Bupivacaine inhibits COX-2 expression, PGE2, and cytokine production in endotoxin-activated macrophages

Transglutaminase 2 Facilitates Murine Wound Healing in a Strain-Dependent Manner

Transglutaminase 2 (TG2) plays a role in cellular processes that are relevant to wound healing, but to date no studies of wound healing in TG2 knockout mice have been reported. Here, using 129T2/SvEmsJ (129)- or C57BL/6 (B6)-backcrossed TG2 knockout mice, we show that TG2 facilitates murine wound healing in a strain-dependent manner. Early healing of in vivo cutaneous wounds and closure of in vitro scratch wounds in murine embryonic fibroblast (MEF) monolayers were delayed in 129, but not B6, TG2 knockouts, relative to their wild-type counterparts, with wound closure in 129 being faster than in B6 wild-types. A single dose of exogenous recombinant wild-type TG2 to 129 TG2-/- mice or MEFs immediately post-wounding accelerated wound closure. Neutrophil and monocyte recruitment to 129 cutaneous wounds was not affected by Tgm2 deletion up to 5 days post-wounding. Tgm2 mRNA and TG2 protein abundance were higher in 129 than in B6 wild-types and increased in abundance following cutaneous and scratch wounding. Tgm1 and factor XIIA (F13A) mRNA abundance increased post-wounding, but there was no compensation by TG family members in TG2-/- relative to TG2+/+ mice in either strain before or after wounding. 129 TG2+/+ MEF adhesion was greater and spreading was faster than that of B6 TG2+/+ MEFs, and was dependent on syndecan binding in the presence, but not absence, of RGD inhibition of integrin binding. Adhesion and spreading of 129, but not B6, TG2-/- MEFs was impaired relative to their wild-type counterparts and was accelerated by exogenous addition or transfection of TG2 protein or cDNA, respectively, and was independent of the transamidase or GTP-binding activity of TG2. Rho-family GTPase activation, central to cytoskeletal organization, was altered in 129 TG2-/- MEFs, with delayed RhoA and earlier Rac1 activation than in TG2+/+ MEFs. These findings indicate that the rate of wound healing is different between 129 and B6 mouse strains, correlating with TG2 abundance, and although not essential for wound healing, TG2 facilitates integrin- and syndecan-mediated RhoA- and Rac1-activation in fibroblasts to promote efficient wound contraction.

Naproxen-Derived New Compound Inhibits the NF-κB, MAPK and PI3K/Akt Signaling Pathways Synergistically with Resveratrol in RAW264.7 Cells

Naproxen is widely used for anti-inflammatory treatment but it can lead to serious side effects. To improve the anti-inflammatory activity and safety, a novel naproxen derivative containing cinnamic acid (NDC) was synthesized and used in combination with resveratrol. The results showed that the combination of NDC and resveratrol at different ratios have a synergistic anti-inflammatory efficacy in RAW264.7 macrophage cells. It was indicated that the combination of NDC and resveratrol at a ratio of 2:1 significantly inhibited the expression of carbon monoxide (NO), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), induced nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2) and reactive oxygen species (ROS) without detectable side effects on cell viability. Further studies revealed that these anti-inflammatory effects were mediated by the activation of nuclear factor kappa-B (NF-κB), mitogen-activated protein kinase (MAPK) and phosphoinositide-3 kinase (PI3K)/protein kinase B (Akt) signaling pathways, respectively. Taken together, these results highlighted the synergistic NDC and resveratrol anti-inflammatory activity that could be further explored as a strategy for the treatment of inflammatory disease with an improved safety profile.

