Effect of glutamate on inflammatory responses of intestine and brain after focal cerebral ischemia.

AIM: To study the modulation of glutamate on post-ischemic intestinal and cerebral inflammatory responses in a ischemic and excitotoxic rat model.
METHODS: Adult male rats were subjected to bilateral carotid artery occlusion for 15 min and injection of monosodium glutamate intraperitoneally, to decapitate them at selected time points. Tumor necrosis factor alpha (TNF-alpha) level and nuclear factor kappa B (NF-kappaB) activity were determined by enzyme-linked immunosorbant assay (ELISA) and electrophoretic mobility shift assay (EMSA), respectively. Hemodynamic parameters were monitored continuously during the whole process of cerebral ischemia and reperfusion.
RESULTS: Monosodium glutamate (MSG) treated rats displayed statistically significant high levels of TNF-alpha in cerebral and intestinal tissues within the first 6 h of ischemia. The rats with cerebral ischemia showed a minor decrease of TNF-alpha production in cerebral and intestinal tissues. The rats with cerebral ischemia and treated with MSG displayed statistically significant low levels of TNF-alpha in cerebral and intestinal tissues. These results correlated significantly with NF-kappaB production calculated at the same intervals. During experiment, the mean blood pressure and heart rates in all groups were stable.
CONCLUSION: Glutamate is involved in the mechanism of intestinal and cerebral inflammation responses. The effects of glutamate on cerebral and intestinal inflammatory responses after ischemia are up-regulated at the transcriptional level, through the NF-kappaB signal transduction pathway.