Effects O F Experimental Form-Deprivation Myopia On Expression Of Smad3 Protein In The Retina Of Guinea Pig

Objective:To investigate the expression of Smad3 protein in experimental form-deprivation myopia in the retina of guinea pig and to study the relationship between the expression of Smad3 protein and the experimental form-deprivation myopia. Methods: Thirty healthy guinea pigs of 2-week-old were chosen and were assigned randomly to the experimental group(n=20) and the blank control group(n=10,20 eyes).The right eyes of the guinea pigs in the experimental group were wore a translucent goggles(FDM group,20 eyes) and the left eyes were not treated with anything(self-control group,20 eyes). The refractive state and axial length of the three groups were measured by retinoscope and A/B scan ultrasonography respectively at the begin of the experiment and 8 weeks after the experiment.The expression of Smad3 protein in the retina of guinea pig was determined by immunohistochemistry at 8 weeks after the experiment of all 3 groups. Results: The refractive state of the FDM group, the self-control group and the blank control group were(+2.48 ±0.76)D,(+2.45 ±0.68)D and(+2.47 ±0.74)D;and the axial length were(6.63±0.29)mm,(6.57±0.26)mm and(6.59±0.28)mm at the begin of the experiment.Eight weeks after the experiment,the refractive state of the FDM group, the self-control group and the blank control group were(-5.17±1.12)D,(+1.76 ±0.48)D and(+1.72 ±0.47)D;and the axial length were(8.35±1.86)mm,(7.06±0.57)mm and(7.03±0.59)mm. In the FDM group,the refractive state evolved from the presbyopia(+2.48 ±0.76)D before the experiment to myopia(-5.17±1.12)D at 8 weeks after the experiment, accompanied by the increase of axial length from(6.63±0.29)mm to(8.35±1.86)mm. In the self-control and blank control group, the refractive state of guinea pigs were approaching emmetropia and the axial length increased slowly. At the begin of experiment the differences of the refractive state and axial length were not statistically significant(P>0.05) pairwise compared within group FDM, the self-control and blank control. Compared with the self-control and blank control group, the differences of the refractive state and axial length in the FDM group were statistically significant(P<0.05) at 8 weeks after the experiment, but the differences between the self-control and blank control group were not statistically significant(P>0.05).The retinal photoreceptor cell layer, the retinal pigment epithelium and choroid all have Smad3 protein positive expression and sclera weakly positive expression in group FDM at 8 weeks after the experiment. However in the self- control and blank control group, the weakly positive expression mainly occurs in retina and choroid. Compared with the self- control and blank control group, Smad3 protein positive expression in FDM group visibly increased and the differences were statistically significant(P<0.05), whereas the differences between the self-control and blank control group were not statistically significant(P>0.05). Conclusion: The expression of Smad3 protein in experimental form-deprivation myopia in the retina of guinea pig was found to increase,which suggested that the Smad3 protein might play a role in the occurrence of experimental form-deprivation myopia in guinea pig,and the further study on the mechanism of influence is needed.