Background: Lack of interstitial cells of Cajal (ICC) and neuropathy were the most possible pathological mechanisms of diabetic gastroparesis. Gastric electrical stimulation (GES) is a promising way to treat gastroparesis. The aims of the present study were to explore the impact of GES on ICC together with enteric neurons in diabetic rats and the possible mechanisms involved.
Methods: Sixty rats were randomized into the normal rats, diabetic rats (DM), diabetic rats with sham GES (DM+SGES), and three diabetic rats with GES (DM+GES1, DM+GES2 and DM+GES3). The proliferation of ICC and expressions of 5-HT2B, nNOS, CHAT, PGP9.5 and GDNF were evaluated by immunofluorescence staining or Western blot. The expressions of 5-HT in blood and tissue were determined by ELISA.
Results: (1) The proliferation of ICC was hardly observed in the DM group together with the DM+SGES group but increased in the three DM+GES groups. (2) The expression of 5-HT2B was decreased in the DM group and enhanced in the DM+GES groups. Similarly, the expressions of 5-HT in the blood and distal stomach tissue were increased in the DM+GES groups. (3) Both nNOS labeled neurons and CHAT positive neurons were reduced in myenteric plexus of the DM group, while plenty of these neurons were observed the DM+GES groups. (4) The expression of GDNF protein in the diabetic rats was down-regulated, while GES increased the expression of GDNF.
Conclusion: GES improves the proliferation of ICC possibly related with 5-HT/5-HT2B signal pathway, and alters enteric nervous system 52 partly though the GDNF expression.