| Objective:In this study, we applicate poly ADP ribose polymerase (poly ADP-ribose polymerase, PARP) inhibitor 3-aminobenzamide (3-AB) to intervent the early diabetic mellitus (diabetes mellitus, DM) rats modal.The main purpose of this experiment is to observe the impacts of PARP inhibitor on DM rat modal and the expression of nuclear factor Kappa B (nuclear factor-kappa B, NF-κB) on lens epithelial cells. To investigate whether there is a protection on lens epithelial cells of diabetic cataract (diabetic cataract, DC) by PARP inhibitor and provide a new way for the prevention of DC. Methods:Among forty healthy-adult-male Wistar rats, nine were used as control, and diabetes were on the other thirty-one rats by intraperitional injection of 1% streptozotocin(Stretozocin,STZ) at a doze of 50mg/kg.Before the experiment,we use the slit lamp to exclude the lens lesions.Diabetes were characterized by an increase in blood glucose(>16.7mmol/L) 72 hours after injection. The death and unformed rats were removed out of the experimental group. Eighteen of the successful diabetic rats models were used in the experiment. According to the experimental time point, the above twenty-sevent rats were further divided into N 2w group (3 rats), N 4w group (3 rats), N 8w group (3 rats), DM 2w group (3 rats), DM 4w group (3 rats), DM 8w group (3 rats), DM+P 2w group (3 rats), DM+P 4w group (3 rats), DM+P 8w group (3 rats). Starting from the third day after modeling, DM+P group were given 3-AB 30mg/kg per day orally. General situations (mental status/pelage/pad and hydroposia) of rats were observed.The changes of blood glucose and body weight were monitored once a week, when the blood glucose go above 28mmol/L of the corresponding measurement in the DM rats,give to the effect of insulin (protamine, recombinant human insulin) subcutaneously to maintain blood glucose at 28mmol/L or so. (28-29mmol/L injection of 1U,29-30mmol/L injection of 2U,>30mmol/L injection 3U).In order to prevent the ketoacidosis death, if necessary, intensive monitor the blood glucose according with its general situation. Progression of cataract formation in both lens of all rat was recorded using slit lamp observation once a week. At 2nd,4th,8th week, the rats were sacrificed and the lenses were removed for measurement.Compared the blood glucose, body weight, general changes, and the progress in lens opacity. 6 lenses in each group were embedded in paraffin to detected the expression of NF-κB in lens epithelial cells by immunohistochemistry method. Determined the concentration of the NF-κB in serum by enzyme-linked immunosorbent assay (ELISA) method. And the results were statistically analyzed. Results:(1) About 87.1% of the rats responded to STZ injection (50mg/kg) (blood glucose>16.7mmol/L). The blood glucose of diabetic rats was statistically significant higher than that of control group (P<0.01). The body weight of diabetic rats was statistically significant lower than the control group (P<0.01). (2) The lens in the control group were totally transparent during the experiment. The lens of diabetic untreated rats did not progress to opacity until the 3rd week after STZ injection. Otherwise the lens of diabetic treated rats progress to opacity since the 3rd week after STZ injection. (3) The immunohistochemistry results showed that:The expression of NF-κB p65 increased statistically in DM group at the 2nd,4th and the 8th week compared with the DM+P group(P<0.01, P<0.01, P<0.05); The expression of NF-κB p65 increased statistically in DM+P group than N group at the corresponding time points 2nd,4th and the 8th week (P<0.05, P<0.01, P<0.05); compared with the DM group, the expression of NF-kB p65 in DM+P group was significantly reduced (P<0.01, P<0.01, P<0.05) at the 2nd,4th and the 8th week. (5) The ELIS A assay results showed that:The concentration of NF-κB p65 in serum in the DM group and the DM+P group at each time point showed significant increase than that in the N group (P<0.01), and at each time point, there was statistically significant difference between the DM+P group and DM group (P <0.01). Conclusion:(1) The diabetic modal induced by STZ (50mg/kg) intraperitoneal is reliable for our study in early DC,for the survival rate is relatively high, basically followed the formation of diabetic cataract.(2)NF-KB may be involved in the reconstruction and play an important role in the process of DC at an early stage (3) PARP inhibitor 3-AB have a protective effect in DC on an early stage,3-AB delayed, but did not prevent the formation of diabetic cataract. The mechanism may be by reducing the expression of NF-κB on the rat LECs, then inhibit the apoptosis of LECs, thereby delaying the occurrence of DC. |
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