Cheng-Yao Wang

Dexmedetomidine attenuates lipopolysaccharide-induced proinflammatory response in primary microglia

BACKGROUND Neuroinflammation mediated by microglia has been implicated in delirium. Suppression of microglial activation may therefore contribute to alleviate delirium. It has been reported that dexmedetomidine (DEX) has a potent anti-inflammatory property. In the present study, we investigated the effects of DEX on the production of proinflammatory mediators in lipopolysaccharide-stimulated microglia. MATERIALS AND METHODS The concentrations of DEX were chosen to correspond to 1, 10, and 100 times of clinically relevant concentration (i.e., 1, 10, and 100ng/mL). The levels of proinflammatory mediators, such as inducible nitric oxide synthase or nitric oxide, prostaglandin E(2), interleukin 1β, and tumor necrosis factor α, were measured. RESULTS DEX at 1ng/mL did not affect the production of proinflammatory mediators. DEX at 10 and 100ng/mL significantly inhibited the release of nitric oxide, prostaglandin E(2), interleukin 1β, and tumor necrosis factor α and the expression of inducible nitric oxide synthase messenger RNA. CONCLUSIONS These results suggest that DEX is a potent suppressor of lipopolysaccharide-induced inflammation in activated microglia and may be a potential therapeutic agent for the treatment of intensive care unit delirium.

Protective effects of penehyclidine hydrochloride on septic mice and its mechanism.

Anticholinergics can have protective effects against septic shock. Penehyclidine hydrochloride (PHC) is a novel anticholinergic agent exhibiting few cardiovascular side effects. This work explored the protective effects of PHC on septic mice and its mechanism. Mice were randomly divided into four groups: sham control, cecal ligation and puncture (CLP), CLP/0.3 mg/kg PHC, and CLP/0.45 mg/kg PHC, with 10 mice in each. One hour before surgery, PHC-treated mice received an intraperitoneal injection of PHC and an equal volume of saline in the other two groups. Blood plasma and tissue samples were collected at 12 h after surgery. Serum TNF-α, histopathology, superoxide dismutase (SOD), malondialdehyde (MDA), and expression of iNOS in lung and hepatic tissues were examined. Another 40 mice were randomly assigned to four equal groups to observe survival status during 96 h after operation. Treatment of 0.45 mg/kg PHC markedly decreased TNF-α, MDA content, and iNOS mRNA expression, and enhanced SOD activity (P < 0.05 and P < 0.01). Treatment of 0.45 mg/kg PHC might have a protective effect against sepsis. Its action mechanisms are probablyinvolved in the inhibition of inflammatory factor production and suppression of iNOS mRNA expression and lipidperoxidation.ABBREVIATIONS - PHC-penehyclidine hydrochloride; CLP-cecal ligation and puncture; SOD-superoxide dismutase; MDA-malondialdehyde; COPD-chronic obstructive pulmonary disease; ELISA-enzyme-linked immunosorbent assay; HR-heart rate; ALT-alanine aminotransferase; AST-aspartate aminotransferase; MODS-multiple organ dysfunction syndrome

Toll-like receptor 4 regulates heme oxygenase-1 expression after hemorrhagic shock induced acute lung injury in mice: requirement of p38 mitogen-activated protein kinase activation.

Acute lung injury (ALI) leading to respiratory distress is a common sequela of shock or trauma. The toll-like receptors (TLRs) stand at the interface of innate immune activation in the settings of both infection and sterile injury by responding to a variety of microbial and endogenous ligands alike. This work explored the effects of TLR-4 on hemorrhage-induced ALI and characterizes the signaling pathways and the mechanisms involved in noninfectious ALI. Mice underwent hemorrhagic shock and resuscitation (HSR). Arterial blood gases; expressions of TLR-4, heme oxygenase 1 (HO-1), and p38 mitogen-activated protein kinase (p38MAPK); myeloperoxidase activity; lung wet/dry ratios; and IL-10 levels in lung tissues were obtained at 6, 24, and 48 h after HSR. Hemorrhagic shock and resuscitation induced significant expressions of TLR-4, HO-1, and p38MAPK in C3H/HeN mice. IL-10 and myeloperoxidase were markedly increased at 24 h after HSR, and C3H/HeN mice had ALI with PaO2/fraction of inspired oxygen less than 300 mmHg. The induced amount of each cytokine level and the expressions of TLR-4, HO-1, and p38MAPK of C3H/HeN mice were significantly higher compared with C3H/HeJ mice. This study demonstrated that lung p38MAPK is activated after HSR, and p38MAPK inhibitor FR167653 suppresses HO-1 induction after ALI. We concluded that TLR-4 might induce HO-1 messenger RNA expression, which is probably involved in p38MAPK activation in the development of the lung dysfunction after HSR.

The cyclooxygenase-2 inhibitor parecoxib inhibits surgery-induced proinflammatory cytokine expression in the hippocampus in aged rats.

