Effects Of GM1 On Healing Process Of Tibial Fracture In Rats

Objective: To study the effect of exogenous ganglioside GM1 on the healing process of tibia fractures in rats,and to provide experimental reference for early clinical treatment of patients with nonunion or delayed fracture healing.Methods:Forty-eight male SD rats were randomly divided into two groups: A(GM1),B(Normalsaline,NS).Rats in each group were asked to establish a model of right middle tibia fractures according to the aseptic operation requirements and treated with intramedullary internal fixation(Kirschner wire,D=1mm).After the preparation of the fracture model,local injection of drugs was given once A day for 7 consecutive days.Group A(ganglioside gm1 0.3ml).Group B(0.3ml normal saline).In each group,5 rats were randomly selected for femoral artery blood collection at 1 week,3 weeks and 5 weeks after the operation,and then sacrificed to observe fracture healing by X-ray observation.Fracture specimens were cut and fixed in 4% paraform aldehyde for 48 h,and then decalcified with 20%EDTA.Paraffin-embedded,proximal and distal serially sectioned,each approximately 5mm thick.HE staining and immunohistochemical staining were performed respectively.The osteogenesis index of trabecular bone in callus,the mean trabecular width and the immunohistochemical expression of NGFR-Trk A in fracture were measured.The serum levels of VEGF and NGF in rats at 1,3 and 5 weeks were determined by BLASA method.Results: 1、1 week,3 weeks and 5 weeks after the operation,the gross specimens showed that the size,hardness and callus maturity of the new hard tissue in group A were larger than that in group B;2、Postoperative X-ray showed: on the 7th day after the fracture,the fracture line at the fracture end was clear in group B,no obvious callus shadow was observed,but obvious thickening of periosteum or even A small amount of callus was observed in group A.on the 21 st day after the fracture,A small amount of sparse and uneven callus could be generated at the fracture end of group B,and at the fracture end of group A and beyond the bone The callus formed by membrane proliferation was significantly more than that of group B.on the 35 th day after the fracture,double-click on the fracture can show A further increase in blank,the fracture line in group A disappears,and callus generated from the outer bone membrane completely wraps the fracture end;In group A,the callus of the outer membrane of bone did not completely cover the fracture end,and the fracture line was dimly visible;3、Histological observation: at the first week after the operation,A large amount of fibrous callus and calcified tissue were formed in group A,with irregular trabecular arrangement,while callus in group B grew sparsely,forming A typical trabecular structure.A few fibrous callus are seen.At 3 weeks after the operation,A lot of hard callus and bone trabeculae grew in group A,forming an obvious flat bone structure.Group B consisted mostly of immature braided bones with increased trabeculae and no obvious flat bone structure.At 5 weeks after surgery,the outer callus of group a was basically repaired as plate bone,and some cartilage can be seen in the outer callus As shown in FIG.4 ~ 6,callus analysis: 1 week after surgery,3 weeks of callus mean trabecular width group A "was significantly higher than group B(P<0.05),and there was no statistically significant difference in callus mean trabecular width for 5 weeks after surgery;4、Serum VEGF and NGF content were determined by elisa: serum VEGF content in group A was higher than that in group B,and the difference was statistically significant(p < 0.05);1 week and 3 week after surgery,NGF content in group A was higher than that in group B.However,there was no significant difference in NGF content between group A and group B at week 5;5、Immunohistochemical assay of NGF receptor TRKA: the positive level of TRKA expression in group A was higher than that in group B and was statistically significant.Conclusions:1.Local injection of exogenous ganglioside drugs can promote tibial fracture healing in rats;2.Ganglioside drugs may promote fracture healing by increasing the expression and release of NGF and VEGF;3.Ganglioside can promote the osteogenic function of NGF by increasing the expression of NGF receptor TRKA.