Association between CT-based adipose variables, preoperative blood biochemical indicators and pathological T stage of clear cell renal cell carcinoma.

Background: Clear cell renal cell carcinoma (ccRCC) is corelated with tumor-associated material (TAM), coagulation system and adipocyte tissue, but the relationships between them have been inconsistent. Our study aimed to explore the cut-off intervals of variables that are non-linearly related to ccRCC pathological T stage for providing clues to understand these discrepancies, and to effectively preoperative risk stratification. Methods: This retrospective analysis included 218 ccRCC patients with a clear pathological T stage between January 1st, 2014, and November 30th, 2021. The patients were categorized into two cohorts based on their pathological T stage: low T stage (T1 and T2) and high T stage (T3 and T4). Abdominal and perirenal fat variables were measured based on preoperative CT images. Blood biochemical indexes from the last time before surgery were also collected. The generalized sum model was used to identify cut-off intervals for nonlinear variables. Results: In specific intervals, fibrinogen levels (FIB) (2.63-4.06 g/L) and platelet (PLT) counts (>200.34 × 109/L) were significantly positively correlated with T stage, while PLT counts (<200.34 × 109/L) were significantly negatively correlated with T stage. Additionally, tumor-associated material exhibited varying degrees of positive correlation with T stage at different cut-off intervals (cut-off value: 90.556 U/mL). Conclusion: Preoperative PLT, FIB and TAM are nonlinearly related to pathological T stage. This study is the first to provide specific cut-off intervals for preoperative variables that are nonlinearly related to ccRCC T stage. These intervals can aid in the risk stratification of ccRCC patients before surgery, allowing for developing a more personalized treatment planning.

Ferroptosis is involved in PGPS-induced otitis media in C57BL/6 mice.

Otitis media (OM) is a common disease that can cause hearing loss in children. Currently, the main clinical treatment for OM is antibiotics, but the overuse of antibiotics might lead to bacterial resistance, which is a worldwide public health challenge. Studying the pathogenesis of OM will help us develop new effective treatments. Ferroptosis is one type of programmed cell death characterized by the occurrence of lipid peroxidation driven by iron ions. Many studies have shown that ferroptosis is associated with infectious diseases. It is presently unclear whether ferroptosis is involved in the pathogenesis of OM. In this study, we explored the relationship between ferroptosis and OM by PGPS-induced OM in C57BL/6 mice and treating the induced OM with ferroptosis inhibitors deferoxamine (DFO), Ferrostatin-1 (Fer-1), and Liperoxstatin-1 (Lip-1). We examined the expression of ferroptosis-related proteins acyl-CoA synthetase long chain family member 4 (ACSL4) and prostaglandin-endoperoxide synthase 2 (Cox2), glutathione peroxidase 4 (GPX4) protein as well as lipid peroxidation markers 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). The results showed that in PGPS-induced OM model mice, several ferroptosis-related proteins including ACSL4 and Cox2 were up-regulated compared to mice treated with saline. Meanwhile, a ferroptosis-related protein GPX4 was down-regulated upon PGPS treatment. The DFO treatment in PGPS-inoculated mice effectively inhibited the development of OM. The inhibitors treatment caused a significant decrease in the expression of ACSL4, Cox2, 4 HNE, MDA, reduction in free iron. Meanwhile, the ferroptosis inhibitors treatment caused increase in the expression of inflammation-related factors tumor necrosis factor-α (TNF-α) and antioxidant protein GPX4. Our results suggest that there is a crosstalk between ferroptosis signaling pathway and the pathogenesis of OM. Ferroptosis inhibition can alleviate PGPS-induced OM.

Naringin attenuates cisplatin- and aminoglycoside-induced hair cell injury in the zebrafish lateral line via multiple pathways.

