| Objective:Through the observation of rabbit scleral tissue in morphology and biomechanical properties of different month age and changes in collagen content, to explore the rabbit sclera collagen fibers, fibroblasts in postembryonic growth process on the biomechanical properties of the sclera effect.Methods:1. The 1, 2 and 3 month old New Zealand white rabbits were divide into three groups with the month age and each group had 6 rabbits. Kill the rabbits through ear margin venous embolism; pick the eyeballs of both eyes. The eyeballs were obtained for measuring the diameter and axial length by vernier caliper, and the thickness of scleral tissues by tissue tachymeter. The tissue of posterior scleral was cut into strips were measured the sclera elastic modulus on the Instron5544 testing machine. The scleral tissue of each groups were respectively made into HE dyeing slice and electron microscope slices in order to the microscope observation.The remainder of the scleral tissue was respectively measured the content of collagen after tissue homogenate.2. In the study, the changes between 1 and 2 months old ages are obvious. In order to further specify the changes of the growth sclera tissue during that time, 20 New Zealand white rabbits aged 1 month were randomly divided into 5 groups of 4broilers each, separately feed till 4, 5, 6, 7, 8 weeks. Pick the eyeballs of both eyes and conduct the same test and observation.Results: 1. In the 1-3 month period, the change of the sclera organizationalstructure and biomechanical properties.(1) The changes of eyeball shape, scleral thickness and biomechanical properties in the process of growth: The axial length of the 1, 2, 3 months rabbits’ eyes were 13.6±0.3, 15.7±0.4, 16.1±0.1mm, scleral thickness were 0.31±0.01,0.40±0.01, 0.47±0.02 mm, elastic modulus were 2.24±0.08, 2.39±0.11, 2.58±0.11 MPa, they were all increased with the age, and has statistics differentiation(P<0.05).(2) The HE stain: The number of the sclera fibroblasts is decreased with increasing age.(3) Electron microscope slices: During 1-3 months, the diameter of collagen fiber increase gradually, and the proportion of thick collagen fibers increased.(4) Collagen content determination: The content of hydroxyproline during 1, 2,3 age group were 2.11±0.07, 3.40±0.07, 3.79±0.07μg/mg, compared with the previous group were increased. The statistics are statistically significant(P<0.05).2. in the 1-2 month period, the change of the sclera organizational structure and biomechanical properties.(1) The changes of eyeball shape, scleral thickness and biomechanical properties in the process of growth: The axial length of the 4, 5, 6, 7, 8 weeks rabbits’ eyes were 1.47±0.03, 1.51±0.01, 1.52±0.01, 1.55±0.01, 1.58±0.01 mm,scleral thickness were 0.28±0.02, 0.31±0.01, 0.32±0.01, 0.34±0.01, 0.37±0.01 mm,elastic modulus were.29±0.07, 2.33±0.07, 2.34±0.07, 2.41±0.04, 2.51±0.03 MPa,they were all increased with the age(P<0.05).(2) The HE stain: The number of the sclera fibroblasts is decreased with increasing age.(3) Electron microscope slices: The diameter of the collagen fibers are increased with age, and the proportion of the thick fibers were increased in the total number of collagen fibers.(4) Collagen content determination: The content of hydroxyproline during 4, 5,6, 7, 8 weeks group were 2.64±0.05, 2.74±0.08, 2.84±0.06, 2.99±0.08,3.25±0.07μg/mg, compared with the previous group were increased. The statisticsare statistically significant(P<0.05).Conclusions: 1. the rabbit eyeball shape is related to the diameter and axial length of the eyeball, the thickness and elastic modulus of sclera.2. Along with age increased of rabbits, collagen fibrils diameter are increased and scleral Fibroblast density are decreased, while the elastic modulus and thickness of scleral tissue are all increased.3. The changes of scleral collagen content and the elastic modulus are corresponding; collagen changes will affect the biomechanical properties of the sclera. |
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