ABSTRACT
Objective To compare the biological characteristics of eyeballs between Zmu-1:DHP and DHP guinea pigs,and to explore the retinal mechanism of myopia in Zmu-1:DHP guinea pigs. Methods To measure the refraction, corneal curvature and axial length of the two guinea pig strains at age of 4-12 weeks. Those spontaneous myopic Zmu-1:DHP guinea pigs were chosen to take the retina for pathological examination. The pathological changes in the retina were determined and compared with the DHP guinea pigs. The expression of RALDH, ALDHTH, TH, TK, iNOS, nNOS, bFGF and TGFβ mRNA in the retina were detected by real time-PCR. Results The myopic rate of 3-week old Zmu-1:DHP guinea pigs was 90.21%,while of the DHP guinea pig was only 18.00%. From 4 to 12 weeks, compared with the DHP guinea pigs,myopia and axial length of the Zmu-1:DHP guinea pigs were significantly increased(P<0.01),and the corneal curvature of Zmu-1:DHP guinea pigs was significantly less than the DHP guinea pigs(P<0.01). The retina outer nuclear layer of Zmu-1:DHP guinea pigs was reduced in thickness,the cell volume was smaller,and the cell number was less compared with the DHP guinea pigs. The choroid of Zmu-1:DHP guinea pigs showed atrophy and became thinner. There were few pigment granules in the pigment epithelium of Zmu-1:DHP guinea pigs,while there were plenty of pigment granules in the DHP guinea pigs. Compared with the DHP guinea pigs,the expression of TH mRNA was significantly down-regulated in the retina of Zmu-1:DHP guinea pigs(P<0.01),and the expression of TK,iNOS,nNOS,bFGF and TGFβ was significantly down-regulated(P<0.01, P <0.05, P <0.05, P <0.05, P <0.05). Conclusions Zmu-1:DHP strain guinea pig has a high rate of spontaneous axial myopia. The retinal mechanism of myopia has a relationship with the regulation of several myopia factors.