[Effect of pyruvate on polyol pathway and lens epithelium apoptosis in diabetic rats].
OBJECTIVE
To investigate the effect of polyol pathway on the lens epithelium apoptosis and caspase-3 activity and its reversal by pyruvate in diabetic rats.


METHODS
Two hundred and twenty Wistar rats were divided into 3 groups: control group (60 rats), experiment group (80 rats) and treatment group (80 rats). After streptozotocin (STZ) induced cataract, the treatment group received 2% pyruvate in the diet and drinking. Lens opacification was detected by microscope every 2 weeks. Amounts of glucose and sorbitol in the lens were quantified by high-performance liquid chromatography 4, 8 and 12 weeks after the treatment. The percentage of lens epithelium undergoing apoptosis was measured by Annexin V-PI staining. The activity of caspase-3 was analyzed by Western-blot.


RESULTS
Present study showed that there was significant increase of glucose and sorbitol in the lens in the experiment group, the apoptosis rate and caspase-3 activity of lens epithelium were also gradually increased. Pyruvate treatment decreased the levels of sorbitol, glucose, lens epithelium apoptosis and caspase-3 activity. The progress of cataract was also significantly delayed.


CONCLUSIONS
Activation of polyol pathway, possibly through regulation of the activity of caspase-3, can induce apoptosis of the lens epithelium. Pyruvate ingested orally can effectively inhibit diabetic cataractogenesis in rats through inhibit polyol pathway.
Qi
Yan-xiu
YX
Department of Ophthalmology, the Fourth Affiliated Hospital, China Medical University, Shenyang 110001, China.
Yu
Hai-lian
HL
Meng
De-xin
DX
Zhang
Di
D
Zhang
Jin-song
JS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D007908:Lens, Crystalline / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D019289:Pyruvic Acid / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D019289:Pyruvic Acid; C505410:Casp3 protein, rat; D053148:Caspase 3