Chronic cold exposure affects the antioxidant defense system in various rat tissues.
BACKGROUND
Chronic exposure to stress alters the normal body homeostasis and, hence, leads to the development of various human pathologies, which might involve alterations in the antioxidant defense system. We studied the effect of chronic cold exposure on oxidative stress and antioxidant defense system in various rat tissues.


METHODS
Male albino rats (Wistar strain), 2-3 months old, were exposed to 3 weeks of cold treatment. Antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) were measured in addition to the antioxidants, ascorbic acid (AsA) and glutathione (GSH), and the prooxidants, lipid peroxides (LPO) and xanthine oxidase (XOD), in brain, heart, kidney, liver and small intestine using standard protocols.


RESULTS
Chronic cold exposure resulted in a significant increase in LPO in all the tissues studied while XOD was increased in the brain and intestine. Total SOD activity was significantly decreased in all the tissues, whereas CAT activity was significantly increased in the kidney and decreased in heart, liver and intestine in the animals exposed to cold. GPx activity was increased only in the brain and intestine of stressed rats. Chronic cold exposure resulted in significant decrease in GR activity in heart, liver and intestine. GST activity was increased (except heart) and GSH was significantly decreased in all the tissues in treated rats. AsA was increased in kidney and intestine but decreased in heart of stressed animals.


CONCLUSIONS
The observed changes in the antioxidant defense system are tissue specific, but it is evident that chronic exposure to cold leads to oxidative stress by displacing the prooxidant-antioxidant balance of this defense system by increasing the prooxidants while depleting the antioxidant capacities.
Kaushik
Susmita
S
Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India.
Kaur
Jyotdeep
J
D000818:Animals; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D003080:Cold Temperature; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006706:Homeostasis; D015227:Lipid Peroxidation; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
D000975:Antioxidants; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005978:Glutathione; D001205:Ascorbic Acid