Qi-Xing Zhu

Trichloroethylene induced cutaneous irritation in BALB/c hairless mice: Histopathological changes and oxidative damage

Trichloroethylene (TCE), a colorless and volatile organic solvent, has long been a major chemical hazard during occupational exposure because of its extensive use in industry. Exposure to TCE can cause significant skin lesions, but the effect of TCE on skin irritation has received little attention. We therefore investigated the effect of TCE on skin irritation and oxidative stress using hairless mice. BALB/c hairless mice were subjected to acute and cumulative topical TCE treatment. Skin reactions were evaluated by visual inspection, histopathology examined by microscopy and oxidative stress assessed by measurement of malondialdehyde (MDA) levels, superoxide dismutase (SOD) activities and nitric oxide (NO) production. Under acute and cumulative TCE irritation, the skin developed erythema and edema, and the predominant histopathological features were hyperkeratosis, spongiosis and inflammatory cell infiltrates. In parallel to these morphological changes, acute TCE irritation also concentration-dependently increased MDA levels and inhibited SOD activities of the skin. However, in cumulative irritation, the MDA levels and SOD activities were initially elevated with increased TCE concentrations, but thereafter reduced with further concentration increments; the linear dose-response relationship was not preserved. TCE also concentration-dependently increased NO production both in acute and cumulative irritation. These results suggest that TCE is capable of producing skin irritation effect in vivo, with histopathological changes characterized by hyperkeratosis, spongiosis and inflammatory cell infiltrates. Moreover, oxidative stress may be associated with the clinical manifestations and histopathological abnormalities in TCE-induced skin irritation.

N‐acetylcysteine attenuates subcutaneous administration of bleomycin‐induced skin fibrosis and oxidative stress in a mouse model of scleroderma

Several lines of evidence suggest that the generation of reactive oxygen species (ROS) is of major importance in the pathogenesis of scleroderma, and thus antioxidant therapy may be useful for patients with an impaired oxidative defence mechanism.

Complement C3a binding to its receptor as a negative modulator of Th2 response in liver injury in trichloroethylene-sensitized mice.

Trichloroethylene (TCE) is a major occupational health hazard and causes occupational medicamentosa-like dermatitis (OMLDT) and liver damage. Recent evidence suggests immune response as a distinct mode of action for TCE-induced liver damage. This study aimed to explore the role of the key complement activation product C3a and its receptor C3aR in TCE-induced immune liver injury. A mouse model of skin sensitization was induced by TCE in the presence and absence of the C3aR antagonist SB 290157. Liver function was evaluated by alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in conjunction with histopathological characterizations. C3a and C3aR were detected by immunohistochemistry and C5b-9 was assessed by immunofluorescence. IFN-γ and IL4 expressions were determined by flow cytometry and ELISA. The total sensitization rate was 44.1%. TCE sensitization caused liver cell necrosis and inflammatory infiltration, elevated serum ALT and AST, expression of C3a and C3aR, and deposition of C5b-9 in the liver. IFN-γ and IL-4 expressions were up-regulated in spleen mononuclear cells and their serum levels were also increased. Pretreatment with SB 290157 resulted in more inflammatory infiltration in the liver, higher levels of AST, reduced C3aR expression on Kupffer cells, and decreased IL-4 levels while IFN-γ remained unchanged. These data demonstrate that blocking of C3a binding to C3aR reduces IL4, shifts IFN-γ and IL-4 balance, and aggravates TCE-sensitization induced liver damage. These findings reveal a novel mechanism whereby modulation of Th2 response by C3a binding to C3a receptor contributes to immune-mediated liver damage by TCE exposure.

Protective Effects of Ginkgo biloba Leaf Extracts on Trichloroethylene-Induced Human Keratinocyte Cytotoxicity and Apoptosis

The objective of this study was to assess the protective effects of Ginkgo biloba leaf extracts (EGb) on trichloroethylene (TCE)-induced cytotoxicity and apoptosis in normal human epidermal keratinocytes (NHEK). Cytotoxicity was determined by neutral red uptake, and lipid peroxidation of the cells was assessed by malondialdehyde (MDA) and superoxide dismutase (SOD). Electron microscopy and flow cytometry were used to evaluate NHEK apoptosis. Treatment of NHEK with various concentrations of TCE caused a substantial decrease in cell viability. NR50 from the cytotoxicity assay was found to be 4.53 mM. TCE caused an increase in MDA, while an inhibition of SOD activity, in a concentration-dependent manner. Electron microscopic examination revealed typical morphologic changes of apoptosis in cells treated with TCE. Incubation of NHEK with TCE (0, 0.125, 0.5, 2.0 mM) for 4 h increased the proportion of apoptotic cells from control of 19.23% to nearly 44.35%. Pretreatment of EGb at 10–200 mg/l dose-dependently attenuated the cytotoxic effect of TCE, prevented TCE-induced elevation of lipid peroxidation and decline of antioxidant enzyme activities. Similar inhibition by EGb on TCE-mediated NHEK apoptosis was also observed. These results suggest that EGb can protect NHEK from TCE-induced cytotoxicity and apoptosis, which may be associated with the superoxide scavenging effect and enhancement of antioxidant enzyme activities.

