Objective:To detect itching,anxiety,depression behaviors in chronic itch models of mice and observe the activation of γ-aminobutiric acid(GABA)neurons in the ventral sector of the zona incerta(ZIv),and provide mor-phological evidence for their involvement in the modulation of itch information.Methods:Diphenylcyclopropenone(DCP)was used in glutamic acid decarboxylase 67-green fluorescent protein(GAD67-GFP)knock-in mice to establish chronic itch model.Itch behaviors were detected by video tracking system to verify whether the models were successfully established.The anxiety,depression behaviors of chronic itch model mice were detected by using elevated plus maze test(EPM)and tail suspention test(TST).By using GAD67-GFP mice,the distribution of GABAergic neurons in va-rious sectors of the zona incerta(ZI)was observed.And combined with immunofluorescence staining method,double labeling of GABAergic neurons with FOS in ZIv were observed respectively in control and DCP group mice.Results:In brain slices of GAD67-GFP mice,GABAergic neurons can be observed within all sectors of ZI and are more concentrat-ed in ZIv.Compared with control group mice,DCP group mice showed a significant increase in the bouts of scratching(P＜0.001).The time of immobility in TST was significantly higher in DCP group mice than in control group mice,which displayed depression-like behavior.The EPM test showed that the numbers of entries and proportion of time in the cross region in DCP group mice were less than in control group mice.EPM test revealed that DCP group mice exhibited anxiety-like behavior.The results of immunofluorescence staining showed that the number of FOS-positive cells in ZIv was significantly higher in DCP group mice than in control group mice,and abundant co-labeled neurons of FOS and GABAergic neurons were observed in ZIv.Conclusion:GABAergic neurons were predominantly distributed in ZI,and were more concentrated in ZIv.The activation of GABAergic neurons in ZIv of DCP group mice provides morphological evidence on the involvement of GABAergic neurons in chronic itch and associated negative emotions.

Objective:To analyze the effect of depressive state on Alzheimer's disease(AD)mice,3xTg-AD mice were stimulated with chronic social frustration stress(CSDS)and chronic mild unpredictable stress(CUMS),to estab-lish an early AD-induced depression mouse model,and to detect cognitive and behavioral changes,activation of micro-glia in the hippocampus and neuronal loss.Methods:Three-month-old mice were subjected to 8-day stress stimulation alternately,the depressive state of the mice was evaluated by behavior,the evaluation criteria were formulated,and the cognitive behavior was detected and analyzed,and the hippocampal brain tissue sections were stained with immunofluo-rescence to observe the deposition of β-amyloid(Aβ)and the aggregation of microtubule-associated protein(tau),mi-croglia activation and neuronal loss.Results:Depression-related behavioral results showed that the CSDS+CUMS group had depression-related phenotypes.Cognitive-behavioral testing showed that the new object recognition index of the mice in the CSDS+CUMS group was significantly reduced(P＜0.05),and the Morris water maze showed that the spatial memory ability of the CSDS+CUMS group was significantly reduced(P＜0.05),but there was no obvious fear memory loss in the CSDS+CUMS group in the conditioned fear experiment.The results of immunofluorescence staining showed that Aβ deposition appeared in the hippocampus at 4 months of age,the activated microglia increased(P＜0.001),and a certain degree of neuronal loss appeared in the CSDS+CUMS group(P＜0.001);At 8 months of age,the CSDS+CUMS group showed tau protein aggregation early.Conclusion:We established a model of AD-induced de-pression in AD mice,in which 3xTg-AD mice experienced early decline in learning memory and increased AD-related pathological deposition of neurons in the hippocampus,accompanied by microglial activation and neuronal loss.

Objective:To explore the effects of dopamine receptor D2(DRD2)on astrocytic dedifferentiation based on SOX2-regulated genes in neural stem cells(NSCs)and astrocytes.Methods:Immunofluorescence staining and SOX2-GFP mice were used to examine the lineage differentiation of SOX2-positive cells during the development of cere-bral cortex.Primary NSCs/astrocytes culture,ChIP-seq and Western Blot were adopted to analyze and verify the expres-sion of candidate genes.Pharmacological manipulation,neurosphere formation,photochemical ischemia,immunofluo-rescence staining and behavior tests were adopted to evaluate the effects of activating DRD2 signaling on astrocytic dedif-ferentiation.Results:Immunofluorescence staining demonstrated the NSC-astrocyte switch of SOX2-expression in the normal development of cerebral cortex.ChIP-seq revealed enrichment of DRD2 signaling by SOX2-bound enhancers in NSCs and SOX2-bound promoters in astrocytes.Western Blot and immunofluorescence staining verified the expression of DRD2 in NSCs and reactive astrocytes.Application of quinagolide hydrocholoride(QH),an agonist of DRD2,signifi-cantly promoted astrocytic dedifferentiation both in vitro and in vivo following ischemia.In addition,quinagolide hydro-choloride treatment improved locomotion recovery.Conclusion:Activating DRD2 signaling facilitates astrocytic dedif-ferentiation and may be used to treat ischemic stroke.

