转人CD46基因抑制人补体在转基因小鼠心脏组织中的沉积

Human CD46 transgene inhibits deposition of human complements in transgenic murine heart xenograft

目的观察转人源性膜辅助蛋白（CD46）基因对转基因小鼠心脏中人补体沉积的抑制作用。方法以近交系昆明小鼠为对象，采用显微注射法制备转人CD46基因小鼠，用逆转录聚合酶链法（RT_PCR法）检测外源基因的整合情况。以F0代转基因小鼠11只为实验组，同窝非转基因小鼠10只为对照，快速切取小鼠心脏，用改良的Langendorff法经小鼠主动脉逆行灌注预先制备的含补体的B型血人血浆。观察并记录小鼠心脏搏动时间；采用免疫荧光和免疫组织化学法检测小鼠心脏组织中补体C3。及C9的沉积情况。结果Fn代转基因小鼠外源基因的整合率为33．3％。实验组小鼠心脏搏动时间为（42．6±20．6）min（15±77min），长于对照组的（20．2±12．5）min（7±40min），差异有统计学意义（P〈0．01）。实验组小鼠心脏组织中补体G3c及C9的沉积均少于对照组。结论通过显微注射法制备的转人CD46基因小鼠，其外源基因可稳定表达；转人CD46基因可以抑制人补体C3c及C9在转基因小鼠心脏组织中的沉积。

Objective To investigate the inhibition of human complements deposition by human CD46 expression on transgenic mouse hearts. Methods The whole length cDNA encoding human CD46 was amplified by PCR using human cDNA library. The human CD46 gene was introduced into fertilized mice eggs by microinjection to produce transgenic mice expressing human CD46. Isolated hearts from two groups of mice （wild type and hCD46-expressing） were perfused ex vivo with 10% pooled human plasma by modified Langendorff profusion system. Heart function was evaluated by mean heart beating time. Deposition of complements C3c and C9 in the perfused murine hearts was examined by immunofluorescence and immunohistochemistry respectively. Results Mean heart beating time was prolonged to 42. 6 ± 20. 6 min in the hCD46 expression group （P〈0. 01） in contrast to 20. 2 ± 12. 5 min in the wild type group. The expression of hCD46 in transgenic mice was detected by RT- PCR analysis. In immunohistological examination, hCD46-expressing hearts exhibited a reduction in deposition of complements C9 and C3c compared with nontransgenio mouse hearts. Conclusion Human CD46 transgenic mice have been obtained by microinjection. Expression of human CD46 gene in xenografts could inhibit deposition of human complements C3c and C9.