Role of vitamin B6 status on antioxidant defenses, glutathione, and related enzyme activities in mice with homocysteine-induced oxidative stress.
BACKGROUND
Vitamin B6 may directly or indirectly play a role in oxidative stress and the antioxidant defense system.


OBJECTIVE
The purpose of this study was to examine the associations of vitamin B6 status with cysteine, glutathione, and its related enzyme activities in mice with homocysteine-induced oxidative stress.


METHODS
Four-week-old male BALB/c mice were weighed and divided into one of four dietary treatment groups fed either a normal diet (as a control group and a homocysteine group), a vitamin B6-deficient diet (as a B6-deficient group), or a B6-supplemented diet (a pyridoxine-HCl-free diet supplemented with 14 mg/kg of pyridoxine-HCl, as a B6 supplement group) for 28 days. Homocysteine thiolactone was then added to drinking water in three groups for 21 days to induce oxidative stress. At the end of the study, mice were sacrificed by decapitation and blood and liver samples were obtained.


RESULTS
Mice with vitamin B6-deficient diet had the highest homocysteine concentration in plasma and liver among groups. Significantly increased hepatic malondialdehyde levels were observed in the vitamin B6-deficient group. Among homocysteine-treated groups, mice with vitamin B6-deficient diet had the highest plasma glutathione concentration and relatively lower hepatic glutathione concentration. The glutathione peroxidase activities remained relatively stable in plasma and liver whether vitamin B6 was adequate, deficient, or supplemented.


CONCLUSIONS
Mice with deficient vitamin B6 intakes had an aggravate effect under homocysteine-induced oxidative stress. The vitamin B6-deficient status seems to mediate the oxidative stress in connection with the redistribution of glutathione from liver to plasma, but not further affect glutathione-related enzyme activities in mice with homocysteine-induced oxidative stress.
School of Nutrition, Chung Shan Medical University, Taichung, Taiwan.|Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan.
Cheng-Chin
CC
Hsu
Critical Care and Respiratory Therapy, Taichung Veterans General Hospital, Taichung, Taiwan.
Chien-Hsiang
CH
Cheng
School of Nutrition, Chung Shan Medical University, Taichung, Taiwan.|Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan.
Chin-Lin
CL
Hsu
School of Nutrition, Chung Shan Medical University, Taichung, Taiwan.
Wan-Ju
WJ
Lee
School of Nutrition, Chung Shan Medical University, Taichung, Taiwan.|Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan.
Shih-Chien
SC
Huang
School of Nutrition, Chung Shan Medical University, Taichung, Taiwan.|Department of Nutrition, Chung Shan Medical University Hospital, Taichung, Taiwan; ych@csmu.edu.tw.
Yi-Chia
YC
Huang
antioxidant enzyme activities; glutathione; homocysteine-induced oxidative stress; mice; vitamin B6