A Histopathological Study on the Deleterious Effect of Chronic Levothyroxine Sodium Administration on the Gastric Mucosa of Adult Male Albino Rats

Abstract Background: levothyroxine sodium is considered the top drug for treatment of people with hypothyroidism. It is manufactured from the original biological hormone thyroxine. This replacement treatment is almost the only solution for hypothyroid patients. The mucosal lining of the stomach is one of the defense mechanisms protecting the body from harmful effects of ingested exogenous substances and microorganisms. The gastric mucosa is vulnerable to toxic substances. Aim of the Work: In this work we tried to investigate the histopathological effect of chronic oral levothyroxine sodium administration on the fundic mucosa of the adult male albino rats using a histological study. Materials and Methods: Thirty adult male albino rats weighing 150-200 grams were used, divided into three main groups: Group I (control group): included 10 rats that received no treatment for the same periods as the experimental animals. Group II: It Included 10 rats that each rat received levothyroxine sodium dissolved in distilled water and given for each rat orally by orogastric tube in a dose equal to 2mcg/kg per day for 60 days. Group III This group consisted of 10 rats, each rat received levothyroxine sodium by orogastric tube in a dose equal to 4mcg/kg per day for 60 days. The fundic gastric mucosa specimens were subjected to histological (light, immunostaining and scanning electron microscopic examination). The data were analyzed statistically. Results: The current study of the control group revealed the normal architecture of gastric wall of rats at the fundus formed of the mucosa, submucosa, muscularis mucosa the gastric glands, and muscularis externa. Group II showed widening of the gastric pits and their lining epithelium became thinner, increased mucous secretion filling the dilated pits. Group III showed more obvious widening of the gastric pits and more mucous secretion lodging the pits orifices with sloughing of the surface epithelium. Conclusion: Finally, we can conclude that the long-term administration of oral levothyroxine sodium can produce structural harmful changes in the gastric mucosa of adult male rats.