Ruilin Shen

GSK-3beta Inhibitor Induces Expression of Nrf2/TrxR2 Signaling Pathway to Protect against Renal Ischemia/Reperfusion Injury in Diabetic Rats

Background/Aims: Diabetes mellitus (DM) can lead to renal damage and dysfunction, and exacerbate renal ischemia/reperfusion injury (RI/RI). The aim of this study was to investigate the protective effect of GSK-3β inhibitor TDZD-8 against RI/RI through Nrf2/TrxR2 signaling pathway in a rat DM model. Methods: A DM rat model was established by a single injection of streptozocin. Diabetic rats were pretreated with TDZD-8 (1 mg/kg bw) or TDZD-8+auranofin (10 nmol/L, 5ml/kg bw), and then subjected to 45-min ischemia and 24-h reperfusion. Rats were equally randomized into four groups: a Sham-operated group, a RI/RI group, a TDZD-8 group, and a TDZD-8+auranofin group. Serum levels of BUN and Scr were measured. SOD activity, MDA content, and Nrf2, TrxR2 and caspase-3 expressions in rat kidney tissues were determined. Results: Renal function was improved, oxidative stress and cell apoptosis were reduced, and the expression of Nrf2 and TrxR2 was up-regulated in TDZD-8 treated rats as compared with those in auranofin treated rats. Conclusion: TDZD-8 may exert its protective effect against RI/RI by regulating the Nrf2/TrxR2 signaling pathway in the kidney tissue in DM.

Apocynin Alleviates Renal Ischemia/Reperfusion Injury Through Regulating the Level of Zinc and Metallothionen

The purpose of this research was to evaluate the protective effects of apocynin on renal ischemia/reperfusion (I/R) injury (RI/RI) in rats. Rats preconditioned with apocynin were subjected to renal I/R. Zinc levels in serum and renal tissues, blood urea nitrogen (BUN), and serum creatinine (Scr) were detected. We further measured the activity of superoxide dismutase (SOD); the content of malondialdehyde (MDA), IL-4, IL-6, IL-10, and TNF-α; and the expression of metallothionein (MT) in the renal tissues. Results indicated that the levels of MDA, IL-4, IL-6, IL-10, TNF-α, and MT in the kidney tissue and serum BUN and Scr levels in RI/RI group were significantly higher than those in sham-operated group, while the levels of serum Zn and kidney Zn and SOD were reduced in RI/RI group. Apocynin treatment further decreased the levels of MDA, IL-6, TNF-α, and serum BUN and Scr, whereas it significantly increased the levels of Zn, SOD, IL-4, IL-10, and MT in the kidney tissue and serum Zn. These findings suggest that apocynin might play a protective role against RI/RI in rats through regulating zinc level and MT expression involving in oxidative stress.

Activation of Nrf2/HO-1 Pathway by Glycogen Synthase Kinase-3β Inhibition Attenuates Renal Ischemia/Reperfusion Injury in Diabetic Rats

Background/Aims: Diabetes mellitus can exacerbate renal ischemia-reperfusion (I/R) injury (RI/RI). The aim of the present study was to evaluate the protective effect of GSK-3β inhibition (TDZD-8) on I/R-induced renal injury through the Nrf2/HO-1 pathway in a streptozocin (STZ)-induced diabetic rat model. Methods: STZ-induced diabetic rats preconditioned with TDZD-8 and ZnPP were subjected to renal I/R. The extent of renal morphologic lesions. Renal function was assessed from blood urea nitrogen (BUN) and serum creatinine (Scr), as determined utlizing commercial kits. Oxidative stress and inflammatory activity in the kidney tissue was estimated from levels of malondialdehyde (MDA), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and nitric oxide (NO), as well as the activities of superoxide dismutase (SOD) and glutathione (GSH) using qRT-PCR and ELISA. The expressions of Nrf2, HO-1, Bcl-2 and NF-κB in the renal tissue were measured by qRT-PCR and western blotting. Results: I/R-induced renal inflammation was reduced significantly by TDZD-8 pretreatment. Preconditioning with TDZD-8 suppressed NF-κB expression and enhanced Bcl-2 expression in the renal tissue. The upregulated level of malondialdehyde (MDA), and reduced activities of superoxide dismutase (SOD) and glutathione (GSH) in I/R-shocked rats were markedly restored by TDZD-8 pretreatment. Furthermore, pretreatment with TDZD-8 enhanced activation of the Nrf2/HO-1 pathway in the renal tissue of diabetic RI/RI rats. Conclusion: These findings suggest that preconditioning with TDZD-8 may protect the kidney from I/R-induced damage via the activation of the Nrf2/HO-1 pathway in STZ-induced diabetic rats. Further detailed studies are needed to further clarify the underlying mechanisms.

