Tong Weidong, Jia Houjun, Zhang Lin, Li Chunxue, Ridolfi Timothy J, Liu Baohua
Department of General Surgery, Daping Hospital, Third Military Medical University, Chongqing, China.
Scand J Gastroenterol. 2010 Aug;45(7-8):844-51. doi: 10.3109/00365521003782371.
Interstitial cells of Cajal (ICC) have been endowed with considerable intrinsic plasticity. Blockade of the c-kit signaling pathway results in the shift of ICC towards a smooth muscle-like phenotype. Little is known about stem cell factor (SCF), the ligand of c-kit, and the role it plays in the process of restoration. The aim of this study was to determine whether exogenous SCF can promote ICC replenishment following the blockade of c-kit signaling.
Neutralizing anti-c-kit monoclonal antibody (ACK2) was administered to mice for 8 days after birth. Jejunal muscle strips were cultured up to 7 days. Electrical rhythmic changes were monitored and ICC were examined by immunohistochemistry. Expression of c-kit mRNA was detected by reverse transcriptase-polymerase chain reaction, and expression of Kit protein was detected by Western blot.
When c-kit receptors were blocked, ICC nearly disappeared from the jejunum accompanied by the loss of electrical slow waves. By day 7, after in vitro culture with SCF (100 ng/ml), the amplitude of muscle strip slow waves was restored to 0.19 +/- 0.07 mV (p < 0.05), whereas the frequency recovered to 13.7 +/- 3.32/min (p < 0.01). Furthermore, labeling for c-kit(+) cells in the myenteric plexus increased and c-kit mRNA and protein expression were up-regulated compared to that of non-treatment with SCF.
The c-kit signaling pathway, activated by SCF, is the critical pathway associated with the control of ICC survival and proliferation. The restoration of ICC number and jejunal electrical rhythm, resulting from blockade of the c-kit signaling pathway, could be facilitated by local SCF administration.
Cajal间质细胞（ICC）具有相当大的内在可塑性。c-kit信号通路的阻断会导致ICC向平滑肌样表型转变。关于干细胞因子（SCF），即c-kit的配体，及其在恢复过程中所起的作用，人们了解甚少。本研究的目的是确定外源性SCF是否能在c-kit信号通路阻断后促进ICC的补充。
出生后8天给小鼠注射中和性抗c-kit单克隆抗体（ACK2）。空肠肌条培养7天。监测电节律变化，并通过免疫组织化学检查ICC。通过逆转录聚合酶链反应检测c-kit mRNA的表达，通过蛋白质印迹法检测Kit蛋白的表达。
当c-kit受体被阻断时，ICC几乎从空肠消失，同时电慢波丧失。在与SCF（100 ng/ml）进行体外培养7天后，肌条慢波的振幅恢复到0.19±0.07 mV（p<0.05），而频率恢复到13.7±3.32次/分钟（p<0.01）。此外，与未用SCF处理相比，肌间神经丛中c-kit(+)细胞的标记增加，c-kit mRNA和蛋白表达上调。
由SCF激活的c-kit信号通路是与ICC存活和增殖控制相关的关键通路。局部给予SCF可促进因c-kit信号通路阻断而导致的ICC数量和空肠电节律的恢复。
