The protective mechanism of N-acetylcysteine against ischemia/reperfusion induced gastric injury in rats / 生理学报

The present study aimed to investigate the protective mechanism of N-acetylcysteine (NAC) against gastric ischemia /reperfusion (GI/R) injury in rats. After intravenous injection (IV) of NAC (150 mg/kg) into femoral vein, the rats were subjected to 30 min of ischemia induced by clamping the celiac artery followed by 60 min of reperfusion. After the gastric mucosal damage index (GMDI) had been calculated, gastric mucosal cell in situ apoptosis was detected by TUNEL method. The protein expression of p-ERK, p-JNK and NF-kappaB, and mRNA expression of TNF-alpha and Caspase-3 in gastric mucosa were evaluated by using Western-blot or RT-PCR, respectively. The results showed that NAC not only attenuated the GI-R injury, but also decreased gastric mucosal cellular apoptosis. Furthermore, NAC increased the protein expression of p-ERK, while inhibited protein expression of p-JNK, NF-kappaB in gastric mucosa. NAC also decreased the expression of TNF-alpha mRNA and Caspase-3 mRNA in gastric mucosa. Capsazepine (CPZ) (400 mg/kg, IV) reversed the protective effect of NAC against GI/R injury in rats. These results suggest that NAC can protect rats against GI/R injury. This protective effect is possibly mediated by the up-regulation of p-ERK and down-regulation of p-JNK and NF-kappaB. In addition, vanilloid receptor subtype 1 may be involved in the protective mechanism of NAC against GI/R injury.

The neuroregulatory effect of cerebellar fastigial nucleus stimulation on gastric ischemia-reperfusion injury in rats / 生理学报

In the present study, rat model of gastric ischemia-reperfusion (GI-R) injury was established by clamping the celiac artery for 30 min followed by 1 h of reperfusion. Subsequently, the regulatory effect of electrical stimulation of cerebellar fastigial nucleus (FN) on GI-R injury and its neural mechanisms were investigated in Sprague-Dawley rats. The results are as follows. Electrical stimulation of the cerebellar FN not only obviously attenuated the GI-R injury in an intensity-dependent manner, but also decreased the apoptosis rate of gastric mucosal cells. Chemical lesion of FN eliminated the protective effect of electrical stimulation of FN on GI-R injury. Electrical stimulation of cerebellar FN decreased both the frequency and amplitude of the discharges of greater splanchnic nerve, but it could not change the discharge of greater splanchnic nerve following the lesion of the lateral hypothalamic area (LHA). After bilateral section of the greater splanchnic nerves, electrical stimulation of the FN also attenuated the GI-R injury. Chemical lesion of the LHA reversed the protective effect of electrical stimulation of FN on GI-R injury. Electrical stimulation of FN increased the activity of superoxide dismutase (SOD), but decreased the content of malondialdehyde (MDA) in gastric mucosa under GI-R. These results indicate that the cerebellar FN may regulate GI-R injury. Therefore, the cerebellar FN is an important brain site protecting the stomach against GI-R. The LHA and greater splanchnic nerves participate in the regulatory effects of cerebellar FN stimulation on GI-R injury. In addition, antioxidation may also be involved in the protection mechanism of cerebellar FN stimulation.