Effects of Different Concentrations of PM2.5 on the Expression of the Nasal Mucosa, Olfactory Bulb, and Related Inflammatory Factors in Rats

Abstract BackgroundAlthough the damaging effect of inhaled smoke on the respiratory system has been widely reported, there are relatively few studies on the effects of inhaled smoke on the nasal mucosa and olfactory bulb. In this study, we observed the activities of adult rats chronically exposed to different concentrations of PM2.5 and analyzed its effects on the olfactory function and the expression of inflammatory factors in the serum, nasal mucosa, and olfactory bulb of rats.MethodsSD rats were randomly divided into normal control, low-smoke, middle-smoke, and high-smoke groups. The groups exposed to different concentrations of PM2.5 smoke were treated with smoke environment intervention for 4 h twice daily for 90 days, while the normal control group was fed routinely,After 90 d,the behavior of in the food-seeking glomeruli of rats was analyzed. The contents of IL-1β, IL-6, and TNF-ɑ in the serum, nasal mucosa, and olfactory bulb of rats were determined by ELISA, and the correlation between them was analyzed. taken for HE staining and TUNEL detection to observe the pathological damage of the nasal mucosa and olfactory bulb.ResultsAfter a series of tests, we found that Long-term exposure to the low, medium, and high concentrations of moxa smoke can cause pathological changes in the nasal mucosa, increase the number of apoptotic cells in the nasal mucosa and olfactory bulb, and increase the expression of IL-1β, IL-6, and TNF-ɑ in the serum, nasal mucosa, and olfactory bulb. Simultaneously,The behavior of the rats also changed. The rats in the medium and high concentrations of moxa smoke searched for food longer, traveled shorter distances and slowed down.ConclusionLong-term exposure to medium and high concentrations of moxa smoke can decrease the olfactory sensitivity of rats.