Mutation Of Adenomatous Polyposis Coli (APC) Gene Lead To Postnatal Development Of Myopia In Mice

Objective To indentify the role of APC gene in the eye refractive development of the mice and tentative exploration its mechanism by observing the eye refractive parameter of the APC gene mutation mice.Methods Select10WT mice and10APCMin mice as cross-referenced, all mice were born21days. Measurement of the Refraction, the Corneal curvature radius(CCR), the ocular parameters(including corneal thickness(CT), anterior chamber depth(ACD), lens thickness(LT), vitreous cavity depth(VCD), retinal thickness(RT) and ocular axial length(AL), using the machine called OCT) of every mouse were taken at P28、 P35、P42、P49、P56、P70、P84. Using transmission electron microscopy (tern) to observing the microscopic structure of the sclera. Then, Compared the structure of the retina in WT mice and APCMin mice by observing the HE staining result of the retinal frozen section at84days of after birth. And detect the expression of Ki67protein in the retina by western blotting analysis. Finally, the abundance of TH protein in the retina was quantified by immunofluorescent staining and western blotting analysis.Results After70days after birth, the APCMin mice (P70,-4.39±1.50diopter) show a significant myopic refractive error compared with the WT mice (P70,-1.06±1.90diopter); the APCMin mice show a significantly thinner lens thickness, a longer vitreous depth, and a shorter axial lengths compared with the WT mice, but the corneal curvature, the pupil diameter and anterior chamber depth had no significant difference. The arrangement of the scleral collagen fibers in APCMm mice was disordered, the diameter of fibers were inconsistent, the clearance among fibers were uneven. The choroid and retinal pigment epithelium was obvious thickening but their structure was loose, intercellular space increased as well. The retina was generally hypertrophy especially the inner nuclear layer. The expression of Ki67protein was increased which reflect a proliferous of the retina The level of TH protein in the retina was significantly reduced.Conclusion For the first time confirmed that the mutation of APC gene had an effect on the ocular refractive development in mice. The mutation of APC gene lead to postnatal development of myopia and relative small eye in mice. The mutation of APC gene not only played an important role in the synthesis and decomposition of the scleral collagen in mice, but also leaded the unusually high level of Ki67protein in the retina which reflect a proliferous hypertrophy of the retina.The mutation of APC also decreased the expression of dopamine in retina to participate in the occurrence of myopia.