Effects of boron on learning and behavioral disorders in ratautism model induced by intracerebroventricular propionic acid

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by learning, social interaction and repetitive movements seen in the first years of life, and its medical treatment has yet to be found. The aim of the present study was to investigate the learning, sociability, biochemical and histopathological effects of boron in rats in which an experimental autism model was induced by propionic acid (PPA). For this purpose, 40 male Spraque-Dawley rats were divided into 5 groups as control, autism, autism+4 mg/kg boron, autism+16 mg/kg boron and autism+risperidone. Behavioral tests were performed on the animals before experimental modeling, and then autism was expected to occur following intra-brain applications made via intracerabroventricular route. Post-autism, boric acid and risperidone were applied for 28 days and then behavioral tests were repeated. On the last day of the study, the rats were euthanized under anesthesia and brain tissue samples were collected. Histopathological analyses were conducted on BDNF in the left hippocampus, proinflammatory cytokines (TNF-α, IL-1β, IL-6), right hippocampus and cerebellum. In the behavioral tests, learning and direct social interaction skills were found to be impaired in the experimental autism groups when compared to the control group (p<0.05). When the boron-treated groups (4 and 16 mg/kg) were assessed, recovery in behavioral disorders caused by autism was only detected in the 4 mg/kg boron group. There was no statistically significant difference between the control and experimental groups in terms of BDNF levels of the brain tissues (p>0.05). TNF-α, IL-1β, IL-6 levels of proinflammatory cytokines were determined to increase in the autism groups in comparison with the control groups, but boron treatment lead to the improvement in these parameters (p<0.05). In the autism groups, while decreases were observed in cerebellum purkinje cell numbers, microglia (CD11b) and astrocyte (GFAP) activation in the cerebellum and hippocampus increased significantly in comparision with the control group (p<0.05). In conclusion, it was revealed that 4 mg/kg boron treatment provided more positive improvements in comparion with the reference drug, risperidone, based on the results of behavioral disorders such as learning and social interaction, biochemical and histopathological analyzes of brain tissue in experimental ASD modelling.