Effects of hypothalamic paraventricular nuclei on apoptosis and proliferation of gastric mucosal cells induced by ischemia/reperfusion in rats

AIM: To investigate the effects of electrical stimulation of hypothalamic paraventricular nuclei (PVN) on gastric mucosal cellular apoptosis and proliferation induced by gastric ischemia/reperfusion (I/R) injury. METHODS: For different experimental purposes, stimulating electrode plantation or electrolytic destruction of the PVN was applied, then the animals' GI/R injury model was established by clamping the celiac artery for 30min and allowing reperfusing the artery for 30min, 1h, 3h or 6h respectively. Then histological, immunohistochemistry methods were used to assess the gastric mucosal damage index, the gastric mucosal cellular apoptosis and proliferation at different times. RESULTS: The electrical stimulation of PVN significantly attenuated the GI/R injury at 30 min, 1h and 3h after reperfusion. The electrical stimulation of PVN decreased gastric mucosal apoptosis and increased gastric mucosal proliferation. The electrolytic destruction of the PVN could eliminate the protective effects of electrical stimulation of PVN on GI/R injury. These results indicated that the PVN participated in the regulation of GI/R injury as a specific area in the brain, exerting protective effects against the GI/R injury, and the protection was associated with the inhibition of cellular apoptosis and the promotion of gastric mucosal proliferation. CONCLUSION: Stimulating PVN significantly inhibits the gastric mucosal cellular apoptosis and promots gastric mucosal cellular proliferation. This may explain the protective mechanisms of electrical stimulation of PVN against GI/R injury.

Role of mitogen-activated protein kinases in the regulation of paraventricular nucleus to gastric ischemia-reperfusion injuries

Background We investigated the role in electrical stimulations of paraventricular nucleus （PVN） on gastric mucosal cells and the activity of mitogen-activated protein kinases （MAPKs） family members induced by gastric ischemia-reperfusion （GI-R）. And we elucidated the molecular mechanisms of the protection of PVN from GI-R injuries. Methods Sprague-Dawley rats were divided randomly into 4 groups： Group I, the sham-operated GI-R control group; Group II, the sham-operated electrical stimulations to PVN ＋ sham-operated GI-R control group; Group III, the GI-R group; and Group IV, the electrical stimulations to PVN ＋ GI-R group. In all of the experiments, the PVN was stimulated prior to the induction of GI-R. The GI-R model was established by clamping the celiac artery for 30 minutes to induce ischemia and then was released to allow reperfusion for 30 minutes, 1 hour, 3 hours and 6 hours, respectively. The gastric mucosal cellular apoptosis, proliferation, and the expression and activity of MAPKs protein were observed by immunohistochemistry and Western blotting, respectively. Results Compared with the GI-R group, the application of electrical stimulations in the PVN significantly depressed gastric mucosal cellular apoptosis and enhanced gastric mucosal cellular proliferation following the 30-minute, 1-hour and 3-hour intervals of reperfusion; it also promoted the activation of p-ERK during the early phase of reperfusion but inhibited the activation of p-JNK1/2 and p-p38 following the 30-minute, 1-hour and 3-hour intervals of reperfusion. Conclusions The protection of PVN against GI-R injuries may attribute to the inhibition of apoptosis and the promotion of the proliferation of gastric mucosal cells during GI-R. This protective effect is mediated by activating the ERK pathway and depressing the JNK, the JNK. p38 MAPK oathwavs of the oastric mucosal cells.