Self-powered, light-controlled, bioresorbable platforms for programmed drug delivery.

Degradable polymer matrices and porous scaffolds provide powerful mechanisms for passive, sustained release of drugs relevant to the treatment of a broad range of diseases and conditions. Growing interest is in active control of pharmacokinetics tailored to the needs of the patient via programmable engineering platforms that include power sources, delivery mechanisms, communication hardware, and associated electronics, most typically in forms that require surgical extraction after a period of use. Here we report a light-controlled, self-powered technology that bypasses key disadvantages of these systems, in an overall design that is bioresorbable. Programmability relies on the use of an external light source to illuminate an implanted, wavelength-sensitive phototransistor to trigger a short circuit in an electrochemical cell structure that includes a metal gate valve as its anode. Consequent electrochemical corrosion eliminates the gate, thereby opening an underlying reservoir to release a dose of drugs by passive diffusion into surrounding tissue. A wavelength-division multiplexing strategy allows release to be programmed from any one or any arbitrary combination of a collection of reservoirs built into an integrated device. Studies of various bioresorbable electrode materials define the key considerations and guide optimized choices in designs. In vivo demonstrations of programmed release of lidocaine adjacent the sciatic nerves in rat models illustrate the functionality in the context of pain management, an essential aspect of patient care that could benefit from the results presented here.

Wireless, battery-free, subdermally implantable platforms for transcranial and long-range optogenetics in freely moving animals.

Wireless, battery-free, and fully subdermally implantable optogenetic tools are poised to transform neurobiological research in freely moving animals. Current-generation wireless devices are sufficiently small, thin, and light for subdermal implantation, offering some advantages over tethered methods for naturalistic behavior. Yet current devices using wireless power delivery require invasive stimulus delivery, penetrating the skull and disrupting the blood-brain barrier. This can cause tissue displacement, neuronal damage, and scarring. Power delivery constraints also sharply curtail operational arena size. Here, we implement highly miniaturized, capacitive power storage on the platform of wireless subdermal implants. With approaches to digitally manage power delivery to optoelectronic components, we enable two classes of applications: transcranial optogenetic activation millimeters into the brain (validated using motor cortex stimulation to induce turning behaviors) and wireless optogenetics in arenas of more than 1 m2 in size. This methodology allows for previously impossible behavioral experiments leveraging the modern optogenetic toolkit.

Artificial dermis combined with negative pressure wound therapy and platelet-rich plasma to treat traumatic wounds: a retrospective study.

OBJECTIVE: The reconstruction of complex soft tissue defects with exposure of bones and tendons represents an increasing challenge in wound care, especially in large extremity wounds. The aim of this study was to detect the clinical efficacy of combined use of negative pressure wound therapy (NPWT), artificial dermis (ADM), platelet-rich plasma (PRP) and split-thickness skin grafting (STSG) in the reconstruction of large traumatic extremity skin defects. METHOD: In this study, eight cases were treated with combined therapies for repairing complex extremity wounds and the results were reviewed retrospectively. After surgical debridement, all wounds received ADM, PRP and delayed STSG, which were all aided with NPWT. RESULTS: The patients consisted of five males and three females, with a mean age of 44 years. A total of six lower extremity wounds were located at the foot/ankle, with exposed tendon in five, bone exposure in three and both in two. Of the group, two patients had exposed tendon on arm/hand wounds. The size of wounds and ADM averaged 126cm2 and 42.3cm2, respectively. ADM was used to cover the exposed bone or tendon, the granulation and muscular tissue were covered with vacuum sealing drainage (VSD) directly, for NPWT. The survival rate of ADM averaged 98.9%. The average time for survival of ADM was 12.8 days and the mean uptake of autologous skin graft was 93.5%. Only one patient received repeated skin grafts. All patients achieved successful healing and reported no complications. The mean length of hospital stay was 36.1 days. CONCLUSION: Our study revealed that ADM in conjunction with NPWT, PRP and STSG could be used for repairing large traumatic extremity wounds. Wound closure was achieved without flaps, the aesthetic and functional outcomes were acceptable, and only one patient developed a 35% loss of skin graft. DECLARATION OF INTEREST: This work was supported by grants from the Natural Science Foundation of Hubei Province (grant no. 2020CFB464) and Youth Foundation of Wuhan Municipal Health Commission (grant no. WX20Q15). The authors have no conflicts of interest to declare.