Targeted delivery of puerarin/glycyrrhetinic acid-PEG-PBLA complex attenuated liver ischemia/reperfusion injury via modulating Toll-like receptor 4/nuclear factor-κB pathway

AIM To synthesize a puerarin nanoparticle based on glycyrrhetinic acid (GA)-PEG-PBLA and evaluate it in vivo. MATERIALS & METHODS In this study, drug nanoparticle was synthesized, characterized and assessed as puerarin delivery system. Nanoparticle GA-PEG-PBLA could combine with puerarin via hydrophobic interaction to form the compound. Puerarin could be quickly and efficiently loaded via the nanoparticle GA-PEG-PBLA at pH 7.4. Further, GA-PEG-PBLA-mediated puerarin delivery system could target for the liver that had GA receptor binding. The antiliver ischemia/reperfusion injury role of puerarin/GA-PEG-PBLA was measured in rats using free puerarin and puerarin/PEG-PBLA as the controls. RESULTS GA-PEG-PBLA displayed efficient loading and sustained release. Puerarin/GA-PEG-PBLA showed strengthened antiliver ischemia/reperfusion injury characteristics. CONCLUSION Overall, the results show that GA-PEG-PBLA could be regarded as an underlying puerarin nanoparticle.

Ethylenediaminetetraacetic Acid Inhibits Vibrio Vulnificus -Induced Dendritic Cell Apoptosis by Lowering [Ca 2+ ] i

Background/Aims: Vibrio vulnificus (V. vulnificus) is a Gram-negative marine bacterium that can cause life-threatening primary septicemia, especially in the innate immune system. But how V. vulnificus affects and acts on dendritic cells (DC) is not well understood. The aim of the present study is to investigate [Ca2+]i change and the expression of the mTor-STAT3-Bcl-2 signaling pathway in V. vulnificus B2-induced DC apoptosis, and explore the protective effect of ethylenediaminetetraacetic acid (EDTA) against DC apoptosis in a V. vulnificus B2 and DC2.4 cell coculture infection model, using EDTA as an intervenient. Methods: The apoptosis rate, [Ca2+]i, and the expression of STAT3, m-Tor and Bcl-2 were detected by cytometry, Fluo-8-AM and Western blotting respectively. Results: The results demonstrated that EDTA inhibited the increase of [Ca2+]i, upregulated the expression of m-Tor-STAT3-Bcl-2 signaling pathway, and protected DC against V. vulnificus B2-induced apoptosis. Conclusions: EDTA inhibits V. Vulnificus-induced DC apoptosis by lowering [Ca2+]i via m-Tor-STAT3-Bcl-2 signaling pathway.

Association between COMT Polymorphism Val158Met and Opioid Consumption in Patients with Postoperative Pain: A Meta-Analysis

