Research progress of TRPV4 in ocular pathophysiological function / 国际眼科杂志(Guoji Yanke Zazhi)

Transient receptor potential vanilloid receptor 4(TRPV4)is a non-selective cation channel responsible for sensing changes in cell swelling, temperature, mechanical stretch, shear stress and osmotic pressure by regulating transmembrane calcium signaling and thereby influencing gene expression, cell morphology, and cytoskeletal construction. TRPV4 is widely expressed throughout the body. Intraocularly, TRPV4 is functionally expressed in the cornea, lens, ciliary body, trabecular meshwork and retina. In this article, the expression and physiopathological functions of TRPV4 in various tissues of the eye were described. With the in-depth study of TRPV4 in ocular pathophysiological functions, TRPV4 may become a potential drug target in corneal injury repair, glaucoma and retinal angiogenesis, but further in-depth study is still needed.

A-80426 suppresses CFA-induced inflammatory pain by suppressing TRPV1 activity via NFκB and PI3K pathways in mice

Abstract Objectives Pain is associated with many circumstances, including inflammatory reactions, which arise from modification of the features of signaling pathways. α2-adrenergic receptor antagonists are widely utilized in narcosis. Here, the authors focused on the narcotic effect of A-80426 (A8) on Complete Freund's Adjuvant (CFA) injections-triggered chronic inflammation pain in WT and TRPV1-/- mice and explored whether its antinociceptive impact was modulated via Transient Receptor Potential Vanilloid 1 (TRPV1). Method CFA with or without A8 was co-administered to the mice, which were categorized randomly into four groups: CFA, A8, control, and vehicle. Pain behaviors underwent evaluation through mechanical withdrawal threshold, abdominal withdrawal reflex, and thermal withdrawal latency of WT animals. Results Quantitative polymerase chain reaction revealed that inflammation-promoting cytokines (IL-1β, IL-6, and TNF-α) were upregulated in Dorsal Root Ganglion (DRG) and Spinal Cord Dorsal Horn (SCDH) tissues of WT animals. A8 administration reduced the pain behaviors and production of pro-inflammatory cytokines; however, this effect was significantly reduced in TRPV1-/- mice. Further analysis showed that CFA treatment reduced the TRPV1 expression in WT mice and A8 administration increased its expression and activity. The co-administration of SB-705498, a TRPV1 blocker, did not influence the pain behaviors and inflammation cytokines in CFA WT mice; however, SB-705498 the effect of A8 in WT mice. In addition, the TRPV1 block decreased the NFκB and PI3K activation in the Dorsal Root Ganglia (DRG) and Spinal Cord Dorsal Horn (SCDH) tissues of WT mice. Conclusions Together, A8 exerted a narcotic impact on CFA-supplemented mice via the TRPV1-modulated NFκB and PI3K pathway.

Intervention effect of Qufeng Gutong Cataplasm on myofascial pain syndrome in rats and its mechanism / 中国中药杂志

This paper aims to investigate the intervention effect of Qufeng Gutong Cataplasm(QFGT) on myofascial pain syndrome(MPS) in rats and to preliminarily explain its mechanism from the perspective of improving muscle inflammation and pain. Male SD rats were divided into 6 groups, namely normal group, model group, positive control drug(Huoxue Zhitong Ointment, HXZT) group, and low, medium, and high-dose QFGT groups(75, 150, and 300 mg·d~(-1)). The rat model of MPS was established by striking combined with centrifugation for 8 weeks, during which QFGT and HXZT were used for corresponding intervention. Standard VonFrey fiber was used to evaluate the mechanical pain threshold, and acetone was used to detect the cold pain threshold. The electrophysiological activity of muscle at trigger point was detected, and the electromuscular analysis of trigger point was performed. CatWalk gait analyzer was used to detect pain-induced gait adaptation changes. The hematoxylin-eosin(HE) staining was used to observe the pathological changes in muscle and skin tissues at the trigger point of rats. Immunohistochemistry was used to detect the expression of capsaicin receptor transient receptor potential vanilloid 1(TRPV1) in muscle tissues and interleukin(IL)-33 in skin tissues at the trigger point. The protein expression levels of TRPV1, protein kinase B(Akt), phosphorylated protein kinase B(p-Akt), IL-1β, and tumor necrosis factor-α(TNF-α) in muscle tissues at the trigger point were detected by Western blot. The results showed that as compared with the model group, the mechanical pain threshold and cold pain threshold of rats in other groups were increased after treatment with QFGT. The spontaneous electromyography(EMG) activity was observed in the model group, but QFGT alleviated the EMG activity in a dose-dependent manner. Gait analysis showed that standing duration, average intensity, swing speed, maximum contact point, maximum contact area, paw print length, paw print width, and paw print area were significantly improved in all QFGT groups. Pathological results showed that the disorder of muscle arrangement at the trigger point was decreased, muscle fiber adhesion and atrophy were reduced, and inflammatory cell infiltration was alleviated after treatment with QFGT. In addition, QFGT and HXZT both inhibited the protein expression of TRPV1, PI3K, Akt, p-Akt, IL-1β, and TNF-α in the muscle tissues of rats with MPS. However, there was no significant difference in the pathological structure and expression of IL-33 in the treated skin as compared with the normal group. The related results have proved that QFGT can inhibit the release of inflammatory factors by inhibiting the TRPV1/PI3K/Akt signaling pathway in the muscle trigger point of rats with MPS and finally attenuate the atrophy and adhesion of local muscles and inflammatory infiltration, thereby relieving the muscle pain of rats with MPS, and local administration has no skin irritation.