A controlled release bupivacaine-alginate construct: Effect on chondrocyte hypertrophy conversion

Objective:

Osteoarthritis is a degenerative disease of the joint, affecting over 30 million people in the US¹. A key characteristic of OA is chondrocyte hypertrophy, characterized by chondrocyte changes to a more rounded and osteoblastic phenotype, characterized by increased IL-6 and IL-8 secretion². While there are no cures for OA, treatments focus on mitigating pain and inflammation, the two main symptoms of OA. However, the analgesics, NSAIDS and corticosteroids commonly used, do not target regeneration and have negative side effects. Local anesthetics (LA) can be used as a pain management alternative but are usually short lasting and therefore, not suited for chronic conditions such as OA. Our engineered sustained release local anesthetic construct successfully delivers bupivacaine for an extended period of time^3–5. This study is designed to evaluate the effect of the LA system on chondrocytes in an inflammatory OA-like environment.

Design:

Chondrocytes were cultured with bolus, liposomal, or construct LA and either untreated or treated with TNF-α and IL-1α for 24 hrs, 48 hrs, or 96 hrs. Chondrocyte viability, interleukin-8 (IL-8), interleukin-6 (IL-6), collagenase activity and proteoglycan deposition were assessed.

Results:

In the presence of the engineered construct, the chondrocytes retained viability and regenerative function. Moreover, the construct allowed for higher initial doses to be used, which promoted more regeneration and decreased inflammation without compromising cellular viability.

Conclusions:

The construct promotes a less hypertrophic chondrocyte environment while promoting a more anti-inflammatory environment. These two factors are consistent with a less OA progressive environment when using the engineered construct, compared to bolus LA.

Considering the Effect of Rosa damascena Mill. Essential Oil on Oxidative Stress and COX-2 Gene Expression in the Liver of Septic Rats

OBJECTIVES

Sepsis is a clinical illness with a high rate of mortality all over the world. Oxidative stress is considered the main phenomenon that occurs in sepsis. Rosa damascena Mill. is an ancient herbal plant with high pharmacological activities.

MATERIALS AND METHODS

Cecal ligation and puncture (CLP) as a standard model was used to induce sepsis in rats. Male adult rats were randomly divided into 5 groups. Different doses of R. damascena essential oil (50 and 100 mg/kg.bw) were gavaged orally for 14 days and on day 15 CLP was performed. After 24 h, blood samples and liver tissues were removed in order to measure oxidative stress [myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), glutathione-S-transferase, and ferric reducing ability of plasma (FRAP)] and biochemical parameters [alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT), and bilirubin] together with plasma prostaglandin E2 (PGE2) and COX-2 expression.

RESULTS

The essential oil was capable of modulating all of the oxidative stress, antioxidant, and anti-inflammatory parameters induced by CLP as characterized by elevations in MPO and MDA levels as well as increases in AST and ALT concentrations concomitant with PGE2 and COX-2 increments. The antioxidant defense system such as GSH and FRAP was also increased in the essential oil treated groups.

CONCLUSION

Our results showed that the essential oil has antioxidative and hepatoprotective activities through reducing the oxidative injury in sepsis caused by CLP.

Bupivacaine at clinically relevant concentrations induces toxicity in human intervertebral disc cells via the induction of autophagy in vitro

It has been reported that bupivacaine, the most widely used local anesthetic to relieve discogenic back pain in clinical settings, is cytotoxic to intervertebral disc (IVD) cells in vitro; however, the precise mechanisms of cytotoxicity induced by bupivacaine remain unclear. Autophagy is an intracellular lysosomal degradation process that is important for cellular survival. The present study investigated the role of autophagy in the survival of IVD cells subjected to bupivacaine treatment. Human nucleus pulposus (NP) cells isolated from IVD cells were exposed to various concentrations of bupivacaine for 2, 6 and 12 h, and analyzed for cellular viability using MTT assay and western blotting. Additionally, autophagosome formation and autophagy‑associated biomarkers were evaluated by electron microscopy and western blotting to determine the autophagic activity and signaling alterations in NP cells under bupivacaine treatment. Furthermore, autophagic activity was inhibited in vitro using 3‑methyladenine to further analyze the association between autophagy and apoptosis in bupivacaine‑treated NP cells. Bupivacaine exhibited time‑ and dose‑dependent cytotoxic effects on human IVD cells at clinically relevant concentrations. Bupivacaine increased autophagic activity by promoting autophagosome formation, and LC3‑II and Beclin‑1 production. Additionally, bupivacaine inhibited protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/S6 kinase (S6K) signaling, which is a negative regulator of autophagic activity. Of note, pharmacological inhibition of autophagy alleviated bupivacaine‑induced cytotoxicity of IVD cells. The findings indicated that application of clinically relevant concentrations of bupivacaine upregulated autophagic activity via inhibition of Akt/mTOR/S6K signaling. In addition, the inhibition of autophagic activation served as a protective mechanism against bupivacaine‑induced cytotoxicity. Collectively, these findings may provide novel insight into the mechanisms underlying cytotoxicity induced by bupivacaine when controlling spine‑associated pain.

