The Effect Of Valsartan On The Expression Of ERK1/ERK2 In The Diabetic Rats' Retina

Objective: To establish a diabetes mellitus model and observe the changes of the ERK1/ERK2 expression on the retina of diabetic rats which were treated by the angiotensin â…¡ receptor â…  antagonist Valsartan and reveal the therapeutical mechanism of suppressing the rennin-angitensin system on the diabetic retinopathy. Method: 60 rats were divided into normal, diabetes mellitus and treatment group randomly. The diabetic rats model was induced by the peritoneal injection of STZ, and then was treated with Valsartan added to the water. The expression of ERK1/ERK2 in retinal paraffin slide during different periods and in different groups of the rats was tested by immunohistochemistry. Results: (1)Among 40 rats, 36 rats were successfully established and the rate of success is 90 percent; (2)All the successfully established models demonstrated polydipsia, polyuria and the body weight was not increased. 6 rats suffered cataract after 3 months, and 4 rats died in 6 months;(3)There was an approximately 61% loss of retinal ganglion cells in the central retina and the thickness of retina thinner under microscope ( P < 0.01 ) . (4) Electroscope changes include the thinner of retina, disorganization of the membranous disc of the rod cells and the thickness of basal membrane of vessal. (5)In normal group, 1 month dibetes mellitus and 1 month treatmen group, there was no expression of ERK1/ERK2 on the retina tissues. In 3 month diabetes mellitus group, the expression of ERK1/ERK2 was positive. The ERK1/ERK2 expression mainly located in cells of ganglionic layer and inner nuclear layer. In 6 month diabete mellitus group, the expression of ERK1/ERK2 was strong positive, and the location is similar to the 3 month diabetes mellitus, but the pigment epithelium cells and inner nuclear cells were also positive, and the total positive cells increased compared to the 3 month diabetes mellitus .In 3 and 6 month treatment groups, the expression of ERK1/ERK2 was weak positive and positive respectively .And their location was also similar to the diabetes mellitus group. Conclusion: The local retina RAS abnormity participated in the procession of diabetic retinopathy and Angll is its elective factor. Angll participated in the procession by activating ERK1 and ERK2. Valsartan inhibit the expression of ERK1/ERK2. Therefore, the interdiction of RAS and Angll is propitious to the treatment of diabetic retinopathy and ERK1/ERK2 is the important signal transmission factor.