Mechanism of Renshentang in Treatment of Atherosclerosis Based on Autophagic Effect of TRPV1 on Arterial Smooth Muscle / 中国实验方剂学杂志

ObjectiveTo investigate the mechanism of Renshentang， recorded in Synopsis of Golden Chamber， in the treatment of atherosclerosis （AS） based on the autophagic effect of transient receptor potential vanilloid subtype 1 （TRPV1） on arterial smooth muscle. MethodFourteen SPF-grade 8-week-old male C57BL/6J mice were assigned to the normal group and 70 8-week-old apolipoprotein E knockout （ApoE-/-） mice were assigned to the experimental group. The AS model was induced by a high-fat diet in the mice in the experimental group for eight weeks. The model mice were then randomly divided into model group， low-， medium-， and high-dose Renshentang groups （2.715， 5.43， and 10.68 g·kg-1·d-1）， and simvastatin group （0.02 g·kg-1·d-1）. Drug treatment lasted eight weeks. Serum was taken and serum total cholesterol （CHO）， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C）， and high-density lipoprotein cholesterol （HDL-C） levels were measured by assay kits to observe the changes in lipid levels in mice. The aorta was stained with hematoxylin-eosin （HE） to observe the overall pathology of the aortic root and oil red O staining was used to detect the lipid deposition in the aortic plaque and calculate the percentage of the aortic root area to the lumen area. The protein expression of TRPV1， adenylate-activated protein kinase （AMPK）， phosphorylated AMPK （p-AMPK）， autophagy effector-1 （Beclin-1）， and microtubule-associated protein 1 light chain 3 （LC3Ⅱ） in mouse aortic tissues was determined by Western blot. ResultCompared with the normal group， the model group showed increased serum CHO， TG， and LDL-C levels， decreased HDL-C， and increased aortic root plaque area （P<0.01）. Compared with the model group， the Renshentang groups showed decreased levels of CHO， TG， and LDL-C in serum （P<0.05， P<0.01）， especially in the low- and medium-dose Renshentang groups （P<0.01）. Compared with the normal group， the simvastatin group and the Renshentang groups showed reduced aortic root plaque area （P<0.05）， especially in the high-dose Renshentang group （P<0.01）. Compared with the normal group， the model group showed decreased relative expression levels of TRPV1， p-AMPK/AMPK， Beclin-1， and LC3Ⅱ/LC3Ⅰ（P<0.05， P<0.01）. Compared with the model group， the medium- and high-dose Renshentang groups showed increased relative expression levels of TRPV1， p-AMPK/AMPK， Beclin-1， and LC3Ⅱ/LC3Ⅰ（P<0.05，P<0.01）. ConclusionThe anti-AS effect of Renshentang recorded in Synopsis of Golden Chamber may be achieved by up-regulating TRPV1 expression to restore the level of autophagy mediated by AMPK.

