Reseach In Melatonin's Effection On Antioxidaion And Immunologic Function Of Rats Under Heat-stress

Objective: to study the effect of melatonin on mouse immunity,antioxidation and its possible mechanisms. Method: 140 mice (Km, female, 6-8 weeks of age) were divided into 4 groups. Group 1 was treated with physiological saline (for control) ;group 2-4 was given melatonin in 5 mg/kg .wt,10mg/kg.wt,20mg/kg.wt concentration respectively. In each group, some mice were killed at time of 0, 2,4,8,12,24 hours after the last time heat stress (37°C,1 hour) treatment ,the others at room temperature were also killed . weight of stress marker organs ( Adrenal Glands, Spleen,thymus gland ) ,concentration of immunocyte(WBC,LYM,MID,GRAN) in blood, antioxidation index(T-AOC,SOD,GSH-Px,MDA),pathological change of stress marker organs were measured. Data were processed with SPSS soft ware. Results: 1. melatonin could remit the weight decrease and rectal temperature rise caused by heat stress;2. melatonin could relieve thymus and spleen's acute atrophy and adrenal gland's hypertrophy caused by heat stress;3. melatonin with middle and high dose could raise the immune related blood cells amount ;4. the activity of the antioxidase(SOD,GSH-Px) and tatal antioxygen capability declined while contents of MDA rised after heat stress, melatonin could aliminate free radical effectively and elevated the activity of the antioxidase;5. the stress indicating organs presented pathological change after heat stress,the melatonin groups were not obvious .Conclusions:1. The immunity and antioxidation of the mice is obviously damaged after heat stress;2. melatonin could protect the immunity and antioxygen capability of mice under heat stress;3. melatonin could mitigate pathological change coused by heat stress.