Expression Of Sp1 And Collagen Ⅰ In Experimental Myopic Sclera Remodeling In Guinea Pigs And Their Correlation

Objective:To study the expression of collagen I and transcription factor Sp1,a TGF-β1downstream target,and reveal the impact of the TGF-β1-Sp1 signaling pathway on collagen remodeling in myopic sclera.Methods: Seventy-five 1-week-old guinea pigs were randomly divided into normal control,form deprivation myopia(FDM),and self-control groups.FDM was induced for different times using coverage with translucent latex balloons and FDM recovery was performed for 1 week after 4-week treatment(4/-1-weeks);then,changes in refractive power and axial length were measured.Immunohistochemistry and RT-PCR were used to evaluate dynamic changes in collagen I and Sp1 expression in the sclera of guinea pigs with emmetropia and experimental myopia,and the relationship between collagen I and Sp1 levels was analyzed.Results: In the FDM group,the refractive power was gradually changed(from+2.09±0.31 D at week 0 to-1.23±0.69 D,-4.17±0.59 D,-7.07±0.56 D,and-4.30±0.58 D at weeks 2,4,6,and 4/-1,respectively;P<0.05),indicating deepening of myopia.The axial length was increased(from 5.93±0.39 mm at week 0 to 6.62±0.36 mm,7.30±0.34 mm,7.99±0.32 mm,and 7.41±0.36 mm at weeks 2,4,6,and 4/-1;P<0.05).The m RNA and protein expression of Sp1 and collagen I in the sclera of the FDM group was lower than that of the control groups(P<0.05),and the reduction was eye-coverage time-dependent.Furthermore,correlation between Sp1 and collagen I downregulation in the myopic sclera was observed.Conclusion: Our data indicate that transcription factor Sp1 may be involved in the regulation of type I collagen synthesis/degradation during myopic sclera remodeling,suggesting that TGF-β1 signaling plays a role in the development and progression of myopia.