Preliminary study of TRPV4 affects chondrocyte degeneration / 中国骨伤

OBJECTIVE@#To explore and verify that transient receptor potential vanilloid 4(TRPV4) affects chondrocyte degeneration.@*METHODS@#Neonatal SD rats were selected, primary chondrocytes were extracted, and identified by toluidine blue staining and alcian blue staining;an in vitro chondrocyte inflammation model was constructed by IL-1β, and TRPV4 inhibitor was used to treat chondrocytes under inflammatory conditions, and the chondrocytes were treated by RT-PCR method was used to detect matrix metallopeptidase 13(MMP-13), a disintegrin and metalloproteinase with thrombospondin 5, (ADAMTS-5)、nitric oxide synthase 2(NOS2)、Collagen, type II alpha 1(Col2α1)and aggrecan (Acan) mRNA in chondrocytes; primary chondrocytes were treated with different concentrations of TRPV4 overexpression plasmid, and the optimal overexpression dose was screened. The mRNA expressions of TRPV4, MMP-13, ADAMTS-5, NOS2, Col2α1 and Acan in chondrocytes under the optimal TRPV4 overexpression dose were detected.@*RESULTS@#Toluidine blue staining and Alcian blue staining identified the extracted cells as primary chondrocytes;RT-PCR showed that TRPV4, MMP-13, ADAMTS-5, NOS2 mRNA in chondrocytes treated with TRPV4 inhibitor under inflammatory conditions. The expression of Col2α1 mRNA was significantly decreased (P<0.05), and the expression of Col2α1 mRNA was increased (P<0.05). Although there was no significant difference in the expression of Acan mRNA, the overall trend was also increasing. The expression of Col2α1 and Acan mRNA in chondrocytes was significantly decreased (P<0.05), and the expression of NOS2 mRNA was increased(P<0.05), but there was no significant difference in MMP-13 and ADAMTS-5 (P>0.05).@*CONCLUSION@#Inhibiting the expression of TRPV4 can down-regulate the expression of genes related to chondrocyte degeneration.

Research progress of chondrocyte mechanotransduction mediated by TRPV4 and PIEZOs / 生物医学工程学杂志

Mechanical signal transduction are crucial for chondrocyte in response to mechanical cues during the growth, development and osteoarthritis (OA) of articular cartilage. Extracellular matrix (ECM) turnover regulates the matrix mechanical microenvironment of chondrocytes. Thus, understanding the mechanotransduction mechanisms during chondrocyte sensing the matrix mechanical microenvironment can develop effective targeted therapy for OA. In recent decades, growing evidences are rapidly advancing our understanding of the mechanical force-dependent cartilage remodeling and injury responses mediated by TRPV4 and PIEZOs. In this review, we highlighted the mechanosensing mechanism mediated by TRPV4 and PIEZOs during chondrocytes sensing mechanical microenvironment of the ECM. Additionally, the latest progress in the regulation of OA by inflammatory signals mediated by TRPV4 and PIEZOs was also introduced. These recent insights provide the potential mechanotheraputic strategies to target these channels and prevent cartilage degeneration associated with OA. This review will shed light on the pathogenesis of articular cartilage, searching clinical targeted therapies, and designing cell-induced biomaterials.

Improvement effect of Shegan Mahuang Decoction on rats with cold-induced asthma based on TRPV1/NRF-1/mtTFA pathway / 中国中药杂志

This study investigated the therapeutic effect of Shegan Mahuang Decoction(SGMHD) on cold-induced asthma in rats and explored its underlying mechanism. Seventy-two healthy male SD rats of specific pathogen free(SPF) grade were randomly divided into a blank group, a model group, a positive control group(dexamethasone, 0.4 mg·kg~(-1)), and low-, medium-, and high-dose SGMHD groups(3.2, 6.4, and 12.8 g·kg~(-1)). The blank group received saline, while the other groups were sensitized by intraperitoneal injection of ovalbumin(OVA) solution. Subsequently, the rats were placed in a cold chamber adjustable to 0-2 ℃, and OVA solution was ultrasonically nebulized to induce cold-induced asthma in rats. After three weeks of treatment, the general behaviors of rats were observed. Hematoxylin-eosin(HE) staining was used to evaluate pathological changes in lung tissues, periodic acid-Schiff(PAS) staining assessed mucin changes, and Masson staining was performed to examine collagen deposition. Enzyme-linked immunosorbent assay(ELISA) was used to measure the levels of the inflammatory factors interleukin-4(IL-4) and vascular endothelial growth factor(VEGF) in serum and bronchoalveolar lavage fluid(BALF). Real-time quantitative polymerase chain reaction(RT-PCR) was employed to assess the mRNA expression levels of transient receptor potential vanilloid subfamily member 1(TRPV1), nuclear respiratory factor 1(NRF-1), and mitochondrial transcription factor A(mtTFA) in lung tissues. Western blot was used to measure the protein expression levels of TRPV1, NRF-1, and mtTFA in lung tissues. Compared with the blank group, the model group exhibited signs of rapid respiration, increased frequency of defecation with looser stools, and disheveled and dull fur. Pathological results showed significant infiltration of inflammatory cells in lung tissues, narrowing of bronchial lumens, increased mucin secretion, and enhanced collagen deposition in the model group. Additionally, the levels of IL-4 and VEGF in serum and BALF were significantly elevated, and the mRNA and protein expression levels of TRPV1, NRF-1, and mtTFA in lung tissues were significantly increased. Compared with the model group, SGMHD improved the behaviors of rats, alleviated pathological changes in lung tissues, mucin production, and collagen deposition, significantly decreased the levels of IL-4 and VEGF in serum and BALF, and reduced the mRNA expression levels of TRPV1, NRF-1, and mtTFA in lung tissues, with the medium-dose SGMHD group showing the most significant effect. Moreover, the protein expression levels of TRPV1, NRF-1, and mtTFA in lung tissues were also reduced, with the medium-dose SGMHD group exhibiting the most significant effect. In conclusion, this study demonstrates that SGMHD can alleviate airway inflammation and inhibit airway remodeling in cold-induced asthma rats. These effects may be associated with the modulation of the TRPV1/NRF-1/mtTFA signaling pathway.

