The Effect of Smokeless Tobacco on the Histopathology of Thyroid Gland in Albino Rats

Abstract

Objective: To investigate the effect of smokeless tobacco on the histopathology of the thyroid gland in albino rats. Methodology: The experimental study was conducted at the Animal House of Sindh Agriculture University over a three-month duration from June to August 2018. Thirty healthy, non-pregnant female albino rats, aged 8-10 weeks and weighing 200-230 grams, were divided into three groups. The Control group received a standard diet, Experimental Group A was exposed to 5% smokeless tobacco, and Group B to 10%. Rats were housed under hygienic conditions. After the experiment, the rats were weighed, euthanized via cervical dislocation, and their thyroid glands were removed for detailed dissection. Tissues were preserved in 10% formaldehyde, processed for microscopic examination through paraffin embedding and sectioning (2-5 µm thick), and finally stained with Hematoxylin and Eosin (H&E) and trichrome stain. Results: Significantly reduced weight was observed in albino rats from Group 2 and 3 compared to controls (p-value < 0.0001). In the control group (Group I), histological examination revealed a normal structure of thyroid follicles. In Group 2, stroma exhibited mild infiltration of chronic inflammatory cells, whereas Group 3 showed benign lesions with mild fibrosis. Conclusion: In summary, smokeless tobacco has adverse effects on the weight of albino rats and may alter the normal histology of the thyroid gland. Further investigation into the effects on thyroid hormone levels and a study of the dose-dependent effects of various chemicals in smokeless tobacco on the thyroid gland are recommended.