AIM: To investigate the effect and possible mechanism of poly ADP-ribose polymerase(PARP)inhibitor 3-aminobenzene(3-AB)on the lens opacity in the diabetic rats.

METHODS: Wistar rats were randomly divided into three groups: control group, diabetic group and 3-AB group. The rats of diabetic group and 3-AB group were treated with intraperitoneal injection of streptozotocin(STZ). The rats of control group were given the same volume of citrate buffer. After the model constructed, 3-AB group was treated with 3-AB(30 mg/kg)gavage daily while the control group and diabetic group were given the same volume of 0.9% NS instead. The progress of lens opacity of rats was observed and recorded. After administrated for 2, 4 and 8 weeks, rats were sacrificed and taken lens respectively. The lens were used to detected the activity of glutathione peroxidase(GSH-px), superoxide dismutase(SOD), the level of malondialdehyde(MDA)and advanced glycation end products(AGE), the expression of matrix metalloproteinase-2(MMP-2)and basic fibroblast growth factor(bFGF)in lens epithelial cells.

RESULTS: Lens of diabetic group and 3-AB group appeared various degree of cloudy since the third week. The level of diabetic group was higher than 3-AB group(P<0.01)in the fourth and eighth week. The GSH-Px and SOD activities of diabetic group were lower than 3-AB group(all P<0.05)at the 2, 4, 8 weeks, but all of them lower than control group(P<0.01). The content of MDA increased in diabetic group and 3-AB group, compared with control group(P<0.01), and its content in diabetic group was higher than in 3-AB group(P<0.05)at the 2, 4, 8 weeks. The content of AGE in the lens that come from control group were lower than diabetic group and 3-AB group(all P<0.05)in each time. At 2, 4 weeks, its content in diabetic group was higher than in 3-AB group(P<0.05), but there was no difference at 8 weeks(P>0.05). There was rare expression of MMP-2 in control group, the MMP-2 expression of diabetic group is statistically significant higher than 3-AB group(P<0.05)in the 2, 4, 8 weeks. bFGF was expressed in the three groups, and the bFGF expression of control group was lower than diabetic group and 3-AB group(all P<0.05)in the 2, 4, 8 weeks. There was no difference between diabetic group and 3-AB group in each time.

CONCLUSION: 3-AB has a certain inhibitory effect for lens opacity in the STZ-induced diabetic rats, the possible mechanism: alleviates the oxidative damage of lens epithelial cells, reduces the level of non-enzyme glycation, and inhibits the expression of MMP-2 suggested that it can alleviate the degradation of lens epithelial cells' extracellular matrix, which lead to inhibit the lens opacity.