Effect of Kiwifruit Extract (Actinidia deliciosa) on Body Weight, Thyroid Hormones, Pain and Memory in Hypothyroidism Male Rats

Oxidative stress due to hypothyroidism causes behavioral deficits. Kiwifruit contains various vitamins and antioxidants. In this study the effect of kiwifruit extract on body weight, memory, pain and serum T4 and T3 in hypothyroidism male rats was evaluated. Subjects and

Wistar male rats (200-250g) were divided into 8 groups (n=8) randomely as following: 1) Control, the remaining groups were hypothyroidism that received methimazole (500mg/L in drinking water) for 3 weeks. 2-7) Treated groups received orally either different doses of Kiwifruit extract (50,100,150, 200, 400 mg/kg/5ml or the same volume of normal saline for 14 days. 8) Positive control group receiving 1 mg/L of levothyroxine in drinking water. Serum thyroid hormones (with radioimmunoassay), body weight, pain (by tail-flick test), and memory (by shutle box) were measured for all groups. Data were analyzed with one-way ANOVA followed by Tukey’s post hoc and P<0.05 was assigned as least significant difference.

Serum T4 and T3, body weight and memory and pain reflex latency were decreased significantly after induction of hypothyroidism (P<0.01). Treatment with 150 and 200 mg/kg doses, without affecting the thyroid hormone serum level, improved memory and pain significantly (P<0.001) Higher doses of extract had no effect on above parameters.

Treatment with kiwifruit extract didn’t change thyroid hormones; therefore, had no effect on hypothalamus-pituitary-thyroid axis. Improving effects of Kiwifruit extract on behavioral deficits following hypothyroidism might be related to its antioxidant property in brain.