The Expression Of VIP In Form Deprivation Myopia Guinea Pigs

Backgrounds and Objective: Myopia, as the leading case of ametropia throughout the word in nowadays, its prevalence and danger have maken it become a world-wide attention, its prevention and treatment have been included into the Blindness Program by the World Health Organization (WHO).The researches about it have been more than 200 years, many hypotheses about its mechanism have been put forward, but so far not clearly, nor do precise and effective control methods. A number of experimental studies suggest that form deprivation myopia (FDM) may be regulated by the local retina.In recent years, people have found that there is a close relationship between vasoactive intestinal polypeptide (VIP) and myopia. Being one kind of visual information element, VIP may play a role of transmission and regulation in the formation of visual induced myopia. People have found that in the models of chicks and primates of myopia, the expression of VIP in retina is significantly higher, and have a similar change with the degree of myopia in chicks. However, whether there is a similar dynamic change in FDM guinea pigs, which are closer to human being, has not been proved yet.With different experimental techniques, we intend to observe and compare the expression of VIP in the retina of FDM guinea pigs between experimental group and control groups at different time points and whether the change is similar to that in young chicks, so to get a better understanding about its possible involvement in the occurrence or development in the mammalian myopia and to provide a theoretical basis for a new treatment or prevention as well.Methods:60 tri-color guinea pigs of 2-3 weeks old were chosen.40 of them were divided into pre-covered and covered 1w.2w.3w group randomly,10 in each group, and form deprived by monocular deprivation (MD). The right eye was experimental group and the left eye was exposed for self-control. In addition,5 guinea pigs with the same age that were also randomly selected were not covered as a normal control group. After detecting the diopter of each group by retinoscopic refraction and measuring the eyeball axis by ophthalmology ultra-A at pre-covered and 1w,2w,3w after MD, the corresponding guinea pigs' eyes were taken out for HE and immunohistochemistry (IHC), as well as PT-PCR, and the results were analyzed by statistical analysis. Results:①Diopter, eyeball axis:There was no significant difference between each group before MD (P>0.05) while the diopter and eyeball axis were significantly higher after MD 1 w,2w,3w(diopter P＜0.01,P＜0.01,P＜0.05, eyeball axis all P<0.01). The diopter and eyeball axis increase as MD prolonged while the difference in the normal control group was not significant (P>0.05).②The difference of VIP in the retina between each group before MD was not significant in the protein and mRNA level (P>0.05) and it was significantly higher after MD 1w,2w,3w(均P＜0.01). The protein and mRNA of VIP in the retina increased as MD prolonged in both experimental and self-control group while it was not significant in the normal group (P>0.05).Conclusion:①Myopia can be formed by lw's form deprivation. The diopter and eyeball axis increase as MD prolonged.②VIP may have some relevance of the occurrence and development of FDM. The expression of VIP in the retina of FDM guinea pigs also increases as MD prolonged, concordant with the change of diopter and eyeball axis.