Background/Aims: Several factors influencing postoperative pain and the effect of opioid analgesics have been investigated on an individual level. The aim of this study was to clarify the impact of catecholamine-O-methyltransferase (COMT) gene Val158Met on opioid consumption in postoperative patients. Methods: A systematic review and meta-analysis of the literature up to September 30, 2017, were performed by using PubMed, Cochrane Library, ISI Web of Science, and Chinese National Knowledge Infrastructure (CNKI) database. The meta-analysis examined all studies involving the association between genetic polymorphisms of COMT Val158Met and opioid consumption during the acute postoperative period. Results: Of the 153 identified studies, 23 studies were retrieved for systematic review and 10 studies were retrieved for meta-analysis. However, it was impossible to conduct meta-analysis on the association between COMT Val158Met polymorphism and postoperative pain because of heterogeneity of the data. Overall, meta-analysis showed that COMT Val/Met carriers consumed less opioid for analgesia within the first 24 hours after surgery (SMD = 0.14, 95% CI = [0.03, 0.25], P = 0.01) but not within 48 hours (SMD = 0.14, 95% CI = [0.08, 0.36], P = 0.21). There was no significant difference in opioid consumption between Val/ Val and Met/Met patients. Conclusion: Patients with Val/Met but not Met/Met allele variant consumed less opioid, though larger and better-designed studies are required to obtain an exclusive conclusion about the correlation between postoperative pain and COMT Val158Met polymorphism.

Role of Calcium Sensing Receptor in Streptozotocin-Induced Diabetic Rats Exposed to Renal Ischemia Reperfusion Injury

Background/Aims: Renal ischemia/reperfusion (I/R) injury (RI/RI) is a common complication of diabetes, and it may be involved in altering intracellular calcium concentrations at its onset, which can result in inflammation, abnormal lipid metabolism, the production of reactive oxygen species (ROS), and nitroso-redox imbalance. The calcium-sensing receptor (CaSR) is a G-protein coupled receptor, however, the functional involvement of CaSR in diabetic RI/ RI remains unclear. The present study was intended to investigate the role of CaSR on RI/RI in diabetes mellitus (DM). Methods: The bilateral renal arteries and veins of streptozotocin (STZ)-induced diabetic rats were subjected to 45-min ischemia followed by 2-h reperfusion with or without R-568 (agonist of CaSR) and NPS-2143 (antagonist of CaSR) at the beginning of I/R procedure. DM without renal I/R rats served as control group. The expressions of CaSR, calmodulin (CaM), and p47phox in the renal tissue were analyzed by qRT-PCR and Western blot. The renal pathomorphology, renal function, oxidative stress, inflammatory response, and calcium disorder were evaluated by detection of a series of indices by hematoxylin-eosin (HE) staining, transmission electron microscope (TEM), commercial kits, enzyme-linked immunosorbent assay (ELISA), and spectrophotofluorometry, respectively. Results: Results showed that the expressions of CaSR, CaM, and p47phox in I/R group were significantly up-regulated as compared with those in DM group, which were accompanied by renal tissue injury, increased calcium, oxidative stress, inflammation, and nitroso-redox imbalance. Conclusion: These results suggest that activation of CaSR is involved in the induction of damage of renal tubular epithelial cell during diabetic RI/RI, resulting in lipid peroxidation, inflammatory response, nitroso-redox imbalance, and apoptosis.

Pharmacological Signatures of the Exenatide Nanoparticles Complex Against Myocardial Ischemia Reperfusion Injury

