Tetrandrine regulates hepatic stellate cell activation via TAK1 and NF-κB signaling

We investigated the anti-fibrotic mechanism of tetrandrine, a bisbenzylisoquinoline alkaloid from the Chinese herb, Stephania tetrandra, on the immortalized HSC-T6 rat hepatic stellate cell line. Tetrandrine (0.39–50 μM) dose- and time-dependently inhibited HSC-T6 cell viability within 24 h and exhibited almost no cytotoxicity at concentrations lower than 6.25 μM in the presence of tumor necrosis factor-α (TNF-α). At a much high concentration (50 μM), tetrandrine caused fatal cytotoxity in both HSCs and hepatocytes. TNF-α time-dependently increased α-smooth muscle actin (α-SMA) expression, while a lower concentration of tetrandrine (6.25 μM) prior to TNF-α treatment reduced the expression of α-SMA and TNFR-1-associated death domain (TRADD). TNF-α treatment induced TGF-β-activated kinase-1 (TAK1) and c-Jun N-terminal kinase (JNK) phosphorylation, which were attenuated by tetrandrine. Furthermore, TNF-α treatment activated nuclear factor-κB (NF-κB) nuclear translocation and IκB-α degradation. Tetrandrine treatment prior to TNF-α reduced nuclear phosphorylated and total NF-κB p65, while the cytosolic IκB-α and NF-κB p65 levels significantly increased. In addition, treatment with only tetrandrine induced the cleavage of caspase-3 and PARP within a range of higher concentrations. Tetrandrine-induced apoptosis was confirmed by the TUNEL assay and flow-cytometric analysis. Treatment with only tetrandrine markedly reduced α-SMA expression, except for at lower concentrations of tetrandrine. A higher concentration of tetrandrine (25 μM) induced a significant increase in JNK and extracellular signal-regulated kinase (ERK) phosphorylation, NF-κB nuclear translocation and IκB-α degradation. In conclusion, the anti-fibrogenic effects of tetrandrine on HSCs involved a dosage-dependent signaling pathway, based on the tetrandrine concentration, by regulating TAK1, JNK and NF-κB. The present data provides strong evidence for the anti-fibrotic dosage-dependent signaling pathway of tetrandrine.     

Cationic nanoparticles disrupt cellular signaling in a cholesterol dependent manner

In this study, we investigate the interaction of charged polystyrene particles with respiratory epithelial cells. Experiments were designed to reveal the effect of cellular interaction with particles of varying size and charge and how such interactions could alter cytokine induced cellular processes. A549 cells, containing a stably transfected Interleukin-8 (IL-8) Luciferase promoter construct, were cultured in the presence of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) and polystyrene particles for 4.5 h. Several endpoints were measured: IL-8 gene expression, IL-6 protein, IL-8 protein, and NF-кB translocation. At 4.5 h, cellular viability was maintained for the particle exposed cells. Interestingly, we found that only the cationic nanoparticles have the ability to disrupt the TNF-α stimulated cellular signaling by reducing the IL-8 promoter activity, IL-6 and IL-8 protein. Cationic nanoparticles reduce these processes through interfering with NF-κB translocation. However, the activity of the cationic nanoparticles on the IL-8 promoter and NF-κB translocation is lost when cholesterol is depleted from A549 cells before particle exposure, which suggests that cationic nanoparticles rely on membrane cholesterol integrity to disrupt cellular signaling.     

Protective effects of Acanthopanax vs. Ulinastatin against severe acute pancreatitis-induced brain injury in rats

ObjectivesTo observe the protecting effects of Acanthopanax and Ulinastatin against severe acute pancreatitis (SAP)-induced brain injury in rats.MethodsSAP-modeled rats were equally randomized into three groups: model group, Acanthopanax-treated group and Ulinastatin-treated group. A sham-operation group was used as negative control. Serum tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and IL-10 levels were assayed by enzyme linked immunosorbent assay (ELISA). Nuclear factor kappa B p65 (NF-κB p65) activity in the brain tissue was determined by immunohistochemistry. The mortality, pathological changes of the pancreas and brain, and expression of TNF-α mRNA, IL-6 mRNA and IL-10 mRNA in the brain tissue were observed at 6, 12 and 24 h after operations in all groups.ResultsThe mortality of the model group was significantly higher than that of both treatment groups at 24 h (P < 0.01). Serum levels of TNF-α and IL-6, activity of NF-κB p65, expression levels of TNF-α and IL-6 mRNA in the brain tissue, and the pathological scores of the pancreas and brain in the two treatment groups were lower than those in the model group at 12 and 24 h after operation (P < 0.01), while serum IL-10 and IL-10 mRNA expression levels of the brain tissue in the two treatment groups were higher. There was no significant difference in all indexes between Acanthopanax and Ulinastatin groups at all designated time points (P > 0.05).ConclusionsAcanthopanax and Ulinastatin have similar protecting effects against SAP-induced brain injury in rats.     

