Dexmedetomidine attenuates P2X4 and NLRP3 expression in the spine of rats with diabetic neuropathic pain

Abstract Purpose: To evaluate the effects of Dexmedetomidine (Dex) on spinal pathology and inflammatory factor in a rat model of Diabetic neuropathic pain (DNP). Methods: The rats were divided into 3 groups (eight in each group): normal group (N group), diabetic neuropathic pain model group (DNP group), and DNP model with dexmedetomidine (Dex group). The rat model of diabetes was established with intraperitoneal streptozotocin (STZ) injections. Nerve cell ultrastructure was evaluated with transmission electron microscopy (TEM). The mechanical withdrawal threshold (MWT) and motor nerve conduction velocity (MNCV) tests documented that DNP rat model was characterized by a decreased pain threshold and nerve conduction velocity. Results: Dex restored the phenotype of neurocytes, reduced the extent of demyelination and improved MWT and MNCV of DNP-treated rats (P=0.01, P=0.038, respectively). The expression of three pain-and inflammation-associated factors (P2X4, NLRP3, and IL-IP) was significantly upregulated at the protein level in DNP rats, and this change was reversed by Dex administration (P=0.0022, P=0.0092, P=0.0028, respectively). Conclusion: The P2X4/NLRP3 signaling pathway is implicated in the development and presence of DNP in vivo, and Dex protects from this disorder.

Propofol Attenuates Hypoxia/Reoxygenation-Induced Apoptosis and Autophagy in HK-2 Cells by Inhibiting JNK Activation

PURPOSE: The aim of this study was to investigate whether propofol could attenuate hypoxia/reoxygenation-induced apoptosis and autophagy in human renal proximal tubular cells (HK-2) by inhibiting JNK activation. MATERIALS AND METHODS: HK-2 cells were treated with or without propofol or JNK inhibitor SP600125 for 1 hour and then subjected to 15 hours of hypoxia and 2 hours of reoxygenation (H/R). Cell viability and LDH release were measured with commercial kits. Cell apoptosis was evaluated by flow cytometry. The expressions of p-JNK, cleaved-caspase-3, Bcl-2, and autophagy markers LC3 and p62 were measured by Western blot or immunofluorescence. RESULTS: HK-2 cells exposed to H/R insult showed higher cell injury (detected by increased LDH release and decreased cell viability), increased cell apoptosis index and expression of cleaved-caspase-3, a decrease in the expression of Bcl-2 accompanied by increased expression of p-JNK and LC3II, and a decrease in expression of p62. All of these alterations were attenuated by propofol treatment. Similar effects were provoked upon treatment with the JNK inhibitor SP600125. Moreover, the protective effects were more obvious with the combination of propofol and SP600125. CONCLUSION: These results suggest that propofol could attenuate hypoxia/reoxygenation induced apoptosis and autophagy in HK-2 cells, probably through inhibiting JNK activation.

Role of TXNIP∕NLRP3 signaling pathway in renal ischemia?reperfusion injury in diabetic rats / 中华麻醉学杂志

Objective To evaluate the role of thioredoxin?interacting protein(TXNIP)∕oligomer?ization domain?like receptor family pyrin domain?containing 3(NLRP3)signaling pathway in renal ische?mia?reperfusion(I∕R)injury in diabetic rats. Methods Pathogen?free healthy male Sprague?Dawley rats, aged 8-12 weeks, weighing 200-220 g, were used in the study. Diabetes mellitus was induced by intrap?eritoneal injection of 1% streptozotocin 65 mg∕kg and confirmed by blood glucose≥16.7 mmol∕L 3 days lat?er. Twenty?four diabetic rats were divided into 3 groups(n=8 each)using a random number table: sham operation group(group S), renal I∕R group(group I∕R)and resveratrol(TXNIP inhibitor)group (group R). Resveratrol 10 mg∕kg was intraperitoneally injected every day for 7 consecutive days starting from 3rd week after successful establishment of the model in group R. At 4th week after successful establish?ment of the model, renal I∕R was produced by occlusion of bilateral renal pedicles for 25 min followed by reperfusion in anesthetized rats in group R. The animals were sacrificed at 48 h of reperfusion, and renal specimens were obtained for microscopic examination of pathologic changes and for measurement of malondi?aldehyde(MDA)content, superoxide dismutase(SOD)activity and superoxide anion scavenging capa?bility(using colorimetric method), interleukin?1beta(IL?1β)and IL?18 contents(by enzyme?linked immunosorbent assay), cell apoptosis(using TUNEL)and expression of TXNIP, NLRP3 and caspase?1 in renal tissues(using Western blot). Blood samples were obtained from the left ventricle for determination of serum urea nitrogen(BUN)and creatinine(Cr)concentrations. Results Compared with group S, the serum Cr concentration and apoptosis index were significantly increased, superoxide anion scavenging capability in renal tissues was decreased, and the expression of TXNIP, NLRP3 and caspase?1 was up?reg?ulated in I∕R and R groups, and the serum BUN concentration and contents of MDA, IL?1β and IL?18 in renal tissues were increased, the SOD activity was decreased(P<0.05), and the pathological changes of renal tissues were aggravated in group I∕R. Compared with group I∕R, the serum BUN and Cr concentra?tions were significantly decreased, the contents of MDA, IL?1β and IL?18 and apoptosis index were de?creased, the SOD activity and superoxide anion scavenging capability were increased, the expression of TXNIP, NLRP3 and caspase?1 was down?regulated(P<0.05), and the pathological changes of renal tis?sues were significantly attenuated in group R. Conclusion The pathophysiological mechanism of renal I∕R injury is associated with the activation of TXNIP∕NLRP3 signaling pathway in diabetic rats.