Photocurable bioresorbable adhesives as functional interfaces between flexible bioelectronic devices and soft biological tissues.

Flexible electronic/optoelectronic systems that can intimately integrate onto the surfaces of vital organ systems have the potential to offer revolutionary diagnostic and therapeutic capabilities relevant to a wide spectrum of diseases and disorders. The critical interfaces between such technologies and living tissues must provide soft mechanical coupling and efficient optical/electrical/chemical exchange. Here, we introduce a functional adhesive bioelectronic-tissue interface material, in the forms of mechanically compliant, electrically conductive, and optically transparent encapsulating coatings, interfacial layers or supporting matrices. These materials strongly bond both to the surfaces of the devices and to those of different internal organs, with stable adhesion for several days to months, in chemistries that can be tailored to bioresorb at controlled rates. Experimental demonstrations in live animal models include device applications that range from battery-free optoelectronic systems for deep-brain optogenetics and subdermal phototherapy to wireless millimetre-scale pacemakers and flexible multielectrode epicardial arrays. These advances have immediate applicability across nearly all types of bioelectronic/optoelectronic system currently used in animal model studies, and they also have the potential for future treatment of life-threatening diseases and disorders in humans.

Self-affirmation enhances the processing of uncertainty: An event-related potential study.

We proposed that self-affirmation can endow people with more cognitive resource to cope with uncertainty. We tested this possibility with an event-related potential (ERP) study by examining how self-affirmation influences ambiguous feedback processing in a simple gambling task, which was used to investigate risk decision-making. We assigned 48 participants randomly to the affirmation and non-affirmation (i.e., control) groups. All participants accepted the manipulation first and then completed the gambling task with an electroencephalogram (EEG) recording, in which participants might receive a positive (winning), negative (losing), or ambiguous (unknown valence) outcome after they made a choice. We considered both the feedback-related negativity (FRN) and P3 components elicited by the outcome feedback, which reflected the amount of cognitive resources being invested in the early and late stages of the outcome feedback processing, respectively. ERP results showed that ambiguous feedback elicited a larger FRN among affirmed participants than unaffirmed participants but exerted no influence on the P3. This finding suggests that self-affirmation may help coping with uncertainty by enhancing the early processing of uncertainty.

Salidroside Suppresses IL-1ß-Induced Apoptosis in Chondrocytes via Phosphatidylinositol 3-Kinases (PI3K)/Akt Signaling Inhibition.

BACKGROUND Salidroside, a natural dietary isothiocyanate, has been widely studied for its multiple effects, including promoting proliferation, anti-inflammation, and anti-apoptosis. In the present study, these effects of Salidroside were explored to assess whether it could prevent osteoarthritis (OA) in vitro. MATERIAL AND METHODS The cytotoxic and proliferating effects of Salidroside on chondrocytes were detected by use of the Cell Counting Kit 8 assay. The expression levels of proteins were detected by Western blot. The cell apoptosis level was assessed by flow cytometry, and the levels of ROS, NO, caspase 3, and caspase 9 were assessed to evaluate the level of apoptosis. The expression level of pro-inflammatory factors was detected by ELISA. RESULTS Our results demonstrated that Salidroside promotes chondrocytes proliferation, inhibits IL-1ß-induced apoptosis and inflammation, and scavenges reactive oxygen species (ROS) and NO of chondrocytes. Salidroside upregulates the level of Bcl-2 and downregulates the level of Bax. Salidroside also inhibits the production of caspase 3/9 and suppresses the phosphorylation of PI3K and AKT. CONCLUSIONS Our results suggest that Salidroside prevents OA by its powerful pro-proliferating, anti-phlogistic, and anti-apoptotic effects by inhibiting PI3K/AKT.

