Peripheral BDNF Regulates Somatosensory-Sympathetic Coupling in Brachial Plexus Avulsion-Induced Neuropathic Pain / 神经科学通报·英文版

Brachial plexus avulsion (BPA) is a combined injury involving the central and peripheral nervous systems. Patients with BPA often experience severe neuropathic pain (NP) in the affected limb. NP is insensitive to the existing treatments, which makes it a challenge to researchers and clinicians. Accumulated evidence shows that a BPA-induced pain state is often accompanied by sympathetic nervous dysfunction, which suggests that the excitation state of the sympathetic nervous system is correlated with the existence of NP. However, the mechanism of how somatosensory neural crosstalk with the sympathetic nerve at the peripheral level remains unclear. In this study, through using a novel BPA C7 root avulsion mouse model, we found that the expression of BDNF and its receptor TrκB in the DRGs of the BPA mice increased, and the markers of sympathetic nervous system activity including α1 and α2 adrenergic receptors (α1-AR and α2-AR) also increased after BPA. The phenomenon of superexcitation of the sympathetic nervous system, including hypothermia and edema of the affected extremity, was also observed in BPA mice by using CatWalk gait analysis, an infrared thermometer, and an edema evaluation. Genetic knockdown of BDNF in DRGs not only reversed the mechanical allodynia but also alleviated the hypothermia and edema of the affected extremity in BPA mice. Further, intraperitoneal injection of adrenergic receptor inhibitors decreased neuronal excitability in patch clamp recording and reversed the mechanical allodynia of BPA mice. In another branch experiment, we also found the elevated expression of BDNF, TrκB, TH, α1-AR, and α2-AR in DRG tissues from BPA patients compared with normal human DRGs through western blot and immunohistochemistry. Our results revealed that peripheral BDNF is a key molecule in the regulation of somatosensory-sympathetic coupling in BPA-induced NP. This study also opens a novel analgesic target (BDNF) in the treatment of this pain with fewer complications, which has great potential for clinical transformation.

Dexamethasone protects the glycocalyx on the kidney microvascular endothelium during severe acute pancreatitis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

OBJECTIVE@#This study demonstrated that dexamethasone (DEX) protects the endothelial glycocalyx from damage induced by the inflammatory stimulus tumor necrosis factor-α (TNF-α) during severe acute pancreatitis (SAP), and improves the renal microcirculation.@*METHODS@#Ninety mice were evenly divided into 3 groups (Sham, SAP, and SAP+DEX). The SAP mice model was established by ligature of pancreatic duct and intraperitoneal injection of cerulein. Renal perfusion and function, and morphological changes of the glycocalyx were evaluated by laser Doppler velocimetry, electron microscopy, and histopathology (hematoxylin and eosin (H&E) staining), respectively. Serum levels of syndecan-1 and TNF-α were assessed by enzyme-linked immunosorbent assay (ELISA). The protective effects of dexamethasone on the glycocalyx and renal microcirculation were evaluated.@*RESULTS@#Significantly high levels of serum TNF-α were detected 3 h after the onset of SAP. These levels might induce degradation of the glycocalyx and kidney hypoperfusion, resulting in kidney microcirculation dysfunction. The application of dexamethasone reduced the degradation of the glycocalyx and improved perfusion of kidney.@*CONCLUSIONS@#Dexamethasone protects the endothelial glycocalyx from inflammatory degradation possibly initiated by TNF-α during SAP. This is might be a significant discovery that helps to prevent tissue edema and hypoperfusion in the future.

Polygala anatolica Boiss. et Heldr.: is a potential remedy for inflammation and pain? / Polygala anatolica Boiss. et Heldr.: ¿es un remedio potencial para la inflamación y el dolor?

Species of Polygala genus have been used for the treatment of inflamation and pain in Turkish traditional medicine. The aim of the present study is to assess the anti-inflammatory and analgesic activities of P. anatolica. n-Hexane, ethyl acetate and methanol extracts of the aerial parts and roots of P. anatolica were investigated for their anti-inflammatory and analgesic effects. The methanol extracts prepared from the aerial parts and roots of P. anatolica were found to be active in carrageenan- and PGE2-induced paw edema models and in Whittle method. Methanolic extract of the aerial part inhibited serotonin-induced hind paw edema, while the root extract did not exert inhibitory effect in the same model. In addition, Fr. B and C obtained from the methanol extract of P. anatolica aerial parts showed significant anti- inflammatory activity. Morover, the analgesic effect of the methanol extracts prepared from the roots and aerial parts and Fr.B and Fr.C were found to be statistically significant without inducing ulceration. The methanol extract obtained from the aerial parts of the plant and its saponoside and flavonoid fractions showed anti-inflammatory and analgesic activities in the trials.

