alpha-Tocopherol protects against alpha-naphthylisothiocyanate-induced hepatotoxicity in rats less effectively than melatonin.
The protective effect of alpha-tocopherol (alpha-Toc), which exerts antioxidant and anti-inflammatory actions, against alpha-naphthylisothiocyanate (ANIT)-induced hepatotoxicity in rats was compared with that of melatonin because orally administered melatonin is known to protect against ANIT-induced hepatotoxicity in rats through its antioxidant and anti-inflammatory actions. Rats intoxicated once with ANIT (75 mg/kg, intraperitoneal (i.p.)) showed liver cell damage and biliary cell damage with cholestasis at 24 h, but not 12 h, after intoxication. ANIT-intoxicated rats received alpha-Toc (100 or 250 mg/kg) or melatonin (100 mg/kg) orally at 12 h after intoxication. The alpha-Toc administration protected against liver cell damage in ANIT-intoxicated rats, while the melatonin administration protected against both liver cell damage and biliary cell damage with cholestasis. ANIT-intoxicated rats had increased hepatic lipid peroxide concentration and myeloperoxidase activity at 12 and 24 h after intoxication. ANIT-intoxicated rats also had increased serum alpha-Toc and non-esterified fatty acid (NEFA) concentrations at 12 and 24 h after intoxication and increased serum triglyceride and total cholesterol concentrations at 24h. The administration of alpha-Toc to ANIT-intoxicated rats increased the hepatic alpha-Toc concentration with further increase in the serum alpha-Toc concentration and attenuated the increased hepatic lipid peroxide concentration and myeloperoxidase activity and serum NEFA concentration at 24 h after intoxication. The melatonin administration did not affect the hepatic alpha-Toc concentration but attenuated the increased hepatic lipid peroxide concentration and myeloperoxidase activity and serum alpha-Toc, NEFA, triglyceride, and total cholesterol concentrations at 24 h after ANIT intoxication. These results indicate that orally administered alpha-Toc protects against ANIT-induced hepatotoxicity in rats possibly through its antioxidant and anti-inflammatory actions less effectively than orally administered melatonin.
Ohta
Yoshiji
Y
Department of Chemistry, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan. yohta@fujita-hu.ac.jp
Kongo-Nishimura
Mutsumi
M
Imai
Yoichiro
Y
Matsura
Tatsuya
T
Kitagawa
Akira
A
Yamada
Kazuo
K
D015058:1-Naphthylisothiocyanate / Q000633:toxicity*; D000818:Animals; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D024502:alpha-Tocopherol / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*
D015058:1-Naphthylisothiocyanate; D024502:alpha-Tocopherol; D008550:Melatonin