Study the Effects of Prenatal Exposure to Relaxin-3 on Reflexive Motor Behaviours Development in Mice Offspring

Relaxin-3 is a member of a structurally related peptide superfamily that includes relaxin and insulin-like peptide hormones, which play a role in regulating stress, memory, nutrition, pregnancy and childbirth, mental illnesses, including anxiety, depression and schizophrenia, cardiovascular protective effects, and regulating social behaviour and nutritional behaviour of children with autism. However, there is no information about the effect of relaxin-3 during pregnancy on the development of behavioural and motor reflexes in mice offspring. This study aims to determine the effects of prenatal exposure to relaxin-3 on reflexive motor behaviours in mice offspring. Twelve pregnant female NMRI mice (8-10 weeks old) were randomly and equally allocated into four groups. In the control group, mice received water, while in groups 2-4, female mice were i.p. administered relaxin-3 (12.5, 25 and 50 μg/kg) at 5, 8, 11, 14 and 17 days of gestation (GD). Following delivery, 10 pups from each pregnant mouse were selected, and reflexive motor behaviours including ambulation, hind-limb foot angle, surface righting, grip strength, front- and hind-limb suspension, and negative geotaxis were determined. Based on the findings, maternal exposure to relaxin-3 promoted an increase in ambulation scores and hind-limb suspension in offsprings (p < 0.05). Also, maternal exposure to relaxin-3 (25 and 50 μg/kg) promoted an increase in grip strength and front limb suspension scores in newborns (p < 0.05). Maternal exposure to relaxin-3 decreased surface righting (p < 0.05). Prenatal exposure to relaxin-3 (25 and 50 μg/kg) decreased hind-limb foot angle and negative geotaxis in pups (p < 0.05). These results suggested that relaxin-3 exposure during pregnancy had a positive effect on all tested reflexive motor behaviours in mice offspring.