Exposure to ototoxic drugs is a significant cause of hearing loss that affects about 30 thousand children with potentially serious physical, social and psychological dysfunctions every year. Cisplatin (CP) and aminoglycosides are effective antineoplastic or bactericidal drugs, and their application has a high probability of ototoxicity which results from the death of hair cells (HCs). Here, we describe the therapeutic effect of the flavonoid compound naringin (Nar) against ototoxic effects of cisplatin and aminoglycosides include gentamicin (GM) and neomycin (Neo) in zebrafish HCs. Animals incubated with Nar (100-400 µmol/L) were protected against the pernicious effects of CP (150-250 µmol/L), GM (50-150 µmol/L) and Neo (50-150 µmol/L). We also provide evidence for the potential mechanism of Nar against ototoxicity, including antioxidation, anti-apoptosis, promoting proliferation and hair cell regeneration. We found that mRNA levels of the apoptotic- and pyroptosis-related genes are regulated by Nar both in vivo and in vitro. Finally, by proving that Nar does not affect the anti-tumour efficacy of CP and antibacterial activity of aminoglycosides in vitro, we highlight its value in clinical application. In conclusion, these results unravel a novel therapeutic role for Nar as an otoprotective drug against the adverse effects of CP and aminoglycosides.

Ferrostatin-1 protects auditory hair cells from cisplatin-induced ototoxicity in vitro and in vivo.

Cisplatin is used in a wide variety of malignancies, but cisplatin-induced ototoxicity remains a major issue in clinical practice. Experimental evidence indicates that ferroptosis plays a key role in mediating the unwanted cytotoxicity effect caused by cisplatin. However, the role of ferroptosis in cisplatin-induced ototoxicity requires elucidation. Ferrostatin-1 (Fer-1) was identified as a potent inhibitor of ferroptosis and radical-trapping antioxidant with its ability to reduce the accumulation of lipid peroxides and chain-carrying peroxyl radicals. In the current study, we investigated the effects of Fer-1 in cisplatin-induced ototoxicity in in vitro, ex vivo, and in vivo models. We found, for the first time that Fer-1 efficiently alleviated cisplatin-induced cytotoxicity in HEI-OC1 cells via a concentration-dependent manner. Furthermore, Fer-1 mitigated cisplatin cytotoxicity in transgenic zebrafish sensory hair cells. In HEI-OC1 cells, Fer-1 pretreatment not only drastically reduced the generation of intracellular reactive oxygen species but also remarkably decreased lipid peroxidation levels induced by cisplatin. This was not only ascribed to the inhibition of 4-hydroxynonenal, the final product of lipid peroxides, but also to the promotion of glutathione peroxidase 4, the protein marker of ferroptosis. MitoTracker staining and transmission electron microscopy of mitochondrial morphology suggested that in HEI-OC1 cells, Fer-1 can effectively abrogate mitochondrial damage resulting from the interaction with cisplatin. In addition, Fer-1 pretreatment of cochlear explants substantially protected hair cells from cisplatin-induced damage. Therefore, our results demonstrated that ferroptosis might be involved in cisplatin ototoxicity. Fer-1 administration mitigated cisplatin-induced hair cell damage, further investigations are required to elucidate the molecular mechanisms of its otoprotective effect.

Role of Endoplasmic Reticulum Stress in Otitis Media.

Endoplasmic reticulum (ER) stress occurs in many inflammatory responses. Here, we investigated the role of ER stress and its associated apoptosis in otitis media (OM) to elucidate the mechanisms of OM and the signaling crosstalk between ER stress and other cell damage pathways, including inflammatory cytokines and apoptosis. We examined the expression of inflammatory cytokine- and ER stress-related genes by qRT-PCR, Western blotting, and immunohistochemistry (IHC) in the middle ear of C57BL/6J mice after challenge with peptidoglycan polysaccharide (PGPS), an agent inducing OM. We also evaluated the effect of the suppression of ER stress with tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor. The study revealed the upregulation of ER stress- and apoptosis-related gene expression after the PGPS treatment, specifically ATF6, CHOP, BIP, caspase-12, and caspase-3. TUDCA treatment of PGPS-treated mice decreased OM; reduced the expression of CHOP, BIP, and caspase 3; and significantly decreased the proinflammatory gene expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These results suggest that PGPS triggers ER stress and downstream proinflammatory gene expression in OM and that inhibition of ER stress alleviates OM. We propose that ER stress plays a critical role in inflammation and cell death, leading to the development of OM and points to ER stress inhibition as a potential therapeutic approach for the prevention of OM.

