| With the technology development, the near work demands are increasing, worldwide incidence of myopia has also increased year by year, myopia serious impact on the patient's study, work, life, so short-sighted global issues of common concern. Although for the last two hundred years of myopia in the ongoing study of the various factors that may affect the continuous discovery, but its etiology and pathogenesis is still no definite conclusion, so the study of myopia is an important scientific research of the world's Ophthalmology experts.Since Wiesel built up form deprivation myopia (FDM) on rhesus monkey in 1977 for the first time, the method to establish animal models of myopia has also been developed. At present, basically two kinds of animal model of myopia were established:form deprivation myopia (form deprivation myopia, FDM), myopic defocus (defocus myopia). Form deprivation myopia refers to stitching the eyelids or wearing translucent goggles dispersion lenses or serious damage to the visual shape of animals, then myopia happened. Defocus myopia is forced animals to see close, or depending on wearing a negative lens so that objects focus on behind the retina, causing adjustment occurs, so that axial extension caused by myopia. Both animal models of myopia make the occurrence of myopia, development and prognosis have a better understanding, but also Ophthalmology experts have a more indepth study. Current research shows that:form-deprived retina can lead to a variety of neurotransmitter and growth factor levels change, and these studies found that induced myopia, the material mainly from the neurosensory retina. General generating process as follows:retinal neuroepithelial generated by a first messenger acting on the retinal pigment epithelium (retinal pigment epithelium, RPE) and choroid, thus producing lower levels of biochemical substances, also known as the secondary messenger, acting on the two messenger sclera, scleral growth control so that sclera remodeling, causing excessive axial extension of the formation of short-sighted. A number of other autocrine or paracrine loops involving cytokines, growth factor and its tyrosine kinase receptor may be pathological changes in RPE cells play a crucial role. The impact of the mechanism of these factors needs to be further studied.Melatonin (melatonin, MLT) will enter the frog after frog melanocytes lighter body color, so called melatonin. Under physiological conditions the pineal gland at night a methoxy indole secretion, chemical, called N-acetyl-5-methoxy tryptamine, is a 5-HT transformation comes from the cross on their secretion rhythm nuclei to be controlled under the circadian rhythm. For a long time, people think melatonin is mainly regulate the biological role of the circadian rhythm, center temperature, blood sugar metabolism, as well as rhythm sleep-wake circadian rhythm phase-change and improve sleep. However, with the in-depth study of melatonin, Melatonin is also found to have (1) direct free radical scavenging; (2) to enhance the vitality of antioxidant enzymes and gene expression; (3) inhibit the activity of nitric oxide synthase; (4) a powerful mitochondrial protection. In recent years, studies have shown that NO has been the development of retinal, visual excitement and visual information transduction, suggesting its possible participation in the formation of myopia. And, in Jaworski, etc, and Kumi study found that early gene c-fos via regulation of AP-1 sites of dopamine rate-limiting enzyme-tyrosine hydroxylase (tyrosine hydroxylase, TH) and tissue inhibitor of metallopro-teinase (tissue inhibitor of metalloproteinases, MMPs), have also been proved have an important role in the occurrence and development of myopia, in addition, c-fos with the anti-apoptotic features on the development of myopia, and melatonin by suprachiasmatic nucleus c-fos gene regulation, to achieve photoperiod signals.In this study, the proposed FDM model of guinea pig, to observe the expression and effects of melatonin and iNOS, c-fos in guinea pig retina FDM.Material and MethodsUse thirty seven-days-old healthy multicolor guinea pigs, covering their right eye with semi-transparent goggle, the left eyeas the control eye. Experiments carried out before the cycloplegic retinoscopy guinea pigs to exclude congenital myopia and other eye diseases, the methods of form deprivation myopia model used to establish. After form-deprived 8 weeks, to detect eye refraction and axial length. HE staining was observed under optical microscope, the sclera retina pathological changes detected by immunohistochemical staining of retinal melatonin receptor, iNOS and c-fos expression. Application of Image-Pro Plus 6.0 image to analysis of protein expression, expression intensity with the average optical density value expressed.Experimental data are available, said use of SPSS 13.0 statistical software package homogeneity of variance test, Paired-Samples T test were used to analyze the difference between the experimental and control groups. In this based on single-factor analysis of variance and correlation tests. Withα=0.05 as the test standard.Results1. Before covered, form-deprived eyes were (3.85±0.80D) and the control eyes were (3.75±1.20D), there is no significant difference (P>0.05), covered after 8 weeks form-deprived eyes were (-7.25±2.60D), the control eye refraction (2.85±0.96D) (P<0.05); before form deprivation the covered eye axial length (6.78±0.18mm) and the control eye axial length (6.86±0.22mm), there is no significant difference (P>0.05),8 weeks after form deprivation, covering eye axial length (8.54±0.20mm), control eye axial length (7.12±0.17mm), were significantly different (P <0.05). Before covering refraction, form-deprived eyes and control eyes's axial length was no significant difference (P>0.05), form-deprived for 8 weeks, form-deprived eyes and control eyes's axial length were significantly different (P<0.05).2. Immunohistochemistry Before covered the expression of form-deprived eyes melatonin (0.3650±0.0518A) and the control eyes (0.4142±0.0778A) were no significant difference (P>0.05), iNOS expression in the deprived eyes (0.3321± 0.0476A) and the control eyes (0.3431±0.0354A) were no significant difference (P >0.05), c-fos expression in the deprived eyes (0.3752±0.0560A) and the control eyes (0.3756±0.0822A) were no significant difference (P>0.05); form deprivation for 8 weeks cover the eye after the expression of melatonin (0.3199±0.0279A) and the control eyes (0.3960±0.0932A) were significantly different (P<0.05), the expression of iNOS in the deprived eyes (0.4005±0.0605A) and the control eyes (0.3326±0.1071 A) were significantly different (P<0.05), c-fos expression in the deprived eyes (0.2083±0.0604A) and the control eyes (0.3654±0.0733A) were significantly different (P<0.05), which is covered than in the control eye retina reduction in the expression of melatonin receptor, the expression of iNOS increased, the expression of c-fos decreased.3. Cover the eyes of the melatonin receptor and iNOS expression (r=-0.8132, P= 0.026<0.05), negative correlation with c-fos expression (r=0.7085, P=0.075>0.05) were positively correlated.Conclusion1. Covered with monocular translucent goggles after 8 weeks the myopia was formed, animal form deprivation myopia model has been successfully established.2. In the expression of monocular retinal melatonin receptors in covered significan-tly reduced, suggesting that melatonin may be involved in the formation of myopia.3. Covering group the expression of monocular retinal iNOS was significantly increased, suggesting that iNOS may be involved in the formation of myopia.4. Covering group the expression of monocular retinal c-fos was significantly reduced, suggesting that c-fos may be involved in the formation of short-sighted.5. Covering group of retinal melatonin and the expression of iNOS were significantly negative related to melatonin and c-fos showed significant positive correlation. Presumably in form deprivation myopia in the formation of melatonin affected the iNOS, c-fos expression and activity, leading to the formation of myopia.
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