Pyridoxine supplementation before puberty ameliorates MAM-induced cognitive and sensorimotor gating impairments

Schizophrenia is a kind of neurodevelopmental mental disorder in which patients begin to experience changes early in their development, typically manifesting around or after puberty and has a fluctuating course. Environmental disturbances during adolescence may be a risk factor for schizophrenia-like deficits. As a better treatment option, preventive intervention prior to schizophrenia may be more beneficial than direct treatment. More effective stress-relieving interventions during the critical puberty period may prevent schizophrenia-like neuronal changes and the transition to schizophrenia in adulthood. Pyridoxine deficiency alters the function of NMDA (n-methyl-D-aspartic acid) receptors and plays a key role in learning and memory. In this study, we prepared a progeny model of schizophrenia by exposing pregnant rats to methoxymethanol acetate (MAM) on gestational day 17. The offspring rats were injected intraperitoneally with pyridoxine daily from birth to prepuberty PND12-PND21), and behavioral changes in the offspring rats were observed in adulthood. Cannabinoid receptor interacting protein 1 (CNRIP1) and cannabinoid receptor-1 (CB1R), which regulate memory, cognitive and motor activity, were detected in the prefrontal cortex (PFC) and hippocampus of the offspring rats, and the cell proliferation in the hippocampal dentate gyrus (DG) was also observed. The results showed that the MAM rats spent less time the open arm in the elevated plus maze test, decreased discrimination coefficient in novel object recognition test, and decreased prepulse inhibition, while the MAM rats supplemented with pyridoxine in prepuberty did not show any of the above abnormal behavioral changes in adulthood. By examining related proteins in the PFC and hippocampus, we found that only CB1R protein expression was downregulated in the PFC, whereas CNRIP1 expression was not only elevated in the hippocampus, but also significantly increased in pyridoxine- supplemented MAM rats. Meanwhile, pyridoxine supplementation alleviated the reduction of doublecortin (DCX)-positive cells and Ki67-positive cells in MAM rats. These results indicate that prepuberty pyridoxine supplementation has a positive effect on the prevention of cognitive deficits and sensorimotor gating impairment in MAM-induced schizophrenia-like rats, accompanied by changes in the CB1R and CNRIP1 expression in PFC and hippocampus, as well as the regeneration of neurons in the DG region.