Eyesight, "five Children On The Experimental Study Of Its Mechanism Of Action Of Retinal Photochemical Injury Prevention

Objective: To observe the morphologic, biochemical and electrophysiologic changes of the retina in rats after exposure to light, and study the protective effect and mechanism of MingMuWuZi against photic injury of retina.Methods: Sprague-Dawley (SD) rats were exposed to green fluorescent light for 24 hours. The phathological changes of the retina were examined with light and eletron microscope, and the thickness of the outer nucleus layer (ONL) was measured before and immediately, 14 days after exposure. Simultaneously the apoptotic cells were detected with TUNEL method. The level of aspartate (ASP), glutamate (GLU), glycine (GLY)and Y -aminobutyric acid (GABA) were measured by amino acid automatic analytical apparatus in the retina of rats. Muhifocal electroretinograms (mfERG) examination was given in rats before and immediately, 3, 7, 14 days after exposure. In the second experiment, MingMuWuZi was given at high, low dosage before light exposure in the same model and lasted for 14 days. The phathological changes of the retina were examined with light and eletron microscope, and the ONL was measured, and the apoptotic cells were detected with TUNEL method after mfERG examination before and 14 days after exposure. The expression of GFAP and bFGF was observed by irnmunohistochemical methods. Content of nitric oxide (NO) in retina were examined by nitric acid reductase method. The level of amino acid was measured in retina.Results: (1) The retina was morphologically normal before light exposure. A significant number of TUNEL-positive nuclei occurred in retina after light exposure, and the ONL was much thinner than before light exposure, compared with before light exposure the differences of both were significant in statistically (P<0.01). regular arrangement of outer and inner segments was disordered, dividing line wasn't distinct, the nucleus and the mitochondrion of inner segment were swollen, discmembrane of outer segment were swollen, vacuolation, disorganization, the apical microvilli of RPE cell almost disappeared with an increase of lysosomes. The damages of all became lessened after 14 days. But the ONL was more attenuate. Compared with the model group, the thickness of the ONL in high dosage group of MingMuWuZi was increased and ratio of apoptotic cell was decreased obviously and the differences were evident(P<0.01). (2) Compared with the model group, the expression of GFAP was decreased and bFGF was increased evidently in high dosage group of MingMuWuZi, which showed significant difference (P<0.01). Both had distinctly negative relativity in statistically (P<0.01). (3) Compared with the normal group, the level of ASP, GLU and GABA in retina after light exposure immediatelyand after 14 days were increased evidently (P<0.01). Compared with the model group, the level of amino acid in high dosage group was decreased, which showed significant difference (P<0.05). (4) The content of NO in retina increased distinctly after light exposure, compared with the control group the difference was significant. Compared with the model group, the content of NO in high and low dosage group was decreased significantly, the difference was obvious (P<0.05~0.01). (5)The Nl, PI waves response densities of 1~5 rings markedly decreased in rats after light exposure, compared with before light exposure the difference was significant. Compared with the model group, the Nl, PI waves response densities of 1-5 rings were increased statistically in high dosage group, which showed significant difference in statistically (P<0.05).Conclusion: MingMuWuZi could release the photic injury of retina, accelerate the renovation of retina after light exposure, and ameliorate the function of retina. The mechanism might relate to inhibit the apoptosis and gliosis, enhance the expression of bFGF in retina, and regulate the neural transmitter in retina.