Potential regulatory role of circular RNA in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive type of interstitial pneumonia with unknown causes, poor prognosis and no effective therapy available. Circular RNAs (circRNAs), which serve as potential therapeutic targets and diagnostic biomarkers for certain diseases, represent a recent hotspot in the field of RNA research. In the present study, a total of 67 significantly dysregulated circRNAs were identified in the plasma of IPF patients by using a circRNA microarray. Among these circRNAs, 38 were upregulated, whereas 29 were downregulated. Further validation of the results by polymerase chain reaction analysis indicated that Homo sapiens (hsa)_circRNA_100906, hsa_circRNA_102100 and hsa_circRNA_102348 were significantly upregulated, whereas hsa_circRNA_101225, hsa_circRNA_104780 and hsa_circRNA_101242 were downregulated in plasma samples of IPF patients compared with those in samples from healthy controls. The majority of differentially expressed circRNAs were generated from exonic regions. The host genes of the differentially expressed circRNAs were involved in the regulation of the cell cycle, adherens junctions and RNA transport. The competing endogenous RNA (ceRNA) network of the circRNAs/micro(mi)RNAs/mRNAs indicated that circRNA­protected mRNA participated in transforming growth factor­ß1, hypoxia­inducible factor­1, Wnt, Janus kinase, Rho­associated protein kinase, vascular endothelial growth factor, mitogen­activated protein kinase, Hedgehog and nuclear factor κB signalling pathways or functioned as biomarkers for pulmonary fibrosis. Furthermore, luciferase reporter assays confirmed that hsa_circRNA_100906 and hsa_circRNA_102348 directly interact with miR­324­5p and miR­630, respectively, which were downregulated in IPF patients. The present study provided a novel avenue for exploring the underlying molecular mechanisms of IPF disease.

Celastrol attenuates angiotensin II mediated human umbilical vein endothelial cells damage through activation of Nrf2/ERK1/2/Nox2 signal pathway.

Angiotensin II (Ang II), as a crucial factor of endothelial dysfunction, participates in endothelial oxidative damage and inflammation, which is present in all cardiovascular disease (CVD). Celastrol, extracted from Trypterygiun wilfordii Hook F. ("Thunder of God Vine"), is a natural compound with antioxidant and anti-inflammatory activities. In this study, the protective effects of celastrol on human umbilical vein endothelial cell (HUVEC) injury induced by Ang II were observed and its mechanisms were elucidated. Compared with the control group, Ang II significantly increased nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, enhanced reactive oxygen species levels and proinflammatory cytokines, decreased antioxidant enzyme activities, and suppressed cellular viability and promoted cell apoptosis. It accomplished this via inhibition of the nuclear factor erythroid 2-related factor 2 (Nrf2), increasing the expression levels of Nox2 and AngII type 1 receptor (AT1 receptor), and inducing the phosphorylation of extracellular signal regulated kinase (ERK1/2). In contrast, celastrol effectively suppressed reactive oxygen species generation, improved endothelial cell activity, and ameliorated Ang II-mediated HUVEC injury through activation of Nrf2, inhibition of Nox2/AT1 receptor expression, and upregulated phosphorylation of ERK1/2. After treatment with brusatol, a specific inhibitor of Nrf2, the protective effects of celastrol on Ang II-induced damage in HUVECs were remarkably alleviated. Taken together, celastrol-induced activation of Nrf2 and inhibition of NADPH oxidase activity were critical for the inhibition of Ang II-mediated endothelial dysfunction, and demonstrated the potential application of celastrol in CVD therapy.

The ROS derived mitochondrial respirstion not from NADPH oxidase plays key role in Celastrol against angiotensin II-mediated HepG2 cell proliferation.

Angiotensin II (AngII) is an important factor that promotes the proliferation of cancer cells, whereas celastrol exhibits a significant antitumor activity in various cancer models. Whether celastrol can effectively suppress AngII mediated cell proliferation remains unknown. In this study, we studied the effect of celastrol on AngII-induced HepG2 cell proliferation and evaluated its underlying mechanism. The results revealed that AngII was able to significantly promote HepG2 cell proliferation via up-regulating AngII type 1 (AT1) receptor expression, improving mitochondrial respiratory function, enhancing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, increasing the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines. The excess ROS from mitochondrial dysfunction is able to cause the apoptosis of tumor cells via activating caspase3 signal pathway. In addition, the reaction between NO and ROS results in the formation of peroxynitrite (ONOO-), and then promoting cell damage. celastrol dramatically enhanced ROS generation, thereby causing cell apoptosis through inhibiting mitochodrial respiratory function and boosting the expression levels of AngII type 2 (AT2) receptor without influencing NADPH oxidase activity. PD123319 as a special inhibitor of AT2R was able to effectively decreased the levels of inflammatory cytokines and endothelial nitric oxide synthase (eNOS) activity, but only partially attenuate the effect of celastrol on AnII mediated HepG2 cell proliferation. Thus, celastrol has the potential for use in liver cancer therapy. ROS derived from mitochondrial is an important factor for celastrol to suppress HepG2 cell proliferation.

