Sm. Shin et al., PROTECTIVE EFFECT OF ALPHA-TOCOPHEROL ON BRAIN-CELL MEMBRANE-FUNCTIONDURING CEREBRAL CORTICAL HYPOXIA IN NEWBORN PIGLETS, Brain research, 653(1-2), 1994, pp. 45-50
Protective effect of alpha-tocopherol on the structure and function of
brain cell membranes was investigated by measuring Na+,K+-ATPase acti
vity and products of lipid peroxidation (fluorescent compounds) in bra
in cell membranes obtained from newborn piglets. Four groups of anesth
etized, ventilated piglets were studied: five hypoxic piglets and five
normoxic piglets were pretreated with free alpha-tocopherol (20 mg/kg
/dose i.m.), five additional hypoxic piglets received i.m. placebo and
five normoxic piglets served as control. Placebo and alpha-tocopherol
were given 48 and 3 h prior to onset of hypoxia. Hypoxic hypoxia was
induced and cerebral hypoxia was documented as a decrease in the ratio
of phosphocreatine to inorganic phosphate (PCr/P-i) using P-31 NMR sp
ectroscopy. PCr/P-i decreased from baseline of 2.62 +/- 0.54 to 1.05 /- 0.27 in alpha-tocopherol-pretreated and from 2.44 +/- 0.48 to 1.14
+/- 0.30 in the placebo-pretreated group during hypoxia. Na+,K+-ATPase
activity was unchanged in both normoxic and hypoxic alpha-tocopherol-
pretreated groups. However, in placebo-pretreated hypoxic group, Na+,K
+-ATPase activity decreased as compared with control (44.9 +/- 9.7 vs.
61.8 +/- 5.7 pmol P-i/mg protein/h, P < 0.005). The level of fluoresc
ent compounds increased in placebo-pretreated but not in alpha-tocophe
rol-pretreatcd group as compared with control. During hypoxia, serum a
lpha-tocopherol levels were higher in alpha-tocopherol-pretreated grou
ps as compared with placebo-pretreated hypoxic group. The present data
indicates that alpha-tocopherol protects brain cell membranes in newb
orn piglets from lipid peroxidative damage during tissue hypoxia proba
bly by being incorporated in cell membrane and also as circulating ant
ioxidant.