Background Exposure to heavy metals has potential adverse impacts on human health, and the concentration of heavy metals in abandoned mining areas may still be higher than that in general areas, so the health risk assessment in such areas cannot be ignored. Objective To explore the health risk of heavy metal exposure and the spatial distribution characteristics of associated main metals in a typical abandoned mining area. Methods Environmental samples of irrigated soil, rice, and drinking water were collected from 13 natural villages under the jurisdiction of a township in Liuzhou, Guangxi from November to December 2019, where a typical abandoned mining was located. Finally, 13 irrigation soil samples, 11 rice samples, and 13 drinking water samples were collected. The concentrations of six metals and metalloid elements in each environmental sample were detected by inductively coupled-plasma mass spectrometry (ICP-MS), including cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr), copper (Cu), and zinc (Zn). At the same time, 251 local residents were recruited for health risk assessment. Model parameters such as body weight, rice intake, and drinking water intake of local residents were obtained through field survey, and the median metal concentration of each environmental sample was taken as the risk assessment parameter of the region. The health risk of heavy metal exposure of local residents was assessed by using oral health risk assessment model of U.S. Environmental Protection Agency. The spatial distribution characteristics of health risks associated with heavy metals were evaluated by empirical Bayes interpolation method using Geographic Information System (GIS) technology. Results The positive rates of Cd, As, Pb, Cr, Cu, and Zn in the irrigated soil samples were 100.00%. The positive rate of Pb was 63.64% in the rice samples, while the rates of other metals were 100.00%. The positive rates of Cd, As, Pb, Cr, Cu, and Zn in the drinking water samples were 53.85%, 76.92%, 92.31%, 15.38%, 84.62%, and 100.00%, respectively. The results of non-carcinogenic risk assessment of oral exposure to heavy metals suggested that the contribution of heavy metals causing non-carcinogenic risk from high to low was As (70.52%) > Cd (18.03%) > Zn (6.63%) > Cu (4.12%) > Pb (0.64%) > Cr (0.06%), and the corresponding estimated non-carcinogenic risk values were 3.54 × 10⁰, 9.05 × 10⁻¹, 3.33 × 10⁻¹, 2.07 × 10⁻¹, 3.23 × 10⁻², and 5.42 × 10⁻⁴, respectively. The results of carcinogenic risk assessment of oral exposure to heavy metals suggested that the contribution of studied metals from high to low was Cd (87.00%) > As (10.24%) > Cr (2.60%) > Pb (0.16%), and the estimated carcinogenic risks were 4.35× 10⁻³, 5.12 × 10⁻⁴, 1.30 × 10⁻⁴, and 3.08 × 10⁻⁷, respectively. Rice was the leading media associated with non-carcinogenic risk and carcinogenic risk (99.4% and 99.8% respectively). The spatial distribution characteristics of GIS showed no obvious regularity in the distribution of As in irrigated soil, rice, and drinking water. In rice and irrigated soil, the content of Cd in the villages adjacent to the mining area was obviously higher than that in the other villages, while in drinking water, the content in the villages far away from the mining area was higher. Conclusion As and Cd are the main heavy metals that increase the health risk of local residents in a typical abandoned mining area, and the distribution characteristics of the two heavy metals in different environmental media are not completely consistent.