Objective:To analyze the activation of primary somatosensory cortex(S1)neurons in post-traumatic stress disorder(PTSD)mice after tactile stimulation of whiskers and the changes of S1 cortical neurons in PTSD mice.Methods:Using the neuron cytoskeleton-associated protein(Arc)labeling strategy and immunofluorescence staining technique,the Arc of S1 cortical neurons in PTSD mice and control mice after whisker stimulation was marked and ob-served.By analyzing the difference in the spatial expression position of Arc labeled neurons and the number of positive cells,the activation level of S1 cortical neurons in the two groups was compared and analyzed.The pyramidal neurons of S1 cortex were labeled by sparse virus labeling method,and the number of dendrites and the morphology and number distribution of dendritic spines were compared between the two groups.Results:After whisker stimulation,it was found that Arc positive neurons were distributed from shallow layer to deep layer of S1,and more densely distributed in layersⅡ/Ⅲ and V.Compared with the control group,the number of positive neurons in different layers of the PTSD group was significantly increased.The results of cell morphology and structure analysis showed that,compared with the control group,the density of dendritic spines in layer Ⅱ/Ⅲ of mice with PTSD increased,and the number of mushroom dendrit-ic spines increased,while the number of filamentous pseudopod dendritic spines decreased.The number of dendritic spines of Si V layer mushroom type and slender type was higher,but the total number of dendritic spines was not sig-nificantly different.Conclusion:After whisker stimulation in PTSD mice,S1 neurons were over-activated,and the structure and morphology of neurons changed significantly.

Objective To study the effect of leucine rich repeat kinase 2(LRRK2)on pain sensitivity in neuro-pathic pain(NP)rats and explore its possible mechanism.Methods 48 SD rats were randomly divided into four groups:sham surgery(Sham),model,LRRK2 inhibitor(MLi-2),and LRRK2 inhibitor+p3 8 mitogen activated pro-tein kinase(MAPK)agonist(MLi-2+Anisomycin),with 12 rats in each group.The NP rat model was induced by chronic constriction injury(CCI)of the sciatic nerve.Intrathecal injection of MLi-2(1 mg/kg,10 μl)or Anisomy-cin(20 μmol/L,10 μl)was started from the 8th day after surgery,once a day for 7 consecutive days.Pain sensi-tivity tests were conducted before surgery(day 0)and on postoperative days 7 and 14,respectively.The changes in mechanical withdrawal threshold(MWT)and paw withdraw thermal latency(PWTL)were analyzed in each group of rats.ELISA was used to detect the levels of interleukin-1 β(IL-1β),IL-6 and tumor necrosis factor-α(TNF-α)in the dorsal horn of the rat spinal cord.Nissl staining was used to observe the pathological changes of neurons in rat spinal cord tissue.Immunofluorescence staining was used to observe the expression levels of ionized calcium-binding adapter molecule-1(Iba-1),a marker of microglia in the spinal cord of rats.Western blot was used to detect the protein expression levels of LRRK2,p-p38 mitogen activated protein kinase(MAPK),p38 MAPK,and Iba-1 in the dorsal horn of the rat spinal cord.Results Compared with the sham group,the model group showed a significant decrease in MWT and PWTL in the right hind limb of rats(P＜0.01).The levels of IL-1,IL-6,and TNF in the spi-nal dorsal horn tissue,as well as the expression levels of LRRK2,Iba-1 proteins and p-p38 MAPK/p38 MAPK pro-tein ratio significantly increased(P＜0.01).The proportion of Iba-1 positive cells in the spinal cord tissue signifi-cantly increased(P＜0.01),while Nissl bodies were significantly reduced(P＜0.01).Compared with the model group,the MLi-2 group showed a significant increase in MWT and PWTL in the right hind limb of rats(P＜0.01),a significant increase in Nissl bodies(P＜0.01),a significant decrease in the proportion of Iba-1 positive cells in the spinal cord tissue(P＜0.01),and a significant decrease in the levels of IL-1,IL-6,and TNF and the expression levels of LRRK2,Iba-1 proteins and p-p38 MAPK/p38 MAPK protein ratio(P＜0.01).However,Anisomychin in-tervention could activate the p38 MAPK signaling pathway and partially reverse the beneficial effects of MLi-2 on pain sensitivity and neuroinflammation in rats with neuropathic pain.Conclusion Inhibiting the expression of LRRK2 can alleviate pain sensitivity in NP rats induced by microglia activation mediated neuroinflammation,and its mechanism of action may be related to regulating the p38 MAPK signaling pathway.

As an important part of the enteric nervous system(ENS),enteric glial cells(EGCs)play an important role in regulating intestinal homeostasis and maintaining intestinal health in hu-mans and animals.This review focuses on the role of EGCs in maintaining intestinal barrier homeo-stasis,maintaining gastrointestinal transit and motor function,regulating the niche of intestinal cells,and the role in the occurrence and development of intestinal diseases,hoping to provide new ideas for further research on the function and mechanism of EGCs in the intestine and the occur-rence,development and treatment of related intestinal diseases.