Sodium butyrate inhibits the NF-kappa B signaling pathway and histone deacetylation,and attenuates experimental colitis in an IL-10 independent manner

Butyrate is a bacterial metabolite of dietary fiber in the colon that has been used to treat inflammatory disease. However, the effect of oral supplementation with butyrate on colitis has not been fully explored. We evaluated the effects of and mechanisms underlying oral supplementation with butyrate on experimental murine colitis. In an in vitro study, we found that LPS induced the secretion of cytokines (i.e., IL-8 in COLO 205; TNF-α, IL-6, IL-12, and IL-10 in RAW 264.7; and TNF-α, IL-6 and IL-12 in peritoneal macrophages obtained from IL-10-deficient [IL-10^−/−] mice). Butyrate (100 μM and 500 μM) inhibited pro-inflammatory cytokine production (i.e., IL-8 in COLO205 and TNF-α, IL-6 and IL-12 in macrophages) but promoted anti-inflammatory cytokine (i.e., IL-10) production in RAW264.7 cells. Butyrate attenuated both the LPS-induced degradation/phosphorylation of IκBα and DNA binding of NF-κB and enhanced histone H3 acetylation. To confirm that butyrate played a protective role in colitis, an acute colitis model was induced using dextran sulfate sodium (DSS) and a chronic colitis model was induced in IL-10^−/− mice. The administration of oral butyrate (100 mg/kg) significantly improved histological scores in both colitis models, including the IL-10^−/− mice. In immunohistochemical staining, IκBα phosphorylation was attenuated, and histone H3 acetylation was reversed in the treated colons of both colitis models. Our results indicate that oral supplementation with butyrate attenuates experimental murine colitis by blocking NF-κB signaling and reverses histone acetylation. These anti-colitic effects of butyrate were IL-10-independent. Butyrate may therefore be a therapeutic agent for colitis.     

Interleukin-37 suppresses ICAM-1 expression in parallel with NF-κB down-regulation following TLR2 activation of human coronary artery endothelial cells

IntroductionThe inflammatory receptor Toll-like receptors (TLRs) activation could induce endothelial inflammatory responses, which plays an important role in the development of many diseases including atherosclerosis. We already found that TLR2 activation of Peptidoglycan (PGN) stimulation could increase intercellular adhesion molecule-1 (ICAM-1) expression in HCAECs. Since anti-inflammatory cytokine interleukin (IL)-37 exhibits intra- and extracellular properties for suppressing innate inflammation, we want to investigate whether IL-37 suppresses ICAM-1 expression and this effect is in parallel with the inhibition of nuclear factor kappa B (NF-κB) activation upon PGN stimulation in HCAECs.MethodsHCAECs were treated with IL-37-transfection plasmid or silent mRNA or nothing for 24 h, and we test IL-37 expression by immunoblotting. Same treatments prior to PGN stimulation (10 μg/ml), we analyzed the expression of ICAM-1 and NF-κB mRNA at 0, 30 min, 1 and 2 h by real-time PCR. ICAM-1 protein at 24 h and NF-κB activation at 0–2 h were measured by immunoblotting.ResultsIL-37 and silent IL-37 transfection change the expression of IL-37 protein. Stimulation of PGN increased both NF-κB activation and ICAM-1 expression at mRNA and protein level, but these inflammatory cytokines’ expression was significantly decreased in IL-37-transfection cells. Interestingly, both NF-κB activation and ICAM-1 expression were significantly increased when IL-37 was silent.ConclusionsAs an anti-inflammatory cytokine, IL-37 could decrease both NF-κB and ICAM-1 expression upon TLR2 activation in HCAECs. The suppressed effect of IL-37 on ICAM-1 may be due to its inhibition on NF-κB.     