TMCO1 Is an ER Ca(2+) Load-Activated Ca(2+) Channel.

Maintaining homeostasis of Ca(2+) stores in the endoplasmic reticulum (ER) is crucial for proper Ca(2+) signaling and key cellular functions. The Ca(2+)-release-activated Ca(2+) (CRAC) channel is responsible for Ca(2+) influx and refilling after store depletion, but how cells cope with excess Ca(2+) when ER stores are overloaded is unclear. We show that TMCO1 is an ER transmembrane protein that actively prevents Ca(2+) stores from overfilling, acting as what we term a "Ca(2+) load-activated Ca(2+) channel" or "CLAC" channel. TMCO1 undergoes reversible homotetramerization in response to ER Ca(2+) overloading and disassembly upon Ca(2+) depletion and forms a Ca(2+)-selective ion channel on giant liposomes. TMCO1 knockout mice reproduce the main clinical features of human cerebrofaciothoracic (CFT) dysplasia spectrum, a developmental disorder linked to TMCO1 dysfunction, and exhibit severe mishandling of ER Ca(2+) in cells. Our findings indicate that TMCO1 provides a protective mechanism to prevent overfilling of ER stores with Ca(2+) ions.

SMND-309 promotes neuron survival through the activation of the PI3K/Akt/CREB-signalling pathway.

Context In clinical practice, the promotion of neuron survival is necessary to recover neurological functions after the onset of stroke. Objective This study aimed to investigate the post-ischaemic neuroprotective effect of SMND-309, a novel metabolite of salvianolic acid, on differentiated SH-SY5Y cells. Materials and methods SH-SY5Y cells were differentiated by pre-treating with 5 µM all-trans-retinoic acid for 6 d. The differentiated SH-SY5Y cells were exposed to oxygen-glucose deprivation (OGD) for 2 h and reperfusion (R) for 24 h to induce OGD/R injury. After OGD injury, differentiated SH-SY5Y cells were treated with or without SMND-309 (5, 10, 20 µM) for another 24 h. Cell viability was detected through Cell counting kit-8 assay and lactate dehydrogenase leakage assay. Apoptosis was evaluated through flow cytometry, caspase-3 activity assay. Changes in protein levels were assessed through Western blot. Results SMND-309 ameliorated the degree of injury in the differentiated SH-SY5Y cells by increasing cell viabilities (5 µM, 65.4% ± 4.1%; 10 µM, 69.8% ± 3.7%; 20 µM, 75.3% ± 5.1%) and by reducing LDH activity (20 µM, 2.5 fold) upon OGD/R stimulation. Annexin V-fluorescein isothiocyanate/propidium iodide staining results suggested that apoptotic rate of differentiated SH-SY5Y cells decreased from 43.8% induced by OGD/R injury to 19.2% when the cells were treated with 20 µM SMND-309. SMND-309 significantly increased the Bcl-2 level of the injured differentiated SH-SY5Y cells but decreased the caspase-3 activity of these cells by 1.6-fold. In contrast, SMND-309 did not affect the Bax level of these cells. SMND-309 evidently increased the protein expression of BDNF when Akt and CREB were activated. This function was antagonized by the addition of LY294002. Conclusion SMND-309 can prevent neuronal cell death in vitro. This process may be related to the activation of the PI3K/Akt/CREB-signalling pathway.

Blocking macrophage migration inhibitory factor activity alleviates mouse acute otitis media in vivo.

