Efeitos da exposição ao material particulado (MP2,5) no sistema nervoso central de ratas Wistar e sua prole durante os períodos gestacional e lactação

Abstract

Exposure to environmental pollution represents an important risk factor for health, the particulate matter (PM2.5) present in the atmosphere has been implicated in the development and worsening of various central nervous system (CNS) pathologies. The interaction between PM2.5 and the CNS may occur through the olfactory pathway, being related to neurodegenerative processes. Exposure to PM2.5 may interfere with the development of the embryonic CNS resulting in behavioral changes in Wistar rats. From the collected PM2.5 samples, two dilutions 1:50 and 1:25 were prepared for intranasal instillation of pregnant females during the periods of pregnancy and lactation (39 days), allocated in three experimental groups, blank and dilutions 1:50 and 1:25. The objectives of this study were to evaluate exposure to PM2.5 related to behavior, detect and quantify the metallic components of PM2.5 in the hippocampus and prefrontal cortex, evaluate the formation of reactive oxygen species (ROS) and the activity of the enzyme superoxide dismutase (SOD). Two behavioral tasks were performed, the novel objects in the open field and the Y maze. The results obtained in the recognition of objects showed significant differences, between the females the group 1:25 (4.8 ± 1.3) and the blank group (9.1 ± 1.3) (p = 0.061) related to new object interaction. Among males, a significant difference (p = 0.0128) was found related to the interaction with the family object between the blank (3.7 ± 1.0) and the 1:50 (7.2 ± 1.0) groups. A significant difference was also found (p = 0.0207) between the blank group (7.5 ± 1.0) and the 1:25 group (4.2 ± 1.0) in the interaction with the new object, indicating a reduction in exploratory behavior and a decline in short and long-term memory, especially in males. In the Y maze, the offsprings showed significant differences between females and males, blank group females (67.02 ± 5.41) males (39.60 ± 5.41) (p < 0.0001), group 1:50 females (62.62 ± 5.41) males (42.47 ± 5,41) (p = 0.0014) and 1:25 females (64.25 ± 5.41) males (40.22 ± 5.41) (p = 0.0002) indicating a reduction in spatial memory in males. The behavioral data obtained point to a higher susceptibility of males in relation to females when exposed to PM2.5. The detection and quantification in the hippocampus and prefrontal cortex (PFC) revealed the presence of metallic components of PM2.5. Regarding the ROS formation, there was no significant difference between the groups (p > 0.05), while the analysis of SOD activity in offspring PFC was found a significant difference (p = 0.0095) between the blank (50, 62 ± 10.84) and 1:50 (91.86 ± 10.84) groups, indicating an increase in antioxidant activity. In the hippocampus of the matrices a significant difference (p = 0.0001) was found between the blank (79 ± 13.18) and 1:25 (6.10 ± 13.18) groups. The results indicated the presence of PM2.5 in the nervous tissues, and alteration in the spatial memory of the offspring males, and an alteration in the redox balance was also observed.