Antrodia camphorata suppresses lipopolysaccharide-induced nuclear factor-κB activation in transgenic mice evaluated by bioluminescence imaging

In an earlier study, we found that Antrodia camphorata inhibited the production of lipopolysaccharide (LPS)-induced cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 by blocking nuclear factor-κB (NF-κB) activation in cultured RAW 264.7 macrophages. This study was aimed at evaluating the inhibitory effects of the fermented culture broth of A. camphorata in terms of LPS-induced NF-κB activation in transgenic mice by using a non-invasive, real-time NF-κB bioluminescence imaging technique. Transgenic mice carrying the luciferase gene under the control of NF-κB were given A. camphorata (570 mg/kg, p.o.) for three consecutive days and then injected with LPS (4 mg/kg, i.p.). In vivo imaging showed that treatment with LPS increased the luminescent signal, whereas A. camphorata suppressed the LPS-induced inflammatory response significantly. Ex vivo imaging showed that A. camphorata suppressed LPS-induced NF-κB activity in the small intestine, mesenteric lymph nodes, liver, spleen, and kidney. Immunohistochemical staining revealed that A. camphorata suppressed production of the LPS-induced tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and NF-κB p65 subunit in these organs. Furthermore, A. camphorata attenuated the productions of LPS-induced TNF-α and IL-1β in serum from transgenic mice. We report the first confirmation of the anti-inflammatory action in vivo of this potentially beneficial mushroom.     

Sertraline ameliorates inflammation in CUMS mice and inhibits TNF-α-induced inflammation in microglia cells

Evidence indicates that inflammation plays a crucial role in depression. Therefore, new antidepressants might be identified by screening drugs for their anti-inflammatory actions. Sertraline hydrochloride (SERT), a widely used antidepressant, has anti-inflammatory effects in clinical studies, but the mechanism involved is unclear. In this study, we used cell and molecular biology to determine the possible anti-inflammatory mechanism of SERT in vivo and in vitro. Experimental data from the in vivo study showed that mice exposed to chronic unpredictable mild stress (CUMS) had significantly higher levels of major inflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β] and inducible nitric oxide synthase [iNOS]) in peripheral and central tissues compared with the control group. Treatment of CUMS mice with SERT significantly reduced the levels of these inflammatory cytokines and inhibited the phosphorylation of nuclear factor-κB (NF-κB) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α). Moreover, SERT reduced serum levels of transaminase in CUMS mice. Our in vitro study revealed that SERT suppressed TNF-α-induced NF-κB activation in a dose-dependent manner. SERT also inhibited the TNF-α-induced nuclear translocation of NF-κB by inhibiting IκB-α phosphorylation. Furthermore, SERT inhibited TNF-α-induced inflammatory cytokines in BV2 microglia cells. SERT directly bound to TNF-α and TNF-α receptor 1 (TNFR1) to potently block TNF-α/TNFR1-triggered signaling. These results indicate that SERT might treat depression by inhibiting the activation of microglia via the NF-κB signaling pathway. This study provides a basis for the research and development of antidepressants that act to reduce inflammation and the expression of inflammatory mediators.     

Alpha-lipoic acid protects mice against concanavalin A-induced hepatitis by modulating cytokine secretion and reducing reactive oxygen species generation

BackgroundAlpha-lipoic acid (α-LA), which exits in almost all types of prokaryotic and eukaryotic cells, is a key regulator of energy metabolism in mitochondria. This study was designed to explore the protective effect of α-LA against concanavalin A (Con A)-induced hepatitis in mice and explore the potential mechanism.MethodsAcute autoimmune hepatitis was induced by intravenous (IV) injection of Con A (15 mg/kg) in C57BL/6 mice. α-LA (100 mg/kg) was administered four days before Con A injection. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and histopathological change of the liver tissue were measured. Serum cytokine TNF-α, IL-6, IFN-γ and IL-10 were detected by ELISA. The mRNA levels of these inflammatory cytokines in the liver were detected by RT-PCR. Malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD) and reduced/oxidized glutathione (GSH/GSSG) in liver were determined using commercial kits. Phosphorylated NF-κB p65, IκBα and phosphorylated MAPK were measured by Western blot.ResultsCon A injection induced severe immune responses and extensive hepatocellular apoptosis within 12 h. Pretreatment of α-LA markedly reduced the serum ALT and AST activity and the increase of plasma TNF-α, IL-6, IFN-γ and IL-10. In addition, α-LA pretreatment decreased the tissue MPO activity and lipid peroxidation, but increased SOD and GSH levels. α-LA inhibited the phosphorylation of NF-κB p65, IκBα and JNK.ConclusionPretreatment of α-LA markedly attenuated Con A-induced hepatitis by modulating cytokine secretion and reducing reactive oxygen species generation.     

