Effects of hyperthyroidism on histopathology of airway in an allergic animal model

Objectives: Asthma and thyroid dysfunction both are common disorders that sometimes may happen simultaneously. The mechanism of interaction between thyroid hormones and asthma is not known. The present study aimed at evaluation of the effects of hyperthyroidism on histopathology of airway in an animal model.Materials Methods: Thirty six male Dunkin-Hartley guinea pigs were randomly placed in to 4 group: 1. Control (CTL), 2. Allergic (ALG), 3. Hyperthyroid (HPR), 4. Hyperthyroid-Allergic (HPR-ALG). HPR was induced by administration of ip L-thyroxin. ALG was induced after determination of thyroid dysfunction by ipovalbumine and aluminum hydroxide. ALG animals were double challenged inhalation of ovalbumine on day 14. Animals were anesthetized by CO2 gas and blood samples were taken via heart puncture. Thereafter, they were euthanized by an excess dose of the gas, thyroid glands and tracheas were removed for further experiments.Results: In the present study, L-thyroxin administration caused HPR situation as shown in biochemical and histopathological examinations. In the histopathological study, HPR resulted in an increase of blood vessels. HPR-ALG was induced goblet cell hyperplasia, swelling of the airway wall, arease of denuded epithelium and edem. Cell number in the BALF did not increase immediately after the challenge with ovalbumine. HPR animals had an increased cell infiltration in the BALF (P 0.05) although most cells had lost their viabilities.Conclusions: In this study, HPR was induced histopathological changes in the airway. These chenges were significant in HPR-ALG group. This clearly demonstrated a change of the airway by thyroid hormones. ,