Effects of vitamin C on myocardial mitochondrial function and ATP content in hypoxic rats.
OBJECTIVE
To observe the effects of large dose of vitamin C (Vc) on myocardial mitochondrial function, ATP content, and myocardial structure in acute and chronic hypoxic rats.


METHODS
Rats were exposed to a simulated altitude 4000 m (barometric pressure = 43 kPa) for 3 and 30 d. Vc (0.75 g.kg-1.d-1) was injected i.p. The heart mitochondrial respiratory function were determined by Clark-type O2 electrode; mitochondrial membrane fluidity (MMF) were assayed through fluorescence polarizative method; the contents of ATP, ADP, and AMP in myocardial tissue were measured with HPLC.


RESULTS
After administration of Vc, the ATP content was increased from 35 +/- 3 mg.g-1 to 53 +/- 3 mg.g-1 in acute hypoxic rats (P < 0.01), from 42 +/- 4 mg.g-1 to 48 +/- 3 mg.g-1 in chronic hypoxic rats (P < 0.01); Pa, O2 was increased from 7.2 +/- 1.4 kPa to 9.5 +/- 1.2 kPa in acute hypoxic rats (P < 0.01); mitochondrial respiratory control rate (RCR) was increased from 2.1 +/- 0.6 to 4.7 +/- 0.5 in acute hypoxic rats (P < 0.01), and from 3.3 +/- 0.7 to 4.5 +/- 0.6 in chronic hypoxic rats (P < 0.01); MMF was increased in acute and chronic hypoxic rats (P < 0.05); the degree of myocardial necrosis in vitamin C preventive rats was attenuated as compared with those of acute hypoxic rats.


CONCLUSIONS
Vc is effective on improving myocardial energy metabolism and protecting against myocardial structural injury in hypoxic rats.
Luo
G
G
Institute of High Altitude Medicine, Third Military Medical University, Chongqing, China.
Xie
Z Z
ZZ
Liu
F Y
FY
Zhang
G B
GB
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D019069:Cell Respiration / Q000187:drug effects; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects; D008929:Mitochondria, Heart / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D000975:Antioxidants; D000255:Adenosine Triphosphate; D001205:Ascorbic Acid