Injury to the gastric mucosa and cellular dynamics in a rat model of duodenogastric reflux: the possible significance of gastrin induction and a heat shock protein

Protective effects of heat shock protein70 induced by geranylgeranylacetone in atrophic gastritis in rats

AIM

To investigate the effect of geranylgeranylacetone (GGA) on the progression of atrophic gastritis in rats and its potential mechanism.

METHODS

Atrophic gastritis was induced in Sprague-Dawley rats with 0.1% ammonia solution, 60% ethanol, and 20 mmol/L deoxycholic acid for 24 weeks. Accompanied by the induction of atrophic gastritis, 200 mg/kg GGA was administered by oral gavage for 8 weeks (weeks 17-24). The histological changes in gastric mucosa were quantitated by the index of inflammation, the gastric mucosal thickness, and the amount of glands of 1 mm horizontal length in antrum. Endogenous heat shock protein (HSP)70 levels and distribution were determined by immunoblotting and immunohistochemistry in gastric mucosa.

RESULTS

GGA alleviated the pathological progression of atrophic gastritis with inflammation relief (inflammation index: 1.40 in the GGA group and 1.65 in the atrophic gastritis group) and glandular restoration (mucosal thickness and quantity of glands: 194.3 microm and 38.7 mm in the GGA group; 123.3 microm and 32.7 mm in the atrophic gastritis group; P<0.05). GGA significantly induced HSP70 synthesis (P<0.05). Moreover, quercetin, an inhibitor of HSP70 expression, aggravated the infiltration of inflammatory cells and glandular loss in the antrum.

CONCLUSION

GGA prevented the progression of atrophic gastritis in rats via the induction of HSP70 expression.

Ulceration as a possible link between duodenogastric reflux and neoplasms in the stomach of rats

BACKGROUND

Duodenogastric reflux predisposes to gastric cancer. This study investigates whether ulceration induced by duodenogastric reflux is associated with the development of neoplasms in the stomach.

MATERIALS AND METHODS

In a rat experiment, duodenal fluid was directed into the corpus (jejunal reflux) or through the pylorus into the antrum (pyloric reflux). Sham-operated animals served as controls. The animals were sacrificed after 24, 36, or 52 weeks.

RESULTS

Ulcerations and neoplasms occurred more frequently in the corpus than in the antrum. In the corpus, ulceration was observed significantly more often in animals with jejunal reflux (62, 55, and 53% at 24, 36, and 52 weeks, respectively) than in animals with pyloric reflux (15, 21, and 30%). The incidence of neoplasm in the corpus increased significantly with time from 38% at 24 weeks to 89% at 52 weeks in animals with jejunal reflux and from 12 to 33% in animals with pyloric reflux. Ulceration and neoplasms shared location in the corpus adjacent to the gastrojejunostomy and by 24 weeks, all but one neoplasm in the jejunal reflux and one in pyloric reflux groups occurred adjacent to ulceration. In the antrum, 37% of the animals had a prepyloric ulceration after 24 weeks of pyloric reflux and only one of these animals had a neoplasm. By 52 weeks 20% of animals with pyloric reflux had a neoplasm that appeared in the prepyloric area.

CONCLUSIONS

Ulceration and neoplasm occurred at the same sites in the stomach, and ulcerations preceded the development of neoplasms in the antrum and very likely in the corpus. The results suggest that ulceration plays an important role in the genesis of neoplasms in the stomach and that the vulnerability to duodenogastric reflux is more pronounced in the corpus than in the antrum mucosa.

Expression of heat shock protein 70 in grossly resected esophageal squamous cell carcinoma

BACKGROUND

The aim of the present study was to use immunohistochemical methods to clarify the clinical implication of heat shock protein (HSP) 70 expression in esophageal squamous cell carcinoma and to investigate the function of HSP70 as a chaperone for p53.

METHODS

Seventy-one patients with esophageal squamous cell carcinoma were admitted in the present study. Expression of HSP70 was analyzed by immunohistochemistry and correlated with TNM classification, vessel invasion, p53 expression, and clinical outcome after operation.

RESULTS

Overexpression of HSP70 was related to sex (p < 0.05), tumor configuration (p < 0.05), lymph node metastasis (p < 0.01), and lymphatic vessel invasion (p < 0.05). Expression of p53 and HSP70 were not correlated with each other (p = 0.824). Esophageal squamous cell carcinoma with HSP70 expression exhibited a significantly better prognosis compared with HSP70-negative esophageal squamous cell carcinoma in univariate analysis (p < 0.05), but no significance was found in multivariate analysis.

CONCLUSIONS

We suggest that HSP70 expression might be of use to assess the progression, lymph node metastasis, and lymphatic vessel invasion of esophageal squamous cell carcinoma. Inasmuch as both lymph node metastasis and HSP70 expression are prognostic variables in esophageal squamous cell carcinoma, examination of HSP70 expression may be of use to assess clinical outcome after operation.