Effect of atmospheric PM_2.5 on the protein expression of brain-derived neurotrophic factor and its receptor TrkB in the hippocampus tissue of rats

Objective To investigate the effect of atmospheric fine particulate matter (PM_2.5) exposure on the protein expression of brain-derived neurotrophic factor (BDNF) and its related proteins of tyrosine receptor kinase B (TrkB) in the hippocampus tissue of rats.

Methods PM_2.5 was collected to prepare a suspension. Forty-eight specific pathogen-free male Sprague-Dawley rats were randomly divided into control groups and exposure groups, with 8 rats in each group. Rats in the exposure groups were treated with 20 mg/kg PM_2.5 suspension via intratracheal instillation, and rats in the control groups were treated with the same amount of normal saline. The treatments were performed once a week for 1 month, 3 months, and 6 months, respectively. The protein expression of PKA in the hippocampal tissue of the rats was determined by immunohistochemistry, and the protein expression levels of BDNF, TrkB, AKT, and CREB in the hippocampal tissue of the rats were determined by Western blot.

Results Compared with the corresponding control groups, the 3-and 6-month exposure groups had significantly decreased PKA positive cells in the hippocampus tissue of the rats and significantly decreased protein expression levels of BDNF, TrkB, AKT, and CREB (P < 0.05).

Conclusion Exposure to atmospheric PM_2.5 can reduce the protein expression levels of BDNF, TrkB, AKT, CREB, and PKA in the hippocampus tissue of rats.