Subchronic effects of perfluorooctanesulfonate exposure on inflammation in adult male C57BL/6 mice.

Previous studies indicate that exposure to perfluorooctanesulfonate (PFOS), a ubiquitous and highly persistent environmental contaminant, induces immunotoxicity in mice. However, few studies have specifically assessed the effects of PFOS on inflammation. This study utilized a standard 60-day oral exposure period to assess the effects of PFOS on the response of inflammatory cytokines [tumor necrosis factor α (TNF-α), interleukin-1 ß (IL-1ß), and interleukin-6 (IL-6)]. Adult male C57BL/6 mice were dosed daily by oral gavage with PFOS at 0, 0.0083, 0.0167, 0.0833, 0.4167, 0.8333 or 2.0833 mg/kg/day to yield a targeted Total Administered Dose (TAD) over 60 days of 0, 0.5, 1, 5, 25, 50, or 125 mg PFOS/kg, respectively. The percentage of peritoneal macrophages (CD11b+ cells) was significantly increased at concentrations ≥ 1 mg PFOS/kg TAD in a dose-dependent manner. Ex vivo IL-1ß production by peritoneal macrophages was elevated substantially at concentrations of ≥ 5 mg PFOS/kg TAD. Moreover, PFOS exposure markedly enhanced the ex vivo production of TNF-α, IL-1ß and IL-6 by peritoneal and splenic macrophages when stimulated either in vitro or in vivo with lipopolysaccharide (LPS). The serum levels of these inflammatory cytokines observed in response to in vivo stimulation with LPS were elevated substantially by exposure to PFOS. PFOS exposure elevated the expression of pro-inflammatory cytokines TNF-α, IL-1ß, IL-6, and proto-oncogene, c-myc, in the spleen. These data suggest that exposure to PFOS modulates the inflammatory response, and further research is needed to determine the mechanism of action.

Sub-chronic effect of perfluorooctanesulfonate (PFOS) on the balance of type 1 and type 2 cytokine in adult C57BL6 mice.

As a ubiquitous and highly persistent environmental contaminant, the clear mechanisms to explain any perfluorooctanesulfonate (PFOS)-induced immunotoxicity are still unknown. This study here sought to examine the ability of PFOS to potentially perturb T-helper (T(H))-1 and T(H)-2 cell cytokine secreting activities, as well as to cause shifts in antibody isotype levels, and possible mechanisms involved in PFOS-induced immunotoxicity. Adult male C57BL/6 mice were exposed to PFOS daily via gavage for 60 days [0, 0.5, 1, 5, 25, or 50 mg/kg total administered dose (TAD)]. One day after the final exposure, the ex vivo production of the T(H)1-type cytokines (IL-2 and IFN-γ), T(H)2-type (IL-4), and IL-10 cytokines by isolated splenocytes, serum levels of immunoglobulin (Ig) were assessed via ELISA or ELISPOT. The results showed that IL-4 secretion was increased at exposure ≥5 mg PFOS/kg TAD in a dose-dependent manner. PFOS exposure increased IL-10 but decreased IL-2 and IFN-γ formation markedly at 50 mg PFOS/kg TAD. Serum levels of sheep red blood cells (SRBC)-specific IgM synthesis decreased significantly with PFOS exposure in a dose-related manner; serum SRBC-specific IgG, IgG1, and IgE levels increased with 50 mg PFOS/kg TAD regimens. These results indicated that, after a long-term exposure to PFOS, a host's immune state is likely to be characterized by a shift toward a more T(H)2-like state that, in turn, may lead to enhancement of their humoral response and suppression of their cellular response at levels of upper range for occupationally exposed workers or approximately 150-fold for general human population.

The modifier protein of glyceraldehyde-3-phosphate dehydrogenase reduces free radical-mediated renal damage in a rat model of acute kidney injury.

