Cage Cleaning Impairs Novel Object Recognition Memory In Mice And Its Glucocorticoid Receptor-dependent Effect

? Background ? Environmental stressor is an important modulator in the processes of learning and memory.Increasing evidence suggests that cage cleaning,a routine laboratory procedure in animal studies,can function as a mild stressor.However,the issue of cage cleaning effects on learning and memory remains to be determined.Here,we assessed whether cage cleaning affected the acquisition,consolidation and retrieval of novel object recognition(NOR)memory in mice.?Method?The NOR test procedure involved three sessions including habituation(on day 1),sampling(on day 2)and test(on day 3).Mice was subjected to cage cleaning 1 or 3 h pre-sampling,or immediately or 6 h post-sampling,or 1 or 3 h pre-test.The non-cage cleaning mice(control group)were stayed in the home cages without disturbance as control.? Result ? In experiment 1,compared with the control group,cage cleaning significantly affected the DI value of the cleaning group 1 hour before sampling(F(2,25)= 6.835,P <0.01)without affecting the cleaning group 3 hours before sampling.In Experiment 2,compared with the control group,the cage cleaning significantly affected the DI value of the cleaning group immediately after sampling(F(2,27)= 4.145,P <0.05)without affecting the cleaning group 6 hours after sampling;In Experiment 3,cage cleaning before testing had no significant effect on DI in mice(F(2,25)= 2.096,P>0.05);in experiment 4A,cage cleaning had a significant major effect on DI.(F(3,36)= 8.934,P < 0.001),the glucocorticoid receptor antagonist RU486 reversed this effect.In experiment 4B,cage cleaning had a significant major effect on DI(F(3,36)= 10.985,P < 0.001),and the glucocorticoid receptor antagonist RU486 also reversed this effect.In addition,in Experiment 5,there was no significant main effect(F(1,18)= 1.179,P>0.05)or group-time interaction(F(1,18)= 0.475,P> 0.05).This suggests that NOR memory impairment caused by cage cleansing is not caused by changes in non-specific responses(exploration motivation or spontaneous activity).The results showed that cage cleaning impaired memory acquisition and consolidation in mice,but did not affect NOR memory extraction by activating glucocorticoid receptors in mice.?Conclusion?Cage cleaning impairs novel object recognition memory in mice through a glucocorticoid receptor-dependent effect.