Protective effect of melatonin on methylmercury-Induced mortality in mice

Tohoku J Exp Med. 2000 Aug;191(4):241-6. doi: 10.1620/tjem.191.241.

Abstract

Effect of melatonin on the mortality in methylmercury chloride (MMC)-intoxicated mice was evaluated. Mice were given MMC in the diet (40 mg Hg/g) with or without melatonin in drinking water (20 mg/ml) for 5 weeks. In the control group, given MMC alone, 4 of 10 mice began to show neurological signs (e.g., abnormal righting reflex, staggering gaitfallen and posture on its side) concomitant with loss of body weight 4-7 days before death. This group also showed 60% of survival rate on the 35th day. However, the treated group, concomitantly given melatonin, showed a 100% of survival rate on the 35th day, although 1 of 10 mice began to show the neurological signs on the 33rd day. The level of thiobarbituric acid reactive substance in the brain, as an indication of oxidative damage, showed a significant decrease in the treated group compared with the control group. Thus, the 100% survival rate in the treated group may be partly due to antioxidative effect of melatonin on the MMC induced neurotoxicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology
  • Brain / drug effects
  • Brain / metabolism
  • Kidney / metabolism
  • Liver / metabolism
  • Male
  • Melatonin / pharmacology*
  • Mercury / metabolism
  • Methylmercury Compounds / antagonists & inhibitors*
  • Methylmercury Compounds / toxicity*
  • Mice
  • Mice, Inbred ICR
  • Nervous System / drug effects
  • Nervous System / physiopathology
  • Neurotoxins / antagonists & inhibitors*
  • Neurotoxins / toxicity*
  • Thiobarbituric Acid Reactive Substances / metabolism

Substances

  • Antioxidants
  • Methylmercury Compounds
  • Neurotoxins
  • Thiobarbituric Acid Reactive Substances
  • Mercury
  • Melatonin
  • methylmercuric chloride