烧伤应激对胃动力的影响

Changes in serum ghrelin and small intestinal motility in rats with cerebral arterial thrombosis

AIM: To determine the changes in serum ghrelin and small intestinal motility in rats with cerebral arterial thrombosis and to explore their relationship.

METHODS: Forty-eight Wistar rats were randomly divided into two groups: control group (n = 8) and middle cerebral artery occlusion (MCAO) group (n = 40). The MCAO group was further equally divided into 5 subgroups for testing at 3, 6, 12, 24 and 48 h after cerebral arterial thrombosis. MCAO was induced in rats using the thread occlusion method proposed by Longa. Neurologic examinations were conducted and neurologic findings were scored at each time point. Triphenyltetrazolium chloride (TTC) staining of brain tissue was performed. The content of serum ghrelin was determined by enzyme-linked immunosorbent assay, and small intestinal motility was measured by methylene blue staining. The ileum tissue was examined by light and electron microscopy.

RESULTS: The neurologic scores were 0 for all the rats in the control group and 1-3 for those in the MCAO group. Small intestinal motility was significantly lower in the MCAO group than in the control group (P < 0.05), reaching the lowest level at 24 h. Serum ghrelin level increased at 3 h and reached the peak at 24 h. Serum ghrelin level was significantly higher in the MCAO group than in the control group (P < 0.05). Correlation analysis showed a linear relationship between serum ghrelin levels and small intestinal motility (r = -0.841, P < 0.05) in rats with MCAO. Intestinal mucosal injury could be seen by light and electron microscopy, such as intestinal villus swelling, chondrosome swelling, vacuolar degeneration, apoptosis, etc.

CONCLUSION: Changes in serum ghrelin and small intestinal motility occur in rats with MCAO. The change of intestinal motility is significant at 24 h after cerebral ischemia.

Formalin-induced acute pain upregulates the expression of annexin 5 mRNA in the stomach and submandibular gland of rats

AIM: To investigate the effects of formalin-induced acute pain on the expression of annexin 5 mRNA in the stomach and submandibular gland of Sprague-Dawley (SD) rats.

METHODS: Acute pain was induced in SD rats by subcutaneous injection of 2 mL of 50 g/L formalin into the plantar surface of the left hindpaw. Control rats were injected with equal volume of normal saline solution. The samples of the stomach and submandibular gland were collected under terminal anaesthesia with ketamine (40 mg/kg) at 1, 6, 24 and 72 h after formalin injection. The expression of annexin 5 mRNA in the stomach and submandibular gland was analyzed by fluorescent quantitative polymerase chain reaction (PCR).

RESULTS: Fluorescent quantitative PCR showed that the expression of annexin 5 mRNA in the stomach significantly increased at 1 h after formalin injection compared to that in control mice (7.43 ± 2.67 vs 1.00 ± 0.00, P < 0.01), and then decreased to basic level at 6 h (P > 0.05). In the submandibular gland, the expression of annexin 5 mRNA also increased at 1 h after formalin injection (4.33 ± 1.50 vs 1.00 ± 0.00, P < 0.01), and returned to normal level at 72 h (P > 0.05).

CONCLUSION: Formalin injection-induced acute pain upregulats the expression of annexin 5 mRNA in the stomach and submandibular gland of rats. Annexin 5 may be an acute stress response protein in the digestive system.