Social defeat stress exacerbates the blood abnormalities in Opisthorchis felineus-infected mice.

A model of chronic opisthorchiasis combined with social stress is examined; this situation is more likely for humans and animals than a separate impact of the infectious factor. For this purpose, we evaluated the effects of Opisthorchis felineus ("OP" group) and 30-day social stress (confrontations between males, "SS" group) alone and in combination ("OP + SS" group) in inbred C57BL/6 male mice and compared these effects according to the parameters listed below. The animals exposed to neither factor formed the control group ("CON").

Combined effects of social stress and liver fluke infection in a mouse model.

The effects of two influences, social stress and acute opisthorchiasis, were investigated in inbred C57BL/6J male mice. In the model of social stress, mice were repeatedly attacked and defeated by aggressive outbred ICR male mice and were in continuous sensory contact with an aggressive conspecific mouse in their home cage for 20 days. Acute opisthorchiasis was provoked by invasion of Opisthorchis felineus (50 larvae per animal) on the fourth day after the social stress was induced.

Repeated positive fighting experience in male inbred mice.

Repeated aggression is a frequent symptom of many psychiatric and neurological disorders, including obsessive-compulsive and attention deficit hyperactivity disorders, bipolar and post-traumatic stress disorders, epilepsy, autism, schizophrenia and drug abuse. However, repeated aggression is insufficiently studied because there is a lack of adequate models in animals. The sensory contact model (SCM), widely used to study the effects of chronic social defeat stress, can also be used to investigate the effects of repeated aggression.

Effect of MAO A deficiency on different kinds of aggression and social investigation in mice.

Monoamine oxidase A (MAO A) degrades serotonin, dopamine and noradrenaline, factors critically involved in the regulation of aggression. Different kinds of aggression were investigated in Tg8, a transgenic mouse strain lacking a functional MAO A gene. MAO A-deficient mice differ from wild-type C3H/HeJ (C3H) in terms of showing higher territorial, predatory and isolation-induced aggression.