Inhibition of YAP/TAZ Activity in Spinal Cord Suppresses Neuropathic Pain.

UNLABELLED: Neuropathic pain, often caused by nerve injury, is a major clinical challenge. Mechanisms that underlie neuropathic pain remain elusive and effective medications are limited. Numerous investigations of pain mechanisms have focused on alterations and phenotypic switches of the nociceptive transmitters and modulators, as well as on their receptors and downstream signaling pathways that have already exerted roles in the pain processes of mature nervous systems. We have demonstrated recently that nerve injury may elicit neuronal alterations that recapitulate events occurring during development. Signaling of the representative activated molecule Wnt thus becomes a trigger for the development of neuropathic pain and is a potential therapeutic target. We report that the transcriptional regulators YAP and TAZ, which orchestrate Wnt response via incorporation in the ß-catenin destruction complex, are key in the pathogenesis of neuropathic pain and may serve as an "ON-OFF" switch for neuropathic pain status in rats. Peripheral nerve injury causes rapid-onset and long-lasting nuclear accumulation of YAP/TAZ/ß-catenin in the spinal dorsal horn. Spinal inhibition or knock-down of either YAP or TAZ suppresses mechanical allodynia induced by nerve injury or the pain initiators lysophosphatidic acid and Wnt3a. Promoting the nuclear accumulation of YAP/TAZ leads to mechanical hypersensitivity in naive animals. Further, we discovered a new small molecule, dCTB, which targets YAP/TAZ/ß-catenin and can greatly suppress neuropathic pain and the associated neurochemical alterations. Our study reveals that YAP and TAZ are core mechanisms underlying the pathogenesis of neuropathic pain and are targets in the screening for potent analgesics for the treatment of neuropathic pain. SIGNIFICANCE STATEMENT: Mechanisms that underlie neuropathic pain remain elusive. We have demonstrated recently that nerve injury can activate Wnt signaling, which becomes a trigger for the development of neuropathic pain. We report that the transcriptional regulators YAP and TAZ, which orchestrate Wnt response via incorporation in the ß-catenin destruction complex, are key in the pathogenesis of neuropathic pain and may serve as an "ON-OFF" switch for neuropathic pain status. Further, we discovered a new small molecule, dCTB, which targets YAP/TAZ/ß-catenin and can greatly suppress neuropathic pain. Our study reveals that YAP and TAZ are core mechanisms underlying the pathogenesis of neuropathic pain and are targets in the screening of potent analgesics for the treatment of neuropathic pain.

Trajectory of Nostalgia in Emerging Adulthood.

We examined the change and stability of nostalgia in emerging adulthood. We followed 327 students through their 4 university years with six assessments. Nostalgia demonstrated moderate rank stability (r = .25-.79). A Trait-State-Occasion model analysis indicated that the stable trait component, slowing-change trait component, and state component explained 37% to 43%, 10% to 27%, and 29% to 49% of variation in nostalgia on specific occasions, respectively. Longitudinal multilevel analysis revealed that the mean nostalgia level declined across university years. Greater intensity of negative life events at the start of university was associated with higher initial nostalgia and slower decline of it, while the emotion intensified when experiencing more negative life events. Nostalgia in emerging adulthood displays moderate stability, with negative life events contributing to the shape of its trajectory.

Dopamine pathways mediating affective state transitions after sleep loss.

