Establishment Of Rat Tibial Model Of Acute Osteomyelitis

Background:The number of patients with osteomyelitis after trauma has increased year by year.Animal models of osteomyelitis have provided great convenience for the study of post-traumatic osteomyelitis.Objective To explore optimal inoculation dose of staphylococcus aureus to induce acute osteomyelitis of rat tibia.Methods A total of 36 male SD rats were used,holes were drilled through the cortex on the right proximal tibias.0.1ml saline containing different doses of S.aureus(1×10~2~1×10~6CFU)were inoculated into the tibias of experimental groups(G2-G6),0.1ml saline was injected into the tibias of control group.Radiographic assessment was taken one week after inoculation.The rats were killed after radiographic assessment,and the gross and histological assessments were performed.Results One rat was died in G6 group,and no rat died in other groups.There were no significant differences between the mean weight loss of the control group and those of G2,G3(P>0.05),while the mean weight loss of control was significantly less than those of G4、G5、G6 groups(P<0.05).The mean gross bone pathological scores of control、G2、G3 groups were significantly less than those of G4、G5、G6 groups.There were no significant differences for gross bone pathological scores of G4 and those of G5 and G6.The total radiological score showed a clear dose-response curve,furthermore significant differences were found between any two groups for the total radiological scores.The mean histological scores of control、G2、G3 groups were significantly less than those of G4、G5、G6 groups(P<0.05),while there were no significant differences for the mean histological scores of G4 and those of G5 and G6(P>0.05).Conclusion The optimal inoculation dose of staphylococcus aureus was 1ⅹ10~4~1×10~5CFU to induce significant acute osteomyelitis of rat tibia with lower dead rate.