Effect Of "Shixiang Yinyang Formulas" In Diet Therapy On Light Source-induced Myopia In Guinea Pigs

Objective we take the spectral environment as the point to observe the eye axis,retinal dopamine and its D1 receptors expression,as well as the changes of D1 receptors expression in bipolar cells of the ON pathway in guinea pigs.We also explore the effects and the intervention mechanism of diet therapy of "Shixiang Yinyang formulas".Methods Forty 3-weeks-old albino female guinea pigs were randomly divided into 5 groups,8 for each group.They are natural light group,white LED group,natural light-based LED group,LED diet group and natural light-based LED diet group.The natural light group was placed on a shelf,60cm away from the southern window.The white LED group,natural light-based LED group and their diet groups were placed under the light of the corresponding light sources.Meanwhile,all groups experienced an average light intensity of 300 lux without flicker.All lamps were controlled by the regulating switch and the daily lighting time was from 6:00 to 18:00.In this experiment,all guinea pigs were fed for 12 weeks.All diet groups were fed with "Shixiang Yinyang formulas",that is,nourishing Yang formula in 10:00 a.m.and nourishing Yin formula in 22:00 p.m.The guinea pigs in the control groups were routinely fed.Before the experiment and at the 2rd,4th,6th,8th,andlOth week of the experiment,the eye axis of each group of guinea pigs was measured,and at the twelfth week,the guinea pig retinal tissues of each group were taken.The retinal dopamine content were determined by HPLC-MS and the levels of the D1 receptors determined by Western Blot,and RT-PCR was used to determine the mRNA expression of D1R.At the same time,it was used to determine the expression of the retinal D1 receptors of guinea pigs and the level of D1R in ON-type bipolar cells by Immunofluorescence technique.Results 1.The spectral band of natural light is continuous without obvious peaks and valleys.The spectrum of the white LED light is mainly concentrated at 400nm-700nm,and there are peaks at 450nm and 550-600nm,and a valley at 480nm.The spectral range of natural light-based LED light is relatively flat,mainly concentrated at 450nm-660nm,with a peak of wavelength near 455nm.2.There was no significant difference in the eye axis measurement of each group before the experiment,and the axial length of guinea pigs in each group gradually increased.At the 2rd week,the vitreous cavity depth of the white LED group’s guinea pigs had a difference compared with the natural light group(p<0.05),and the depth of the anterior chamber of the white LED group at the 4th and 6th weeks,as well as the axial length of the guinea pigs at the 4th group increased significantly(p<0.01).Afterwards,the difference in experimental results had narrowed significantly.At the 10th week of light exposure,the axial length of the guinea pigs in the white LED group was significantly longer than that in the natural light group(p<0.05),while the natural light-based LED group had no significant difference(p>0.05).At the 2rd week,the anterior chamber depth and lens thickness of the LED diet group increased compared with the white LED group(p>0.05),but in the LED diet group,the anterior chamber depth of the guinea pigs were shorter than those of the control group at the 4th and 6th weeks(p<0.05,p<0.01).After 10 weeks of light exposure,there was no significant difference about the biometric results of the eye axis between the control groups and their diet groups.3.After 12 weeks of light exposure,DA in the white LED group and natural light-based LED group were significantly reduced compared with the natural light group(p<0.01).The content of DA in the LED diet group and the natural light-based LED diet group increased significantly compared with the control groups with the same light source(p<0.01).4.After 12 weeks of light exposure,the relative protein content and the mRNA expression of guinea pigs’ retinal D1 receptors in the white LED group and the natural light-based LED group were significantly less than those of the natural light group(p<0.01).And the expression level of the natural light-based LED group was more than that of the white LED group(p<0.05,p<0.01).After the diet was performed,the relative protein level and mRNA expression of D1 receptors of the LED diet group and the natural light-based LED diet group were significantly up-regulated(p<0.05,p<0.01).5.At the 12th week of the experiment,the expression of D1R in retinal ON-type bipolar cells in the white LED group and the natural light-based LED group decreased significantly(p<0.01),and each diet group increased(p<0.05,p<0.01).Conclusions 1.White LED light may accelerate the development of myopia in guinea pigs.2.ON-type bipolar cells may participate in the occurrence and development of myopia in guinea pigs by reducing the dopamine D1 receptors and inhibiting the release of dopamine content.3.The diet therapy of "Shixiang Yinyang formulas" can increase the expression of DA by promoting the release of DIR in ON-BCs,which can inhibit the light source myopia of guinea pigs caused by white LED light and natural light-based LED light.4.The natural light-based LED light is more helpful to slow down the process of the guinea pigs’ light source-induced myopia than the white LED light.