The pathophysiology of affective disorders-particularly circuit-level mechanisms underlying bidirectional, periodic affective state transitions-remains poorly understood. In patients, disruptions of sleep and circadian rhythm can trigger transitions to manic episodes, whereas depressive states are reversed. Here, we introduce a hybrid automated sleep deprivation platform to induce transitions of affective states in mice. Acute sleep loss causes mixed behavioral states, featuring hyperactivity, elevated social and sexual behaviors, and diminished depressive-like behaviors, where transitions depend on dopamine (DA). Using DA sensor photometry and projection-targeted chemogenetics, we reveal that elevated DA release in specific brain regions mediates distinct behavioral changes in affective state transitions. Acute sleep loss induces DA-dependent enhancement in dendritic spine density and uncaging-evoked dendritic spinogenesis in the medial prefrontal cortex, whereas optically mediated disassembly of enhanced plasticity reverses the antidepressant effects of sleep deprivation on learned helplessness. These findings demonstrate that brain-wide dopaminergic pathways control sleep-loss-induced polymodal affective state transitions.

Genetic polymorphisms, biomarkers and signaling pathways associated with septic shock: from diagnosis to therapeutic targets.

Septic shock is a severe form of sepsis characterized by high global mortality rates and significant heritability. Clinicians have long been perplexed by the differential expression of genes, which poses challenges for early diagnosis and prompt treatment of septic shock. Genetic polymorphisms play crucial roles in determining susceptibility to, mortality from, and the prognosis of septic shock. Research indicates that pathogenic genes are known to cause septic shock through specific alleles, and protective genes have been shown to confer beneficial effects on affected individuals. Despite the existence of many biomarkers linked to septic shock, their clinical use remains limited. Therefore, further investigation is needed to identify specific biomarkers that can facilitate early prevention, diagnosis and risk stratification. Septic shock is closely associated with multiple signaling pathways, including the toll-like receptor 2/toll-like receptor 4, tumor necrosis factor-α, phosphatidylinositol 3-kinase/protein kinase B, mitogen-activated protein kinase, nuclear factor κB, Janus kinase/signal transducer and activator of transcription, mammalian target of rapamycin, NOD-like receptor thermal protein domain-associated protein 3 and hypoxia-induced-factor-1 pathways. Understanding the regulation of these signaling pathways may lead to the identification of therapeutic targets for the development of novel drugs to treat sepsis or septic shock. In conclusion, identifying differential gene expression during the development of septic shock allows physicians to stratify patients according to risk at an early stage. Furthermore, auxiliary examinations can assist physicians in identifying therapeutic targets within relevant signaling pathways, facilitating early diagnosis and treatment, reducing mortality and improving the prognosis of septic shock patients. Although there has been significant progress in studying the genetic polymorphisms, specific biomarkers and signaling pathways involved in septic shock, the journey toward their clinical application and widespread implementation still lies ahead.

Bioresorbable Multilayer Organic-Inorganic Films for Bioelectronic Systems.

Bioresorbable electronic devices as temporary biomedical implants represent an emerging class of technology relevant to a range of patient conditions currently addressed with technologies that require surgical explantation after a desired period of use. Obtaining reliable performance and favorable degradation behavior demands materials that can serve as biofluid barriers in encapsulating structures that avoid premature degradation of active electronic components. Here, this work presents a materials design that addresses this need, with properties in water impermeability, mechanical flexibility, and processability that are superior to alternatives. The approach uses multilayer assemblies of alternating films of polyanhydride and silicon oxynitride formed by spin-coating and plasma-enhanced chemical vapor deposition , respectively. Experimental and theoretical studies investigate the effects of material composition and multilayer structure on water barrier performance, water distribution, and degradation behavior. Demonstrations with inductor-capacitor circuits, wireless power transfer systems, and wireless optoelectronic devices illustrate the performance of this materials system as a bioresorbable encapsulating structure.

Remote optogenetic control of the enteric nervous system and brain-gut axis in freely-behaving mice enabled by a wireless, battery-free optoelectronic device.

