Effect of Losartan on the mucous glands of the trachea in the albino rat- a histomorphometric study

Losartan, an an AT1 receptor antagonist used as an antihypertensive, is known to produce nonproductive cough, bronchoconstriction 1-4 and angioedema 5,6 in some individuals. The structural/histopathological cause has not been ascertained. It is required to know the exact mechanism of these side effects in order to improve the therapeutic effects of the drug. This fact prompted the present study. Inbred adult Wistar albino rats weighing 150-200 grams were used and were divided into two groupsExperimental group (Group I) and Control group (Group II) comprising of 15 animals each. The rats in group I were given the normal therapeutic dose, losartan potassium 50 mg/kg of body weight dissolved in water, orally through a thin tube daily for 15 days. Group II was given the same amount of vehicle. The animals were sacrificed on the 16th day. They were perfused by injecting 10% formal saline under phenobarbitone sodium anesthesia. The trachea was cut into three equal parts; the upper, middle and lower and embedded in paraffin wax. Serial sections of each part were stained with Haematoxylin and Eosin, Masson’s Trichome, PAS, combined Alcian blue and PAS and studied under the light microscope. The Goblet cells in the mucosal lining of the trachea increased statistically after losartan and the number of glands in the submucosa also showed a similar increase in number and amount of secretions. Losartan should be used with caution and the patients on this therapy should be assessed for increase in postnasal secretions and resulting cough.