Research progress of TRPV4 in glaucoma optic neuropathy / 国际眼科杂志(Guoji Yanke Zazhi)

Glaucomatous optic neuropathy(GON)is the difficulty of glaucoma treatment. In recent years, a variety of theories have been put forward about the pathogenesis of GON, but none of them can explain the principle of optic neuropathy caused by all types of glaucoma, which makes the disease difficult to treat in clinical treatment and is not conducive to early intervention. The latest research found that the transient receptor potential channel vanillic acid subfamily 4(TRPV4)in the retina plays an important role in various pathogenesis of GON. This article will review TRPV4 and its role in the occurrence and development of GON in order to find a common “connection point” for the multiple mechanism theories of GON, which will contribute to further understanding and clinical treatment of the disease.

Role of TRPV4 in dexmedetomidine-induced improvement in cognitive function in mice with mechanical ventilator-caused brain injury / 中华麻醉学杂志

Objective:To evaluate the role of transient receptor potential vanillic acid 4 (TRPV4) in dexmedetomidine-induced improvement in cognitive function in mice with mechanical ventilator-caused brain injury.Methods:Ninety clean-grade healthy male C57BL6 mice, weighing 20-25 g, aged 8-12 weeks, were divided into 5 groups ( n=18 each) using a random number table method: control group (group C), mechanical ventilation group (group V), HC-067047 group (group H), dexmedetomidine group (group D), and dexmedetomidine+ GSK1016790A group (group DG). In group C, the animals breathed air spontaneously for 6 h without mechanical ventilation. In group V, the animals were mechanically ventilated for 6 h. In group H, TRPV4 blocker HC-067047 10 mmol was injected into the cerebral ventricle at 3 and 6 h of mechanical ventilation. In D and DG groups, dexmedetomidine 50 μg/kg was intraperitoneally injected at 30 min before mechanical ventilation. In group DG, TRPV4 agonist GSK1016790A 5 μmol was injected into the cerebral ventricle at 60 min before mechanical ventilation. Morris water maze test was performed on 6 mice in each group at 1 day before mechanical ventilation and 3 and 7 days after mechanical ventilation. Six mice in each group were randomly selected and sacrificed at 1 day after mechanical ventilation, and the brain tissue was taken for determination of the neuronal apoptosis in hippocampal CA1 area by TUNEL method, and the apoptosis index was calculated. Six mice in each group were randomly selected and sacrificed at 1 day after mechanical ventilation, and the hippocampal tissues were taken for determination of the expression of TRPV4, serine-threonine protein kinase (Akt), phosphorylated Akt (p-Akt), Bcl-2, Bax and caspase-3 by Western blot. Results:Compared with group C, the escape latency was significantly prolonged and the number of crossing the original platform was reduced at 3 and 7 days after mechanical ventilation, the expression of TRPV4 and caspase-3 was up-regulated, the ratio of Bcl-2/Bax was decreased, and the apoptosis index of neurons was increased in group V and group DG ( P<0.05). Compared with group V, the escape latency was significantly shortened and the number of crossing the original platform was increased at 3 and 7 days after mechanical ventilation, the expression of TRPV4 and caspase-3 was down-regulated, the expression of p-Akt was up-regulated, the ratio of Bcl-2/Bax was increased, and the apoptosis index of neurons was decreased in group D and group H ( P<0.05). Compared with group D, the escape latency was significantly prolonged at 3 and 7 days after mechanical ventilation, the number of crossing the original platform was reduced, the expression of TRPV4 and caspase-3 was up-regulated, the expression of p-Akt was down-regulated, the ratio of Bcl-2/Bax was decreased, and the apoptosis index of neurons was increased in group DG ( P<0.05). Conclusions:TRPV 4 is involved in dexmedetomidine-induced improvement in cognitive function, which is related to up-regulation of p-Akt expression and inhibition of apoptosis in hippocampal neurons in mice with mechanical ventilation-caused brain injury.

