Electroacupuncture at ST36 increases contraction of the gastric antrum and improves the SCF/c-kit pathway in diabetic rats

Electroacupuncture (EA) at ST36 is effective for improving gastric motility. However, the underlying mechanism remains poorly understood. The aim of this study was to investigate the effects of EA on gastric contraction and to determine whether interstitial cells of Cajal (ICCs) are involved. Rats were randomized into control, diabetic (DM), diabetic with sham EA (DM + SEA), diabetic with low frequency EA (DM + LEA) and diabetic with high frequency EA (DM + HEA) groups. EA was performed everyday for four and eight weeks. Contractions in antrum strips were explored using the organ bath technique. Western blotting was employed to determine c-kit and transmembrane stem cell factor (M-SCF) expression in the gastric antrum, and levels of soluble stem cell factor (S-SCF) in serum were determined by enzyme-linked immunosorbent assay (ELISA). The distribution of ICCs was further assessed by immunohistochemistry. The results were as follows: (1) Contractions in the DM group were attenuated at four and eight weeks, but LEA and HEA restored the attenuated contraction. (2) ICCs were significantly decreased at eight weeks without alteration at four weeks in DM group, but were rescued in the LEA and HEA groups. (3) Whereas M-SCF and S-SCF in the DM group were slightly decreased at four weeks and were dramatically reduced at eight weeks, LEA and HEA markedly enhanced SCF at eight weeks. Collectively, the data suggest that in diabetic rats, LEA and HEA at ST36 could facilitate contraction of the gastric antrum, possibly by involving the SCF/c-kit pathway.

Electroacupuncture regulates apoptosis/proliferation of intramuscular interstitial cells of cajal and restores colonic motility in diabetic constipation rats

Injury of interstitial cells of Cajal (ICC) is associated with gut dysmotility in diabetic rats. We have shown an acceleration of the colonic contractility by electroacupuncture stimulation (EAS). However, little is known about potential roles of EAS on colonic transit and ICC. In this study, we evaluate the effect of EAS on colonic transit and investigate whether apoptosis/proliferation of ICC was involved in regulative effect of EAS on colonic transit. Rats were randomly assigned to normal, diabetic, diabetic-plus-sham stimulation, diabetic-plus-low-frequency stimulation, and diabetic-plus-high-frequency stimulation groups. Bead expulsion test was used for measuring the distal colonic transit. The Kit (ICC marker) was detected by western blot. Apoptotic ICC was detected by terminal dUTP nucleotide end labeling. Proliferating ICC was identified by Kit/Ki67 double immunofluorescent staining on whole mount preparations. Ultrastructure changes of ICC were studied using electron microscopy. Results showed that high-frequency stimulation significantly promoted colonic transit. Low- and high-frequency stimulation markedly rescued intramuscular ICC from apoptosis. Abundant proliferating intramuscular ICC was found in low- and high-frequency stimulation groups. Our results indicate that high-frequency EAS has stimulatory effect on the distal colonic transit, which may be mediated by downregulation of the apoptosis and upregulation of the proliferation of intramuscular ICC.