Anti-inflammatory Effects of KOTMIN13: A Mixed Herbal Medicine in LPS-stimulated RAW 264.7 Cells and Mouse Edema Models

BACKGROUND

A Korean herbal medicine, KOTMIN13, composed of Inula japonica Thunberg, Trichosanthes kirilowii Maximowicz var. japonica kitamura, Peucedanum praeruptorum Dunn, and Allium macrostemon Bge, has been used for anti-allergic and anti-asthmatic treatment in oriental clinics, but its activity has not been investigated.

MATERIALS AND METHODS

To evaluate the anti-inflammatory activity of KOTMIN13 for in vitro study, LPS-stimulated RAW 264.7 cells were used to induce the production and expression of inflammatory mediators and its mechanisms. 12-O-Tetradecanoylphorobol-13 aceate (TPA)-induced ear edema and carrageenan-induced paw edema models were also used to evaluate the effect of KOTMIN13 on acute inflammation in vivo.

RESULTS

KOTMIN13 reduced the release of inflammatory mediators [nitric oxide, prostaglandin E2, interleukin (IL)-1β, and IL-6] and the protein expression of inducible nitric oxide synthase and cyclooxygenase-2 in LPS-stimulated RAW 264.7 cells. Mechanism studies showed the attenuation of LPS-induced NF-κB activation by KOTMIN13 via IκBα degradation abrogation and a subsequent decrease in nuclear p65 levels. Activation of mitogen-activated protein kinases (ERK, JNK, and p38) was also suppressed. Furthermore, KOTMIN13 ameliorated the development of TPA-induced ear edema and carrageenan-induced paw edema in acute inflammatory edema mouse models.

CONCLUSION

Our study demonstrates that KOTMIN13 inhibits inflammatory mediators through the inhibitions of NF-κB and MAPK activities in LPS-induced RAW 264.7 cells, as well as acute inflammation in edema models, indicating that KOTMIN13 is an effective suppressor for anti-inflammatory activities.

SUMMARY

KOTMIN13 decrease the production of No, PGE₂, and proinflammatory cytokine (TNF-∝, IL-1β,IL-6).KOTMIN13 Suppressed the degradation of NF-kβ and IKβα and the phosorylation of MAP Kinases.Topical application of KOTMIN13 reduced mouse ear edema.Oral administration of KOTMIN13 decreased carrageenan-induced paw edema. Abbreviations used: NO: nitric oxide; PGE2: prostaglandin E2; iNOS: inducible NO synthase; COX-2: cyclooxygenase-2; TNF-α: tumor necrosis factor-α; IL: interleukin; NF-κB: nuclear factor kappaB; MAPK: mitogen-activated protein kinases; ERK: extracellular signal regulated kinase; JNK: c-jun N terminal kinase; TPA: 12-O-tetradecanoylphorbol-13-acetate.

The effect of two drug delivery systems in ropivacaine cytotoxicity and cytokine release by human keratinocytes and fibroblasts

Objectives

Modified drug delivery systems have been developed to improve pharmacological properties of local anaesthetics. However, the inflammatory potential of these formulations was not investigated. This study compared the in-vitro effects of ropivacaine (ropi) in plain, liposomal (MLV) or 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) formulations on cell viability, apoptosis and cytokine (IL-1α, TNF-α, IL-6 and IL-10) release.