BACKGROUND Neuroinflammatory response triggered by surgery has been increasingly reported to be associated with postoperative cognitive dysfunction. Proinflammatory cytokines, such as interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α), play a pivotal role in mediating surgery-induced neuroinflammation. The role of cyclooxygenase-2 (COX-2), a critical regulator in inflammatory response, in surgery-induced neuroinflammation is still unknown. The aim of the study was to investigate the changes of COX-2 expression and prostaglandin E2 (PGE2) production in the hippocampus in aged rats following partial hepatectomy. The effects of selective COX-2 inhibitor (parecoxib) on hippocampal proinflammatory cytokine expression were also evaluated. METHODS Aged rats were randomly divided into three groups: control (n = 10), surgery (n = 30), and parecoxib (n = 30). Control animals received sterile saline to control for the effects of injection stress. Rats in the surgery group received partial hepatectomy under isoflurane anesthesia and sterile saline injection. Rats in the parecoxib group received surgery and anesthesia similar to surgery group rats, and parecoxib treatment. On postanesthetic days 1, 3, and 7, animals were euthanized to assess levels of hippocampal COX-2 expression, PGE2 production, and cytokines IL-1β and TNF-α expression. The effects of parecoxib on proinflammatory cytokine expression were also assessed. RESULTS Partial hepatectomy significantly increased COX-2 expression, PGE2 production, and proinflammatory cytokine expression in the hippocampus in aged rats on postoperative days 1 and 3. Parecoxib inhibited hippocampal IL-1β and TNF-α expression through downregulation of the COX-2/PGE2 pathway. CONCLUSION COX-2 may play a critical role in surgery-induced neuroinflammation. The COX-2 inhibitor may be a promising candidate for treatment of neuroinflammation caused by surgical trauma.

Transduction of PEP-1-heme oxygenase-1 fusion protein reduces myocardial ischemia/reperfusion injury in rats.

Abstract: Recent studies have uncovered that overexpression of heme oxygenase-1 (HO-1) by induction or gene transfer provides myocardial protection. In the present study, we investigated whether HO-1 protein mediated by cell-penetrating peptide PEP-1 could confer cardioprotection in a rat model of myocardial ischemia/reperfusion (I/R) injury. Male Sprague-Dawley rats were subjected to 30 minutes of ischemia by occluding the left anterior descending coronary artery and to 120 minutes of reperfusion to prepare the model of I/R. Animals were randomized to receive PEP-1–HO-1 fusion protein or saline 30 minutes before a 30-minute occlusion. I/R increased myocardial infarct size and levels of malondialdehyde, serum tumor necrosis factor alpha, and interleukin 6 and reduced myocardial superoxide dismutase activity. Administration of PEP-1–HO-1 reduced myocardial infarct size and levels of malondialdehyde, serum tumor necrosis factor alpha, and interleukin 6 and increased myocardial superoxide dismutase and HO-1 activities. His-probe protein was only detected in PEP-1-HO-1–transduced hearts. In addition, transduction of PEP-1–HO-1 markedly reduced elevated myocardial tissue nuclear factor-&kgr;B induced by I/R. The results suggested that transduction of PEP-1–HO-1 fusion protein decreased myocardial reperfusion injury, probably by attenuating the production of oxidants and proinflammatory cytokines regulated by nuclear factor-&kgr;B.

Effect of TLR-4 and HO-1 on acute lung injury induced by hemorrhagic shock in mice.

OBJECTIVE To examine whether TLR-4 has an effect on hemorrhage induced changes in lung, and to investigate the change of heme oxygenase-1 (HO-1) on acute lung injury (ALI) induced by hemorrhagic shock in mice. METHODS Forty-eight male mice, including C3H/HeN mice and C3H/HeJ mice, were randomly divided into sham group (n=12), hemorrhagic shock group with twelve mice in each phase. Blood pressure (BP) was monitored continuously by attaching carotid artery catheter to a strain gauge pressure transducer/ polygraph. Arterial blood samples were taken for blood gas analysis. A mouse model of non-lethal hemorrhagic shock and resuscitation was used to observe pulmonary myeloperoxidase (MPO) activity and wet/dry weight ratio (W/D). The expression of HO-1 was observed by means of RT-PCR and immunohistochemistry. IL-6 and IL-10 in lung tissue homogenate were assayed by enzyme-linked immunosorbent assay (ELISA). The pulmonary pathologic changes were observed under electron microscope and light microscope. RESULTS Compared with sham group, the expression of HO-1 in lung tissue was significantly higher in Hem 24 h and Hem 48 h of C3H/HeN mice (P less than 0.01). The expression of HO-1 mRNA and the levels of IL-6, IL-10 and MPO in lung tissue were markedly increased in Hem 24 h (P less than 0.01 or P less than 0.05); Compared with C3H/HeN mice, the expression of HO-1 mRNA and the levels of IL-6 and IL-10 in C3H/HeJ mice significantly decreased in Hem 24 h and Hem 48 h (P less than 0.01 or P less than 0.05), and the W/D, MPO in C3H/HeJ mice were obviously lower in Hem 24 h (P less than 0.05). The injuries of lung tissues after hemorrhagic shock have been demonstrated by histological examination with electron microscope and light microscope. CONCLUSIONS TLR-4 and HO-1 might modulate the balance of pro- and anti-inflammatory processes in inflammatory reaction of hemorrhagic shock-induced ALI, and the activation of Toll-like receptor might induce the transcription activity of HO-1, which may play a key role in acute lung injury.

