Establishment of a rat model of stress-induced gastric ulcer by suspending at a great height and intervention effects of different pretreatments

Abstract

Objective To establish a rat model of stress-induced gastric ulcer by exposure to hanging at a great height and assess the intervention effects of different pretreatments in this model. Methods Forty-eight SD rats were randomly divided into 6 groups, including a restraint water-immersion stress (RWIS) group and 5 height exposure groups where the rats were exposed to different heights (by suspending the rats with rubber bands tied to their hind limbs to simulate bungee jump) at 17 m for 30 min (H17-30 group), 40 min (H17-40 group), or 50 min (H17-50 group), at 34 m for 40 min (H34-40 group), or at 46 m for 40 min (H46-40 group). The rats were examined for occurrence of gastric ulcer, ulcer index and gastric mucosal pathology after the exposures. Another 40 SD rats were randomized into normal control group, model group (H17-40 group), ranitidine group (group R), Shenling Baizhu San group (group S) and preconditioning group (group P) with corresponding pretreatments before height exposure at 17 m for 40 min. The incidence of gastric ulcer, gastric acid pH value, serum SOD activity and MDA content of the rats were then examined. Results Height exposures at 17 m for 30, 40, and 50 min all induced gastric ulcer in the rats, whose ulcer indexes was similar with that in RWIS group but appeared to increase with the exposure time. Exposures to heights of 34 m and 46 m for 40 min also induced gastric ulcer in the rats and resulted in significantly higher ulcer indexes than that in RWIS group. Compared with those in group H17-40, the ulcer incidence and MDA content were significantly reduced while the pH value of the gastric acid and serum SOD activity were significantly increased in group R, group S and group P (all P < 0.05); there was no significant difference in the ulcer index, gastric acid pH value, SOD activity or MDA content among the latter 3 groups. Conclusion Rat models of stress-induced gastric ulcer can be established by height exposure, and the severity of gastric ulcer is correlated with the height and duration of the exposure. Pretreatment with ranitidine, Shenling Baizhu San and preconditioning by hanging at a low height can effectively prevent or reduce the severity of stress-induced gastric by reducing gastric acid and oxygen free radicals.

Keywords

• height exposure
• stress ulcer
• ranitidine
• shenling baizhu san
• preconditioning