Preliminary investigation of animal model of tibial defection fracture made by drilling hole method / 中国骨伤

<p><b>OBJECTIVE</b>To compare the differences in damage degree, healing time and healing process between two animal models of defection fracture and provide the research data for the establishment of a new animal model.</p><p><b>METHODS</b>Sixty male SPF Spragur-Dawley rats were divided randomly into control group, sawing group and drilling hole group, with 20 rats in each group. Animals of drilling hole group were treated with hone drill and made an 1 mm hole on tibial plateau animals of sawing group were treated with saw and made an 3 mm defection on tibial plateau; nothing to do in animals of control group. The rats were respectively killed at 2nd, 4th weeks after operation, bone density, bone ash quantity, contents of bone Ca, P were detected.</p><p><b>RESULTS</b>At the 2nd week after operation, bone density, bone ash quantity, contents of bone Ca, P in drilling hole group and sawing group were significantly lower than that of the control group (P < 0.05 or P < 0.01). Two animal models of drilling hole group and sawing group were similar in X-ray films and pathology investigations. At the 4th week after operation, there were no significant defference in bone density and bone ash quantity among three groups (P > 0.05). Rats of sawing group showed more poroma and inflammatory infiltration in histological examination.</p><p><b>CONCLUSION</b>Drilling hole method and sawing method could be used to make animal model of defection fracture, two methods showed similar damage degree, healing time and healing process, hut drilling hole method have advantages of simple operation, easily control damage degree and less inflammatory infiltration and bone disunion.</p>

Biomechanical properties of fibroblasts after posterior scleral reinforcement treatment for rabbit experimental myopia / 医用生物力学

Objective To evaluate the biomechanical properties of fibroblasts for rabbit experimental myopia after Posterior Scleral Reinforcement (PSR) treatment, and discuss the mechanism of PSR in myopia treatment as viewed from biomechanics. Method 45 rabbits of three week old were randomly monocular treated by eyelid suture to prepare experimental myopia eye. After 60 days, the experimental myopia eyes were divided into two groups randomly. Group A was treated by PSR. Group B was treated by similar operation without placing reinforce strap. After three months and six month, the fibroblasts from each group were isolated and cultured in vitro respectively. The cultured cells were then determined to be fibroblasts by using immunocyte chemistry method. Micropipette aspiration technique was used to investigate the viscoelastic properties of the fibroblasts from each group with mechanical model of semi infinite somatic cells. ResultsThree months after operation, the viscoelastic properties of the scleral fibroblasts in Group A and Group B exhibit no significant difference (P>0.05) three months and six months as well (P>0.05) after operation with the equilibrium modulus, E∞, and apparent viscosity, μ of the scleral fibroblasts in Group A (E = (361.2± 121.1)Pa、μ=(2928.2±669.4)Pa·s) compared with that in Group B (E =(347.6± 82.1)Pa、μ=(2820.6± 593.5)Pa·s). Neither in Group A nor Group B, the E∞ and μ at different stages after operation have significant difference (P>0.05). The E∞ and μ in transition zone tissues at different stages after operation have no significant difference(P>0.05) either. Conclusions The enhancement of PSR is caused by transition zone tissues and the strip itself.