Особенности социального поведения мышей после длительного действия психоэмоционального и инфекционного факторов

Abstract

The behavior of male mice of the inbred C57B/6 strain was investigated after prolonged exposure to two factors ‒ social stress and helminth infection, the combination of which is often observed in humans. Four experimental groups of mice were compared: 1) with a long-lasting experience of social defeats in intermale confrontations (30 days) (SS); 2) infected with O. felineus helminths (6 months) (OF); 3) exposed to both factors (SS + OF); 4) intact mice without influence of any factors (CON). The behavior of all animals was assessed in the open field test with a box placed in it, which was empty for the first 3 min of the test and kept an unfamiliar male of the inbred BALB/c strain for the second 3 min. Social stress had a more pronounced effect on the assessed behavioral parameters of mice in this test than infection. Mice SS were the most active in exploring of the box with an unfamiliar male inside than other animals: they climbed on it much more often and had a longer average time spent near the box. In addition, they had increased exploratory (number of wall rearings) and grooming (the number and duration) activities. Behavior of infected OF mice did not differ from CON one in both the first and the second 3 min of the test. In mice with a combined effect of factors (SS + OF), non-social forms of behavior also did not differ from the control indices, and the reaction to an unfamiliar male in the box was weaker than in mice SS. It was concluded that long-lasting experience of social defeats in intermale confrontations has a more pronounced effect on the social and non-social behavior in mice, compared with chronic infection of animals with O. felineus helminths. Moreover, the combination of two influencing factors promotes to the decreasing of social interest in mice.