Role of vitamin B6 status on antioxidant defenses, glutathione, and related enzyme activities in mice with homocysteine-induced oxidative stress

Figures & data

Fig. 1 The study design.

Table 1 Composition of normal and experimental diets

Diet (ingredients)	%	Normal diet (g/kg dry matter)	Vitamin B6-deficient diet (g/kg dry matter)
Casein	14.00	140	140
Dextrinized cornstarch	15.50	155	155
Sucrose	10.00	100	100
Corn starch	46.60	466	466
Alphacel, non-nutritive bulk	5.00	50	50
Soybean oil	4.00	40	40
AIN-93M mineral mix^a	3.50	35	35
l-Cystine	0.18	1.80	1.80
AIN-93-VX vitamin mix^b	1.00	10	–
AIN-93-VX vitamin mix (without pyridoxine-HCl)	1.00	–	10
Choline bitartrate	0.25	2.50	2.50
tert-Butylhydroquinone	0.08×10^−2	0.08×10^−1	0.08×10^−1

All compounds used in the study were of analytical grade.

^aSupplied (g/kg diet), CaCO₃, 357.00; KH₂PO₄, 250.00; K₃C₆H₅O₇·H₂O, 28.00; NaCl, 74.00; K₂SO₄, 46.60; MgO, 24.00; Ferric citrate, 6.06; ZnCO₃, 1.65; MnCO₃, 0.63; CuCO₃, 0.30; KIO₃, 0.01; Na₂O₃Se, 10.25×10⁻³; (NH₄)₆Mo₇O₂₄·4H₂O, 7.95×10⁻³; Na₂O₃Si·9H₂O, 1.45; KCr(SO₄)₂·12H₂O, 2.75×10⁻¹; LiCl, 1.74×10⁻²; B(OH)₃, 8.15×10⁻²; NaF, 6.35×10⁻²; NiCO₃, 3.18×10⁻²; NH₄VO₃, 0.66×10⁻²; powdered sugar, 209.81.

^bSupplied (g/kg diet), nicotinic acid, 3; D-calcium pantothenate, 1.6; pyridoxine-HCl, 0.7; thiamine HCl, 0.60; riboflavin, 0.60; folic acid, 0.20; D-biotin, 0.02; vitamin B-12 (0.1% triturated in mannitol), 2.50; α-tocopherol powder (250 U/g), 30.00; vitamin A palmitate (250,000 U/g), 1.60; vitamin D-3 (400,000 U/g), 0.25; phylloquinone, 0.75×10⁻¹; powdered sucrose, 959.66.

Table 2 Vitamin B6, homocysteine, and cysteine in plasma and liver

	Control (n=9)	Homocysteine (n=9)	B6 deficient (n=9)	B6 supplement (n=9)
PLP (nmol/L)
Plasma	243.98±30.36^b	224.51±15.83^c	26.43±3.67^d	276.58±16.22^a
Liver	6.66±1.28^a	4.90±0.90^b	3.73±0.60^b	4.94±1.33^b
Homocysteine (µmol/L)
Plasma	3.53±0.81^c	15.43±1.93^b	55.41±25.23^a	21.27±4.74^b
Liver	1.32±0.19^d	2.14±0.21^b	3.08±1.10^a	1.79±0.15^c
Cysteine (µmol/L)
Plasma	117.73±21.34^a	120.42±12.80^a	95.80±10.37^b	112.46±11.26^a
Liver	37.39±11.36	32.01±5.03	28.19±3.81	27.54±5.79

PLP, pyridoxal 5’-phosphate. Values with different superscript letters are significantly different among groups; p< 0.05.

Table 3 Oxidative stress indicator, glutathione, and antioxidant enzyme activities in plasma and liver

	Control (n=9)	Homocysteine (n=9)	B6 deficient (n=9)	B6 supplement (n=9)
MDA (µmol/L)
Plasma	3.53±0.64	3.43±0.43	3.50±1.13	3.40±0.46
Liver	1.40±0.47^b	1.37±0.46^b	3.33±1.45^a	1.18±0.55^b
GSH (nmol/mg protein)
Plasma	0.56±0.20^a	0.32±0.09^c	0.43±0.18^b	0.26±0.03^c
Liver	15.39±3.15^a	11.50±0.79^b	9.07±1.26^c	9.72±2.12^c
GPx (nmol/min/mg protein)
Plasma	21.21±2.02	20.89±3.84	21.51±1.36	22.44±2.81
Liver	332.94±43.31	299.11±47.93	315.31±18.69	348.57±55.29
GR (nmol/min/mg protein)
Plasma	3.27±0.73^a	2.15±0.48^b	2.63±0.55^b	2.33±0.77^b
Liver	77.06±6.02^b	76.78±5.17^b	84.51±3.64^a	77.90±2.50^b

MDA, malondialdehyde; GSH, reduced glutathione; GPx, glutathione peroxidase; GR, glutathione reductase.

Values with different superscript letters are significantly different among groups; p<0.05.