Background/Aims: Myocardial ischemia/reperfusion (I/R) injury (MI/RI) is a critical cause of death in patients with heart disease. However, the pharmaco-therapeutical outcome for MI/RI remains unsatisfactory. Innovative approaches for enhancing drug sensitivity and recovering myocardial function in MI/RI treatment are urgently needed. The purpose of this study was to evaluate the protective effects of exenatide-loaded poly(L-lysine)-poly(ethylene glycol)-poly(L-lysine) (PLL-PEG-PLL) nanoparticles (NPs) against MI/RI. Methods: The size of PLL-PEG-PLL NPs and the loading and release rates of exenatide were determined. The in vitro NP cytotoxicity was evaluated using newborn rat cardiomyocytes. Rats pretreated with free exenatide or exenatide/PLL-PEG-PLL polyplexes were subjected to 0.5-h ischemia and 2-h reperfusion in the left anterior descending coronary artery. The histopathologic lesions were assessed using hematoxylin-eosin staining. The general physiological indices, including blood pressure (BP), heart rate (HR), the left ventricular ejection fraction (LVEF) and end-diastolic pressure (LEVDP), and the left ventricular pressure maximal rate of rising (dp/dtmax), were monitored using a non-invasive blood pressure analyzer and color Doppler echocardiography. The antioxidative activity in the myocardial tissue was measured. The myocardial enzymatic activity was further estimated by determining the serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), cardiac troponin T (cTnT), and glucagon-like peptide-1 (GLP-1), as well as the expression of GLP-1R in the myocardial tissue. Results: Exenatide preconditioning attenuated the oxidative stress injury and promoted the myocardial function in I/R-induced myocardial injury, while the application of block copolymer PLL-PEG-PLL as a potential exenatide nanocarrier with sustained release significantly enhanced the bioavailability of exenatide. Conclusion: The block copolymer PLL-PEG-PLL may function as a potent exenatide nanocarrier for augmenting pharmacotherapy against MI/RI with unprecedented clinical benefits. Further study is needed to better clarify the underlying mechanisms.

Lumbrokinase/paclitaxel nanoparticle complex: potential therapeutic applications in bladder cancer

Background Lumbrokinase (LK) is an enzyme complex with antithrombotic, antioxidant, antitumor, and immunomodulatory effects. It has been extensively studied and used in clinical anti-tumor therapy. However, its half-life is short, its bioavailability is low, and its toxicity and side effects are great, which greatly limit its clinical application. Therefore, LK is often combined with other drugs (such as immune agents, hormones, or Chinese herbal medicine) to reduce its dosage and side effects and to improve its anti-tumor effects. Methods and results Here, we described an LK/paclitaxel (PTX) nanocarrier based on poly(ethylene glycol)-b-(poly(ethylenediamine l-glutamate)-g-poly(ε-benzyoxycarbonyl-l-lysine)-r-poly(l-lysine)) (PEG-b-(PELG-g-(PZLL-r-PLL))). In the present study, LK and PTX were loaded by electrostatic and/or hydrophobic effects under mild conditions, thereby increasing the half-life and bioavailability of the drugs via the sustained release and enhancement of tumor site enrichment by the LK/PTX/PEG-b-(PELG-g-(PZLL-r-PLL)) complex through passive targeting. In this study, using bladder cancer cells (J82 cells) and rat bladder cancer model as the object, the structure of the nanocarrier, the relationship between drugs composition and antitumor properties were systematically studied. Conclusion We propose that the block copolymer PEG-b-(PELG-g-(PZLL-r-PLL)) may function as a potent nanocarrier for augmenting anti-bladder cancer pharmacotherapy, with unprecedented clinical benefits.

Paeoniflorin Attenuates Inflammatory Pain by Inhibiting Microglial Activation and Akt-NF-κB Signaling in the Central Nervous System

Background/Aims: Paeoniflorin (PF) is known to have anti-inflammatory and paregoric effects, but the mechanism underlying its analgesic effect remains unclear. The aim of this study was to clarify the effect of PF on Freund’s complete adjuvant (CFA)-induced inflammatory pain and explore the underlying molecular mechanism. Methods: An inflammatory pain model was established by intraplantar injection of CFA in C57BL/6J mice. After intrathecal injection of PF daily for 8 consecutive days, thermal and mechanical withdrawal thresholds, the levels of inflammatory factors TNF-α, IL-1β and IL-6, microglial activity, and the expression of Akt-NF-κB signaling pathway in the spinal cord tissue were detected by animal ethological test, cell culture, enzyme-linked immunosorbent assay, immunofluorescence histochemistry, and western blot. Results: PF inhibited the spinal microglial activation in the CFA-induced pain model. The production of proinflammatory cytokines was decreased in the central nervous system after PF treatment both in vivo and in vitro. PF further displayed a remarkable effect on inhibiting the activation of Akt-NF-κB signaling pathway in vivo and in vitro. Conclusion: These results suggest that PF is a potential therapeutic agent for inflammatory pain and merits further investigation.