Study On Inhibitory Effect And Action Mechanism Of Vitamin B₁₂ On Retinal Neuronal Apoptosis In Diabetic Rats

ObjectiveTo evaluate the inhibitory effect of vitamin B₁₂ on retinal neuronal apoptosis in diabetic rats and explore its mechanism of action.MethodsThirty-six SD rats were randomly divided into negative control group?group NC?,diabetic model control group?group DM?and Vitamin B₁₂-treated group(group VitB₁₂),12 rats in each group.The animals of group DM and group VitB₁₂2 were made into diabetes model.The diabetes model was induced by intraperitoneal injection of streptozotocin?STZ?.100?g/kg Vitamin B₁₂ was given by intragastric administration one time per day for 56 consecutive days in the rats of group VitB₁₂,and an equivalent amount of physiological saline was utilized at a same way in the animals of group NC and group DM.After 10weeks later,all the rats were killed,and the levels of malondialdehyde?MDA?and superoxide dismutase?SOD?in serum were detected.The eyeballs of each group were executed for paraffin section.TUNEL staining was used to observe neuron apoptosis in retina and the apoptosis index?AI?was counted.The expression of Caspase-3 in retina was measured by immunohistochemistry.ResultsThe levels of serum MDA were as follows:group NC?4.47±0.36?nmol/mL,group DM?8.27±0.23?nmol/mL,group VitB₁₂?6.45±0.30?nmol/mL.There was significant difference among three groups?F=471.061,P=0.000?.SOD were as follows:group NC?112.77±4.55?U/mL,group DM?66.51±3.88?U/mL,group VitB₁₂?86.61±4.30?U/mL.There was significant difference among three groups?F=356.923,P=0.000?.AI were as follows:group NC?11.32±6.43?%,group DM?27.29±8.95?%,group VitB₁₂?19.60±5.71?%.There was significant difference among three groups?F=14.926,P=0.000?.Average optical density value of Caspase-3 in retina were as follows:group NC 0.117±0.042,group DM 0.388±0.048,group VitB₁₂ 0.284±0.067.There was significant difference among three groups?F=77.896,P=0.000?.ConclusionsVitamin B₁₂ can inhibit retinal nerve cell apoptosis in diabetic rats.The mechanism might that its antioxidant stress inhibit the expression of Caspase-3and then inhibit apoptosis of retinal nerve cells.