| Objective:To observe the influences of Yangxue Bushen Formula on the expression of MMP-2, TIMP-2, TGF-β and retinal p-Stat3 in experimental high myopia sclera tissue. To provide experimental support for this formula to treat high myopia sclera.Methods : Two-week-old guinea pigs were used to prepare models of form deprivation myopia by covering right eye with translucent goggles for 60 days. The successful models were randomly divided into control and dosing group, and measure the eyes diopter(D) and axial length(L) before and after molding. The dosing group received Yangxu Bushen Formula(crude drug 12.7 g / kg) i. g for 21 d, once a day; the control group without any intervention. Sclera and retina morphological changes were observed by HE staining; scleral tissue was examined by transmission electron microscopy ultrastructure. The immunohistochemistry, Western-blotting were used to detect the sclera MMP-2, TIMP-2, TGF-β and its retinal p-Stat3 expression.Results:The models of experimental eye deprivation myopia were successfully made after 60 d of monocular covering of guinea pigs with translucent goggles. Compared with previous eye presentation, diopter increased significantly: the diopter before deprived was 3.924 ± 3.392 D, the diopter after deprived was-2.583 ± 2.954 deprivation(P <0.05). Axial average length of the right eye before modeling(form deprivation eyes) was(7.557 ± 0.176) mm; after modeling, the average length was(8.278 ± 0.250) mm. The axial length was significantly increased(P<0.05). Compared with the control group, dosing group received i. g for 21 d, and the scleral tissue morphology improved significantly. TEM observation showed that the scleral collagen type of the control and dosing group were I collagen. The sclera collagen fibers of the control group models were sparse, and fiber diameter did not change significantly, and no typical apoptotic cells were detected. The scleral collagen fibers of the dosing group models presented relatively intensive distribution, and the gap between the fibers slightly increased. Compared with the control eye in the control group, the eye collagen diameter was smaller. The gap between the collagen fibers in the modeling eye in the control group were slightly enlarged than those in the control eye in the control group. The extracellular matrix remarkably increased, and the endoplasmic reticulum extended in the modeling eye compared with the control eye. There was weak expression of MMP-2 and TIMP-2 in sclera in both control and dosing groups. After covering, MMP-2 expression increased while TIMP-2 expression decreased. TGF-β expression was weak in both groups. TGF-β expression decreased after covering. p-Stat3 weak expression was only seen in retina of guinea pigs without covering. p-Stat3 expression increased after covering. It was validated that MMP-2, TIMP-2, TGF-β in sclera and retinal p-Stat3 protein were involved in the formation of experimental myopia.Conclusions:Preliminarily study the pathological mechanism of scleral tissue in the development of high myopia by establishing high myopia animal model. Covering can lead to the formation of deprivation myopia, axial extension, weak expression of MMP-2 and TIMP-2 in the sclera of guinea pigs, MMP-2 expression increasing; TIMP-2 expression decreasing, weak TGF-β expression were weak in the sclera of guinea pigs, TGF-β expression decreasing, weak p-Stat3 expression in retina in guinea pigs without covering, p-Stat3 expression increasing after covering. All these showed that MMP-2, TIMP-2, TGF-β in sclera and retinal Stat3 signaling pathway were involved in the formation and development of experimental myopia. Yangxu Bushen Formula could significantly improve the scleral morphology of form deprivation myopia guinea pigs, reduce MMP-2, TGF-β and other factors, and increase TIMP-2. However, there was no influence on the expression of retinal p-Stat3 protein. The results have suggested that Yangxu Bushen Formula can inhibit the apoptosis of scleral cells of myopia by reducing MMP-2, TGF-β and increasing TIMP-2. |
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