转化生长因子β对异种骨移植局部免疫因子表达的调节

背景:异种骨移植免疫排斥反应是影响预后的主要问题。然而,对异种骨移植中免疫因子表达和调节的认识尚少。白细胞介素1,白细胞介素6和肿瘤坏死因子α是重要的免疫因子,与移植后排斥反应密切相关。目的:观察异种骨移植局部白细胞介素1、白细胞介素6和肿瘤坏死因子αmRNA和蛋白质的表达,并探索转化生长因子β对这些免疫因子的调节作用。设计:随机对照实验。单位:解放军第四军医大学西京医院骨科研究所。对象:雄性Balb/c小鼠72只,体质量20～25g,随机分为3组,复合松质骨载体组,单纯松质骨载体组和空白对照组,每组24只。方法:实验于2003-06/2004-06在解放军第四军医大学西京医院骨科研究所完成。复合松质骨载体组小鼠左侧股部肌间隙植入复合转化生长因子β的松质骨载体;单纯松质骨载体组植入单纯松质骨载体;空白对照组仅行手术,不植入材料。术后4,7,14和21d观察各组小鼠植骨或手术区周围组织中增殖细胞记数;应用原位杂交和免疫组化技术检测植骨局部多种免疫因子的表达。主要观察指标:各组小鼠移植骨局部组织学观察及细胞密度测定;移植骨局部白细胞介素1α,白细胞介素6和肿瘤坏死因子αmRNA和蛋白质的表达。结果:①各组小鼠移植骨局部组织学观察及细胞密度测定:7d时,复合松质骨骨粒组较单纯牛松质骨骨粒组增殖组织中细胞密度明显高(470.63±132.89),(311.46±93.69)个/视野,P<0.01];但14,21d时两组间则无明显差异。②各组小鼠移植骨局部白细胞介素1α,白细胞介素6和肿瘤坏死因子αmRNA和蛋白质的表达:异种骨移植后的7,14d,复合了转化生长因子β的异种骨移植局部白细胞介素1α和白细胞介素6蛋白质表达分别较单纯异种骨低(7d白细胞介素1α:42.55±9.65比67.95±17.82,白细胞介素6:48.26±11.17比77.21±15.16;14d白细胞介素1αmRNA:84.77±7.42比112.94±7.02,白细胞介素6:78.10±17.22比121.18±15.44,P<0.01),但对肿瘤坏死因子α而言,则无明显差异(P>0.05)。结论:在异种骨移植局部,多种细胞可以表达白细胞介素1α,白细胞介素6和肿瘤坏死因子αmRNA和蛋白质,且这种表达受到转化生长因子β的调节。提示了转化生长因子β调节异种骨移植免疫的一种方式。

Transforming growth factor beta as a regulator of the regional expression of the immune cytokines in xenogeneic bone transplantation

BACKGROUND: For xenogeneic bone transplantation, immune rejection is the major problem that affects the prognosis. However, the understanding about the expression and regulation of the immune factors in heterogenic bone transplantation is limited. Interleukin-1 (IL-1), interleukin-6 (IL-6)and tumor necrosis factor alpha (TNF-α) are important immune factors, and are closely related with post-transplantation rejection.OBJECTIVE: To observe the regional expressions of mRNA and protein of IL-1α, IL-6 and TNF-α in xenogeneic bone transplantation, and to in vestigate the effect of transforming growth factor (TGF)-β on these immune factors.DESIGN: A randomized controlled experiment. SETTING: The Orthopaedic Institute of Xijing Hospital of the Fourth Military Medical University of Chinese PLA MATERIALS: Totally 72 male Balb/c mice, with a body mass of 20 to 25 g, were randomly divided into 3 groups: combined bovine cancellous bone (bCB) granule group (Group A), simple bCB granule group (Group B) and blank control group (Group C) with 24 mice in each group.INTERVENTIONS: This experiment was conducted at the Institute of Orthopaedics, Xijing Hospital, Fourth Military Medical Univessity of Chinese PLA from June 2003 to June 2004. In Group A, one bCB combined TGF-β was implanted into the muscles of left thigh of each mouse. In Group B, one bCB alone was implanted, and in Group C, no bCB was implanted. The number of proliferation of cells in bone implantation area or adjacent tissues of the operated area was observed at postoperative 4, 7, 14 and 21 days; and the regional expressions of several immune factors in im plants were detected with in situ hybridization and immunocytochemistry methods.MAIN OUTCOME MEASURES: Histological observation and detection of regional cellular density of the implants of the mice in each group; the regional expressions of mRNA and protein of IL-1α,IL-6 and TNF-α in the implants RESULTS: ①) Histological observation and detection of regional cellular density of the implants of the mice in each group: on day 7, the cellular density of the proliferated tissues was significantly higher in the Group A than in the Group B (470.63±132.89), (311.46±93.69)/field,P ＜ 0.01];But on days 14 and 21, there was no significant difference. ②The regional expressions of mRNA and protein of IL-lα, IL-6 and TNF-α of the im plants of the mice in each group. On days 7 and 14 after xenografts were implanted, the regional expressions of IL-1α, IL-6 was respectively lower the xenografts combined with TGF-βthan in the simple xenogeneic bone (day 7: IL-1α 42.55±9.65 vs 67.95±17.82,IL-6 48.26±11.17 vs 77.21±15,16;day 14: IL-1α mRNA 84.77 ±7.42 vs 112.94±7.02,78.1 ±17.22 vs 121.18±15.44,P ＜ 0.01) ,but for the TNF-α, there was no significant difference (P ＞ 0.05).CONCLUSION: In the region of bone xenograft, a variety of cells express mRNAs and proteins of IL-1α, IL-6 and TNF-α, and their expressions are regulated by TGF-β. It may imply a kind of regulation of the immunity of bone xenograft by TGF-β.