The Effect Of Erythropoietin On The Expression Of TIMP-1 In Light-induced RPE Degeneration Of Mice

【Objective】To study the expression of tissue inhibitor of metalloproteinase-1(TIMP-1) inlight-induced retinal pigment epithelium(RPE) degeneration, and the effect of erythropoietin on it,in order to investigate the possible mechanism of EPO's protective function.【Methods】52 BALB/Cmice were randomly divided into simple light-induced group(SL),EPO treatment group(ET) andcontrol group(CON),6h,12h,36h,72h,96h and 7dth six sub group were got for SL and ET groupseparately. The mice of SL and ET were continually exposed to light for 4h, which built model oflight-induced damage. Morphology difference of RPE in different group was examined by lightmicroscope. Different expression of TIMP-1,ERK-1 was examined by immunohistochemicalmethod.【Result】①The histopathologic findings showed that normal mice had clear layers ofretinal structure. RPE was straightly arranged and regularly shaped. Under progressive lightexposure, RPE layer became sparser and cell swelled, at last some cell disappeared and RPE layerdouble-decked., while no significantly changes in ET group.②In the normal retina, a small quantityof TIMP-1 positive cells was found. The expression in SL groups had no obvious changes. In the ETgroup a great quantity of positive numbers appears 12h after light exposure, and reached its peak at95h sub-group.③In normal retina, ERK-1 was negative, and without changes in SL group. A fewof positive cells appeared in RPE 6h after light exposure, the positive expression increased as timeafter light exposure was increased. The expression reached its peak 72h after light exposure.【Conclusion】Continuous light exposure could cause general RPE degeneration in mice, while theexpression of TIMP-1 has no obvious change. Exogenous EPO could increase TIMP-1's expressionin RPE after light exposure, and then be beneficial to regain the balance between MMPs and TIMPs.So the protective function of EPO for light-induced retina degeneration is further confirmed. Inaddition EPO may regulate the secretion and expression of TIMP-1 in RPE by MAPK path.