[Changes of rat gastric mucosal barrier under stress conditions].
OBJECTIVE To explore the changes of rat gastric mucosal barrier under conditions of water immersion restraint stress. METHODS Eighty rats were randomly divided into Group A (20 rats), B (40 rats) and C (20 rats) after being fasted for 24 hours. And then Group A was divided into two subgroups with ten rats in each. The two subgroups in Group A were given normal saline or omeprazole respectively while under the stress condition. The changes of gastric acid or bicarbonate secretion were determined. Group B (40 rats) were randomly divided into four subgroups,which were subgroup control, 1h, 2h and 4h after beginning of the stress. The quantity of glandular mucosal adherent mucus, the thickness of mucus gel layer and ulcer index were measured after stress in Group B. The glandular mucosal samples were labeled by Lanthanum and observed by transmission electromicroscopy. Group C was randomly divided into two subgroups in the same way with Group A. And each subgroup received normal saline or omeprazole respectively   H(+) loss in gastric lumen was calculated by determining the difference of acidity between lavage and drainage fluid H(+) concentration. RESULTS It was found that gastric alkaline secretion decreased progressively (P < 0.05), while gastric acid secretion increased progressively under stress conditions (P < 0.05). The mucus quantity(A/g) in the four subgroups in Group B were 0.137 +/- 0.030, 0.143 +/- 0.012, 0.066 +/- 0.016 and 0.016 +/- 0.016 respectively. The mucus gel thickness(microm) were 71.08 +/- 5.85, 74.50 +/- 12.85, 57.63 +/- 6.45 and 51.35 +/- 2.84 respectively. The ulcer index were 0.2 +/- 0.1,0.4 +/- 0.1,5.2 +/- 1.3 and 10.0 +/- 0.5 respectively. Statistics showed that the mucus quantity was correlated with the mucus gel thickness positively(r = 0.89), while either of them was correlated with the ulcer index negatively(r =  0.85 and "r =  0.83). And it was also found that Lanthanum rarely stained the glandular mucosa in control subgroup, while heavily in stress subgroups. In the subgroup receiving normal saline in Group C, within 5 hours after the beginning of stress, the amount of H(+) loss per hour(micromol) was 2.03 +/- 0.12, 2.00 +/- 0.20, 1.93 +/- 0.49, 2.70 +/- 0.44 and 3.37 +/- 0.35 respectively. It was demonstrated that the amount of H(+) loss was stable within 2h after stress, then increased obviously in normal saline subgroup significantly (P < 0.01). In omeprazole subgroup, the amount of H(+) loss (micromol) was 7.46 +/- 1.22, 4.56 +/- 0.35, 3.11 +/- 0.81, 2.32 +/- 1.42 and 2.13 +/- 1.60, which decreased progressively, however still higher than those in normal saline subgroup (P "< 0.01). CONCLUSIONS The results suggest that gastric bicarbonate secretion is inhibited; gastric barrier is damaged; and hydrogen permeability through gastric mucosal barrier increases under stress conditions.
Zhan
Xianbao
X
Department of Gastroenterology, Changhai Hospital, The Second Military Medical University, Shanghai 200433,China. zhanxianbao@eastday.com
Li
Zhaoshen
Z
Cui
Zhongmin
Z
Duan
Yimin
Y
Nie
Shinan
S
Liu
Jing
J
Xu
Guoming
G
D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D001639:Bicarbonates / Q000378:metabolism; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000503:physiopathology*; D008297:Male; D009093:Mucus; D009853:Omeprazole / Q000494:pharmacology; D011522:Protons; D051381:Rats; D017207:Rats, Sprague-Dawley; D012149:Restraint, Physical / Q000379:methods; D013276:Stomach Ulcer / Q000473:pathology; D013315:Stress, Psychological / Q000503:physiopathology*
D000897:Anti-Ulcer Agents; D001639:Bicarbonates; D011522:Protons; D009853:Omeprazole