β-Glucan modulates the lipopolysaccharide-induced innate immune response in rat mammary epithelial cells

Mastitis, caused by mammary pathogenic bacteria which are frequent implications of Escherichia coli, is an important disease affecting women and dairy animals worldwide. The β-glucan binding of dectin-1 can induce its own intracellular signaling and can mediate a variety of cellular responses. This work was to investigate the effect of β-glucan on the lipopolysaccharide (LPS)-induced in?ammatory response and related innate immune signaling in primary rat mammary epithelial cells. Cells were treated with serum-free medium added with a DMSO solution containing β-glucans at concentrations of 0, 1, 5, 25 μmol/L for 12 h, and then exposed to 10 μg/mL LPS for 40 min. Moreover, cells were pretreated with BAY 11-7082 to inhibit NF-κB and then successively exposed to 5 μmol/L β-glucan, 10 μg/mL LPS, 5 μmol/L β-glucan and 10 μg/mL LPS, according to the specific experimental design. Normal control cultures contained an equal volume of DMSO, which was collected at the same time. After incubating rat mammary epithelial cells for 40 min with 10 μg/mL LPS, TLR4, MyD88 and NF-κB expression all increased (P < 0.05), as did the secretion of TNF-α and IL-1β (P < 0.05), but IκB and β-casein expression both decreased (P < 0.05). Treatment with different concentrations of β-glucan for 12 h activated Dectin1/Syk, which subsequently suppressed TLR4, MyD88 and NF-κB expression and TNF-α and IL-1β secretion. However, it restored the IκB and β-casein expression that had been induced by the 40 min incubation with 10 μg/mL LPS. Pretreatment with BAY 11-7082 at 10 µmol/L for 2 h partially prevented NF-κB induction by LPS, but the presence of β-glucan prevented this inactivation. BAY 11-7082 could not simultaneously inhibit LPS induction of TLR4, MyD88 and β-glucan activation of Dectin1/Syk in rat mammary epithelial cells. These findings demonstrated that β-glucan activation of Dectin1/Syk attenuated LPS induction of TLR4/MyD88/NF-κB and inhibited the LPS-induced inflammation factors in mammary epithelial cells, thereby providing a possibly protective effect of β-glucan in the prevention of LPS-induced dysfunction in mammary epithelial cells.     

Anti-inflammatory effect of corymbocoumarin from Seseli gummiferum subsp. corymbosum through suppression of NF-κB signaling pathway and induction of HO-1 expression in LPS-stimulated RAW 264.7 cells

This study investigated the anti-inflammatory activity of corymbocoumarin, an angular-type pyranocoumarin isolated from Seseli gummiferum subsp. corymbosum in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Corymbocoumarin not only inhibited the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), but also inhibited the protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Corymbocoumarin also attenuated pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Investigation of the effect on nuclear factor κB (NF-κB) signaling pathway showed that corymbocoumarin inhibited the phosphorylation of Akt and inhibitory κB (IκB)-α and decreased the subsequent translocation of the p65 and p50 NF-κB subunits to the nucleus. A further study revealed that corymbocoumarin exerted anti-inflammatory activity through induction of heme oxygenase (HO)-1 expression. The in vivo study showed that corymbocoumarin (20 mg/kg, i.p.) reduced paw swelling in carrageenan-induced acute inflammation model. Taken together, these results suggest that corymbocoumarin exerts its anti-inflammatory effect in LPS-stimulated RAW 264.7 cells by suppressing NF-κB activation and inducing HO-1 expression. Corymbocoumarin may provide a useful therapeutic approach for inflammation-associated diseases.     

