[Experimental study of nimodipine and vascular endothelial growth factor in proliferative retinopathy].

ABSTRACT

OBJECTIVE: To study the therapeutic effect of the calcium channel antagonist nimodipine on the proliferative retinopathy and it's interaction with vascular endothelial growth factor (VEGF). METHODS: A proliferative retinopathy model (OIR) of newborn Sprague-Dawley (SD) rats was induced by hyperoxia. Different dosages of nimodipine were injected to the rats through retrobulbar or intraperitoneal routes. Both eyeballs of newborn rats were enucleated for performing pathological sections and were studied by immunohistochemical method, in order to count the nuclei of proliferative retinal vessels and to investigate the expression of VEGF in the retina. RESULTS: The number of nuclei of proliferative retinal vessels and the expression of VEGF in non-treatment group increased significantly as compared with normal control group (P < 0.01). Both parameters decreased significantly in high dosage and medium dosage of retrobulbar injection group as compared with the non-treatment group (P < 0.01) and there was no significant decrease in low dosage group (P > 0.05). In each dosage group of intraperitoneal injection, there was a significant decrease of the expression of VEGF (P > 0.01). CONCLUSION: VEGF can induce cell proliferation by activating the calcium channel in cell membrane through which the influx of calcium is increased. The calcium channel antagonist nimodipine can inhibit proliferative retinopathy by blocking the influx of calcium. Nimodipine can inhibit the expression of VEGF at certain degrees.