This study was to investigate the role of macrophage migration inhibitory factor (MIF) in mouse acute otitis media (AOM), we hypothesize that blocking MIF activity will relieve mouse AOM. A mouse AOM model was constructed by injecting lipopolysaccharide (LPS) into the middle ear of C57BL/6 mice through the tympanic membrane (TM). MIF levels were measured by real-time PCR (RT-PCR) and ELISA after LPS application. Normal or AOM mice were given PBS or ISO-1 (MIF antagonist) every day for 10 days and the hearing levels were determined by measuring auditory brainstem response (ABR) threshold. After the ABR test finished, H&E staining was conducted and the inflammation was also measured by detecting interleukin (IL)-1ß, tumor necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) levels with RT-PCR and ELISA. TLR-4 expression was determined by western blotting and NF-κB activation was determined by electrophoretic mobility shift assays. Compared with the normal control, MIF levels in the middle ear of LPS-induced AOM mice were significant increased. The ABR results showed that mean ABR thresholds in ISO-1 treated AOM mice were significantly reduced compared with PBS treated AOM mice since day 7, indicating that ISO-1 treatment potentially improved the hearing levels of AOM mice. H&E staining showed that ISO-1 treatment could reduce the mucosal thickness of AOM mice. In ISO-1 treated mice, TLR-4 expression and levels of IL-1ß, TNF-α and VEGF were significantly lower compared with PBS treated AOM mice. ISO-1 treatment also significantly inhibited NF-κB activation in AOM mice compared with PBS treated AOM mice. These results suggested that blocking the activity of MIF by ISO-1 could reduce the inflammation in AOM mice in which process TLR-4 and NF-κB were involved. The reduction in MIF activity is conducive to alleviate mouse AOM, which may serve as a potential therapeutic target for the treatment of AOM.

Alveolar epithelial cells undergo epithelial-mesenchymal transition in acute interstitial pneumonia: a case report.

BACKGROUND: Acute interstitial pneumonia is a rare interstitial lung disease that rapidly progresses to respiratory failure or death. Several studies showed that myofibroblast plays an important role in the evolution of diffuse alveolar damage, which is the typical feature of acute interstitial pneumonia. However, no evidence exists whether alveolar epithelial cells are an additional source of myofibroblasts via epithelial-mesenchymal transition in acute interstitial pneumonia. CASE PRESENTATION: In this report, we present a case of acute interstitial pneumonia in a previously healthy 28-year-old non-smoking woman. Chest high-resolution computed tomography scan showed bilateral and diffusely ground-glass opacification. The biopsy was performed on the fifth day of her hospitalization, and results showed manifestation of acute exudative phase of diffuse alveolar damage characterized by hyaline membrane formation. On the basis of the preliminary diagnosis of acute interstitial pneumonia, high-dose glucocorticoid was used. However, this drug showed poor clinical response and could improve the patient's symptoms only during the early phase. The patient eventually died of respiratory dysfunction. Histological findings in autopsy were consistent with the late form of acute interstitial pneumonia. CONCLUSIONS: The results in this study revealed that alveolar epithelial cells underwent epithelial-mesenchymal transition and may be an important origin of myofibroblasts in the progression of acute interstitial pneumonia. Conducting research on the transformation of alveolar epithelial cells into myofibroblasts in the lung tissue of patients with acute interstitial pneumonia may be beneficial for the treatment of this disease. However, to our knowledge, no research has been conducted on this topic.

Cisplatin upregulates MSH2 expression by reducing miR-21 to inhibit A549 cell growth.

miR-21 can act as an oncogene. MSH2 has been reported that it involved in the DNA mismatch repair (MMR) system and overexpression of MSH2 can induce cell apoptosis. We predicted that MSH2-3'-untranslated region (3'-UTR) was targeted by miR-21 using microRNA analysis softwares. To further explore the roles of miR-21 and MSH2 in A549 cells, we constructed pcDNA-GFP-msh-UTR vector (including MSH2-3'-UTR) to transfect A549 cells with miR-21, GFP positive cells were estimated under a fluorescence microscopy and by flow cytometry. We found miR-21 could obviously downregulate the expression of MSH2, which was further proved by western blotting. Moreover, we treated A549 cells with cisplatin and found that cisplatin could inhibit A549 cell growth in vitro and in vivo. We also found that cisplatin could downregulate miR-21 expression, while increase MSH2 expression in A549 cells. Our results demonstrated that cisplatin could upregulate the expression of MSH2 through downregulating miR-21 to inhibit A549 cell proliferation, which provides new gene targets for drug design or cancer therary.

