The stomach is innervated by the vagal nerve. Several studies have demonstrated that the vagal nerve has a trophic effect on the rat oxyntic mucosa and that the trophic effect of hypergastrinemia is dependent on intact vagal innervation. The effect of vagal denervation on gastric carcinogenesis has been examined in Mastomys natalensis and hypergastrinemic transgenic INS-GAS mice, with no effect of unilateral vagotomy in Mastomys but an anti-carcinogenic effect in INS-GAS mice. A proportion of female Japanese cotton rats develop spontaneous hypergastrinemia and ECL cell derived gastric carcinomas. In the current study we have examined the effects of unilateral anterior subdiaphragmatic vagotomy on gastric carcinogenesis. Female Japanese cotton rats were operated with unilateral anterior vagotomy or sham-operation at age 2 months and were terminated at age 10 months. Ten of fifteen animals operated by anterior vagotomy and 11 of 16 sham-operated developed hypergastrinemia. Vagotomy did not affect intragastric pH or serum gastrin. When comparing the anterior and posterior sides of the stomachs, vagotomy did not affect the occurrence of dysplasia or carcinoma development in the oxyntic mucosa. However, vagotomy resulted in lower stomach weight and reduced oxyntic mucosal thickness on the anterior side. Vagotomy also resulted in a reduction in volume density of chromogranin A positive cells in the oxyntic mucosa. In conclusion, vagotomy reduced the trophic effects of hypergastrinemia on the ECL cell and oxyntic mucosa, but did not prevent gastric carcinogenesis in female Japanese cotton rats. The effects of vagotomy on gastric carcinogenesis in animal models are conflicting and further studies in patients should be done to clarify the clinically significant effects of vagotomy.
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