Repeated injections of interferon-alpha A/D in Balb/c mice: behavioral effects.

Interferon-alpha decreases food intake and activity in mice and humans. The present study further explores parallels between effects of this protein in humans and mice, using a hybrid recombinant interferon-alpha A/D (INF-alpha A/D) that has antiviral and hepatic activity in mice. Measures of activity (open field), muscle strength (forelimb grip strength), and motor ability (swim posture and endurance with 0, 3, and 6% added weight) were examined in Balb/c mice injected with 1600 U/g of hybrid rhuIFN-alpha A/D daily for 5 days (n = 9) or with IFN vehicle (n = 11). Open field activity was significantly depressed in the group exposed to IFN. The number of times the nose dipped under the water when swimming with 3% added body weight was higher in the IFN-treated mice, while float time was decreased with 6% added weight. The IFN-treated mice were slower to adopt the new strategies necessary to swim with added weight. Depression of motor activity is a robust, general effect of IFN treatment observed in this as well as previously published studies. Together, these studies demonstrate activity decrements in two different strains of mice, two different activity measures, acute and chronic injections, and recombinant and nonrecombinant IFN preparations.