慢性骨髓炎感染屏障的机理研究

Mechanism of Infection Barrier in Chronic Osteomyelitis

目的观察慢性骨髓炎模型兔感染段骨质微血管密度(microvessel density,MVD)及万古霉素骨水泥干预下的变化和对残留细菌量的影响。方法将30只新西兰白兔随机分为假手术组、慢性骨髓炎模型组及万古霉素骨水泥组,每组10只,除假手术组外,其余组以开窗注入金黄色葡萄球菌法制成慢性骨髓炎模型,4周后观察各组HE染色后光镜下微血管变化,光镜及免疫组化法观察骨髓MVD,并计算残留细菌量。结果组织学结果显示万古霉素骨水泥组较慢性骨髓炎模型组微血管炎性病变程度轻,内膜较光滑,但与假手术组比较,内皮细胞排列不整齐,细胞核形态不规则。与假手术组比较,慢性骨髓炎模型组MVD明显下降,比较差异有统计学意义(P<0.05);与慢性骨髓炎模型组比较,万古霉素骨水泥组在4周后MVD恢复上升,骨髓金黄色葡萄球菌残留菌量明显下降,比较差异均有统计学意义(P<0.05)。结论慢性骨髓炎病理过程中MVD下降可能是抗生素难于进入骨髓的机理之一,万古霉素骨水泥髓腔途径治疗能提升MVD,降低骨髓细菌量,增加抗菌效能。

Objective To observe the changes of bone microvessel density(MVD)and vancomycin bone cement intervention in the infected segment of rabbits with chronic osteomyelitis model and the effect on the amount of residual bacteria.Methods 30 New Zealand white rabbits were randomly divided into sham operation group,chronic osteomyelitis model group and vancomycin bone cement group,10 rabbits in each group,except for the sham operation group,the remaining groups were injected with Staphylococcus aureus to make chronic osteomyelitis models.After 4 weeks,the microvascular changes in each group were observed under light microscope after HE staining.The bone marrow MVD was observed by light microscope and immunohistochemistry,and the amount of residual bacteria was calculated.Results Histological studies had shown that the degree of inflammatory lesion in vancomycin bone cement group was lighter and the intima was smoother than that in chronic osteomyelitis model group,but compared with sham operation group,the endothelial cells arranged not neat,the nuclear shape was irregular.Compared with the sham operation group,the MVD of the chronic osteomyelitis model group was significantly decreased,the difference was statistically significant(P<0.05).Compared with the chronic osteomyelitis model group,the MVD of the vancomycin bone cement group recovered and increased after 4 weeks,the amount of residual Staphylococcus aureus in bone marrow decreased significantly,the differences were statistically significant(P<0.05).Conclusion The decrease of MVD in the pathological process of chronic osteomyelitis may be one of the mechanisms that antibiotics are difficult to enter the bone marrow.Vancomycin bone cement marrow cavity treatment can increase MVD,reduce the amount of bacteria in the bone,and increase antibacterial efficacy.