Las especies del género Polygala se han utilizado para el tratamiento de la inflamación y el dolor en la medicina tradicional turca. El objetivo del presente estudio es evaluar las actividades antiinflamatorias y analgésicas de P. anatolica. Se investigaron los extractos de n-hexano, acetato de etilo y metanol de las partes aéreas y raíces de P. anatolica por sus efectos antiinflamatorios y analgésicos. Los extractos de metanol preparados a partir de las partes aéreas y raíces de P. anatolica se encontraron activos en modelos de edema de pata inducidos por carragenina y PGE2 por el método de Whittle. El extracto metanólico de la parte aérea inhibió el edema de la pata trasera inducido por serotonina, mientras que el extracto de raíz no ejerció un efecto inhibidor en el mismo modelo. En suma, la fracción B y C obtenidos a partir del extracto metanólico de partes aéreas de P. anatolica mostraron actividad antiinflamatoria significativa. Además, el efecto analgésico de los extractos de metanol preparados a partir de las raíces y las partes aéreas y la fracción B y C resultaron ser estadísticamente significativas sin inducir la ulceración. El extracto de metanol obtenido de las partes aéreas de la planta y sus fracciones de saponósidos y flavonoides mostraron actividades antiinflamatorias y analgésicas en los ensayos.

Effects of aquaporin 4 and inward rectifier potassium channel 4 1 on medullospinal edema after methylprednisolone treatment to suppress acute spinal cord injury in rat

Abstract Purpose: To investigate the effects of aquaporin 4 (AQP4) and inward rectifier potassium channel 4.1 (Kir4.1) on medullospinal edema after treatment with methylprednisolone (MP) to suppress acute spinal cord injury (ASCI) in rats. Methods: Sprague Dawley rats were randomly divided into control, sham, ASCI, and MP-treated ASCI groups. After the induction of ASCI, we injected 30 mg/kg MP via the tail vein at various time points. The Tarlov scoring method was applied to evaluate neurological symptoms, and the wet-dry weights method was applied to measure the water content of the spinal cord. Results: The motor function score of the ASCI group was significantly lower than that of the sham group, and the spinal water content was significantly increased. In addition, the levels of AQP4 and Kir4.1 were significantly increased, as was their degree of coexpression. Compared with that in the ASCI group, the motor function score and the water content were significantly increased in the MP group; in addition, the expression and coexpression of AQP4 and Kir4.1 were significantly reduced. Conclusion: Methylprednisolone inhibited medullospinal edema in rats with acute spinal cord injury, possibly by reducing the coexpression of aquaporin 4 and Kir4.1 in medullospinal tissues.

Possible involvement of nitric oxide in estrogen-induced uterine edema in the immature rat

We examined whether nitric oxide mediates estrogen-induced uterine edema in the immature rat. Immature Wistar rats (19-21 days) received estradiol-17 beta (E2) in a single sc dose of 10 micrograms/animal and 6 h later the animals were sacrificed and the changes in uterine wet and dry weights were determined. E2 treatment caused a 93 per cent increase in uterine wet weight (control, N = 6, 39.88 +/- 3.2 mg; E2 treated, N = 6, 76.8 +/- 4.9 mg), but not in dry weight, suggesting that it induces uterine edema. Pretreatment with L-nitroarginine methyl ester (L-NAME), a competitive antagonist of nitric oxide synthetase, at doses of 10 and 20 mg/kg, ip, caused a dose-related reduction (59 and 86 per cent ) in the uterine wet weight increase induced by E2. Furthermore, L-arginine (300-600 mg/kg, sc), the nitric oxide precursor, was able to reverse L-NAME (20 mg/kg)-induced decreases in uterine weight by 47 and 62 per cent , respectively. The results suggest that nitric oxide is the principal mediator involved in estrogen-induced uterine edema in the immature rat