酪氨酸激酶受体KIT在小鼠结肠黏膜上皮的表达及其功能

目的 探讨酪氨酸激酶受体KIT在小鼠结肠黏膜上皮的表达及作用。 方法 应用Western blotting和RT-PCR技术检测c-kit基因及KIT
蛋白在野生型C57BL/6小鼠结肠黏膜上皮的表达；用免疫荧光染色显示野生型C57BL/6小鼠以及乙基亚硝酸钠（ENU）诱变的c-kit基因点突变纯
合子小鼠（Wads ^m/m）结肠黏膜上皮KIT阳性细胞的部位；腹腔注射5-溴脱氧尿嘧啶核苷（BrdU）（30 mg/kg）观察对比野生型以及Wads m/m
小鼠结肠黏膜上皮BrdU掺入情况及动态变化，分析KIT在结肠黏膜上皮更新过程的作用。 结果 RT-PCR检测结果表明，在野生型小鼠结肠黏膜组
织表达 c-kit基因, Western blotting证明在肠黏膜组织存在KIT蛋白；免疫荧光染色显示，KIT阳性细胞位于结肠黏膜上皮，主要位于肠腺隐
窝基底部，但是Wads ^m/m小鼠KIT阳性细胞数以及KIT蛋白表达量较野生型小鼠明显减少；BrdU掺入实验发现，Wads ^m/m小鼠远端结肠黏膜上皮
BrdU摄入和更新速度较野生型小鼠明显减慢。结论 结肠黏膜上皮表达KIT蛋白与结肠黏膜上皮的更新密切相关。

Expression and function of tyrosine kinase receptor KIT in mouse colonic mucosa epithelium

Objective To investigate the expression and function of KIT in mouse colonic mucosa.Methods Western blotting and
RT-PCR techniques were used to detect the expression of c-kit gene and KIT in colonic mucosa in C57BL/6 mice (wild-type).
Immunofluorescence staining was used to examine the distribution of KIT-positive cells in colonic mucosa epithelium of C57BL/6
mice (wild-type) and N-ethyl-N-nitrosourea (ENU)-induced c-kit point mutant homozygous mice (Wads m/m).Intraperitoneal injection
of 5-bromo-2-deoxyuridin (BrdU, 30 mg/kg) was used to observe and compare the BrdU-positive cells in distal colonic mucosa epithelium
in wild-type and Wadsm/m mice, and to evaluate the effect of KIT on the renewal of colonic mucosa epithelium. Results The result of
RT-PCR indicated that c-kit gene was expressed in colonic mucosa.Western blotting showed that KIT was expressed in colonic mucosa.
Immunofluorescence staining showed that KIT-positive cells existed in the epithelium of colonic mucosa and were mainly located in
the lower part of crypts. BrdU incorporation indicated that the renewal of the epithelium of colonic mucosa in homozygous mice was
significantly slower than that in wild-type mice. Conclusion C-kit gene and KIT protein are wildely expressed in the colonic
mucosa epithelium and might be involved in the renewal of the colonic epithelium.