7-hydroperoxycholesterol and oxysterols as indices of oxidative stress: chronic ethanol feeding and rat skeletal muscle

The present study is undertaken to determine if ethanol affects 7-hydroperoxycholesterol or oxysterols in rat skeletal muscle after chronic ethanol feeding. Wistar rats were fed a liquid diet containing ethanol as 35% of total calories. After 6 weeks, soleus (Type I fibre-predominant) and plantaris (Type II fibre-predominant) skeletal muscles were dissected out. We measured 7alpha- and 7beta-hydroperoxycholest-5-en-3beta-ol (7alpha-OOH and 7beta-OOH) as well as 7alpha- and 7beta-hydroxycholesterol (7alpha-OH and 7beta-OH) and 3beta-hydroxycholest-5-en-7-one (7-keto). We found that in response to chronic alcohol feeding, there were significant increases in soleus 7alpha-OH (P=0.0005), 7beta-OH (P=0.0005) and 7-keto (P=0.0007), but in the plantaris, 7beta-OH increased (P=0.0418). Their elevation in chronic experimental alcoholism, together with increases in cholesterol hydroperoxides, may possibly represent evidence of increased oxidative stress.