Methods

Human immortalized keratinocytes (HaCaT) and human immortalized gingival fibroblasts (HGF) were exposed to 1–100 μm ropi concentrations. The cell viability was measured by XTT and LIVE/DEAD assay. Apoptosis was performed by flow cytometry, and cytokine release was measured by ELISA assay.

Key findings

Human immortalized keratinocyte viability was reduced by ropi and both drug delivery systems. However, none of the formulations induced apoptosis. Results showed a differential regulation of IL-1α TNF-α, IL-6 and IL-10 by HaCaT and HGF. Ropi-HP-β-CD increased twofold the IL-6 release by HGF in comparison with the control, while 100 μm ropi-MLV led to an increased release of all pro-inflammatory cytokines by HGF.

Conclusion

The loss in cell viability was not related to cellular apoptosis. Ropi complexed with HP-β-CD showed a similar cytokine release pattern when compared to the plain formulation. Thus, the HP-β-CD form was a better drug carrier than the MLV form for ropivacaine drug delivery.

Perioperative cerebrospinal fluid and plasma inflammatory markers after orthopedic surgery

Background

Postoperative delirium is prevalent in older patients and associated with worse outcomes. Recent data in animal studies demonstrate increases in inflammatory markers in plasma and cerebrospinal fluid (CSF) even after aseptic surgery, suggesting that inflammation of the central nervous system may be part of the pathogenesis of postoperative cognitive changes. We investigated the hypothesis that neuroinflammation was an important cause for postoperative delirium and cognitive dysfunction after major non-cardiac surgery.

Methods

After Institutional Review Board approval and informed consent, we recruited patients undergoing major knee surgery who received spinal anesthesia and femoral nerve block with intravenous sedation. All patients had an indwelling spinal catheter placed at the time of spinal anesthesia that was left in place for up to 24 h. Plasma and CSF samples were collected preoperatively and at 3, 6, and 18 h postoperatively. Cytokine levels were measured using ELISA and Luminex. Postoperative delirium was determined using the confusion assessment method, and cognitive dysfunction was measured using validated cognitive tests (word list, verbal fluency test, digit symbol test).

Results

Ten patients with complete datasets were included. One patient developed postoperative delirium, and six patients developed postoperative cognitive dysfunction. Postoperatively, at different time points, statistically significant changes compared to baseline were present in IL-5, IL-6, I-8, IL-10, monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, IL-6/IL-10, and receptor for advanced glycation end products in plasma and in IFN-γ, IL-6, IL-8, IL-10, MCP-1, MIP-1α, MIP-1β, IL-8/IL-10, and TNF-α in CSF.

Conclusions

Substantial pro- and anti-inflammatory activity in the central neural system after surgery was found. If confirmed by larger studies, persistent changes in cytokine levels may serve as biomarkers for novel clinical trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0681-9) contains supplementary material, which is available to authorized users.

Comparison of liposomal and 2-hydroxypropyl-β-cyclodextrin–lidocaine on cell viability and inflammatory response in human keratinocytes and gingival fibroblasts

Objectives

The aim of this study was to observe the effect multilamellar liposomes (MLV) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in the in-vitro effects of lidocaine in cell viability, pro-inflammatory cytokines and prostaglandin E2 release of both human keratinocytes (HaCaT) and gingival fibroblasts (HGF) cells.

Methods

HaCaT and HGF cells were exposed to lidocaine 100–1 μm in plain, MLV and HP-β-CD formulations for 6 h or 24 h. The formulation effects in cell viability were measured by XTT assay and by fluorescent labelling. Cytokines (IL-8, IL-6 and TNF-α) and PGE2 release were quantified by ELISA.

Key findings

MLV and HP-β-CD formulations did not affect the HaCaT viability, which was significantly decreased by plain lidocaine after 24 h of exposure. Both drug carriers increased all cytokines released by HGF after 24-h exposure, and none of the carriers was able to reduce the PGE2 release induced by lidocaine.

