Tehran University Medical Journal

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background: Dietary antioxidant vitamins, in particular vitamin C, can play a role in preventing the onset or progression of age-related visual impairment. The aim of this study was to determine the plasma ascorbic acid levels in normal individuals and in senile cataract patients.
Methods: The test group included fifty cataract patients, while the control group members were selected among medical staff and patients' companions after age matching with test group. The use questionnaire contained age, sex and location of residency (Urban or Rural). Five milliliter of drawn blood centrifuged and plasma ascorbic acid level was measured by spectrophotometry. Statistical analysis of plasma ascorbic acid concentrations were done using paired t-test.
Results: The mean plasma ascorbic acid level intest group and incotral group was 0.96±0.08 and 1.12±0.15mg/dl respectively. Plasma ascorbic acid level in test group was significantly lower than control group (p<0.0001). Aging was associated with a reduction in plasma ascorbic acid level in male while it showed no significant alteration in females. Rural and the female gender showed higher plasma ascorbic acid level.
Conclusions: This study revealed plasma ascorbic acid level in patients with senile cataract was lower than normal individuals. Antioxidant vitamins, in particular vitamin C, found in Mediterranean fruits and vegetables could be probably used in the prevention of cataracts, which is a major health service burden in many countries.

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background: Ascorbic acid improves cognitive impairments in several experimental models. Diabetes causes learning and memory deficits. In this study we hypothesized that chronic treatment with ascorbic acid (100mg/kg, p.o) would affect on the passive avoidance learning (PAL) and memory in control and streptozocin-induced diabetic rats.
Methods: Diabetes was induced by a single i.p. injection of STZ (60mg/kg). The rats were considered diabetic if plasma glucose levels exceeded 250mg/dl on three days after STZ injection. Treatment was begun at the onset of hyperglycemia. PAL was assessed 30 days later. Retention test was done 24 h after training. At the end, animals were weighted and blood samples were drawn for plasma glucose measurement.
Results: Diabetes caused impairment in acquisition and retrieval processes of PAL and memory in rats. Ascorbic acid treatment improved learning and memory in control rats and reversed learning and memory deficits in diabetic rats. Ascorbic acid administration also improved the body weight loss and hyperglycemia of diabetics. Hypoglycemic and antioxidant properties of the vitamin may be involved in the memory improving effects of such treatment.
Conclusion: These results show that ascorbic acid administration to rats for 30 days from onset of diabetes alleviated the negative influence of diabetes on learning and memory. Comparing with other nootropic drugs, vitamins have fewer side effects. Therefore, this regimen may provide a new potential alternative for prevention of the impaired cognitive functions associated with diabetes after confirming by clinical trials.

Background: Ascorbic acid (AA) is not synthesized in the brain but it is actively transported through blood-brain barrier by SVCT2 cotransporter and it is stored in high concentrations with heterogeneous distribution in areas such as nucleus accumbens shell (AcbSh) in the mammalian brain. Previous studies have shown that Ascorbic acid injection into AcbSh decreases feeding therefore, in the present study we evaluated the effects of oral Ascorbic acid pretreatment on changes in feeding upon its injection in AcbSh in adult male rats.

Methods: Sixty-three adult male rats (220-280 g) were divided into five treatment and five pretreatment groups. The treatment groups included the control (intact) group, sham-operated Ascorbic acid group that received normal saline as vehicle, and three other groups that received different doses of ascorbic acid (10, 50 and 250 µg/rat) by injection into AcbSh for four days. The pretreatment groups received Ascorbic acid (100 mg/kg) for 15 days via gastric gavage before receiving the aforementioned doses in treatment groups into intra nucleus AcbSh. Feeding measurement was repeated every 12 hours by automatic metabolic cage.

Results: The results indicated that all injected doses of Ascorbic acid (10, 50 and 250 µg/rat) into nucleus accumbens shell decrease food intake (P<0.05) in rats and oral Ascorbic acid pretreatment had no effects in this regard.

Conclusion: Our findings show that ascorbic acid is an effective factor in feeding regulation. Oral pretreatment seems to have no influence on the central effects of ascorbic acid in the nucleus accumbens shell.