Effect of L-carnitine on nucleic acid status of aged rat brain.

The accumulation of damage to DNA plays a significant role in the etiology of the aging process. The importance of nutrition in delaying the aging process is well recognized. L-carnitine is a quaternary ammonium compound heterogeneously distributed in the brain. In the present study the effect of L-carnitine on DNA damage of various brain regions was investigated in a duration dependent way. Male albino rats aged 4 and 24 months were administered L-carnitine (300 mg/kg body weight/day) for 7,14 and 21 days. The activities of antioxidant enzymes, the levels of nucleic acids and the extent of DNA damage were measured in cortex, hippocampus, striatum, hypothalamus and cerebellum. Our results clearly showed that the activities of super oxide dismutase, glutathione peroxidase and the levels of DNA and RNA were significantly low in cortex, hippocampus and striatum of aged rat brain when compared with that of young rats. The regions that have lower antioxidants status are highly susceptible to oxidative DNA damage. Treatment with L-carnitine in aged rats enhanced the nucleic acid, antioxidant activity in a duration dependent manner with maximal effect after 21 days whereas no significant changes could be observed in the brain of young rats. These results suggest that that L-carnitine administration prevents age-related increment of DNA damage, thereby confirming the neuroprotective action of L-carnitine against aging.