Wireless activation of the enteric nervous system (ENS) in freely moving animals with implantable optogenetic devices offers a unique and exciting opportunity to selectively control gastrointestinal (GI) transit in vivo, including the gut-brain axis. Programmed delivery of light to targeted locations in the GI-tract, however, poses many challenges not encountered within the central nervous system (CNS). We report here the development of a fully implantable, battery-free wireless device specifically designed for optogenetic control of the GI-tract, capable of generating sufficient light over large areas to robustly activate the ENS, potently inducing colonic motility ex vivo and increased propulsion in vivo. Use in in vivo studies reveals unique stimulation patterns that increase expulsion of colonic content, likely mediated in part by activation of an extrinsic brain-gut motor pathway, via pelvic nerves. This technology overcomes major limitations of conventional wireless optogenetic hardware designed for the CNS, providing targeted control of specific neurochemical classes of neurons in the ENS and brain-gut axis, for direct modulation of GI-transit and associated behaviours in freely moving animals.

An integrated microfluidic and fluorescence platform for probing in vivo neuropharmacology.

Neurotechnologies and genetic tools for dissecting neural circuit functions have advanced rapidly over the past decade, although the development of complementary pharmacological method-ologies has comparatively lagged. Understanding the precise pharmacological mechanisms of neuroactive compounds is critical for advancing basic neurobiology and neuropharmacology, as well as for developing more effective treatments for neurological and neuropsychiatric disorders. However, integrating modern tools for assessing neural activity in large-scale neural networks with spatially localized drug delivery remains a major challenge. Here, we present a dual microfluidic-photometry platform that enables simultaneous intracranial drug delivery with neural dynamics monitoring in the rodent brain. The integrated platform combines a wireless, battery-free, miniaturized fluidic microsystem with optical probes, allowing for spatially and temporally specific drug delivery while recording activity-dependent fluorescence using genetically encoded calcium indicators (GECIs), neurotransmitter sensors GRAB NE and GRAB DA , and neuropeptide sensors. We demonstrate the performance this platform for investigating neuropharmacological mechanisms in vivo and characterize its efficacy in probing precise mechanistic actions of neuroactive compounds across several rapidly evolving neuroscience domains.

Patterned wireless transcranial optogenetics generates artificial perception.

Synthesizing perceivable artificial neural inputs independent of typical sensory channels remains a fundamental challenge in the development of next-generation brain-machine interfaces. Establishing a minimally invasive, wirelessly effective, and miniaturized platform with long-term stability is crucial for creating a clinically meaningful interface capable of mediating artificial perceptual feedback. In this study, we demonstrate a miniaturized fully implantable wireless transcranial optogenetic encoder designed to generate artificial perceptions through digitized optogenetic manipulation of large cortical ensembles. This platform enables the spatiotemporal orchestration of large-scale cortical activity for remote perception genesis via real-time wireless communication and control, with optimized device performance achieved by simulation-guided methods addressing light and heat propagation during operation. Cue discrimination during operant learning demonstrates the wireless genesis of artificial percepts sensed by mice, where spatial distance across large cortical networks and sequential order-based analyses of discrimination performance reveal principles that adhere to general perceptual rules. These conceptual and technical advancements expand our understanding of artificial neural syntax and its perception by the brain, guiding the evolution of next-generation brain-machine communication.

An implantable device for wireless monitoring of diverse physio-behavioral characteristics in freely behaving small animals and interacting groups.

Comprehensive, continuous quantitative monitoring of intricately orchestrated physiological processes and behavioral states in living organisms can yield essential data for elucidating the function of neural circuits under healthy and diseased conditions, for defining the effects of potential drugs and treatments, and for tracking disease progression and recovery. Here, we report a wireless, battery-free implantable device and a set of associated algorithms that enable continuous, multiparametric physio-behavioral monitoring in freely behaving small animals and interacting groups. Through advanced analytics approaches applied to mechano-acoustic signals of diverse body processes, the device yields heart rate, respiratory rate, physical activity, temperature, and behavioral states. Demonstrations in pharmacological, locomotor, and acute and social stress tests and in optogenetic studies offer unique insights into the coordination of physio-behavioral characteristics associated with healthy and perturbed states. This technology has broad utility in neuroscience, physiology, behavior, and other areas that rely on studies of freely moving, small animal models.

