| Objective:The aims of this study were to investigate the effects of synchronized gastric electrical stimulation of dual pulses(SGES) on gastric motility in different periods diabetic rats and try to explore the possible mechanisms of the effects by observing the changes of enteric glial cell(EGC) in the stomach.Method:Forty-six SD rats were used in this study. The rats were divided into three groups randomly including the age-matched control group, diabetes group and diabetes with gastric electrical stimulation group. All rats were implanted with two pairs of gastric serosal electrodes. The diabetes group was consist of early diabetes group(1-2w) and terminal diabetes group (8-9w), the time in control group and gastric electrical stimulation group was corresponding with that in diabetes group. The gastric electrical stimulation group was then divided into two subgroups containing acute stimulation (ASGES, stimulate60min) and chronic stimulation (CSGES, stimulate one week continuously,60min/day). Gastric slow waves were recorded at baseline, the moment of established models successfully and the end immediately after electrical stimulation. Gastric emptying was assessed by using phenol red solution, the ultrastructure of EGC in gastric antrum was observed with transmission electron microscopy, and the glial marker-S100B expression was explored by immunohistochemistry and RT-PCR. Results:1). The frequency of gastric slow waves increased and gastric emptying accelerated in early diabetes group compared with that in age-matched control group(P<0.05), while the dysrhythmic slow waves in terminal diabetes can be observed, and gastric emptying was slower than terminal control group(P<0.05).2). The gastric emptying in terminal control group was slightly slower than that in early control group, but there was no significant statistical difference(P=0.073). The frequency and rhythm were normal in both groups.3). The S100B expression in terminal control group decreased compared to early control group(P<0.01).4). There was no significant difference in S100B expression between age-matched control and early diabetes group(P>0.05), and the ultrastructure of EGC was roughly normal in these two groups.5). The S100B expression in terminal diabetes group was lower than that in terminal control group(P<0.01), and the dilation of endoplasmic reticulum and swelling of mitochondria in cytoplast can be observed, the filaments decreased seriously. However, mild vacuolization of mitochondria occured and filaments decreased slightly in cytoplast of the terminal control group.6). ASGES and CSGES were able not only to accelerate gastric emptying in terminal diabetes group and early diabetes group but also to normalize gastric slow waves. The S100B expression, the number of mitochondria and filaments increased after SGES. The effect of chronic stimulation was superior to acute stimulation.Conclusion:Our date suggested that the delayed gastric emptying due to the growth of age may be related to the activity of EGC. SGES with appropriate parameters can restore normal gastric slow waves and improve delayed gastric emptying in diabetic rats. The mechanism of the effects may be associated with EGC activation in ENS. |
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