The role of thermosensitive transient receptor potential vanilloid channel in the dissimilation of itching sensitized by warm in atopic dermatitis / 中国医师杂志

Atopic dermatitis (AD) is an inflammatory skin disease characterized by itch. Transient receptor potential vanilloid (TRPV) receptor subtype channel can be activated by different ranges of harmless temperature, and plays an important role in the warm itching in AD. Inhibitors of TRPV channel can alleviate the symptoms of AD, and may be used as a new target for treatment. This paper introduces the role of thermosensitive TRPV channel in the alienation of itching sensitized by warm in AD.

TRPV4-induced Neurofilament Injury Contributes to Memory Impairment after High Intensity and Low Frequency Noise Exposures / 生物医学与环境科学（英文）

OBJECTIVE@#Exposure to high intensity, low frequency noise (HI-LFN) causes vibroacoustic disease (VAD), with memory deficit as a primary non-auditory symptomatic effect of VAD. However, the underlying mechanism of the memory deficit is unknown. This study aimed to characterize potential mechanisms involving morphological changes of neurons and nerve fibers in the hippocampus, after exposure to HI-LFN.@*METHODS@#Adult wild-type and transient receptor potential vanilloid subtype 4 knockout (TRPV4-/-) mice were used for construction of the HI-LFN injury model. The new object recognition task and the Morris water maze test were used to measure the memory of these animals. Hemoxylin and eosin and immunofluorescence staining were used to examine morphological changes of the hippocampus after exposure to HI-LFN.@*RESULTS@#The expression of TRPV4 was significantly upregulated in the hippocampus after HI-LFN exposure. Furthermore, memory deficits correlated with lower densities of neurons and neurofilament-positive nerve fibers in the cornu ammonis 1 (CA1) and dentate gyrus (DG) hippocampal areas in wild-type mice. However, TRPV4-/- mice showed better performance in memory tests and more integrated neurofilament-positive nerve fibers in the CA1 and DG areas after HI-LFN exposure.@*CONCLUSION@#TRPV4 up-regulation induced neurofilament positive nerve fiber injury in the hippocampus, which was a possible mechanism for memory impairment and cognitive decline resulting from HI-LFN exposure. Together, these results identified a promising therapeutic target for treating cognitive dysfunction in VAD patients.

Propofol relieves the subcutaneous chloroquine-induced pruritus in rats via TRPV1 and CB1 receptors of spinal cord / 中国临床药理学与治疗学

AIM: To explore the possible mechanism of propofol in alleviating pruritus induced by subcutaneous injection of chloroquine in rats. METHODS: The pruritus model of chloroquine in SD rats was established and the administration time was determined. 18 rats with successful pruritus model induced by subcutaneous injection of chloroquine were randomly divided into NS group, I group and P group. Normal saline 80 μL/kg, fat emulsion 80 μL/kg and propofol 0.8 mg/kg were injected through internal jugular vein catheter 5 minutes after subcutaneous injection of chloroquine. Another 6 rats were randomly selected as group C, and the same volume of normal saline as the other 3 groups was injected subcutaneously in the back of the neck and through the internal jugular vein catheter. The rats were killed 16 minutes after the corresponding drugs were injected into the internal jugular vein. The expressions of TRPV1 and CB1 receptors in the spinal cord were detected by Western blot. RESULTS: Compared with NS group and I group, the expression level of TRPV1 receptor in the spinal cord of P group rats was significantly increased (P<0.01), while there was no statistically significant difference between C group, NS group, and I group; The expression level of CB1 receptor was significantly higher than that of group C, NS, and I (P<0.05), while there was no statistically significant difference between group C, NS, and I. CONCLUSION: Propofol can significantly alleviate pruritus caused by subcutaneous injection of chloroquine in rats, which may exert an antipruritic effect by increasing the expression of TRPV1 and CB1 receptors in the spinal cord of rats.

Research Development in Patients with Olmsted Syndrome / 罕见病研究

Olmsted syndrome (OS) is an extremely rare hereditary skin disease, that is usually characterized by mutilating palmoplantar keratoderma (PPK) and periorificial keratotic plaques. The diagnosis of this disease depends primarily on the clinical presentation and OS has to be differentiated from other disorders associated with hyperkeratosis. In recent years, there have been many advances in molecular genetic research on the pathogenesis of the disease. The genes that can cause disease after specific mutations include TRPV3, MBTPS2/S2P and PERP. Therefore, genetic testing has become one of the important methods for the diagnosis of this disease.OS treatment is difficult, and conventional therapy uses topical drugs to soften the cuticle of the skin, or oral Avi A.Excision of palmoplantar keratosis may also be used for constricting rings that severely restrict movement, but they often reoccur after initial improvement. In terms of precision treatment, researchers have tried the small molecule drugs erlotinib and sirolimus and have achieved some results. This paper summarizes the etiology, pathogenesis, clinical manifestations, diagnosis, treatment and prognosis of OS, in order to improve the clinicans' awareness of OS.

