Expression Of MMP-2,TIMP-2 And MMP-3 In The Scleral Fibroblasts And The Scleral Fibroblasts Biomechanical Properties Study In Experimental Myopia

Objective: To determine the expression of MMP-2,TIMP-2 and MMP-3 and to study the biomechanical properties changes in cultured guinea pig posterior scleral fibroblasts in lens-induced myopia. Some conclusions were valuable for revealing the pathological mechanism of myopia.Methods: 10 two-week-old guinea pigs were lens-induced monocularly, a spherical lenses of -10.00D were wear to unilateral eyes, another eye in each animal was untreated as self-control (SC). 5 two-week-old guinea pigs were randomly chosen as normal-control (NC). Before and after experiment, refraction was measured using retinoscopy and the ocular axial were determined by A-scan ultrasonography. The scleral fibroblasts of each group were cultured and passaged 1 generations in vitro, The cultured cells was determined to be fibroblasts using immunocytolchemistory methods. Immunocytolchemistry was used to detect the expression of MMP-2,TIMP-2 and MMP-3 in the scleral fibroblasts and to study by light microscope. And to study utilized the micropipette aspiration technique coupled with a viscoelastic solid model to investigate the viscoelastic properties of scleral fibroblasts from normal and myopia guinea pigs. These data was statistically analysed by SPSS 11.5 system.Results:1 Eyes became myopic(-9.08±0.67)D and elongated (1.91±0.22)mm 45 days after insertion of the lenses(p<0.05).2 Cultured cells began to grow out of the sclera after 1 weeks, and grew to confluent after 2 weeks. The cultured cells was determined to be fibroblasts using immunocytolchemistory methods.3 The immunocytolchemistory showed that expression of MMP-2,TIMP-2,MMP-3 were all detected in scleral fibroblasts. The expression of MMP-2 located in cytoplasm and TIMP-2 in cytoplasm too,MMP-3 in cytoplasm and nuclear membrane. The expressions of MMP-2 and MMP-3 in model eyes were lower than control eyes. There were significant diference of the expression of MMP-2 and MMP-3 between model eyes and control eyes(P<0.05). The expression of TIMP-2 in model eyes was higher than control eyes. There was significant diference of the expression of TIMP-2 between model eyes and control eyes(P<0.05).4 Biomechanical research for scleral fibroblasts: Experimental studies have shown that the viscoelastic properties of the scleral fibroblasts in LIM group exhibited a significantly higher equilibrium modulus, instantaneous modulus and apparent viscosity (E=0.43555±0.13043kPa, E0=0.76691±0.21674kPa,μ= 4.17255±1.59239kPa·s,n=58)compared with NC group(E=0.30055±0.07713kPa, E0=0.52553±0.14053kPa,μ=1.94124±1.03281kPa·s, n=52, p<0.05)and SC group(E= 0.34792±0.09709kPa, E0= 0.59722±0.18118kPa,μ= 2.17855±1.22801kPa·s, n=49, (p<0.05).Conclusions: lenses can induce axial growth and lead to myopia in young guinea pigs. Expression of MMP-2,TIMP-2,MMP-3 were all detected in guinea pigs scleral fibroblasts. We can conclude the MMP-2,TIMP-2,MMP-3 play an important role in the course of development of myopia. In response to a step pressure, scleral fibroblasts exhibited viscoelastic solid creep behavior. There were significantly alteration in Young's moduli and viscoelastic properties of scleral fibroblasts with LIM. These findings suggest that mechanical environment of the scleral fibroblasts may be altered in experimental myopia...