自发性高血压大鼠胸腺中胰岛素-I基因的表达降低

Low Expression of InsulinI Gene in Thymus of SHR

目的为了研究自发性高血压大鼠（ＳＨＲ）胸腺功能异常的分子机制，我们用ｃＤＮＡ代表性差异分析ｃＤＮＡｒｅｐｒｅｓｅｎ－ｔａｔｉｏｎａｌｄｉｆｅｒｅｎｃｅａｎａｌｙｓｉｓ（ＲＤＡ）技术比较了ＳＨＲ与其正常血压对照（ＷＫＹ）大鼠二者胸腺基因表达的差异。方法用ｃＤＮＡ代表性差异分析技术比较了ＳＨＲ和ＷＫＹ大鼠胸腺基因表达的差异。差异表达的ｃＤＮＡ接入Ｔ—载体进一步进行差异筛选。挑选阳性克隆进行测序并用ＢＬＡＳＴ软件进行同源性分析。最后用Ｎｏｒｔｈｅｒｎ杂交分析验证差异筛选的结果。结果挑选了４个差异筛选的阳性克隆进行测序，序列同源性分析表明它们均与胰岛素－Ｉ基因序列高度一致。Ｎｏｒｔｈｅｒｎ杂交结果证实了胰岛素－Ｉ基因在ＳＨＲ胸腺中表达降低。结论运用ｃＤＮＡ代表性差异分析技术，结合差异筛选方法，本文观察到ＳＨＲ胸腺中胰岛素－Ｉ基因表达降低，提示局部微环境中的胰岛素缺乏在ＳＨＲ胸腺细胞的发育异常中可能起一定的作用。

Objective \ To investigated molecular events associated with the dysfunction of thymus in spontaneously hypertensive rats (SHRs), we analyzed the difference in gene expression of thymus between SHRs and WistarKyoto (WKY) rats. \ Methods \ cDNA representational difference analysis (cDNARDA) was applied to compare the gene expression of thymus between SHR and WKY. The difference products of cDNARDA were cloned into Tvector for differential screening. The positive clones were sequenced , and the sequences were analyzed by the BLAST program for homology search. Northern blot analysis was used to confirm the results of differential screening.\ Results \ Four positive clones of differential screening were picked out for sequencing. Homology analysis indicated that all of the four clone sequences were the same as that of insulinI gene. By Northern blot analysis, insulinI gene was confirmed to be downregulated in SHR thymus. \ Conclusion \ By using cDNARDA combined with differential screening,it was found insulinI gene is downregulated in SHR thymus, which may be responsible for the abnormal development of thymocytes in SHR.