The Influence Of Catechin On HSP27and MDR Gene Of Diabetic Cataract In The Rats

Objective: In recent years, the area of diabetic cataract has been takenmore and more attention. Diabetes cataract is the second reason, which oftenmade the diabetes patients’ visual loss. Therefore, research of the diabetescataract has been taken more attention of the ophthalmology. The latestresearch indicates that malfunction of glucose metabolism plays an importantrole in diabetes induced cataract. The glucose in lens is overloaded, which leadto abnormal highly activities of aldose reductase, as well as the sorbitolpathway. The result display that sorbitol have been accumulated in the lens,local osmotic pressure heightened. The fiber cells swelling secondary to theloss of transparence or cataract formed. The leading pathological lension ofcataract is the apoptosis of lens cells. HSP27, as a small heat shock proteins, itis not only helping the newly synthesized protein molecules obtained naturalconformation, but also preventing incorrect folding of proteinand helpdenatured protein refolding in stress environment. MDR gene belongs to thelargest gene family of membrane transport proteins: ATP binding cassettesuperfamily structure (ATP binding cassette transporter superfamily, ABCtransporter superfamily), which suggesting that regulated Clˉchannel toimprove the swelling of lens fiber cell in diabetic cataract. Catechins, one ofaldose reductase inhibitors which has anti-oxidation, anti-apoptosis,inflammation and insulin-like effects.Research have indicate that preventiveand cure values on various opthalmological diseases, such as: neovascular ofCornea, age related macular degeneration,the optic nerve degeneration,ischemic and reperfusion etc. The ability what it have with regard toanti-oxidation, anti-apoptosis, inhabit aldose reductase is deserve our deeplystudy the effects of prevention and cure on diabetes induced cataract. In ourstudy, by the preparation and related experimental animal models of diabetic cataract, from the morphology and protein and gene levels of catechinsobserved systemic effects of diabetes, cataract, and to explore its mechanismsto prevention and treatment of diabetic cataract in the search for newtreatments and to clinical application.Methods:60male SD rats with health and cleaning breeding, BW:175±15g, routine eye examination without eye diseases, were selected for theexperiment. They were randomly divided into three groups,normal group with20rats, control group with20rats, and the treated group with20rats. In thecontrol group, treated group, every rat was induced diabetes cataract by STZ(Streptozotocin) intraperitoneal injection. After the model formed, the controlgroup were given catechin stomach lavaging and the treated group receivedstomach lavaging for distilled water until the end of the experiment. Thenormal group without any treatment. Observed the lens morphologicalanalysis and blood sugar once a weeks. At0days,2weeks,4weeks and8weeks after animal models formed, every group was collected5rats (10eyes)for experiment.5lens were taken for RT-PCR detection of MDR gene, and theother5lens were taken to detect HSP27by immunohistochemical. Theexperimental data indicated with x±s, using variance analysis and Chi-squaretest to analysis, using SPSS13.0software package with statistical analysis.Selecting p<0.05as statistical significance.Results:1The general conditions of ratsAll the control and treated－group show significant typical symptoms ofdiabetes，including polyphagia，polydipsia，hyperdiuresis，pelage withered，weight losses. The normal group with no symptoms above. The blood sugarvalues of control and treated group increase constantly in2weeks,4weeks,and8weeks; compared with the normal group, the difference had statisticalsignificance(p<0.05).The value had decreased slightly in experimental process,compared with the control group, the difference had statistical significance in8weeks (p<0.01). 2The morphological observation of the lensThe lens of normal group rats is keeping transparence in all time.Compared with the normal group, control group have been detect graduallyopacity, especially in8weeks；compared with the control group, the lensopacity process of treated group have been hampered，the difference hadstatistical significance in4weeks and8weeks (p<0.05).3The results of immunohistochemicalHSP27Immunohistochemical showed a little expression in the lens tissueof the rats, had no significantly changes at each times in normal group. In thecontrol group, the expression of HSP27increased at2weeks after the diabeteswere induced, reached the peak at4weeks, begun to decrease at8weeks.Compared with the control group, it was increased at each time points in thetreated group, the difference had statistical significance in2weeks and4weeks (p<0.05). In the other experiment points there was no statisticalsignificance.4The results of MDR RT-PCRMDR RT-PCR showed that MDR2mRNA，MDR3mRNA was expressedon every group of the rats lens fibre. There ware no significantly changes ateach time in the normal group. In the control group, he expression of MDRmRNA was higher than the normal group and reach its peak at2weeks. At4weeks and8weeks after diabetes induced the expression were decreasingfollow the time lasting. In the treated group, the expression of MDR mRNAwas higher than the control group at2weeks,4weeks and8weeks, thedifferences had statistical significance (p<0.05).Conclusions：1The expression of MDR2mRNA, MDR3mRNA, HSP27in the rat lenswere increased after the diabetic cataract was induced.2Catechin could increase the expression of MDR2mRNA, MDR3mRNA,HSP27in the rat lens after the diabetic cataract was induced.3Catechin had some prevent and therapeutical effects on diabetic cataractwhich including anti-apotosis and regulate the function of Clˉchannel in lenscells.