Enhanced effect of κ-carrageenan on TNBS-induced inflammation in mice

BackgroundAs a sulfated polysaccharide, carrageenan has been widely used as common food additive.MethodsIn the present study, we investigated the effects of κ-carrageenan on TNBS-induced gut inflammation in mice. BALB/c mice were pretreated with κ-carrageenan for 14 days prior to the administration of TNBS.ResultsOur results showed that κ-carrageenan pretreatment aggravated the loss of body weight and further increased the mortality rate. Histological and morphological analyses revealed that the TNBS-induced colonic inflammation was deteriorated by the κ-carrageenan administration. The ratio of CD4⁺ CD25⁺ CD127dim/CD4⁺ of the κ-carrageenan + TNBS groups was significantly lower than that of the TNBS group. The expression of IL-2, TNF-α and IL-6 was significantly increased, whereas the expression of IL-10 was significantly decreased in the κ-carrageenan + TNBS groups. In addition, κ-carrageenan, together with TNBS, decreased the enzyme activity of SOD and GSH-px and up-regulated the expression of TLR4, NF-κB, p-ERK, p-JNK, p-Jun., IL-8 and MDA in the colonic mucosa.Conclusionsκ-Carrageenan aggravated the TNBS-induced intestinal inflammation, and such an effect could be associated with the oxidative stress and activation of TLR4-NF-κB and MAPK/ERK1/2 pathway.     

Cryptotanshinone protects against IL-1β-induced inflammation in human osteoarthritis chondrocytes and ameliorates the progression of osteoarthritis in mice

Osteoarthritis (OA) is a common degenerative disease characterized by progressive erosion of articular cartilage, subchondral bone sclerosis and synovitis. Cryptotanshinone (CTS), an active component extracted from the root of Salvia miltiorrhiza Bunge, has been shown to have potent anti-inflammatory effects. However, its effects on OA have not been clearly elucidated. This study aimed to assess the effect of CTS on human OA chondrocytes and mice OA models. Human OA chondrocytes were pretreated with CTS (5, 10 and 20 μM) for 2 h and subsequently stimulated with IL-1β for 24 h. Production of NO, PGE2, IL-6, TNF-α was evaluated by the Griess reaction and ELISA. The protein expression of COX-2, iNOs, MMP-3, MMP13, COX-2, ADAMTS-5, JNK, p-JNK, ERK, p-ERK, p38, p-p38, p-IKKα/β, p65, p-p65, IκB-α, and p-IκB-α was tested by Western blot. In vivo, the severity of OA was determined by histological analysis. We found that CTS significantly inhibited the IL-1β-induced production of NO and PGE2; expression of COX-2, iNOS, MMP-3, MMP-13, and ADAMTS-5. Furthermore, CTS in dramatically suppressed IL-1β-stimulated NF-κB and MAPK activation. Immunofluorescence staining demonstrated that CTS could suppress IL-1β-induced phosphorylation of p65 nuclear translocation. In vivo, treatment of CTS prevented the destruction of cartilage and the thickening of subchondral bone in mice OA models. These results indicate that the therapeutic effect of CTS on OA is accomplished through the inhibition of both NF-κB and MAPK signaling pathways. Our findings provide the evidence to develop CTS as a potential therapeutic agent f or patients with OA.     

Human β-defensin-3 alleviates the progression of atherosclerosis accelerated by Porphyromonas gingivalis lipopolysaccharide

