Hyperplastic thyroid gland; vascular and follicular changes produced by dexamethasone during involution

ABSTRACT

The study was conducted to see the vascular and follicular changes induced by dexamethasone [synthetic corticosteroid] during involution of hyperplastic thyroid gland in albino rats. A comparative histological study done in Post Graduate Medical Institute Lahore in 1998. 54 adult rats were taken and divided at random into two control groups having 27 rats and experimental groups containing 27 rats. Control group was given normal diet along with 2 microgram of Potassium iodide intraperitonealy for 21 days while experimental groups further subdivided into group A having 3 rats and group B and C containing 12 rats each. All the experimental groups were treated with Thiourea for 21 days. Group A was sacrificed on day 22 after withdrawal of thiourea. Group B was given Potassium iodide intraperitonealy after stoppage of TU on day 21 and were sacrificed on days 22, 26, 30 and 50 in 4 sub groups [B1-B4] to study the involution process. Group C was injected dexamethasone from 22 to 50 days after withdrawal of TU and sacrificed on same days in 4 subgroups [C1-C4] as sub groups B. The results of experimental group. A showed increase in thyroid and relative tissue weight. Histologically this group exhibited significant increase in stromal congestion with tall follicular cells lining the small sized follicles having scanty colloid. The results of experimental groups B and C demonstrated increase in thyroid and relative tissue weight but microscopically subgroups B revealed early and complete involution whereas subgroups C showed significantly persistent hyperplastic changes in the form of stromal congestion, vessels wall remained well defined and tall follicular cells lining small empty follicles. It was concluded that dexamehasone did retain hyperplastic changes during involution evident by stromal congestion and small sized regular follicle lined by tall follicular cells, so it should be carefully used in thyroid diseases