Conclusion

The effect of drug carrier in the lidocaine effects was dependent on the cell type, concentration and time of exposure. MLV and HP-β-CD showed benefits in improving cell viability; however, both of them showed a tendency to increase cytokine release when compared to the plain solution.

Autophagy-dependent PELI3 degradation inhibits proinflammatory IL1B expression

Lipopolysaccharide (LPS)-induced activation of TLR4 (toll-like receptor 4) is followed by a subsequent overwhelming inflammatory response, a hallmark of the first phase of sepsis. Therefore, counteracting excessive innate immunity by autophagy is important to contribute to the termination of inflammation. However, the exact molecular details of this interplay are only poorly understood. Here, we show that PELI3/Pellino3 (pellino E3 ubiquitin protein ligase family member 3), which is an E3 ubiquitin ligase and scaffold protein in TLR4-signaling, is impacted by autophagy in macrophages (MΦ) after LPS stimulation. We noticed an attenuated mRNA expression of proinflammatory Il1b (interleukin 1, β) in Peli3 knockdown murine MΦ in response to LPS treatment. The autophagy adaptor protein SQSTM1/p62 (sequestosome 1) emerged as a potential PELI3 binding partner in TLR4-signaling. siRNA targeting Sqstm1 and Atg7 (autophagy related 7), pharmacological inhibition of autophagy by wortmannin as well as blocking the lysosomal vacuolar-type H(+)-ATPase by bafilomycin A1 augmented PELI3 protein levels, while inhibition of the proteasome had no effect. Consistently, treatment to induce autophagy by MTOR (mechanistic target of rapamycin (serine/threonine kinase)) inhibition or starvation enhanced PELI3 degradation and reduced proinflammatory Il1b expression. PELI3 was found to be ubiquitinated upon LPS stimulation and point mutation of PELI3-lysine residue 316 (Lys316Arg) attenuated Torin2-dependent degradation of PELI3. Immunofluorescence analysis revealed that PELI3 colocalized with the typical autophagy markers MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 β) and LAMP2 (lysosomal-associated membrane protein 2). Our observations suggest that autophagy causes PELI3 degradation during TLR4-signaling, thereby impairing the hyperinflammatory phase during sepsis.

Triamcinolone decreases bupivacaine toxicity to intervertebral disc cell in vitro

BACKGROUND CONTEXT

Local anesthetics combined with corticosteroids are commonly used for management of back pain in interventional spinal procedures. Several recent studies suggest cytotoxicity of bupivacaine, whereas others report protective and cytotoxic effects of corticosteroids on chondrocytes and intervertebral disc cells. Considering the frequent use of these agents in spinal interventions, it is meaningful to know how they affect intervertebral disc cells.

PURPOSE

This study was conducted to assess the effects of bupivacaine and triamcinolone, both alone and in combination, on viability of intervertebral disc cells in vitro.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nucleus pulposus cells were isolated from human disc specimens from patients undergoing surgery because of disc herniation or degenerative disc disease. They were grown in three-dimensional alginate beads for 1 week to maintain their differentiated phenotypes and to allow for matrix formation before analysis. After 1 week of culture, the cells were exposed to bupivacaine (0.1%, 0.25%, 0.5%, and 1%) or bupivacaine (0.1%, 0.25%, 0.5%, and 1%) with 1 mg of triamcinolone for 1, 3, or 6 hours. Cell viability was measured using trypan blue exclusion assay and flow cytometry. Live cell/dead cell fluorescent imaging was assessed using confocal microscopy.

RESULTS

Trypan blue exclusion assays demonstrated dose- and time-dependent cytotoxic effects of bupivacaine on human nucleus pulposus cells. Similar but reduced cytotoxicity was observed after exposure to the combination of bupivacaine and 1 mg of triamcinolone. Flow cytometry showed a dose-dependent cytotoxic effect of bupivacaine on nucleus pulposus cells after 3 hours of exposure. The reduced cytotoxicity of bupivacaine combined with 1 mg of triamcinolone was also confirmed in flow cytometry. Confocal images showed that the increase in dead cells correlated with the concentration of bupivacaine. Nevertheless, fewer cells died after exposure to several different concentrations of bupivacaine combined with 1 mg of triamcinolone than did after exposure to bupivacaine alone.

