Cell mediated immunity during induced hypothyroidism

The present investigation was carried out on twenty female goat (divided into four groups of five animal each) in the age group of 8 months to 1 year for 70 days, to study the effect of induced hypothyroidism on cell mediated immunity. The experiment was divided in two phases. In induction phase, hypothyroidism was induced with thiourea given @ 100 mg/kg b.wt s. c bid for first 1 to 15 days and @ 66.7 mg/kg b.wt S.c bid from 16 to 30 days. In treatment phase, group A received continued thiourea treatment @ 66.7 mg/kg b. wt s.c., group B was supplemented with thyroxine @ 200 meg/goat per os. along with thiourea. Group C was substituted with thyroxine at the above mentioned dose. Control group was given NSS as placebo throughout the experiment For Lymphocyte Stimulation Test blood collection was done at every 15th day. T-cell and B-cell blastogenesis were carried out using ConA and LPS as mitogen respectively. Delayed type hypersensitivity reaction was carried out at 55^th day of experiment using DNCB as allergen. Hypothyroidism was induced successfully as was indicated by low plasma thyroxine (T4), triiodothyronine (T3) and T4:T3 ratio of all treated groups during induction phase and subsequent fall in hormonal levels continued in thiourea treated groups while in thyroxine substituted group, levels were restored by end of experiment.

There was significant decline T-cell and B-cell blastogenesis along with reduced level of delayed type hypersensitivity reaction in groups given thiourea treatment. The immune responses were restored in group receiving thyroxine supplementation during treatment phase.