Hypoxia-inducible factor and vascular endothelial growth factor pathway for the study of hypoxia in a new model of otitis media with effusion.

The hypoxia-inducible factor and vascular endothelial growth factor (HIF-VEGF) pathway in hypoxic conditions of the middle ear due to dysfunction of the eustachian tube is still unknown, but it is considered as one pathogenetic mechanism in otitis media. This study was designed to investigate the possible involvement of the HIF-VEFG pathway in otitis media with effusion induced by dysfunction of the eustachian tube. We adopted a soft palate approach to obstruct the orifice of the eustachian tube to establish otitis media in a rat model. Auditory evoked brainstem response and tympanometry were used as hearing function tests, hypoxia-related factors were examined by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of hypoxia-related proteins was detected by Western blot and immunostaining. The model of otitis media with effusion was successfully induced by cauterizing the orifice of the eustachian tube. RT-PCR showed up-regulation of hypoxia-related factors in cauterized ears. Western blot and immunostaining showed that the expression of hypoxia-related proteins in cauterized ears was increased. Hypoxia-induced vascular proliferation and an increase in permeability may be one pathogenetic mechanism of otitis media due to dysfunction of the eustachian tube.

[Toll-like receptor 2 and Toll-like receptor 4 participates in mediation of acute otitis media and mortality in pneumococcal infections in mice].

OBJECTIVE: To investigate the roles of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) in host defense against Streptococcus pneumoniae infection in the middle ear. METHODS: Wild-type (WT) C57BL/6J, TLR2-deficient (TLR2(-/-)) and TLR4-deficient (TLR4(-/-)) mice were inoculated with Streptococcus pneumoniae (1 × 10(6)CFU) through the tympanic membrane. All animals were tested the mouse ABR thresholds and tympanometry measurement before, and 1 day, 3 days and 7 days following pneumococcal challenge. Blood bacterial titer were determined by plating 50 µl volumes of 10-fold diluted blood. Histological analysis of middle ear and inner ear were performed by fixation, decalcification, embedded section, and counterstained with hematoxylin/eosin and toluidine blue staining. Semi-quantitative RT-PCR was applied to determine mRNA accumulation of TLR2 and TLR4 related genes. RESULTS: Forty of 68 TLR2(-/-) mice and twenty-one of 59 TLR4(-/-) mice showed bacteremia and died within 3 days after the pneumococcal challenge, however, only 9 of 52 WT mice died. The survive mice were shown have more severe hearing loss in the TLR2(-/-) and TLR4(-/-) mice than in the WT mice, indicated by ABR thresholds, at 3 or 7 days postinoculation. The histological pathology was characterized by effusion and tissue damage in the middle ear, and in the TLR2(-/-) and TLR4(-/-) mice, the outcome of infection became more severe at 7 days. At both 3 and 7 days after challenge, the TLR2(-/-) mice had higher blood bacterial titers than WT mice (P < 0.05). Temporal bone histopathologic change indicated that 3 days after the pneumococcal challenge, the TLR2(-/-) and TLR4(-/-) mice showed effusion and tissue damage in the middle ear, and the infection became more severe at 7 days postinoculation. TLR2(-/-) mice showed severe inflammatory cell infiltration in the cochlear, the organ of Corti showed the outer hair cells damage, the tectorial membrane swelling, degeneration of the stria vascularis, and severe loss of spiral ganglion cells; However, the WT mice was not found the cell infiltration and tissue damage in the cochlear, the organ of Corti shown normal of outer hair cells. Mast cells were not found in the middle ear mucosa of TLR2(-/-) mice, but in the TLR4(-/-) and WT mice, more mast cells were found in the middle ear mucosa of effusion ear by 3 and 7 days postchallenge. Moreover, by 3 days postchallenge, the mRNA accumulation levels of NF-κB, tumor necrosis factor alpha (TNFα), interleukin1ß, MIP-1α, MUC5AC and MUC5B were significantly lower in the ears of TLR2(-/-) mice than that in WT and TLR4(-/-) mice. CONCLUSIONS: TLR2(-/-) mice may produce relatively low levels of proinflammatory cytokines following pneumococcal challenge, thus hindering the clearance of bacteria from the middle ear and leading to sepsis and high mortality rate. This study indicated that TLR2 and TLR4 are important in the molecular pathogenesis and host response to otitis media.