Accelerated gastric ulcer healing in thyroxine-treated rats: roles of gastric acid, mucus, and inflammatory response

The roles of gastric acid, mucus, and inflammation on the pro-ulcer-healing effect of thyroid hormone were investigated. Male Wistar rats were randomly divided into four groups: control, thyroidectomised, thyroidectomised with thyroxine treatment (100 mu g.kg(-1).day(-1)), and sham-operated animals treated with thyroxine. Thirty-five days after thyroidectomy, sham surgery, or thyroxine treatment, an ulcer was experimentally induced. Healing was assessed 3, 7, and 10 days post-ulceration by measurement of the ulcer area, gastric mucus and acid secretion, and neutrophil lymphocyte ratio (NLR) as an index of inflammation. By day 10, the ulcer area had decreased in all groups. Recovery was significantly greater (P < 0.05) in thyroxine-treated rats (78.5% +/- 1.6% reduction in ulcer area) than in controls (72.3% +/- 1.2% reduction) or thyroidectomised rats (63.3% +/- 1.9% reduction). Thyroxine-treated animals also had the highest reduction in NLR (65.0% +/- 2.5%). Mucus secretion was significantly lower (P < 0.05) in thyroidectomised rats by days 3 and 7. Furthermore, by day 10, the concentration of basal acid decreased by 77.4% +/- 2.6% in thyroxine-treated, 65.0% +/- 0.0% in control, and 51.5% +/- 3.3% in thyroidectomised rats. We conclude that thyroxine accelerates gastric ulcer healing by altering mucus and acid secretion and reducing NLR.