Methylene blue relieves the development of osteoarthritis by upregulating lncRNA MEG3

Methylene blue (MB) is a long-term inhibitor of peripheral nerve axons, thereby alleviating or permanently eliminating pain. However, it remains unknown whether MB is safe and effective method of treating osteoarthritis (OA). MB was injected into the knee joints of rabbits and they were monitored for any histological structural changes. The results revealed no evident changes in the histological structure of the normal knee joint following injection of 1 mg/kg MB at 1, 4, 8 and 24 weeks post-injection. Compared with the vehicle control, MB treatment significantly enhanced the weight distribution and significantly decreased the swelling ratio of the rabbits. Additionally, levels of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) mRNA were significantly increased following treatment with MB, but the protein expression of P2X purinoceptor 3 (P2X3) was significantly suppressed compared with the vehicle control. The levels of interleukin (IL) 6, tumor necrosis factor (TNF)α, IL-1β and IL-8 were significantly suppressed following MB treatment, indicating that MB protects against OA progression. It was also revealed that MEG3 overexpression significantly suppresses levels of P2X3 protein. ELISA indicated that the MEG3-induced reduction of IL-6, TNFα, IL-1β and IL-8 expression was significantly reversed following P2X3 overexpression. Therefore, the results of the present study demonstrated that MB is an effective method of treating OA-associated pain by upregulating lncRNA MEG3 levels. Additionally, lncRNA MEG3 relieves the OA-associated pain and inflammation in a rabbit model of OA by inhibiting P2X3 expression.

Reduced peripheral blood miR‑140 may be a biomarker for acute lung injury by targeting Toll‑like receptor 4 (TLR4)

Acute lung injury (ALI) is a common complication of sepsis to which patients often succumb due to poor effective pharmacological interventions. Recent studies have focused on the potential application of circulating microRNAs (miRs or miRNAs) as novel prognostic and therapeutic biomarkers. The present study focuses mainly on miR-140, the role of which is poorly understood in the progression of ALI. The results of the present study revealed that toll-like receptor 4 (TLR4) expression was upregulated the lungs of rats with ALI. Meanwhile, serum levels of tumor necrosis factor-α, interleukin (IL)-6 and IL-1β were significantly increased in rats with ALI compared with normal control rats. These data indicated the successful establishment of LPS-induced ALI. Furthermore, miR-140 was decreased in the peripheral blood of patients with ALI compared with control subjects. Receiver operator characteristic analysis indicated that miR-140 could be used to screen ALI patients and distinguish them from healthy controls. MiR-140 was demonstrated to be downregulated in the plasma and lungs of rats with ALI compared with the normal control group. A dual luciferase reporter assay indicated that TLR4 was a target gene of miR-140. To investigate whether miR-140 exerted its role via TLR4, a specific TLR4-targeting small interfering RNA was selected. It was revealed that TLR4 silencing was able to suppress the phosphorylation of NF-κB even in cells transfected with miR-140 inhibitor. In summary, reduced miR-140 expression and increased TLR4 signaling activation may serve a key role in the progression of ALI.

Ketamine ameliorates ischemia–reperfusion injury after liver autotransplantation by suppressing activation of Kupffer cells in rats

This study aimed to investigate the protective effects of ketamine against hepatic ischemia-reperfusion (I/R) injury by suppressing activation of Kupffer cells (KCs) in rat liver autotransplantation. Male Sprague-Dawley rats were randomized into 3 groups (n = 10 each). Group I, the sham group, received saline. Group II received saline and underwent orthotopic liver autotransplantation (OLAT). Group III received 10 mg/kg ketamine and underwent OLAT. Blood samples were obtained at 3, 6, 12, and 24 h after I/R, and following ALT, AST, LDH, IL-6, TNF-α, IL-1β, and IL-10 in serum were detected. Model rats were sacrificed at the indicated time points and the graft liver tissues were evaluated histologically. KCs were isolated from rat liver tissues, and inflammatory products and proteins of NF-κB signaling pathway were detected using quantitative RT-PCR and Western blotting. Our results showed that ketamine significantly decreased ALT, AST, LDH, IL-6, TNF-α, and IL-1β levels and increased IL-10 level. Furthermore, ketamine alleviated the histopathology changes, by less KC infiltration and lower hepatocyte apoptosis. Moreover, activity of NF-κB signaling pathway in KCs was suppressed. In addition, production of pro- and anti-inflammatory factors is consistent with the results in tissues. Ketamine ameliorated I/R injury after liver transplantation by suppressing activation of KCs in rats.