Innovative accumulative risk assessment strategy of co-exposure of As and Pb in medical earthworms based on in vivo-in vitro correlation.

Recent studies on risks assessment of heavy metal(loid) are usually based on their total concentrations. Nevertheless, such an analysis does not assess their real amounts absorbed by human body. To scientifically assess the health risks, in this study medical earthworms were analyzed for relative bioavailability (RBA) of arsenic (As) and lead (Pb) using a multiple gavage mouse model with liver, kidneys, brain, and leg bones as biomarkers for the first time. Metal(loid) bioaccessibility was determined using in vitro physiologically based extraction (PBET) assay. We are the first to develop a novel accumulative health risk assessment strategy by combinational analyzing bioavailability of heavy metal(loid) levels to calculate target organ toxicity dose (TTD) modification of the HI and total cancer risk (TCR), which has capacity to evaluate the health risks of co-exposure of Pb and As in medical earthworms. As a result, As-RBA ranged from 7.2% to 45.1%, and Pb-RBA ranged from 16.1% to 49.8%. Additionally, As and Pb bioaccessibility varied from 6.7% to 48.3% and 7.8% to 52.5%, respectively. Moreover, strong in vivo-in vitro correlations (IVIVCs) were observed between metal-RBA and bioaccessibility, indicating the robustness of the in vitro PBET assay to predict metal-RBA in medical earthworms. The refined accumulative assessment strategy revealed that when adjusted by heavy metal(loid) bioavailability, the TTD modification of HI method typically exhibited an acceptable health risk caused by the co-exposure of Pb and As for cardiovascular, hematological, neurological, and renal system. The TCR levels associated with exposure to Pb and As due to the ingestion of medical earthworms were also acceptable after adjustment by bioavailability. Collectively, our innovation on accumulative risk assessment based on in vivo-in vitro correlation provides a novel approach engaging in assessing the risks due to co-exposure of As and Pb in medical earthworms.

[Synergistic apoptotic effect of the combination of diosgenin and TRAIL on non-small-cell lung cancer cell line A549 evaluated with the Chou-Talalay method].

This study is to investigate the apoptotic induction effect of the combination of diosgenin and TNF-related apoptosis-inducing ligand (TRAIL) on non-small-cell lung cancer cell line A549 by using the Chou-Talalay method, and observe the mechanism of the combination. The apoptotic effect of diosgenin or TRAIL alone and their combination on A549 and normal cell line 293T proliferation was measured by MTT assay. Chou-Talalay method was used to evaluate the combination effect. Apoptosis was examined by Hoechst 33342 staining and flow cytometry assay. Western blotting detects the expression of apoptosis-associated proteins. Diosgenin or TRAIL alone can inhibit proliferation ofA549 in a concentration-dependent manner. According to the Chou-Talalay method, when f(a) = 0.1, CI > 1, when f(a) > 0.1, CI < 1. Combined with TRAIL, the IC50 of diosgenin decreases from 21.864 to 14.810 micromol x L(-1) (P < 0.05) on A549 cells. But for 293T cells, IC50 of diosgenin does not change significantly. As with Hoechst 33342 staining and flow cytometry assay, the apoptosis ratios also increased in the combination group. At protein expression level, combination-treated group displays increased Caspase-8, Caspase-9, Bid, Caspase-3 activation and PARP cleavage, significantly decreased Bcl-2 and increased Bax expression, and MAPK pathways were activated. The combination of diosgenin and TRAIL has synergistic effect on A549 cells.