Transient receptor potential vanilloid 1 (TRPV1) receptor stimulation by topical capsaicin for the functional assessment of diabetic neuropathy leading to diabetic foot disease

Objectives: As neuropathy predominates vasculopathy, predicting functional deterioration of autonomic neurovascular dysfunction is essential to reduce diabetic foot ulcers. The present study has evaluated the possibility of stimulating the TRPV1 receptors of the small fibres using topical capsaicin to assess diabetic neuropathy in the dorsum of the foot functionally. Materials and Methods: A prospective cross-sectional study was carried out on ten healthy volunteers and 20 diabetic patients after receiving ethical approval. The subjects underwent vascular Doppler analysis after giving written agreement followed by monofilament testing. Then, topical capsaicin was applied to measure the local autonomic neurovascular reaction. With the use of an infrared-based digital instrument that was specially created, the vasodilation and proportional increase in temperature brought on by the application of capsaicin were quantified. Results: The percentage change in the local temperature in the control group varied from 0.478 to 3.315 compared to the diabetic group, which varied from 1.862 to ?3.932. There is a statistically significant difference in the mean of the two groups (P = 0.006) at a 95% confidence interval. Conclusion: This study suggests that TRPV1 receptor stimulation using capsaicin and resultant vasodilation monitored by the increase in local temperature can be used as a quantitative predictor of the early small fibre neuropathy in Distal Symmetric Polyneuropathy before the patient ends up with diabetic foot ulcer.

Muscle pain induced by static contraction is modulated by transient receptor potential vanilloid 1 and ankyrin 1 receptors

Abstract Molecular mechanisms involved in the development of muscle pain induced by static contraction are not completely elucidated. This study aimed to evaluate the involvement of the transient receptor potential vanilloid 1 (TRPV1) and the transient receptor potential ankyrin 1 (TRPA1) receptors expressed in peripheral and central terminals of primary afferents projected to gastrocnemius muscle and spinal cord in muscle pain induced by static contraction. An electrical stimulator provided the contraction of rat gastrocnemius muscle and mechanical muscle hyperalgesia was quantified through the pressure analgesimeter Randall-Selitto. AMG9810 and HC030031 were used. When administered in ipsilateral, but not contralateral gastrocnemius muscle, drugs prevented mechanical muscle hyperalgesia induced by static contraction. Similar results were obtained by intrathecal administrations. We propose that, in an inflammatory muscle pain, peripheral and central TRPV1 and TRPA1 work together to sensitize nociceptive afferent fibers, and that TRPV1 and TRPA1 receptors are potential target to control inflammatory muscle pain.

Inhibition of intracellular proton-sensitive Ca2+-permeable TRPV3 channels protects against ischemic brain injury

Ischemic brain stroke is pathologically characterized by tissue acidosis, sustained calcium entry and progressive cell death. Previous studies focusing on antagonizing N-methyl-d-aspartate (NMDA) receptors have failed to translate any clinical benefits, suggesting a non-NMDA mechanism involved in the sustained injury after stroke. Here, we report that inhibition of intracellular proton-sensitive Ca2+-permeable transient receptor potential vanilloid 3 (TRPV3) channel protects against cerebral ischemia/reperfusion (I/R) injury. TRPV3 expression is upregulated in mice subjected to cerebral I/R injury. Silencing of TRPV3 reduces intrinsic neuronal excitability, excitatory synaptic transmissions, and also attenuates cerebral I/R injury in mouse model of transient middle cerebral artery occlusion (tMCAO). Conversely, overexpressing or re-expressing TRPV3 increases neuronal excitability, excitatory synaptic transmissions and aggravates cerebral I/R injury. Furthermore, specific inhibition of TRPV3 by natural forsythoside B decreases neural excitability and attenuates cerebral I/R injury. Taken together, our findings for the first time reveal a causative role of neuronal TRPV3 channel in progressive cell death after stroke, and blocking overactive TRPV3 channel may provide therapeutic potential for ischemic brain injury.