Objective:To evaluate the role of spinal Leucine-rich Repeat Kinase 2 (LRRK2) in neuropathic pain in rats.Methods:Fifty SPF healthy male Sprague-Dawley rats, aged 6-7 weeks, weighing 210-245 g, were divided into 5 groups ( n=10 each) using a random number table method: control group (C group), neuropathic pain group (NP group), low dose GNE-7915 group (low-dose GNE-7915 group), medium-dose GNE-7915 group (medium-dose GNE-7915 group), and high-dose GNE-7915 group (high-dose GNE-7915 group). Neuropathic pain was induced by the spared nerve injury in anesthetized rats. At 7 days after developing the model, LRRK2 inhibitor GNE-7915 12.5, 25.0 and 50.0 mg/kg were intraperitoneally injected in low-, medium- and high-dose GNE-7915 groups, respectively. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured before developing the model, at 7 days after developing the model, and at 4 h after injecting the inhibitor. After measurement of the pain threshold, the rats were sacrificed and the spinal cord tissues were taken for determination of the positive expression of ionized calcium-binding adapter molecule 1(Iba-1) (by immunofluorescence staining), contents of interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) and IL-18 (by enzyme-linked immunosorbent assay), positive expression of phosphorylated LRRK2 (p-LRRK2) (by immunofluorescence staining), and expression of LRRK2, IL-1β, MCP-1 and IL-18 (by immunoblotting). The ratio of p-LRRK2/LRRK2 was calculated. Results:Compared with C group, the MWT was significantly decreased, the TWL was shortened, the proportion of Iba-1 and p-LRRK2 positive cells in spinal cord tissues, contents of IL-1β, MCP-1 and IL-18, and p-LRRK2/LRRK2 ratio were increased, and the expression of IL-1β, MCP-1 and IL-18 proteins was up-regulated in NP group ( P<0.05). Compared with NP group, the MWT was significantly increased, the TWL was prolonged, the proportion of Iba-1 and p-LRRK2 positive cells in spinal cord tissues, contents of IL-1β, MCP-1 and IL-18, and p-LRRK2/LRRK2 ratio were decreased, and the expression of IL-1β, MCP-1 and IL-18 proteins was down-regulated in low-, medium- and high-dose GNE-7915 groups ( P<0.05). Conclusions:LRRK2 in the spinal cord may be involved in the pathophysiological mechanism of neuropathic pain by activating microglia and inducing inflammatory responses in rats.

Parvalbumin interneurons belong to the major types of GABAergic interneurons. Although the distribution and pathological alterations of parvalbumin interneuron somata have been widely studied, the distribution and vulnerability of the neurites and fibers extending from parvalbumin interneurons have not been detailly interrogated. Through the Cre recombinase-reporter system, we visualized parvalbumin-positive fibers and thoroughly investigated their spatial distribution in the mouse brain. We found that parvalbumin fibers are widely distributed in the brain with specific morphological characteristics in different regions, among which the cortex and thalamus exhibited the most intense parvalbumin signals. In regions such as the striatum and optic tract, even long-range thick parvalbumin projections were detected. Furthermore, in mouse models of temporal lobe epilepsy and Parkinson's disease, parvalbumin fibers suffered both massive and subtle morphological alterations. Our study provides an overview of parvalbumin fibers in the brain and emphasizes the potential pathological implications of parvalbumin fiber alterations.
Mice ; Animals ; Epilepsy, Temporal Lobe/pathology* ; Parvalbumins/metabolism* ; Parkinson Disease/pathology* ; Neurons/metabolism* ; Interneurons/physiology* ; Disease Models, Animal ; Brain/pathology*

Objective:To analyze the differences in neuronal activation during fear memory extinction in various sub-regions of the hippocampus in post-traumatic stress disorder(PTSD)mice.Methods:Two immediate early gene-pro-tein labeling strategies were employed to label neurons associated with fear extinction in PTSD mice.In the first group,Arc protein in hippocampal neurons was labeled and observed through immunofluorescence staining in wild-type mice.In the second group,Fos-CreERT2;Ai9 transgenic mice were injected with tamoxifen 23 hours prior to inducing fear memory extinction,and the relevant neurons were labeled with fluorescent proteins for observation.The number of labeled hippocampal neurons and the dendritic branch structure were analyzed to compare the activation levels of hipp-ocampal neurons and the plasticity of neuronal dendrites.Results:The two groups of Arc and Fos positive neurons were mainly distributed in the dorsal hippocampus,in which Arc protein chromogenic was enriched in CA3 and DG subre-gions,while CA1 and CA2 subregions were scattered,while Fos-positive neurons were enriched in the DG subregion of hippocampus and scattered in CA1,CA2 and CA3 subregions.Compared to the control group,there was no significant difference in the number of neurons expressing Arc protein in each subregion of the hippocampus in the PTSD group.The number of Fos-positive neurons in CA1,CA3 and DG subregions in the hippocampus of the PTSD group was signifi-cantly increased(P＜0.01).The dendritic branches of neurons in the hippocampal region were observed and analyzed in Fos-CreERT2;Ai9 mice from both groups,but no significant changes were found.Conclusion:Abnormal activation of neurons occurs in different subregions of the hippocampus during fear extinction in PTSD mice,although there are no significant plasticity changes in the dendritic branches of the activated neurons.