Effect of alpha-lipoic acid supplementation on trace element levels in serum and in postmitotic tissue in aged rats

Redistribution of redox-active divalent metal ions (e.g. copper, zinc, and iron) in postmitotic tissues of lipoic acid supplemented aging rats has been proposed to contribute to metal-catalyzed protein oxidation. DL-alpha lipoic acid (LA) (100 mg/kg body wt/day) was administered intraperitoneally to the Sprague-Dawley rats for 14 days. Serum copper levels lowered in the aged rats with LA supplementation compared to the rats without LA supplementation. On the other hand, serum zinc and iron levels increased in the aged rats with LA supplementation compared to the rats without LA supplementation. Copper levels of the postmitotic tissues were not changed in the aged rats with LA supplementation compared to the controls. The heart zinc levels detected in LA supplemented rats were significantly lower than controls. Similarly, the iron levels of the heart were found to be significantly lower in LA supplemented rats when compared to control rats. LA supplementation did not affect brain and muscle iron levels. The brain and muscle zinc levels remained the same in both group of rats. Based on the findings of our study, we have concluded that LA may exhibit prooxidant effect depending on the altered trace element homeostasis. Therefore, our results emphasize the importance of monitoring the dose of LA supplementation, duration of treatment and its potential harmful effects in the postmitotic tissues of aged rats.