ABSTRACT
BACKGROUND:Insulin analogues have been extensively applied in the treatment of diabetes mellitus.Insulin glargine has a higher affinity for insulin like growth factor 1 receptor compared with human insulin.Further research is needed to ensure whether insulin and its analogues exert same effects on fracture healing in type 2 diabetes mellitus.OBJECTIVE:To observe the osteocalcin expression and callus formation in the healing of fracture in type 2 diabetic rats induced by human insulin and insulin glargine,to observe the difference between two treatment methods,and to explore the related mechanisms.METHODS:Sixty-four Sprague-Dawley rats were randomly assigned into human insulin group (group A),insulin glargine group (group B),diabetes mellitus group (group C) and control group (group D).Rats in the groups A,B and C were fed with high-sugar and high-fat diet for 4 weeks followed by intraperitoneal injection of small-dosage streptozotocin twice,to establish the rat models of type 2 diabetes mellitus.After the right tibia of each rat was broken,insulin glargine and Novolin 30R were used in the groups A and B,respectively.Fracture healing was observed on X-ray,callus formation and number of osteoblasts were observed by microscope,and serum level of osteocalcin was measured by ELISA method at 1,2,4,and 6 weeks after modeling.RESULTS AND CONCLUSION:X-ray results revealed better fracture healing in the groups A,B and D than the group C.Osteoblast proliferation in callus was significantly better in the groups A,B and D than in the group C.Serum level of osteocalcin in each group was on the rise,which was significantly higher in the groups A,B and D than the group C (P ＜ 0.05),but had no significant difference among groups A,B and D (P ＞ 0.05).In summary,insulin glargine can increase the serum level of osteocalcin,accelerate the callus formation,and improve the healing of fracture in type 2 diabetic rats.Furthermore,there is no significant difference in the therapeutic efficacy between insulin glargine and human insulin.