Complement Activation and Liver Impairment in Trichloroethylene-Sensitized BALB/c Mice:

Our recent studies have shown that trichloroethylene (TCE) was able to induce multisystem injuries in the form of occupational medicamentosa-like dermatitis, including skin, kidney, and liver damages. However, the role of complement activation in the immune-mediated liver injury is not known. This study examined the role of complement activation in the liver injury in a mouse model of TCE-induced sensitization. Treatment of female BALB/c mice with TCE under specific dosing protocols resulted in skin inflammation and sensitization. Skin edema and erythema occurred in TCE-sensitized groups. Trichloroethylene sensitization produced liver histopathological lesions, increased serum alanine aminotransferase, aspartate transaminase activities, and the relative liver weight. The concentrations of serum complement components C3a-desArg, C5a-desArg, and C5b-9 were significantly increased in 24-hour, 48-hour, and 72-hour sensitization-positive groups treated with TCE and peaked in the 72-hour sensitization-positive group. Depositions of C3a, C5a, and C5b-9 into the liver tissue were also revealed by immunohistochemistry. Immunofluorescence further verified high C5b-9 expression in 24-hour, 48-hour, and 72-hour sensitization-positive groups in response to TCE treatment. Reverse transcription–polymerase chain reaction detected C3 messenger RNA expression in the liver, and this was significantly increased in 24-hour and 48-hour sensitization-positive groups with a transient reduction at 72 hours. These results provide the first experimental evidence that complement activation may play a key role in the generation and progression of immune-mediated hepatic injury by exposure to TCE.

The Effect of Intravenous Immunoglobulin Combined with Corticosteroid on the Progression of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Meta-Analysis.

Background Intravenous immunoglobulin (IVIG) treatment is commonly used to treat Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) with controversial therapeutic effect. Methods We conducted a comprehensive meta-analysis through combining the published eligible studies to evaluate the effectiveness of IVIG on SJS and TEN treatment. Results A total of 26 studies were selected from public available databases. The combination of IVIG and corticosteroid markedly reduced the recovery time (by 1.63 days, 95% CI: 0.83–2.43, P < 0.001), compared with solo corticosteroid group. The favorable effects were greater in Asian (2.19, 95% CI: 1.41–2.97, P < 0.001), TEN (2.56, 95% CI: 0.35–4.77, P = 0.023) and high-dose IVIG treated individuals (1.78, 95% CI: 0.42–3.14, P = 0.010). The hospitalization length reduced by 3.19 days (95% CI: 0.08–6.30, P = 0.045), though the outcome was proven to be unstable. We found heterogeneities, which sources were probably regional factors. Besides, IVIG was inclined to decrease SJS/TEN mortality (SMR: 0.84, 95% CI: 0.66–1.08, P = 0.178). This impact was possibly more profound when patients were treated with high dose IVIG (SMR: 0.74, 95% CI: 0.50–1.08, P = 0.116), or when patients were diagnosed as TEN (SMR: 0.68, 95% CI: 0.45–1.01, P = 0.058). Conclusions Our current meta-analysis suggests that IVIG combined with corticosteroid could reduce recovery time for SJS and TEN. This effect is greater among Asian patients. Whereas, its impact on reducing mortality is not significant.

Complement C5a–C5aR interaction enhances MAPK signaling pathway activities to mediate renal injury in trichloroethylene sensitized BALB/c mice

We have previously shown complement activation as a possible mechanism for trichloroethylene (TCE) sensitization, leading to multi‐organ damage including the kidneys. In particular, excessive deposition of C5 and C5b‐9‐the membrane attack complex, which can generate significant tissue damage, was observed in the kidney tissue after TCE sensitization. The present study tested the hypothesis that anaphylatoxin C5a binding to its receptor C5aR mediates renal injury in TCE‐sensitized BALB/c mice. BALB/c mice were sensitized through skin challenge with TCE, with or without pretreatment by the C5aR antagonist W54011. Kidney histopathology and the renal functional test were performed to assess renal injury, and immunohistochemistry and fluorescent labeling were carried out to assess C5a and C5aR expressions. TCE sensitization up‐regulated C5a and C5aR expressions in kidney tissue, generated inflammatory infiltration, renal tubule damage, glomerular hypercellularity and impaired renal function. Antagonist pretreatment blocked C5a binding to C5aR and attenuated TCE‐induced tissue damage and renal dysfunction. TCE sensitization also caused the deposition of major pro‐inflammatory cytokines IL‐2, TNF‐α and IFN‐γ in the kidney tissue (P < 0.05); this was accompanied by increased expression of P‐p38, P‐ERK and P‐JNK proteins (P < 0.05). Pretreatment with the C5aR antagonist attenuated the increase of expression of P‐p38, P‐ERK and P‐JNK proteins (P < 0.05) and also consistently reduced the TCE sensitization‐induced increase of IL‐2, TNF‐α and IFN‐γ (P < 0.05). These data identify C5a binding to C5aR, MAP kinase activation, and inflammatory cytokine release as a novel mechanism for complement‐mediated renal injury by sensitization with TCE or other environmental chemicals. Copyright