Ultrathin, Transferred Layers of Silicon Oxynitrides as Tunable Biofluid Barriers for Bioresorbable Electronic Systems.

Bio/ecoresorbable electronic systems create unique opportunities in implantable medical devices that serve a need over a finite time period and then disappear naturally to eliminate the need for extraction surgeries. A critical challenge in the development of this type of technology is in materials that can serve as thin, stable barriers to surrounding ground water or biofluids, yet ultimately dissolve completely to benign end products. This paper describes a class of inorganic material (silicon oxynitride, SiON) that can be formed in thin films by plasma-enhanced chemical vapor deposition for this purpose. In vitro studies suggest that SiON and its dissolution products are biocompatible, indicating the potential for its use in implantable devices. A facile process to fabricate flexible, wafer-scale multilayer films bypasses limitations associated with the mechanical fragility of inorganic thin films. Systematic computational, analytical, and experimental studies highlight the essential materials aspects. Demonstrations in wireless light-emitting diodes both in vitro and in vivo illustrate the practical use of these materials strategies. The ability to select degradation rates and water permeability through fine tuning of chemical compositions and thicknesses provides the opportunity to obtain a range of functional lifetimes to meet different application requirements.

Bioresorbable shape-adaptive structures for ultrasonic monitoring of deep-tissue homeostasis.

Monitoring homeostasis is an essential aspect of obtaining pathophysiological insights for treating patients. Accurate, timely assessments of homeostatic dysregulation in deep tissues typically require expensive imaging techniques or invasive biopsies. We introduce a bioresorbable shape-adaptive materials structure that enables real-time monitoring of deep-tissue homeostasis using conventional ultrasound instruments. Collections of small bioresorbable metal disks distributed within thin, pH-responsive hydrogels, deployed by surgical implantation or syringe injection, allow ultrasound-based measurements of spatiotemporal changes in pH for early assessments of anastomotic leaks after gastrointestinal surgeries, and their bioresorption after a recovery period eliminates the need for surgical extraction. Demonstrations in small and large animal models illustrate capabilities in monitoring leakage from the small intestine, the stomach, and the pancreas.

TGM2 accelerates migration and differentiation of BMSCs by activating Wnt/ß-catenin signaling.

BACKGROUND: Transglutaminase 2 (TGM2) is a gene previously reported to be associated with the differentiation of bone marrow mesenchymal stem cells (BMSCs). The study was developed to reveal the impact of TGM2 on the migration and differentiation of BMSCs. METHODS: Cells were isolated from bone marrow of mice and then the surface antigens were identified by flow cytometry. Wound healing assays were conducted to assess the migratory ability of BMSCs. The mRNA levels of TGM2 and osteoblast-associated genes (ALP, OCN, and RUNX2) were subjected to RT-qPCR analysis, and protein levels of these genes as well as ß-catenin were quantitated by western blotting. Alizarin red staining was conducted for detection of osteogenic ability. The activation of Wnt signaling was assessed by TOP/FOP flash assays. RESULTS: Surface antigens were positively identified in MSCs, indicating good multidirectional differentiation ability of cells. TGM2 silencing suppressed BMSC migration while weakening mRNA and protein levels of osteoblast-associated genes. While TGM2 overexpression exerts the opposite impact on cell migration and expression levels of osteoblast-associated genes. Additionally, overexpressed TGM2 promotes the mineralization of BMSCs according to results of Alizarin red staining. Moreover, TGM2 activated the Wnt/ß-catenin signaling, and DKK1 (an inhibitor of Wnt signaling) reversed the promoting influence of TGM2 on cell migration and differentiation. CONCLUSION: TGM2 promotes the migration and differentiation of BMSCs via activation of the Wnt/ß-catenin signaling.

