miRNA-378a过表达巨噬细胞株复合胶原蛋白海绵:抗炎及促进组织修复

miRNA-378a overexpression of macrophage cell line composite collagen sponge:anti-inflammation and tissue repair promotion

背景:巨噬细胞M1/M2极化方向的调节在组织工程应用中尤为关键,及时调控可最大程度地减少促炎、促进抗炎或组织愈合反应。目的:将慢病毒介导的miRNA-378a过表达巨噬细胞株复合胶原蛋白海绵回植入动物模型,据此检测免疫调节在体内环境中的相关表达水平等组织修复相关的指标,进一步阐明在体内环境中miRNA-378a是否促进巨噬细胞M2极化及其对免疫调节和组织修复的作用。方法:将慢病毒介导的miRNA-378a过表达巨噬细胞株、阴性对照病毒巨噬细胞株扩增、筛选,复苏培养巨噬细胞株后与胶原蛋白海绵共培养以此构成复合体,具体分组如下:①阳性组:过表达miRNA-378a巨噬细胞-胶原蛋白海绵复合体;②阴性组:阴性对照病毒介导的miRNA-378a巨噬细胞-胶原蛋白海绵复合体;③对照组:巨噬细胞-胶原蛋白海绵;④空白对照组:胶原蛋白海绵。通过免疫荧光及扫描电镜观察各组细胞密度、表型、黏附情况,后回植入小鼠背部皮下模型,分别于造模后4,7 d处死小鼠,通过大体观察、苏木精-伊红染色、Masson染色、免疫组化分析慢病毒介导的miRNA-378a过表达巨噬细胞胶原蛋白海绵复合体中巨噬细胞极化的方向及其对机体免疫调控、组织修复的作用。结果与结论:①免疫荧光镜下观察各组巨噬细胞株确实与胶原蛋白海绵形成复合体;②扫描电镜下慢病毒介导的miRNA-378a巨噬细胞(阳性组)较其他分组细胞密度增加,细胞出现球形、椭圆形及多边形分化,具有更多的伪足;③大体观察下总体7 d愈合好于4 d,慢病毒介导的miRNA-378a过表达巨噬细胞(阳性组)无论4,7 d愈合均好于其他分组;④苏木精-伊红染色、Masson染色下,慢病毒介导的miRNA-378a过表达巨噬细胞(阳性组)具有较多量的纤维细胞、毛细血管、成纤维细胞以及胶原纤维增生;⑤免疫组化显示,慢病毒介导的miRNA-378a过表达巨噬细胞(阳性组)无论4,7 d M2极化细胞阳性率均大于其他分组;对照组及阴性组巨噬细胞无论4,7 d M2极化细胞阳性率均大于空白对照组,而对照组及阴性组之间无统计学差异;阳性组、阴性组、对照组无论4,7 d染色细胞数量均大于空白对照组,且阳性组>阴性组≈对照组>空白对照组;⑥提示在体内环境中miRNA-378a过表达巨噬细胞具有较多量的纤维细胞、毛细血管、成纤维细胞以及胶原纤维增生,对组织修复起到了正向作用,并且能促进巨噬细胞向M2型极化并抑制M1型极化,从而有助于减少机体炎症反应。

BACKGROUND:The regulation of M1/M2 polarization direction of macrophages is particularly critical in tissue engineering applications,and timely regulation can minimize proinflammatory,anti-inflammatory,or tissue healing responses.OBJECTIVE:To implant lentivirus-mediated miRNA-378a macrophage strain complex collagen to detect the expression level of immune regulation in the in vivo environment,and further clarify the influence of miRNA-378a in promoting macrophage M2 polarization in immune regulation and tissue repair in the in vivo environment.METHODS:Lentivirus-mediated miRNA-378a overexpressing macrophage cell lines and negative control virus macrophage lines were amplified and screened,and the macrophage lines were recovered and cultured together with collagen sponge to form a composite scaffold,which was divided into the following groups:(1)Positive group:miRNA-378a overexpressing macrophage-collagen sponge composite;(2)negative group:negative control of virus-mediated miRNA-378a macrophage-collagen sponge composite;(3)control group:macrophage-collagen sponge;(4)blank control group:collagen sponge.The cell density,phenotype,and adhesion of each group were observed by immunofluorescence and scanning electron microscopy.The cells were implanted into the subcutaneous model of the back of mice,and the mice were sacrificed 4 and 7 days after modeling.The direction of macrophage polarization in the collagen sponge composite of macrophages with miRNA-378a overexpression mediated by lentivirus and its effect on immune regulation and tissue repair were analyzed by gross observation,hematoxylin-eosin staining,MASSON staining,and immunohistochemistry.RESULTS AND CONCLUSION:(1)Under immunofluorescence microscopy,the macrophage cell lines in each group were observed to form a composite scaffold with the collagen sponge.(2)Under scanning electron microscope,lentivirus-mediated miRNA-378a macrophages in the positive group proliferated in cell density,had spherical,elliptic and polygonal differentiation,and had more pseudofeet than other groups.(3)Under general observation,the overall 7-day healing was better than that at 4 days.Lentivirus-mediated miRNA-378a macrophages in the positive group healed better than other groups regardless of 4 and 7 days.(4)Lentivirus-mediated miRNA-378a macrophages in the positive group under hematoxylin-eosin staining and MASSON staining had more amounts of fibrocytes,capillaries,fibroblasts,and collagen fiber hyperplasia.(5)Immunohistochemistry showed that lentivirus-mediated miRNA-378a macrophages in the positive group were more positive in 4-and 7-day M2 polarized cells than in other groups.The macrophages of the control and negative groups in 4-and 7-day M2 polarized cells were greater than that of the blank control group.There was no statistical difference between the control group and the negative group.The number of stained cells in the positive,negative,and control groups regardless of 4 and 7 days was higher than that in the blank control group,and the positive group>negative group≈control group>blank control group.(6)It is concluded that macrophages with miRNA-378a overexpression have a large amount of fibroblasts,capillaries,fibroblasts,and collagen fiber hyperplasia in vivo,which has a positive effect on tissue repair,and can promote the polarization of macrophages towards M2 type and inhibit the polarization of M1 type,thus contributing to reducing the inflammatory response of the body.