| OBJECTIVE:This study was to establish the diabetic rabbit's posterior capsular opacification (PCO) model by intravenous injection of alloxan (ALX), and to explore the method of reducing mortality and the early effects of high blood glucose on PCO. Besides, the early impact of Kistrin on the proliferation of lens epithelial cells (LECs), connexin43 and the expression of collagen IV was also investigated, which will provide experimental evidence for prevention and treatment of diabetic cataract by using Kistrin.METHORD:Sixty clean healthy male New Zealand white rabbits were randomly divided into 2 groups.90mg/kg of alloxan were injected via ear vein once in 30 rabbits to create the diabetic animal models, and the equivalent amount of normal saline solution was injected at the same way as normal blood glucose group. The successful models were selected in the animals with the blood glucose level over 12.0 mmol/L two weeks later, and PCO of lens were graded based on the method of Odrich under the slit lamp. Extracapsular lens extraction was then performed on the right eye of rabbits in both groups, and the posterior capsules were obtained from these eyes at the 6th,10th and 14th days after operation. The expression of proliferating cell nuclear antigen (PCNA) in posterior capsular lens epithelial cell was detected by immunohistochemistry. According to these results, twelve diabetic rabbit's PCO models were randomly divided into experimental group and control group,0.2ml of Ringers solution and 0.2ml of 80ng/ml Kistrin were injected into the surgery eyes'anterior chamber of rabbits in control group and experimental group, respectively. The expressions of PCNA, connexin43 and collagen IV in LECs of diabetic rabbits at 14th day after surgery were evaluated in two groups by using immunohistochemical staining and immunofluorescence.RESULT:The modeling successful rate was 70% after injection of alloxan. The body weight of rabbits in high blood glucose group was significantly lowed and the blood glucose was significantly elevated in comparison with normal blood glucose group (all P<0.05). Two weeks after surgery,2 eyes occurred 2 grade of PCO and only one eye showed the 1 grade of PCO in the high blood glucose group. while three rabbits in the normal blood glucose group appeared 1 grade of PCO. There were no statistically significant between the two groups in the grade of PCO at the 6th,10th,14th day after surgery (all P>0.05). Biopsy revealed that PCNA was positively expressed in the cell nuclei of LECs in high blood glucose group rather than the normal blood glucose group from the 10th day after surgery. The proliferation index (PI) of PCNA was 0.78±0.10 and 0.25±0.03 respectively in high blood glucose group and normal blood glucose group, showing a significant difference between them (t=-16.171, P=0.000). The PI index of experimental group and control group were 0.57+0.11, 0.78±0.10. respectively, The ratio of Cx-43 positive fluorescent area was (0.016±0.002)% in the experimental group and (0.136±0.026)% in the control group. The Integrated optical density (IOD) of type IV collagen was 170.6±8.5 in the experimental group and 255.7±15.6 in the control group. All these measurements in the experimental group were statistically significantly lower than those in the control group (all P＜0.05).CONCLUSION:Stable diabetic models of rabbits can be created by intravenous injection of 90 mg/kg ALX. High blood glucose level is one of the important factors for the proliferation of LECs. Kistrin with concentration of 80ng-ml-1 could significantly inhibit the expressions of PCNA, Connexin 43 and collagen IV in LECs of diabetic rabbits at 14 days. Kistrin can effective inhibit the PCO formation in early stage.
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