Purpose: This study was conducted to evaluate scleral remolding-related gene expression after scleral collagen cross-linking (SCXL) using ultraviolet A (UVA) and riboflavin in lens-induced myopia (LIM) guinea pigs.
Methods: A total of 100 4-week-old pigmented guinea pigs were randomly divided into five groups (n = 20): SCXL + LIM, LIM, SCXL, Sham, and Control. Refraction, anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL) were measured using streak retinoscope and A-scan ultrasonography. SCXL was performed using 0.1% riboflavin solution and 365 nm UVA irradiation. Lens-induced myopia was achieved by wearing -10 D concave lenses. Quantitative real-time PCR (qPCR) and western blot were used to measure mRNA and protein levels, respectively.
Results: Myopia was successfully induced in the LIM group, while myopic refraction was higher and ACD and AL were shorter in SCXL + LIM compared with LIM, suppressing myopia progression. The scleral COL1A1 mRNA levels were significantly decreased and MMP2 and ACTA2 mRNA levels were significantly increased in LIM compared with other groups, while COL1A1 mRNA levels were increased and MMP2 and ACTA2 mRNA levels were decreased in SCXL + LIM compared with LIM. The scleral COL1A1 protein levels were significantly increased at 1 week and 4 weeks and MMP2 protein levels were significantly decreased at 1 week in SCXL compared with SCXL + LIM, LIM and Control. MMP2 protein levels were significantly decreased in SCXL + LIM and SCXL compared with LIM at 4 weeks. The differences in TGFB1, BMP2, CCN2, ITGA2, and ITGB1 mRNA levels and ACTA2 protein levels between the five groups were not significantly different.
Conclusion: SCXL using UVA and riboflavin could influence the expression of scleral remolding-related genes, including COL1A1, MMP2, TIMP2, and ACTA2, and thus contribute to improving collagen synthesis and reducing collagen degradation and might have an effect on slowing myopia progression.
Keywords: Cross-linking; Guinea pig; gene expression; myopia; scleral remodeling; ultraviolet A.