Dexmedetomidine protects against renal ischemia and reperfusion injury by inhibiting the P38-MAPK/TXNIP signaling activation in streptozotocin induced diabetic rats

Abstract Purpose: To determine whether dexmedetomidine (DEX) could attenuate acute kidney injury (AKI) induced by ischemia/reperfusion (I/R) in streptozotocin (STZ)-induced diabetic rats. Methods: Four groups each containing six rats were created (sham control(S), diabetes-sham (DS), diabetes I/R (DI/R), and diabetes-I/R-dexmedetomidine (DI/R-DEX). In diabetes groups, single-dose (65 mg/kg) STZ was administered intraperitoneally (i.p.). In Group DI/R, ischemia reperfusion was produced via 25 min of bilateral renal pedicle clamping followed by 48 h of reperfusion. In Group DI/R-DEX, 50 μg/kg dexmedetomidine was administered intraperitoneally 30 minutes before ischemia. Renal function, histology, apoptosis, the levels of TNF-α, IL-1β, and oxidative stress in diabetic kidney were determined. Moreover, expression of P38 mitogen-activated protein kinase (P38-MAPK), phosphorylated-P38-MAPK(p-P38-MAPK) and thioredoxin-interacting protein (TXNIP) were assessed. Results: The degree of renal I/R injury was significantly increased in DI/R group compared with S group and DS group. The levels of TNF-α, IL-1β, oxidative stress and apoptosis were found significantly higher in DI/R Group when compared with S Group and DS Group. The protein expression of p-P38-MAPK and TXNIP were significantly increased after I/R. All these changes were reversed by DEX treatment. Conclusion: The renoprotective effects of DEX-pretreatment which attenuates I/R-induced AKI were partly through inhibition of P38-MAPK activation and expression of TXINP in diabetic kidney.

Toll-like receptor 7 involves the injury in acute kidney ischemia/reperfusion of STZ-induced diabetic rats

ABSTRACT PURPOSE: To determine whether Toll-like receptor 7 (TLR7) is the potential targets of prevention or progression in the renal ischemia/reperfusion (I/R) injury of STZ-induced diabetic rats. METHODS: Thirty six Sprague-Dawley rats were randomly arranged to the nondiabetic (ND) or diabetic group (DM), with each group further divided into sham (no I/R injury), I/R (ischemia-reperfusion) and CD (given by Chloroquine) group. Preoperatively, Chloroquine (40 mg/kg, intraperitoneal injection.) was administrated 6 days for treatment group. I/R animals were subjected to 25 min of bilateral renal ischemia. Renal function, histology, apoptosis, cytokines, expression of TLR7, MyD88 and NF-κB were detected. RESULTS: The serum levels of blood urea nitrogen, creatinine, IL-6 and TNF-α, apoptotic tubular epithelial cells, expression of TLR7, MyD88 and NF-κB were significantly increased in DM+I/R group, compared with ND+I/R group (p<0.05). All these changes were further improved by TLR7 inhibition Chloroquine except Paller scores (p<0.05). CONCLUSION: Toll-like receptor 7 inhibition attenuates the acute renal ischemia/reperfusion injury of STZ-induced diabetic in SD rats.