Mechanism of Aconiti Kusnezoffii Radix Processed with Chebulae Fructus Against H9c2 Cardiomyocyte Toxicity Based on TRPV1 Channel / 中国实验方剂学杂志

ObjectiveTo explore the role of transient receptor potential vanilloid 1 （TRPV1） channel in reducing cardiomyocyte toxicity of Aconiti Kusnezoffii Radix processed with Chebulae Fructus. MethodH9c2 cardiomyocytes cultured in vitro were used as a model to assess cell viability by methyl thiazolyl tetrazolium （MTT） assay， the expression of TRPV1 mRNA was detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the leakage rate of lactate dehydrogenase （LDH）， the changes of nucleus， reactive oxygen species （ROS）， mitochondrial membrane potential and Ca2+ contents were detected by enzyme linked immunosorbent assay （ELISA）. ResultCompared with the blank group， when the concentration was ≥0.5 g·L-1， the cell viability was significantly decreased （P<0.01）， the leakage rate of LDH， the release of ROS and Ca2+ were increased， the mitochondrial membrane potential was decreased， and the nucleus was pyknosis or even broken in raw Aconiti Kusnezoffii Radix and Aconiti Kusnezoffii Radix processed with Chebulae Fructus groups. When the concentration was ≥0.5 g·L-1， compared with the same mass concentration of raw Aconiti Kusnezoffii Radix group， the cell viability increased significantly （P<0.01）， the leakage rate of LDH， the release of ROS and Ca2+ decreased， the mitochondrial membrane potential increased， and the nuclear morphology improved in Aconiti Kusnezoffii Radix processed with Chebulae Fructus group. Application of the same mass concentration of raw Aconiti Kusnezoffii Radix to H9c2 cardiomyocytes pretreated with the TRPV1 inhibitor BCTC significantly increased cell viability， decreased leakage rate of LDH， ROS and Ca2+ release， increased mitochondrial membrane potential and improved nuclear pyknosis compared with untreated H9c2 cardiomyocytes. Application of the same mass concentration of Aconiti Kusnezoffii Radix processed with Chebulae Fructus to H9c2 cardiomyocytes pretreated with BCTC decreased cell viability， increased LDH leakage rate， ROS and Ca2+ release， reduced mitochondrial membrane potential compared with untreated H9c2 cardiomyocytes. Real-time PCR results showed that both raw Aconiti Kusnezoffii Radix and Chebulae Fructus decoction could increase the expression of TRPV1 mRNA in cardiomyocytes in a concentration dependent manner. ConclusionRaw Aconiti Kusnezoffii Radix can induce cardiomyocyte apoptosis and cardiotoxicity by activating TRPV1 channel， while Aconiti Kusnezoffii Radix processed with Chebulae Fructus can attenuate the toxicity through TRPV1 channel， which may be related to the synergistic effect of acid components in Chebulae Fructus and alkaloids in Aconiti Kusnezoffii Radix on TRPV1 channel.

Role of TRPV1/NF-κB signaling pathway in dexmedetomidine-induced alleviation of VILI in rats / 中华麻醉学杂志

Objective:To evaluate the role of transient receptor potential vanilloid receptor 1 (TRPV1)/nuclear factor-κB (NF-κB) signaling pathway in dexmedetomidine-induced alleviation of ventilator-induced lung injury (VILI) in rats.Methods:One hundred clean-grade healthy male Sprague-Dawley rats, weighing 270-320 g, aged 4-5 months, were divided into 5 groups ( n=20 each) using a random number table method: control group (group C), VILI group (group V), AMG9810 group (group A), dexmedetomidine group (group D), and dexmedetomidine + RTX group (group DR). VILI model was prepared by mechanical ventilation with a tidal volume of 40 ml/kg for 4 h. In group A, TRPV1 inhibitor AMG9810 30 mg/kg was intraperitoneally injected at 1 h before mechanical ventilation.Dexmedetomidine 5.0 μg/kg was intravenously infused at 20 min before mechanical ventilation, and dexmedetomidine was intravenously infused at the rate of 5.0 μ g·kg -1·h -1 during ventilation in group D and group DR.In group DR, RTX 70 μ g/kg was intraperitoneally injected for 3 consecutive days before mechanical ventilation.At 4 h of mechanical ventilation, the concentrations of interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and IL-6 in bronchoalveolar lavage fluid (BALF) were detected, oxygenation index (OI) and wet/dry lung weight (W/D) ratio were measured, the histopathological changes of lung tissues were observed, and lung injury was assessed and scored.The expression of TRPV1 and NF-κB in lung tissues was detected by Western blot, and real-time polymerase chain reaction was used to detect the expression of TRPV1 and NF-κB mRNA. Results:Compared with group C, the concentrations of IL-1β, TNF-α and IL-6 in BALF were significantly increased, OI was decreased, the W/D ratio and lung injury scores were increased, and the expression of TRPV1 and NF-κB protein and mRNA was up-regulated in group V ( P<0.05). Compared with group V, the concentrations of IL-1β, TNF-α and IL-6 in BALF were significantly decreased, OI was increased, the W/D ratio and lung injury scores were decreased, and the expression of TRPV1 and NF-κB protein and mRNA was down-regulated in A, D and DR groups ( P<0.05). Compared with group D, the concentrations of IL-1β, TNF-α and IL-6 in BALF were significantly increased, OI was decreased, the W/D ratio and lung injury scores were increased, and the expression of TRPV1 and NF-κB protein and mRNA was up-regulated in group DR ( P<0.05). Conclusions:The mechanism by which dexmedetomidine alleviates VILI is partially related to inhibition of the activation of TRPV1/NF-κB signaling pathway and inhibition of the inflammatory responses in lung tissues of rats.

