Antinociceptive Effect of Ghrelin in a Rat Model of Irritable Bowel Syndrome Involves TRPV1/Opioid Systems.

BACKGROUND/AIMS: Irritable bowel syndrome (IBS), defined as recurrent abdominal pain and changes in bowel habits, seriously affects quality of life and ability to work. Ghrelin is a brain-gut hormone, which has been reported to show antinociceptive effects in peripheral pain. We investigated the effect of ghrelin on visceral hypersensitivity and pain in a rat model of IBS. METHODS: Maternal deprivation (MD) was used to provide a stress-induced model of IBS in Wistar rats. Colorectal distension (CRD) was used to detect visceral sensitivity, which was evaluated by abdominal withdrawal reflex (AWR) scores. Rats that were confirmed to have visceral hypersensitivity after MD were injected with ghrelin (10 µg/kg) subcutaneously twice a week from weeks 7 to 8. [D-Lys3]-GHRP-6 (100 nmol/L) and naloxone (100 nmol/L) were administered subcutaneously to block growth hormone secretagogue receptor 1α (GHS-R1α) and opioid receptors, respectively. Expression of transient receptor potential vanilloid type 1 (TRPV1) and µ and κ opioid receptors (MOR and KOR) in colon, dorsal root ganglion (DRG) and cerebral cortex tissues were detected by western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemical analyses and immunofluorescence. RESULTS: Ghrelin treatment increased expression of opioid receptors and inhibited expression of TRPV1 in colon, dorsal root ganglion (DRG) and cerebral cortex. The antinociceptive effect of ghrelin in the rat model of IBS was partly blocked by both the ghrelin antagonist [D-Lys3]-GHRP-6 and the opioid receptor antagonist naloxone. CONCLUSION: The results indicate that ghrelin exerted an antinociceptive effect, which was mediated via TRPV1/opioid systems, in IBS-induced visceral hypersensitivity. Ghrelin might potentially be used as a new treatment for IBS.

[Effects of hyperbaric oxygen therapy in the management of chronic wounds and its correlation with CD34(+) endothelial progenitor cells].

OBJECTIVE: To evaluate the effects of hyperbaric oxygen (HBO) therapy in the management of chronic wound and observe the correlation between wound healing and CD34+ endothelial progenitor cells (EPCs). METHODS: A total of 119 patients with chronic wound in lower extremities lasting > 3 months were recruited for this randomized, single-center, placebo-controlled clinical trial. The changes of CD34+ average count before and after HBO therapy were detected by flow cytometry (FACS). There were 97 patients on long-term HBO therapy and in 22 patients on hyperbaric air therapy as control group. The CD34/Scal-1+ and CD34/CXCR4 dual-positive populations of gated cell were determined respectively by FACs. The outcomes of two groups were compared. Treatment was administered within a single-place hyperbaric chamber for 90-min daily (session duration 120 min) for 5 days a week for 4 weeks (20 treatment sessions). RESULTS: The wound size decreased at the 4-week end point (62.7% ± 22.3% in the HBO group vs 34.4% ± 20.6% in the control group, P < 0.05). After 10 episodes of HBO therapies for chronic non-healing wound, the peripheral CD34+ EPCs average count rose from 0.24% ± 0.03% at pre-treatment to 1.32% ± 0.05% while the number was 1.75% ± 0.17% after 20 episodes of HBO (P < 0.05). Both were significantly different from that of the patients at pre-treatment. However the overall circulating white cell count was not significantly elevated. The CD34/Scal-1+ and CD34/CXCR4 dual-positive populations of gated cell in HBO group were 5.8 and 5.2 folds than those at pre-treatment respectively. The number of EPCs was positively correlated with wound healing in lower extremities (correlation coefficient 0.84; P < 0.01). CONCLUSION: Adjunctive treatment of HBO facilitates the healing of chronic non-healing wound in selected patients through the mobilization of EPCs.

[Mechanism of apoptosis induced by specific COX-2 inhibitor SC236 in gastric cancer cells].

OBJECTIVE: To investigate the underlying mechanism of apoptosis-inducing effect of a specific COX-2 inhibitor SC236 in gastric cancer cells. METHODS: Western blot analysis was used to measure apoptosis-related proteins, cytochrome c, and caspase-3. The catalytic activity of the caspases was measured using a colorimetric assay. RESULTS: Treatment of AGS gastric cancer cells with SC236 caused a significant elevation of the pro-apoptotic protein Bak, release of cytochrome c to the cytosol, and activation of caspase-3. A specific caspase-3 inhibitor, z-DEVD-fmk, blocked SC236-induced apoptosis. CONCLUSION: SC236 inhibits cell growth and induces apoptosis in gastric cancer cells at least partly through the up-regulation of Bak, stimulation of cytochrome c release, and activation of caspase-3.