CONCLUSIONS

The combination of bupivacaine and triamcinolone induced dose- and time-dependent cytotoxicity on human intervertebral disc cells in vitro, but the cytotoxicity was much weaker than that of bupivacaine alone. This study shows a potential protective influence of triamcinolone on intervertebral disc cells.

Magnesium sulfate inhibits the secretion of high mobility group box 1 from lipopolysaccharide-activated RAW264.7 macrophages in vitro

BACKGROUND

High mobility group box 1 (HMGB1) is an important inflammatory factor that is closely related to mortality in patients with sepsis. High magnesium therapy has been proved to reduce sepsis-related mortality and sepsis-induced pathologic complications. These effects result from reduced expression and release of many inflammatory cytokines, although it is not clear whether high magnesium affects the expression and release of HMGB1. In the present study, we explored the effect of magnesium sulfate on the expression and release of HMGB1 in lipopolysaccharide (LPS)-activated macrophages.

METHODS

RAW264.7 cells were incubated with LPS in the presence or absence of various concentrations of magnesium sulfate. An enzyme-linked immunosorbent assay was used to detect the levels of HMGB1 in the culture supernatant. Real-time polymerase chain reaction was used to assess the expression of HMGB1 mRNA. The nuclear/cytoplasm extraction kit was used to extract the nuclear and cytoplasmic proteins. Western blotting was used to observe the changes in the translocation of HMGB1 from the nucleus to the cytoplasm. The nuclear factor (NF)-κB p50/p65 Transcription Factor Assay Kit was used to analyze NF-κB activity in the nuclear extract.

RESULTS

We found that magnesium sulfate inhibited translocation of HMGB1 from the nucleus to the cytoplasm and its extracellular release in LPS-activated macrophages and also suppressed the expression of HMGB1 mRNA. Furthermore, magnesium sulfate inhibited the translocation of NF-κB from the cytoplasm to the nucleus in LPS-activated macrophages in a dose-dependent manner.

CONCLUSIONS

Our study has demonstrated that magnesium sulfate inhibits the translocation of HMGB1 from the nucleus to the cytoplasm and the expression of HMGB1 mRNA in a dose-dependent manner. The mechanism responsible for these effects involves the NF-κB signaling pathway.

Aciculatin inhibits lipopolysaccharide-mediated inducible nitric oxide synthase and cyclooxygenase-2 expression via suppressing NF-κB and JNK/p38 MAPK activation pathways

OBJECTIVES

Natural products have played a significant role in drug discovery and development. Inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been suggested to connect with various inflammatory diseases. In this study, we explored the anti-inflammatory potential of aciculatin (8-((2R,4S,5S,6R)-tetrahydro-4,5-dihydroxy-6-methyl-2H-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one), one of main components of Chrysopogon aciculatis, by examining its effects on the expression and activity of iNOS and COX-2 in lipopolysaccharide (LPS)-activated macrophages.

METHODS

We used nitrate and prostaglandin E2 (PGE2) assays to examine inhibitory effect of aciculatin on nitric oxide (NO) and PGE2 levels in LPS-activated mouse RAW264.7 macrophages and further investigated the mechanisms of aciculatin suppressed LPS-mediated iNOS/COX-2 expression by western blot, RT-PCR, reporter gene assay and confocal microscope analysis.

RESULTS

Aciculatin remarkably decreased the LPS (1 μg/mL)-induced mRNA and protein expression of iNOS and COX-2 as well as their downstream products, NO and PGE2 respectively, in a concentration-dependent manner (1-10 μM). Such inhibition was found, via immunoblot analyses, reporter gene assays, and confocal microscope observations that aciculatin not only acts through significant suppression of LPS-induced NF-κB activation, an effect highly correlated with its inhibitory effect on LPS-induced IκB kinase (IKK) activation, IκB degradation, NF-κB phosphorylation, nuclear translocation and binding of NF-κB to the κB motif of the iNOS and COX-2 promoters, but also suppressed phosphorylation of JNK/p38 mitogen-activated protein kinases (MAPKs).

