Thyroxine accelerates ulcer healing in rats, new study shows

Gastric ulcers in rats that were given thyroid hormone healed significantly faster than ulcers in rats not given the hormone, according to a recent study in the Canadian Journal of Physiology and Pharmacology.

“Gastric acid secretion, mucus secretion, and blood cells have been found to affect ulcer healing, therefore, this research aimed to further investigate the mechanisms by which thyroid hormones affect ulcer healing by measuring acid secretion, mucus secretion, and neutrophil lymphocyte ratio (NLR) during healing in rats,” wrote researchers led by Olasupo S. Adeniyi, Department of Physiology, Faculty of Basic and Allied Medical Sciences, Benue State University, Makurdi, Nigeria.

“This study is the first to also examine gastric acid secretion, mucus secretion, and systemic inflammation by measuring neutrophil to lymphocyte ratio during healing in acetic acid induced ulcer that closely resembles human ulcer.”

NLR serves as a marker for inflammation and is calculated by dividing the neutrophil count by the lymphocyte count. This study showed for the first time that NLR has the potential to be used to monitor healing in acute gastric ulcer, Dr. Adeniyi and colleagues wrote.

• Previous researchers have shown that thyroid hormone helps the healing of gastric ulcers by:
• Hastening the inflammatory and proliferative phases of healing
• Modifying apoptosis and hematological parameters
• Decreasing lipid peroxidation

For this study, the researchers randomly assigned 120 albino Wistar rats into the following four weight-matched treatment groups:

• Sham thyroidectomy and no thyroxine treatment (the control)
• Thyroidectomy and no thyroxine treatment
• Thyroidectomy and treatment with 100 μg/kg/day of levothyroxine sodium orally for 35 days
• Sham thyroidectomy and treatment with 100 μg/kg/day of levothyroxine sodium orally for 35 days

After 35 days of thyroxine treatment, the researchers then surgically induced gastric ulcers in all rats, and measured ulcer healing during two phases.

During the first phase, the researchers divided 60 rats into four groups of 15 rats each. On days 3, 7, and 10 following ulcer induction, they randomly selected 5 rats from each group for blood cell counts and stomach removal to measure ulcer area and mucus secretion.

During the second phase, the researchers divided the remaining rats into four equal groups and treated these rats similarly, except that they studied them only for gastric acid secretion.

First, researchers observed that by day 10, healing occurred most rapidly in thyroxine-treated rats. When compared with day 3, the area of the ulcer in these rats significantly decreased by 78.5% (P < 0.05) compared with a 72.3% reduction in the control group and 63.3% in thyroidectomized rats. Finally, researchers observed that in thyroidectomized rats receiving thyroxine replacement therapy, there was also a significant reduction in ulcer area of 77.5%.

Second, researchers observed that by day 10, reduction in NLR in thyroxine-treated rats (65%) was significantly greater than that of rats receiving thyroxine after thyroidectomy (46%), controls (28.3%), and thyroidectomized rats (20.1%).

Third, researchers observed that by days 3 and 7, mucus secretion was significantly lower in rats that had thyroidectomy (P < 0.05). By day 10, mucus secretion was lower in all groups of rats; however, this decrease was only significant in control and thyroxine-treated rats but not in thyroidectomized rats.

Finally, researchers observed that by day 10, gastric acid secretion decreased by 77.4% in thyroxine-treated rats, 65% in control rats, and 51.5% in thyroidectomized rats.

“In conclusion,” the researchers wrote, “this study shows that during acute gastric ulcer, thyroxine facilitates healing by increasing mucus secretion, by modulating the body’s immune system (reducing neutrophil lymphocyte ratio) and acid secretion.”