Cataract Model Induced By Ultraviolet-b Radiation Ray And The Therapeutic Effect By Dithiothreitol

Cataract is still a main disease of growing blind in our country. It is the world's common diseases that affecting our health at present. Cataract is a multi-cause disease such as gene mutation,oxidative stress,radiation,age and so on. So the pathogenesis is still not clear. The key point of cataract is opacity in lenses that the light can not be penetrated.Ultraviolet radiation is electromagnetic wave that wavelength is 100～400nm. It is include:near ultraviolet ray UV-A(315nm～380nm),far ultraviolet ray UV-B(290nm～315nm)and super-short ultraviolet ray UV-C(<290nm). It has been confirmed in lots of epidemiological investigation and empirical study that ultraviolet could cause cataract. Research indicate, the injury of lenses epithelial cells by ultraviolet vary with the wavelength: UV-A couldn't damage lenses' DNA, but the role of UV-B is strong. Long-term subject to chronic ultraviolet radiation is also the important factor for senile cataract. And the influence of ultraviolet radiation on the crystal is long-term,chronic accumulation of oxidative damage.Preliminary research results in our laboratory show that anti-lenses degeneration of DTT is well. It is a chemical reductant that can untie disulfide linkage within the protein molecular and intermolecular. It also can inhibit the thermal denaturation of lens protein and non-specificity aggregation as sulfhydryl protective agent. Studies have been proved the nucleus plaque of selenite induced rat nuclear cataract after using DTT is significant less than control group.So, my experiment will evaluate the effect of DTT for cataract induced by ultraviolet-B and study the etiopathogenesis of this cataract based above results. These demand establishment cataract model induced by UVR.At present, most of domestic literature about ultraviolet cataract model use guinea pig, and the model cycle is relatively long. And then, foreign literature only analyze from single factor. In view of this, my topic will detailed discussion the establishment of the UV model, explore optimize conditions and shorten model time in order to facilitate the latter study. Also, on this basis, the curative effect of DTT would be investigated.Purpose:Investigate the experimental method for SD rat cataract model induced by ultraviolet-B radiation ray and grading-up the experiment condition. Study the mechanism of the cataract induced by ultraviolet-B. Discuss the inhibition of DTT.Method:1. Construct ultraviolet ray cataract animal model SD rat, 6 weeks old, are radiated by UV-B. We observe the lenses morphologic change everyday and grade based on standard. Remove lenses and culture in vitro. Then, observe its ultrastructure using transmission electron microscopy and scanning electron microscope.2. The mechanisms of ultraviolet induced cataract Remove lens of experiment and control groups, and determine content of SOD,GSH of two groups. Moreover, compare these indexes with normal eyes that didn't radiate.3. Appraise therapeutic effect of DTT When UV irradiate, the left eye drops DTT as control group, 4 times a day each one drops. Contrast lenses of both lens morphologic change with slit lamp, then extract lens and do immunohistochemistry.RUSULT:1. 6 week old male SD rats, peritoneal injected 10% Chloral hydrate 0.7ml, using 300nm UV-B radiated eyes 15 minutes after pupil dilation,once a day,1×103uw/cm2 irradiance. lenses opacity occurred after 2 days,and 7 days can form typical cortical cataract.2. SOD,GSH in the eyes of experiment groups are lower than the controls; and Ca2+,Na+ in serum are higher than controls. K,P,Mg2+ are lower than control groups.3. The right eyes are almost all cortical cataract after UV irradiation. Lens volume increase and cortical obviously become turbid. Turbidity of the left eyes which drop DTT significantly reduced. Control group, left eyes are 2 level, comparing right eyes 3 level, some even 4 level, and crystal in blank control group, no UV radiation, are transparence.Conclusion:1. The method is practicable and a fast way in vivo UV-induced cataract of rats and most are cortical cataract.2. The DTT eye drops has obvious inhibitory effect on UVR-B–induced S-D rat cataract.