Background and aimPorphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) is reported to be associated with the progression of atherosclerosis (AS). In this study, we explored the potential of human β-defensin-3 (hBD3), an antimicrobial peptide with immunomodulatory properties, to alleviate AS progression accelerated by P. gingivalis LPS and the mechanism underlying this effect.Materials and methodsApolipoprotein E-deficient mice were injected intraperitoneally with hBD3, P. gingivalis LPS, or hBD3 + P. gingivalis LPS. The aorta was assessed immunohistologically and mRNA levels of inflammatory cytokines were determined by quantitative PCR. Macrophages and vascular endothelial cells were stimulated in vitro to investigate the hBD3 target cells. Inflammatory cytokines in serum and cell culture supernatants were detected using cytometric bead arrays. Signaling pathways were investigated by Western blotting.ResultsIn P. gingivalis LPS-treated mice, hBD3 significantly reduced serum IL-6 and TNF-α levels and aortic expression of ICAM-1, IL-6, and MCP-1 (mRNA and protein). The area and severity of atherosclerotic lesions were also diminished, with less advanced plaque formation, more continuous and distinct elastic lamina, and more normal smooth muscle cells arranged along the tunica media layer. In vitro, hBD3 decreased TNF-α, IL-1β, IL-6 secretion and downregulated TNF-α, IL-1β, IL-6, IL-8, VCAM-1, and IL-10 mRNA levels in macrophages. hBD3 did not influence TNF-α, IL-6, and IL-8 levels in HUVECs culture supernatants. Furthermore, hBD3 suppressed P. gingivalis LPS-induced activation of the NF-κB, p38 and JNK pathways.ConclusionhBD3 alleviates AS progression accelerated by P. gingivalis LPS in apolipoprotein E-deficient mice by downregulating the cytokine expression in macrophages via the MAPK and NF-κB signaling pathways.     

Inhibition of TNF-α-induced adhesion molecule expression by diosgenin in mouse vascular smooth muscle cells via downregulation of the MAPK,Akt and NF-κB signaling pathways

Atherosclerosis is a chronic inflammatory disease and the expression of adhesion molecules on vascular smooth muscle cells (VSMCs) contributes to the progress of the disease. Diosgenin, a precursor of steroid hormones, has been shown to have a variety of biological activities including anti-inflammatory activity; however, its molecular mechanisms are poorly understood. This study examined the effect of diosgenin on the expression of adhesion molecules induced by TNF-α in cultured mouse VSMC cell line, MOVAS-1. Preincubation of VSMCs for 2 h with diosgenin (0.1–10 μM) dose-dependently inhibited TNF-α-induced adhesion of THP-1 monocytic cells and mRNA and protein expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Diosgenin abrogated TNF-α induced production of intracellular reactive oxygen species (ROS) and phosphorylation of p38, ERK, JNK and Akt. Diosgenin was also shown to inhibit NK-κB activation induced by TNF-α. Furthermore, diosgenin inhibited TNF-α-induced IκB kinase activation, subsequent degradation of IκBα, and nuclear translocation of NF-κB. Our results indicate that diosgenin inhibits the adhesive capacity of VSMC and the TNF-α-mediated induction of ICAM-1 and VCAM-1 in VSMC by inhibiting the MAPK/Akt/NF-κB signaling pathway and ROS production, which may explain the ability of diosgenin to suppress inflammation within the atherosclerotic lesion and modulate immune response.     

Exogenous C3 protein enhances the adaptive immune response to polymicrobial sepsis through down-regulation of regulatory T cells

BackgroundThe role of complement system in bridging innate and adaptive immunity has been confirmed in various invasive pathogens. It is still obscure how complement proteins promote T cell-mediated immune response during sepsis. The aim of this study is to investigate the role of exogenous C3 protein in the T-cell responses to sepsis.MethodsSepsis was induced by colon ascendens stent peritonitis (CASP) in wild-type C57BL/6 mice, sham-operated mice for control. Human purified C3 protein (HuC3, 1 mg) was intraperitoneally injected at 6 h post-surgery, with 200 μl phosphate-buffered saline as control. The levels of C3 and cytokines, the expression of FOXP3 and NF-κB, and the percentages of CD4⁺ T-cell subsets were compared among the groups at given time points.ResultsThe polymicrobial sepsis produced considerable release of TNF-α and IL-10, and caused complement C3 exhaustion. Exogenous C3 administration markedly improved the 48 h survival rate, as compared with nontreatment (40% vs. 5%, P < 0.01). The expression of FOXP3 protein was increased during sepsis, but can be suppressed by HuC3 administration. A single injection of HuC3 postponed the decline of differentiated Th1 cells, and depressed the activation of Th2/Th17 cells. Besides, the Th1–Th2 shift in late stage of sepsis can be controlled under C3 supplementation. The suppression of NF-κB pathway might be related to the appearance of immunocompromise.ConclusionsThe study confirmed the important role of exogenous C3 in up-regulation of adaptive immune response to sepsis. The complement pathway would be a pivotal target for severe sepsis management.