Effect of ethanol administration on thyroid gland of adult albino rat: histological and steriological study

ABSTRACT

Excessive consumption of ethanol is well known to cause many harmful health effects, involving damage to various organs and systems. The effect of continuous administration of 10% ethanol, the only drinking fluid for eight weeks on the structure of the gland were studied. Ten male albino rats Wistar strain of ten weeks old and 250 gm initial body weight were used. The animals were randomly divided into two groups. One group was received 10% ethanol as the only drinking fluid [ad-libitum], for eight weeks. The second group drank distilled water free of ethanol, and served as control. Thyroid lobes were collected and immediately fixed. Fixation was done in formaldehyde 10% [for paraffin section] and gluteraldehyde 5% for semithin sections, for 24 hours for both. Paraffin sections were cut at 7 micro/m and routinely were stained with hematoxylin and eosin [Hx and E] for morphological examination by a light microscope, and others were stained by Van Gisson stain for the reticular fibres. Toluidine blue stain was done for the semithin sections [0.5 micro m]. Stereological techniques were done to estimate the volume proportion of the reticular fibres and fibrous element relative to total glandular tissue of both control and treated animals using the point counting technique. Also the thickness of the follicular epithelium was measured. Exposure to ethanol results in changes in the histology and morphometry of the thyroid. Changes were in the form of desquamation of the lining epithelium in some follicles, increased thickness of the glandular epithelium, increased amount of fibrous tissues between the follicles. Increased number of dilated blood vessels in the thyroid gland of the rats exposed to ethanol. Our study seems to indicate that excessive consumption of ethanol can affect the structure of the thyroid gland