The association of mannose-binding lectin genetic polymorphisms with the risk of rheumatoid arthritis: a meta-analysis

Abstract Objective: To better understand the risks of rheumatoid arthritis (RA) and certain subsets conferred by mannose-binding lectin (MBL2) polymorphisms in different races. Materials and methods: Eighteen articles (4810 cases and 4585 controls) were identified from the latest literature search carried out in May 2014 using PubMed, Web of Science, Wanfang Database (Chinese) and Chinese National Knowledge Infrastructure. Three single nucleotide polymorphisms of codon 52, 54 and 57, exonic and extended genotypic variance in MBL2 were synthesized. Results: Codon 54 mutation of MBL2 was unlikely to be a risk factor for RA in overall population, but turned out to be deleterious in East Asian (four studies with 523 cases and 647 controls, pooled OR:1.63, 95% CI: 1.23–2.17). Codon 54 mutation increased the risk of seropositive and erosive RA by 44% and 162%, respectively (three studies with 281 cases and 358 controls, 95% CI: 1.01–2.05; 3 studies with 180 cases and 499 controls, 95% CI: 1.77–3.88). Furthermore, those risks were relatively stronger when restricted in East Asian (two studies with 147 cases and 244 controls, pooled OR: 1.85, 95% CI: 1.19–2.87; 2 studies with 170 cases and 291 controls, pooled OR: 2.78, 95% CI: 1.85–4.20). No remarkable associations were detected regarding codon 52, 57, exon 1 and extended genotype of MBL2. Conclusions: Polymorphism of codon 54 in MBL2 may predispose to RA, especially seropositive or erosive RA, which East Asian appears to be more vulnerable.

Bleomycin-induced epithelial–mesenchymal transition in sclerotic skin of mice: Possible role of oxidative stress in the pathogenesis

Epithelial-mesenchymal transition (EMT) derived myofibroblasts are partly responsible for the increased collagen synthesis and deposition that occur in tissue fibrosis; however EMT occurrence in skin fibrosis and its mechanism remain unknown. The aim of this study was to investigate whether epithelial cells undergo EMT and determine the role of oxidative stress in this process. BALB/c mice were subcutaneously injected with bleomycin (BLM) or phosphate buffer saline (PBS) into the shaved back daily for 2, 3, and 4weeks. Skin collagen deposition was evaluated by histopathology and Western blotting. EMT characteristics in the skin were determined by histopathology and immunofluorescent staining for E-cadherin and vimentin, which were further evaluated by Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR). To investigate the role of oxidative stress in EMT, the antioxidant N-acetylcysteine (NAC) was intraperitoneally (100mg/kg body weight/day) injected daily for 3weeks. The epithelial suprabasal cells were detached from the basement membrane zone (BMZ) in the sclerotic skin treated with BLM. Immunofluorescent staining indicated vimentin-positive epithelial cells frequently occurring in the thickened epidermis of BLM-treated mice. Western blotting and RT-PCR showed that the expression of E-cadherin was significantly decreased but that of vimentin significantly increased in the skin treated with BLM. NAC attenuated BLM induced oxidative damage, changes in E-cadherin and vimentin expressions and collagen deposition in the sclerotic skin of mice. This study provides the first evidence that BLM induces the EMT of the epithelial cells superficial to the basement membrane zone in the skin fibrosis. Oxidative stress may contribute, at least in part, to BLM induced EMT and skin fibrosis in mice.

Gestational and lactational exposure to low-dose bisphenol A increases Th17 cells in mice offspring.

Increasing evidence demonstrates that perinatal exposure to Bisphenol A (BPA) can cause immune disorders throughout the life span. However, the biological basis for these immune disorders is poorly understood and the effects of exposure to BPA on Th17 development are unknown. The present study sought to characterize alterations of Th17 cells in childhood and adulthood following gestational and lactational exposure to environmentally relevant low-dose of BPA and the underlying mechanisms. Pregnant dams were exposed to BPA (10, 100 or 1000nM) via drinking water from gestational day (GD) 0 to postnatal day (PND) 21. At PNDs 21 and 42, offspring mice were anesthetized, blood was obtained for cytokine assay and spleens were collected for Th17 cell frequency and RORγt mRNA expression analysis. Perinatal exposure to low-dose BPA resulted in a dose-dependent and gender-specific persistent rise in Th17 cells accompanied by an increase of RORγt mRNA expression in the offsprings. The contents of major Th17 cell-derived cytokines (IL-17 and IL-21) and those essential for Th17 cell differentiation (IL-6 and IL-23) were also increased compared to those in controls. These changes were more pronounced in female than in male offsprings. However, perinatal exposure to low-dose BPA had little effect on serum TGF-β, another key regulator for Th17 cell development. Our results suggest that gestational and lactational exposure to a low-dose of BPA can affect Th17 cell development via an action on its transcription factor and the regulatory cytokines. These findings provide novel insight into sustained immune disorders by BPA exposure during development.