Noise exposure at different developmental ages can induce different short and long term habituation memory alterations. Correlation with hippocampal oxidative state.

BUJAN, GE; RODRIGUEZ GONZÁLEZ, M; GUELMAN, LR; MOLINA, SJ; CAPANI, F

San diego, CA

Congreso; 48th Annual Meeting of the Society for Neuroscience (SFN); 2018

Society for neurocience (SFN)

We have previously shown that exposure of immature rats to moderate noise levels was able to induce hippocampus (HC)-related behavioral and molecular alterations during the peri-adolescence period. The housing of these animals in an enriched environment (EE) reversed most of these alterations. However, comparative data of behavioral performances between animals evaluated at different intervals post-training (short and long-term) was not obtained yet.Thus, the aim of the present work was to test behavioral parameters of rats exposed to noise at two early developmental ages and at different intervals post training in an open field device (OF), as well as to evaluate a potential correlation with differences in HC oxidative markers (thioredoxins Trx1 and Trx2). In addition, housing in an EE was also studied to evaluate the possible reversal of these changes.Male Wistar rats of 7 and 15 days of age (N7 and N15) were exposed to noise (95-97 dB) for 2 hours. After weaning, rats were transferred to an EE, consisting of toys, a wheel, plastic tunnels and ramps, whereas others were placed in standard cages. After one week, OF task was performed to evaluate short and long-term habituation memory and the levels of Trx1and Trx2 were tested through Western blot experiments. Results showed no differences in short-term memory of N7 rats and a decrease in long-term memory when compared to control group. On the contrary, N15 animals showed a decrease in short-term memory without significant changes in long-term memory. Interestingly, short and long-term alterations were fully prevented when animals were housed in EE. Furthermore, western blot experiments showed that N7 and N15 rats had an increase in hippocampal Trx1 levels that was reversed when animals were housed in EE. Finally, no significant changes were observed in Trx2 levels in either group.In conclusion, these findings suggest that rats exposed to noise at different developmental ages might be differentially affected in their behavioral performance. On the other hand, Trx1 seemed to be more sensitive to the effects of noise exposure than Trx2. As differences between behavioral performances were observed but similar results in Trx1and Trx2 levels were found among groups, it could be suggested that these parameters do not seem to be correlated. Moreover, EE was an effective strategy to reverse all the behavioral and molecular alterations found in both groups, suggesting that visual, social and physical stimulation during the peri-adolescence period could be an effective strategy to reverse HC-related behavioral and molecular changes.