In this study the effects of Vitamin C (Vit C) on hypothyroidism-associated learning and memory impairment in juvenile rats was investigated. The pregnant rats were kept in separate cages. After delivery, they were randomly divided into six groups and treated: (1) Control; (2) Propylthiouracil (PTU) which 0.005% PTU in their drinking; (3-5) Propylthiouracil- Vit C groups; besides PTU, dams in these groups received 10, 100 and 500 mg/kg Vit C respectively, (6) one group as a positive control; the intact rats received an effective dose, 100 mg/kg Vit. C. After delivery, the pups were continued to receive the experimental treatments in their drinking water up to 56th day of their life. Ten male offspring of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) which were started at 63th day (one week after stopping of the treatments). Brains were then removed for biochemical measurements. PTU increased time latency and traveled distance during 5 days in MWM while, reduced the spent time in target quadrant in MWM and step-trough latency (STL) in PA. PTU decreased thiol content, superoxide dismutase (SOD) and catalase (CAT) activities in the brain while, increased molondialdehyde (MDA). In MWM test, 10, 100 and 500 mg/kg Vit C reduced time latency and traveled distance without affecting the traveling speed during 5 days. All doses of Vit C increased the spent time in target quadrant in probe trail of MWM and also increased STL in PA test. Vit C increased thiol, SOD and CAT in the brain tissues while, reduced MDA. Results of present study confirmed the beneficial effects of Vit C on learning and memory. It also demonstrated that Vit C has protective effects on hypothyroidism-associated learning and memory impairment in juvenile rats which might be elucidated by the antioxidative effects.

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The results of this study demonstrated that administration of NS hydroalcoholic extract in the neonatal and juvenile growth period has an improving effect on the liver function of PTU- induced hypothyroid rats.

Objective: Free radical induced neural damage is concerned in brain ischemia and antioxidants are reported to have neuroprotective activity. We investigated the protective effects of antioxidant plants that are Pine Bark and Aloe vera extracts against movement activity and oxidative stress in ischemia rats. Materials and methods:Fifty rats were randomly separated into six groups (n=7); control group, middle cerebral artery occlusion (MCAO), MCAO+pine bark 1 (25 mg/kg), MCAO+pine bark 2 (05 mg/kg), MCAO+Aloe vera 1 (50 mg/kg), MCAO+Aloe vera 2 (100 mg/kg). All extracts were infused (IP) to animals for 14 days before MCAO. Then the middle cerebral artery of rats was occluded for 2 h and reperfused for 22 h. The brain malondialdehyde (MDA), Thiol levels and locomotor activity on rotarod test were assessed. Results:The MDA levels of brain were non-significantly increased in MCAO group vs control group. The thiol level of brain was significantly decreased in MCAO group compared to control group (p<0.005). The thiol level in groups pine bark 2 and Aloe vera 2 increased significantly vs MCAO group (p<0.01). The time stands rates on rotarod in MCAO group decreased significantly compared to control group. It was also increased significantly in pine bark 1 and pine bark 2 groups vs MCAO group (p<0.005). Time stands rates on rotarod in Aloe vera 1 and Aloe vera 2 groups were increased significantly compared to MCAO group (p<0.005). Conclusion:Increasing endogenous antioxidant enzymatic activities indicate that Aloe vera and pine bark have neuroprotective role. Thus, herbal treatment of pine bark and Aloe vera may improve the function of ischemiareperfusion brain injury related disorders.