The role of microglia in thalamic reticular nucleus in acupuncture regulating cognitive deficits in insomnia rats

Objective:To explore the mechanism of acupuncture in regulating cognitive deficits in insomnia rats by observing the effect of acupuncture on microglia in thalamic reticular nucleus(TRN).Methods:Thirty rats were randomly divided into a control group,a model group and an acupuncture group,with 10 rats in each group.The insomnia model was established by intraperitoneal injection of para-chlorophenylalanine(PCPA)once a day for 2 d.Rats in the control group were intraperitoneally injected with the same amount of normal saline.Rats in the acupuncture group received acupuncture at Neiguan(PC 6)and Zusanli(ST 36)for 5 consecutive days.The CLOCKLAB 2 data acquisition system was used to dynamically observe the sleep of the rats throughout the experiment.The cognition of rats was evaluated by event-related potentials(ERPs).After intervention,brain tissue was extracted.Immunofluorescence was used to test the fluorescence expression in TRN region.The concentrations of interleukin(IL)-1βand tumor necrosis factor(TNF)-αwere detected by enzyme-linked immunosorbent assay.Results:After intraperitoneal injection of PCPA suspension,the spontaneous activity in light period of rats in the model group and acupuncture group increased significantly compared with the control group(both P<0.01).After acupuncture treatment,the rats in the acupuncture group had much less spontaneous activity during the light period than those in the model group(P<0.01),and the results indicated that acupuncture could effectively improve the sleep quality of insomnia rats.Compared with the control group,rats in the model group showed that the P3 latency,the average optical density of microglia,and the concentrations of IL-1βand TNF-αincreased significantly(all P<0.05),and the P3 amplitude decreased significantly(P<0.01).Compared with the model group,rats in the acupuncture group presented that the P3 latency,the average optical density of microglia,and the concentrations of IL-1βand TNF-αwere significantly decreased(all P<0.05),and the amplitude of P3 was significantly increased(P<0.05).Conclusion:Acupuncture possesses an ability to improve the cognitive state in insomnia rats.The mechanism may be related to inhibiting the microglial activation,diminishing the levels of pro-inflammatory mediators like IL-1βand TNF-α,and promoting the recovery of central nervous system function.

Cross-Modal Interaction and Integration Through Stimulus-Specific Adaptation in the Thalamic Reticular Nucleus of Rats

Stimulus-specific adaptation(SSA),defined as a decrease in responses to a common stimulus that only partially generalizes to other rare stimuli,is a widespread phenomenon in the brain that is believed to be related to novelty detection.Although cross-modal sensory processing is also a widespread phenomenon,the interaction between the two phenomena is not well understood.In this study,the thalamic reticular nucleus(TRN),which is regarded as a hub of the attentional system that contains multi-modal neurons,was investigated.The results showed that SSA existed in an interactive oddball stimulation,which mimics stimulation changes from one modality to another.In the bimodal integration,SSA to bimodal stimulation was stronger than to visual stimulation alone but similar to auditory stimulation alone,which indicated a limited integrative effect.Collectively,the present results provide evidence for independent cross-modal processing in bimodal TRN neurons.