BACKGROUND: The modifier protein (MP) of glyceraldehyde-3-phosphate dehydrogenase has been shown to promote growth of renal epithelial cells in vitro. The aim of this study was to show the in vivo effects of MP in a rat model of gentamicin-induced acute kidney injury (AKI). METHOD: MP was purified from monkey renal tubular epithelial cell line BSC-1 and confirmed by amino acid sequencing. Male Sprague-Dawley rats were divided into the following groups: normal control, gentamicin-treated, epidermal growth factor (EGF) plus gentamicin-treated, and MP plus gentamicin-treated, as well as control groups for EGF and MP alone. Levels of serum creatinine (SCr), serum and tissue lipid peroxide, nitric oxide and glutathione-S-hydrogenase for each group were measured on the 7th and 14th days of treatment. Tissue sections were studied with light microscopy. RESULTS: The gentamicin-treated group showed a marked increase in SCr compared to the normal control group. Co-treatment of gentamicin with MP and/or EGF produced similar significant decreases preventing the increase in SCr. There were also significant reductions in serum and tissue homogenate levels of lipid peroxide and nitric oxide, accompanied by an increase in the level of glutathione-S-hydrogenase, in the MP co-treated groups compared to the gentamicin-treated group. AKI was confirmed histologically in the gentamicin-treated group, with damage to the tubular epithelium recorded. This was attenuated by MP co-treatment. There were also reductions in the expression of intercellular adhesion molecule-1 and proliferating cell nuclear antigen in the MP co-treated groups. CONCLUSION: Using a gentamicin model of AKI, MP was able to reduce free radical production in kidney tissue and in the circulation, thus preventing oxidant injury and minimizing damage in renal epithelial cells.

Type 1 and Type 2 cytokines imbalance in adult male C57BL/6 mice following a 7-day oral exposure to perfluorooctanesulfonate (PFOS).

Previous studies indicate that exposure to perfluorooctanesulfonate (PFOS), a ubiquitous and highly persistent environmental contaminant induces immunotoxicity in mice. However, clear mechanisms to explain any PFOS-induced immunotoxicity are still unknown. The study here sought to examine the ability of PFOS to potentially perturb T-helper (T(H))-1 and -2 cell cytokine secreting activities, as well as to cause shifts in antibody isotype levels, as possible mechanisms involved in PFOS-induced immunotoxicity. Adult male C57BL/6 mice were given by gavage 0, 5, or 20 mg PFOS/kg/d for 7 days. One day after the final exposure, spleens from these hosts were isolated and used for analyses of the ex vivo production of T(H)1-type (interleukin-2 (IL-2), interferon-γ (IFNγ), T(H)2-type (IL-4), and IL-10 cytokines by isolated splenocytes. In addition, serum was isolated from these mice in order to assess their levels of immunoglobulin M (IgM) and IgG antibodies. In all studies, levels of the cytokines of the antibodies were quantified via enzyme-linked immunosorbent assay or enzyme-linked immunosorbent spot. The results here showed that IL-2 and IFNγ formation was reduced, but that IL-4 production increased by the 5 and 20 mg PFOS/kg/d treatments. Serum IgM levels decreased significantly (in dose-related manner) as a result of the PFOS exposures; serum IgG levels increased markedly with 5 mg PFOS/kg/d, but decreased slightly with the 20 mg PFOS/kg/d regimens PFOS exposure increased serum corticosterone levels in a dose-dependent manner. These results indicated that, after a high-dose short-term exposure to PFOS, a host's immune state is likely to be characterized by a shift toward a more T(H)2-like state that, in turn, may lead to suppression of their cellular response and enhancement of their humoral response.

[The influence of the extract of lumbricus on the production of NO and TNF-alpha by mouse MPhi and splenocytes].

AIM: To explore the effect of the abstracts of lumbricus on the secretion of NO and TNF-alpha by mouse Mphi s and splenocytes. METHODS: Murine Mphi s and spleen cell were co-cultured with various doses of lumbricus abstracts for 24 hours and then the supernate was collected. The levels of NO and TNF-alpha were detected by diazotization reaction and MTT colorimetry, respectively. RESULTS: Compared with control group, 0.1 g/L of lumbricus abstracts could increase the NO level and antagonize the inhibition of dexamethasone(Dex). 1 x 10(-4), 1 x 10(-3) g/L of lumbricus abstracts could increase TNF-alpha level and also antagonize the inhibition of Dex on the secretion of TNF-alpha by Mphi s and splenic cells. CONCLUSION: The abstracts of lumbricus can activate Mphi s and splenic cells to secrete NO and TNF-alpha and antagonize the inhibition effect of Dex on these cells.