MiR-145-5p restrains chondrogenic differentiation of synovium-derived mesenchymal stem cells by suppressing TLR4.

Osteoarthritis (OA) is a progressive degeneration of articular cartilage with involvement of synovial membrane, and subchondral bone. Recently, cell-based therapies, including the application of stem cells such as mesenchymal stem cells (MSCs), have been introduced for restoration of the articular cartilage. Toll-like receptors (TLRs) were reported to participate in OA progression and MSC chondrogenesis. Here, the role and molecular mechanism of toll like receptor 4 (TLR4) in chondrogenic differentiation of synovium-derived MSCs (SMSCs) were investigated. Molecular markers (CD44, CD90, CD45 and CD14) on SMSC surfaces were identified by flow cytometry. Multi-potential differentiation capacities of SMSCs for chondrogenesis, adipogenesis and osteogenesis were examined by Alcian blue, oil red O and Alizarin red staining, respectively. TLR4 and miR-145-5p levels in SMSCs were assessed using RT-qPCR. The protein expression of TGFB3, Col II, SOX9 and Aggrecan in SMSCs was tested by western blotting. Cytokine secretions were analyzed with ELISA for IL-1ß and IL-6. Intracellular NAD+ content and NAD+/NADH ratio were assessed. The interaction between miR-145-5p and TLR4 was confirmed by RNA pulldown and luciferase reporter assays. In this study, SMSCs were identified to have immunophenotypic characteristics of MSCs. TLR4 knockdown inhibited chondrogenic and osteogenic differentiation of SMSCs. Mechanistically, TLR4 was targeted by miR-145-5p in SMSCs. Moreover, TLR4 elevation offset the inhibitory impact of miR-145-5p upregulation on chondrogenic differentiation of SMSCs. Overall, miR-145-5p restrains chondrogenesis of SMSCs by suppressing TLR4.

Spinal beta-amyloid1-42 acts as an endogenous analgesic peptide in CCI-induced neuropathic pain.

BACKGROUND: The mechanism for reduced pain sensitivity associated with Alzheimer's disease (AD) has not been illustrated. We hypothesize that amyloid beta 1-42 (Aß1-42) in the spinal cord acts as an endogenous analgesic peptide to suppress pain induced by nerve injury. METHODS: We used chronic constriction injury of the sciatic nerve (CCI) to produce neuropathic pain in Sprague-Dawley rats. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were used to determine the level of Aß1-42, the expression of Wnt3a/5b and glial activation in the spinal cord. Western blotting was used to determine the expression of interleukins, the phosphorylation of NR2B and ERK1/2, and the nuclear accumulation of transcriptional factors YAP/TAZ. Thermal hyperalgesia and mechanical allodynia were assessed after CCI and pharmacological manipulations through intrathecal administration. RESULTS: Nerve injury increases spinal level of Aß1-42, while intrathecal administration of MK-8931 reduces the level of Aß1-42 and facilitates mechanical allodynia. Intrathecal administration of Aß1-42 suppresses pain behaviors in the early and late phases of neuropathy. Spinal administration of Aß1-42 regulates the expression of interleukins, reducing glial activation and phosphorylation of NR2B and ERK1/2 in the spinal cord of CCI rats. Furthermore, intrathecal administration of Aß1-42 decreases Wnt5b expression and suppresses the nuclear accumulation of YAP and TAZ. Blocking the interaction between Aß1-42 and Frizzled receptors by cSP5 reverses the analgesic effects of Aß1-42. CONCLUSIONS: These findings suggest that spinal Aß1-42 acts as an endogenous analgesic peptide through regulating cytokines and Wnt pathways. This study may provide a potential target for the development of novel analgesic peptides. SIGNIFICANCE: This study provides an explanation of reduced pain sensitivity associated with Alzheimer's disease. Furthermore, our findings propose a possible physiological function of beta-amyloid1-42 to regulate pain. This study may provide a potential target for the development of novel analgesics based on an existing endogenous peptide.