ObjectiveTo observe the effect of Banxia Xiexintang containing intestinal absorption solution （BXCIAS） on migration and invasion of polymorphonuclear myeloid-derived suppressor cells （PMN-MDSCs） in gastric cancer microenvironment. MethodThe complex solution （containing 0.63 g·mL^-1 crude drug） was prepared. Gastric cancer cells were subjected to non-contact co-culture with PMN-MDSCs in Transwell chamber to create gastric cancer microenvironment. Cell counting kit-8 （CCK-8） assay was used to screen the optimal intervention concentration and time of BXCIAS on PMN-MDSCs for subsequent experiment. The blank group， model group， FAK inhibitor group， and BXCIAS groups （26%， 18%， and 10%） were designed. Scratch assay and Transwell assay were employed to detect the migration and invasion ability of PMN-MDSCs， and enzyme-linked immunosorbent assay （ELISA） to measure the expression of vascular endothelial cell growth factor （VEGF） and matrix metalloproteinase-9 （MMP-9） in tumor microenvironment. The expression levels of PMN-MDSCs pathway-related proteins FAK， phosphorylated （p）-FAK， protein tyrosine kinase （Src）， and p-Src were detected by Western blot. ResultThe inhibition rates of PMN-MDSCs by 5%， 50%， 75%， and 100% BXCIAS at 48 h were higher than those at 24 h （P<0.05， P<0.01）. The inhibition rate of PMN-MDSCs by 50% BXCIAS at 72 h was lower than that at 48 h （P<0.01）， and the inhibition rates by 5% and 100% BXCIAS at 72 h were higher than those at 48 h （P<0.05， P<0.01）. There was no significant difference in the inhibition rate by other concentration levels at 48 h. The half-maximal inhibitory concentration （IC₅₀） at 48 h was 18.09%， indicating that 18% BXCIAS and 48 h were the optimal concentration and time， respectively. The migration distance of PMN-MDSCs was large （P<0.01）， and the number of migrating and invading cells increased （P<0.01） in the mode group compared with those in the blank group. Compared with model group， FAK inhibitor and BXCIAS at different concentration decreased the migration distance of PMN-MDSCs （P<0.01）， and the number of migrating and invading cells （P<0.01）， especially the 26% BXCIAS （P<0.01）. The expression of PMN-MDSCs pathway-related proteins FAK， p-FAK， Src and p-Src （P<0.01） and the expression of VEGF and MMP-9 （P<0.01） were higher in the model group than in the blank group. Compared with model group， FAK inhibitor and BXCIAS （26%， 18%， 10%） decreased the expression of FAK， p-FAK， and Src （P<0.01）， and FAK inhibitor and 18% BXCIAS reduced the expression of p-Src （P<0.01）， and the expression of VEGF and MMP-9 （P<0.01）. ConclusionBXCIAS can inhibit the migration and invasion of PMN-MDSCs by down-regulating the expression of FAK， p-FAK， Src， and p-Src proteins in the FAK signaling pathway of PMN-MDSCs in gastric cancer microenvironment.

ObjectiveTo observe the effect of Banxia Xiexintang （BXT）-containing intestinal absorption solution on the apoptosis of polymorphonuclear myeloid-derived suppressor cells （PMN-MDSCs） in gastric cancer microenvironment. MethodBXT-containing intestinal absorption solution was prepared， and gastric cancer cells and PMN-MDSCs were non-contact co-cultured in Transwell chamber to establish gastric cancer microenvironment. Cell counting kit-8 （CCK-8） assay was used to screen the optimal intervention concentration and time of 0-100% BXT-containing intestinal absorption solution prepared by 0.63 g·mL^-1 reconstitution solution. Cells were classified into blank group， model group， oxaliplatin group （10 mg·L^-1）， and BXT （26%， 18%， 10% BXT-containing intestinal absorption solution） group， and the apoptosis of PMN-MDSCs was detected by flow cytometry. The expression of apoptosis-related B-cell lymphoma 2 （Bcl-2）， Bcl-2-associated X protein （Bax）， and cysteine-aspartic acid protease-3 （Caspase-3） in PMN-MDSCs was detected by Western blot. ResultAfter treatment for 24 h and 48 h， the PMN-MDSCs-inhibiting rate was increased by 5%， 50%， 75%， and 100% BXT-containing intestinal absorption solution compared with that in the blank group （P<0.05， P<0.01）. At 72 h， the PMN-MDSCs-inhibiting rate by 50% BXT-containing intestinal absorption solution was lower than that at 48 h （P<0.01）， and the PMN-MDSCs-inhibiting rate by 5%， 75%， and 100% BXT-containing intestinal absorption solution showed no significant difference from that at 48 h. Moreover， the half-maximal inhibitory concentration （IC₅₀） at 48 h was 18.40%. Thus， 18% BXT-containing intestinal absorption solution and 48 h were the optimal intervention concentration and time. The survival rate of PMN-MDSCs in model group was higher than that in the blank group （P<0.05）， and the apoptosis rate was lower than that in the blank group （P<0.05）. Compared with model group， BXT containing intestinal absorption solution lowered the survival rate and raised apoptosis rate of PMN-MDSCs （P<0.05）， particularly the 26% BXT-containing intestinal absorption solution （P<0.05）. The expression of Bax and Caspase-3 in PMN-MDSCs was lower in the model group than in the blank group （P<0.05）， and the expression of Bcl-2 was higher in the model group than in the blank group （P<0.05）. The expression of Caspase-3 in PMN-MDSCs increased （P<0.05） and the expression of Bcl-2 decreased （P<0.05） in oxaliplatin group and BXT group compared with those in the model group. The expression of Bax rose in oxaliplatin group and BXT group （10% BXT-containing intestinal absorption solution） （P<0.05）. ConclusionBXT can induce the apoptosis of PMN-MDSCs by regulating the expression of apoptosis-related proteins Bax， Caspase-3， and Bcl-2 in gastric cancer microenvironment.