Abstract:AIM: To investigate the expression and significance of B-cell lymphoma factor(Bcl-2), Bcl2-Associated X protein(BAX)and vascular endothelial growth factor(VEGF)in the retina of early diabetic rats.
METHODS: An early diabetic retinopathy model was made in rat by intraperitoneal injection of streptozotocin(60mg/kg). The model rats were sacrificed at 4,8,12wk after the establishment of the model, and the eyeballs were removed to make paraffin section and retina sheets were prepared. HE staining was used to detected the retinal morphology and vascularity. Immunohistochemistry(IHC)was employed to examine the expression of Bcl-2, Bax and VEGF in the retina. ADP enzyme staining were conducted to evaluate the retinal vascular morphologic change. Nikon-A1 laser confocal microscopy was used to detect the morphology, fluorescence intensity and distribution of Ca2+ in retinal cells.
RESULTS: In the diabetic group, the number of endothelial cells in the inner limiting membrane increased 12wk later. In diabetes mellitus group, there was no vascular area in the middle and peripheral retina, and no vascular area was significantly more than that in the blank control group(P<0.05). There were significant differences in the values of VEGF, Bcl-2 and Bax between diabetic rats and control group(P<0.05). Compared with diabetic rats at 4, 8, 12wk, the fluorescence concentration of calcium ions in RGCs increased gradually, and the ratio of fluorescence staining intensity increased significantly(P<0.05).
CONCLUSION: The expressions of Bcl-2 and Bax were significantly increased, which upgraded the expression of VEGF in the retinas of early diabetic rats. Bcl-2, Bax and VEGF might play an important role in the neovascularization of the retinas in early diabetic rats.
