Effect of pyruvate on polyol pathway and lens epithelial cells apoptosis in diabetic rats

To investigate the effect of polyol pathway on lens epithelial cells apoptosis and the activity of caspase-3 and its reversal by pyruvate in diabetic rats.

220 Wistar rats were divided into 3 groups: control group, model group and treatment group. After streptozotocin (STZ) induced cataract, the treatment group received 2% pyruvate in the diet and drinking. The opacification of lens was detected by microscope every 2 weeks. On 4W, 8W and 12W of the experiment, glucose and sorbitol in the lens were quantified by high-performance liquid chromatography. The percentage of lens epithelial cells undergoing apoptosis was measured by Annexin V/PI staining. The activity of caspase-3 was analyzed by Western-blot.

Studies show that there was significant increase of glucose, sorbitol in lens of model group, the apoptosis rate and caspase-3 activity of lens epithelial cells were also gradually increase. Pyruvate treatment decreased the levels of sorbitol, glucose, lens epithelial cells apoptosis and caspase-3 activity. The progress of cataract was also significantly delayed.

Polyol pathway, possibly through regulation of the activity of caspase-3, can induce apoptosis of lens epithelial cell. Pyruvate ingested orally can effective inhibit diabetic cataractogenesis in rats through inhibit polyol pathway.