CONCLUSION

Our results demonstrated that aciculatin exerts potent anti-inflammatory activity through its dual inhibitory effects on iNOS and COX-2 by regulating NF-κB and JNK/p38 MAPK pathways.

Continuous subcutaneous instillation of bupivacaine compared to saline reduces interleukin 10 and increases substance P in surgical wounds after cesarean delivery

BACKGROUND

Recent evidence suggests that locally delivered local anesthetics may exert tissue-damaging effects such as chondrolysis after intraarticular injection. Alteration of the inflammatory response is a potential mechanism for local anesthetic-induced tissue toxicity. In this study, we tested the effects of continuous local anesthetic infiltration on the release of inflammatory and nociceptive mediators in skin wounds after cesarean delivery.

METHODS

Thirty-eight healthy women undergoing cesarean delivery with spinal anesthesia were enrolled in this study, and were randomized to receive subcutaneous surgical wound infiltration with bupivacaine 5 mg/mL or saline at 2 mL/h for 24 hours after cesarean delivery. Wound exudate was sampled at 1, 3, 5, 7, and 24 hours after cesarean delivery using a subcutaneous wound drain technique. Cytokines, chemokines, substance P, prostaglandin E(2), and nerve growth factor were assayed using multiplex Bio-Plex® (Bio-Rad, Hercules, CA) and enzyme-linked immunosorbent assays.

RESULTS

Bupivacaine wound infusion resulted in a significant decrease of interleukin 10 and increase of substance P in wounds compared with saline infusion (area under the 24-hour concentration-time curve; P < 0.001). No statistically significant differences were detected for other cytokines, nerve growth factor, and prostaglandin E(2).

CONCLUSIONS

This study demonstrates that the continuous administration of clinically used doses of bupivacaine into wounds affects the local composition of wound mediators. Observed changes in interleukin 10 are compatible with a disruption of antiinflammatory mechanisms. Whether such modulation combined with the release of the proinflammatory mediator substance P results in an overall proinflammatory wound response will require future studies of wound healing.

Long-acting local anesthetics attenuate FMLP-induced acute lung injury in rats

BACKGROUND

Endothelin-1 (ET-1) is a mediator of lung diseases and a potent pulmonary vasoconstrictor. In addition to thromboxane A2, it participates in the formation of lung edema. Both lidocaine and mepivacaine attenuate the increase of pulmonary arterial pressure (PAP) and lung edema development. We examined the effects of procaine, bupivacaine, and ropivacaine on experimentally evoked PAP increase and ET-1 release.

METHODS

PAP and lung weight were measured in isolated rat lungs during perfusion with Krebs-Henseleit hydroxyethyl starch buffer. Bupivacaine, ropivacaine, or procaine was added to the solution at concentrations of 10(-2)-10(-7) mg/kg. ET-1 levels were measured in the perfusate by enzyme-immunoassay, and thromboxane A2 levels were assayed by radioimmunoassay. N-formyl-L-leucine-methionyl-L-phenylalanine was used to activate human polymorphonuclear neutrophils.

RESULTS

Bupivacaine, ropivacaine, and procaine significantly attenuated increases of PAP (P < 0.05) and resulted in a reduction of lung weight in these treatment groups compared with the sham group (P < 0.05). The long-acting anesthetics bupivacaine and ropivacaine (P < 0.05), but not procaine, reduced ET-1 levels, produced low inflammation rates, and did not affect lung structures at doses from 10(-3) to 10(-6) mg/kg.

CONCLUSION

Bupivacaine and ropivacaine attenuated N-formyl-L-leucine-methionyl-L-phenylalanine-induced PAP, reduced lung edema, and diminished ET-1 release. Lidocaine and mepivacaine are more effective in reducing PAP and edema formation, but long-acting local anesthetics also inhibit ET-1 depletion and therefore have increased anti-inflammatory properties.