Relationship Between TRPV1 and TRPM8 in Reflux Esophagitis Models / 胃肠病学

Background: Studies have shown that transient receptor potential (TRP) channels play important roles in gastroesophageal reflux disease (GERD), however, the relationship between TRPV1 and TRPM8 in reflux esophagitis (RE) remains unclear. Aims: To investigate the expressions of TRPV1, TRPM8 and their correlation in guinea pigs with RE. Methods: Thirty male guinea pigs aged 3⁃4 weeks were randomly divided into 3 groups: blank control group, negative control group and model group, with 10 animals in each group. Guinea pigs in model group and negative control group were given esophageal perfusion with 0.1 mol/L HCl containing 0.5% pepsin and normal saline, respectively, once a day for 14 days; guinea pigs in blank control group were free to drink sterile water for 14 days. On day 15, the esophagus was dissected for macroscopic and histopathological examination, and Western blotting and/or real⁃time PCR were used to detect the expression levels of TRPV1, TRPM8, GNAQ (an isoform of G protein), and the tight junction proteins and proinflammatory cytokines in esophageal tissue. The co⁃localization of TRPV1 and TRPM8 was assessed by immunofluorescence. Results: Esophageal mucosal congestion, hyperplasia of esophageal epithelial cells, infiltration of inflammatory cells, as well as up⁃regulation of proinflammatory cytokines and down⁃regulation of tight junction proteins were observed in esophageal tissue of guinea pigs in model group, which indicated the successful RE model construction. As compared with the negative control group, expression levels of TRPV1 and GNAQ mRNA and protein were significantly increased, while expression levels of TRPM8 mRNA and protein were significantly reduced in esophageal tissue of guinea pigs in model group (all P<0.05). TRPV1 and TRPM8 channels were co ⁃ localized in the lamina propria of esophageal mucosa. Conclusions: There is a certain equilibrium mechanism between TRPV1 and TRPM8 channels in RE models. G protein⁃coupled receptor signaling pathway and the downstream TRPV1/TRPM8 might be involved in the occurrence and development of GERD.

Rutaecarpine prevents Ang II -induced vascular smooth muscle cell senescence through TRPV1/ SIRT1 pathway / 中国药理学通报

Aim To evaluate the effects of Rutaecarpine(Rut)on the expression of SIRT1 and the senescence of vascular smooth muscle cells(VSMCs)induced by angiotensin Ⅱ.Methods VSMC senescencewas induced by exposure to AngⅡ(1 μmol·L-1)for 72 h.VSMCs were treated with different concentrations of Rut(0.3, 1, 3 μmol·L-1).TRPV1 competitive antagonist CAPZ(10 μmol·L-1)and AMPK inhibitor Compound C(1 μmol·L-1)were used to explore whether TRPV1/AMPK mediated the protective effect of Rut.The quantity of senescent cells were determined by senescence-associated SA-β-Gal staining, and the intracellular ROS level was measured by(DCFH-DA)fluorescent probe.The migration ability of VSMCs was evaluated by Wound-healing assay combined with Transwell assay.The protein level of longevity protein SIRT1 and senescence-related proteins p53, p21 and AMPK phosphorylation level were detected by Western blot.Results Rut significantly inhibited Ang Ⅱ-induced VSMC senescence and ROS production and prevented VSMCs migration.Preprocessing of TRPV1 antagonist CAPZ could abolish the protective effect of Rut.Ang Ⅱ inhibited the expression of longevity protein SIRT1.Rut recovered SIRT1 expression in a dose-dependent manner, while prevented the up-regulation of senescence-related proteins p53 and p21.Ang Ⅱ inhibited AMPK phosphorylation, pre-treatment with Rut restored AMPK phosphorylation level.CAPZ and Compound C eliminated the up-regulating function of Rut on SIRT1 expression.Conclusions Rut up-regulates the expression of SIRT1 and prevents the senescence and migration of VSMCs induced by Angiotensin Ⅱ, which is related to activation of the TRPV1/AMPK signaling pathway.