Mechanisms of burn-induced impairment in gastric slow waves and emptying in rats

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2010-07, Vol.299 (1), p.R298-R305
• Main Authors: Sallam, Hanaa S, Oliveira, Hermes M, Liu, Suhuan, Chen, Jiande D Z
• Format: Article
• Language: English
• Subjects: Animals; Burns; Caprylates; Correlation analysis; Cyclooxygenase 2 - pharmacology; Cyclooxygenase 2 Inhibitors - pharmacology; Digestive system; Gastric Emptying - drug effects; Gastric Emptying - physiology; Ghrelin; Hyperglycemia; Male; Postprandial Period; Rats; Rats, Sprague-Dawley; Rodents; Stomach - physiology; Stomach Diseases - physiopathology
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00135.2010

Delayed gastric emptying is common following severe large cutaneous burns; however, the mechanisms of burn-induced delayed gastric emptying remain unknown. The aim of this study was to explore the possible involvement of hyperglycemia and cyclooxygenase-2 receptors in the burn-induced gastric dysrhythmias. Gastric slow waves and gastric emptying were assessed in rats 6 h following sham or burn injury. Animals were randomized to one sham-burn and seven burn groups: untreated; two groups of saline treated (control); insulin treated (5 IU/kg); cyclooxygenase-2 inhibitor treated (10 mg/kg); ghrelin treated (2 nmol/rat); and gastric electrical stimulation treated. It was found that 1) severe burn injury impaired gastric slow waves postprandially and delayed gastric emptying; 2) the impairment in gastric slow waves included a decrease in the slow-wave frequency and in the percentage of normal slow waves, and an increase in the percentage of bradygastria (P = 0.001, 0.01, and 0.01, respectively vs. preburn values). None of the gastric slow-wave parameters was significantly correlated with gastric emptying; 3) cyclooxygenase-2 inhibitor normalized burn-induced delayed gastric emptying (P = 0.3 vs. sham-burn), but not gastric dysrhythmias (P < 0.002 vs. sham), whereas insulin normalized both gastric emptying (P = 0.4 vs. sham-burn) and gastric dysrhythmias (P = 0.3 vs. sham-burn); 4) both gastric electrical stimulation and ghrelin accelerated burn-induced delayed gastric emptying (P = 0.002 and 0.04, respectively, vs. untreated burn). In conclusion, hyperglycemia alters gastric slow-wave activity and delayed gastric emptying, while cyclooxygenase-2 inhibition delays gastric emptying without altering gastric slow-wave activity.