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

MOLINA, SJ; RODRIGUEZ GONZALEZ, M; BUJÁN, GE; CAPANI, F; GUELMAN, LR

San Diego, CA

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

Society for Neuroscience (SFN)

We have previously shown that exposure of immature rats to moderate noise levels wasable to induce hippocampus (HC)-related behavioral and molecular alterations during theperi-adolescence period. The housing of these animals in an enriched environment (EE)reversed most of these alterations. However, comparative data of behavioral performancesbetween animals evaluated at different intervals post-training (short and long-term) wasnot obtained yet.Thus, the aim of the present work was to test behavioral parameters ofrats exposed to noise at two early developmental ages and at different intervals posttraining in an open field device (OF), as well as to evaluate a potential correlation withdifferences in HC oxidative markers (thioredoxins Trx1 and Trx2). In addition, housing in anEE was also studied to evaluate the possible reversal of these changes.Male Wistar rats of 7and 15 days of age (N7 and N15) were exposed to noise (95-97 dB) for 2 hours. Afterweaning, rats were transferred to an EE, consisting of toys, a wheel, plastic tunnels andramps, whereas others were placed in standard cages. After one week, OF task wasperformed to evaluate short and long-term habituation memory and the levels of Trx1andTrx2 were tested through Western blot experiments. Results showed no differences inshort-term memory of N7 rats and a decrease in long-term memory when compared tocontrol group. On the contrary, N15 animals showed a decrease in short-term memorywithout significant changes in long-term memory. Interestingly, short and long-termalterations were fully prevented when animals were housed in EE. Furthermore, westernblot experiments showed that N7 and N15 rats had an increase in hippocampal Trx1 levelsthat was reversed when animals were housed in EE. Finally, no significant changes wereobserved in Trx2 levels in either group.In conclusion, these findings suggest that ratsexposed to noise at different developmental ages might be differentially affected in theirbehavioral performance. On the other hand, Trx1 seemed to be more sensitive to the effectsof noise exposure than Trx2. As differences between behavioral performances were observed but similar results in Trx1and Trx2 levels were found among groups, it could besuggested that these parameters do not seem to be correlated. Moreover, EE was aneffective strategy to reverse all the behavioral and molecular alterations found in bothgroups, suggesting that visual, social and physical stimulation during the peri-adolescenceperiod could be an effective strategy to reverse HC-related behavioral and molecularchanges.