POSSIBLE INVOLVEMENT OF OXYGEN-DERIVED FREE-RADICALS IN ABNORMAL HEMOSTASIS INDUCED BY SART STRESS (REPEATED COLD STRESS) IN LABORATORY-ANIMALS

Abnormal hemostatic profiles indicating hemorrhagic tendency have been reported in rodents exposed to prolonged fluctuation in ambient tempe rature, known as SART (specific alternation of rhythm in temperature)- stressed animals. In this study, investigation was made of possible in volvement of oxygen-derived free radicals in the development of stress -induced hemostatic alteration. SART-stressed rats and mice exhibited marked decrease in platelet count, fibrinogen level and factor VIII:C activity. Superoxide dismutase, when administered s.c. twice a day to mice for 7 days of stress exposure, inhibited the above alterations. C atalase given in the same manner, had essentially the same ef fect, th ough to a lesser extent. Allopurinol administered orally once daily du ring stress reduced stress-induced thrombocytopenia, but caused consid erable increase in fibrinogen and factor VIII:C activity in stressed a nd unstressed mice. Lipid peroxide significantly increased in the hear t but not in the plasma following stress exposure in rats and mice. Ac tive oxygens would thus appear to be, at least partially, involved in the development of abnormal hemostasis induced by SART stress.