly,but the As the covering time extended,expression of MMP-2 became higher significantly,these differences were significant statistically(P＜0.01),but the change of TIMP-2 was not statistically significant in the same time(P＞0.05).Conclusion:1.The up-regulation expression of MMP-2 occured in the choroid of guinea pigs FDM eyes,the balance of MMP-2 and TIMP-2 was broken2.Probablely the retinoic acid existed in the guinea pigs posterior pole is one of the upper stream factors which involved in the balance of MMP-2 and TIMP-2.