Patients suffering from nerve injury often experience exacerbated pain responses and complain of memory deficits. The dorsal hippocampus (dHPC), a well-defined region responsible for learning and memory, displays maladaptive plasticity upon injury, which is assumed to underlie pain hypersensitivity and cognitive deficits. However, much attention has thus far been paid to intracellular mechanisms of plasticity rather than extracellular alterations that might trigger and facilitate intracellular changes. Emerging evidence has shown that nerve injury alters the microarchitecture of the extracellular matrix (ECM) and decreases ECM rigidity in the dHPC. Despite this, it remains elusive which element of the ECM in the dHPC is affected and how it contributes to neuropathic pain and comorbid cognitive deficits. Laminin, a key element of the ECM, consists of α-, β-, and γ-chains and has been implicated in several pathophysiological processes. Here, we showed that peripheral nerve injury downregulates laminin β1 (LAMB1) in the dHPC. Silencing of hippocampal LAMB1 exacerbates pain sensitivity and induces cognitive dysfunction. Further mechanistic analysis revealed that loss of hippocampal LAMB1 causes dysregulated Src/NR2A signaling cascades via interaction with integrin β1, leading to decreased Ca²⁺ levels in pyramidal neurons, which in turn orchestrates structural and functional plasticity and eventually results in exaggerated pain responses and cognitive deficits. In this study, we shed new light on the functional capability of hippocampal ECM LAMB1 in the modulation of neuropathic pain and comorbid cognitive deficits, and reveal a mechanism that conveys extracellular alterations to intracellular plasticity. Moreover, we identified hippocampal LAMB1/integrin β1 signaling as a potential therapeutic target for the treatment of neuropathic pain and related memory loss.
Animals ; Laminin/genetics* ; Hippocampus/metabolism* ; Neuralgia/metabolism* ; Cognitive Dysfunction/etiology* ; Male ; Peripheral Nerve Injuries/metabolism* ; Extracellular Matrix/metabolism* ; Integrin beta1/metabolism* ; Pyramidal Cells/metabolism* ; Signal Transduction

Objective:To prepare Periplaneta americana thermosensitive hydrogel and investigate its effect on wound healing in diabetic rats. Method:Taking N-isopropylacrylamide (NIPAM) and acrylic acid (AAc) as monomers, thermosensitive poly(NIPAM-co-AAc) [P(NIPAM-co-AAc)] polymeric material was prepared by free radical polymerization, then thermoresponsive copolymer P(NIPAM-co-AAc)-g-HA was synthesized by conjugating P(NIPAM-co-AAc) to hyaluronic acid (HA). The structure and lower critical solution temperature (LCST) of the graft copolymer were characterized by proton nuclear magnetic resonance spectroscopy (¹H-NMR) and ultraviolet spectrophotometry (UV). P. americana thermosensitive hydrogel was prepared by dialysis method, and it was characterized by scanning electron microscope (SEM), rotation rheometer and thermogravimetric analyzer to observe section structure, rheological properties and thermal stability. Differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy were employed to identify the inclusion of P(NIPAM-co-AAc)-g-HA temperature sensitive material for P. americana extract, and to investigate the effect of P. americana thermosensitive hydrogel on wound healing in diabetic rats, and the rate of wound healing was calculated by Image-Pro Plus 6.0 software. Hematoxylin-eosin (HE) and Masson staining were used to observe the pathological changes of the wounds of rats in each group. Result:P(NIPAM-co-AAc)-g-HA temperature sensitive material was successfully synthesized, its LCST was between 29 ℃ and 31 ℃, it had a dense and uniform porous structure and could uniformly include P. americana extract. Pharmacodynamic studies showed that P. americana thermosensitive hydrogel group had the best effect on promoting wound healing, its infiltration degree of inflammatory cells was significantly reduced, collagen and fibroblasts arranged neatly and compactly, and the density of neovascularization was significantly increased by comparing with the model group. Conclusion:P. americana thermosensitive hydrogel can effectively promote wound healing of diabetic rats and overcome the shortage of marketed P. americana liquid preparations, this paper can provide a reference for the development of P. americana extract preparations to promote wound healing in diabetic patients.