RESUMO
Objectives To investigate the adverse effect of manganese exposure on the iron metabolism in peripheral blood of professionally exposed workers. Methods The manganese in air was collected using personal air sampler, and the time weighted average (TWA) concentration of exposure to manganese was then calculated. The subjects were divided into exposure group (n=85) and control group (n=80) based on the exposure doses they received. The concentrations of iron and manganese in the plasma and blood cells of the subjects were determined using flame atomic absorption detector and graphite furnace atomic absorption detector. Serum ferritin, transferrin, transferrin receptor and total iron binding capacity were determined using enzyme linked immunosorbent assay. Results The manganese contents in both plasma and blood cells were much higher in exposure group than in control group (P0.05). It was revealed by linear correlation analysis that no linear correlation existed between the professional exposure time and manganese and iron contents in both plasma and blood cells, serum ferrin, transferrin, transferring receptor and total iron binding capacity (P>0.05). Conclusion The long-term exposure to high dose manganese may result in an imbalance of iron metabolism in the peripheral blood in exposed population, manifesting a decrease of plasma iron and serum transferrin receptors, and an increase of serum transferrin.
RESUMO
Objective To investigate the p53,Bax,bcl-2 gene in NaAsO2-induced human embryonic lung fibroblasts(HELF)apoptosis.Methods HELF was divided into HELF cells transfected with p53 plasmid(p53 group),HELF cells transfected with PC plasmid(PC group)and normal cultured HELF cells(normal group).The mRNA expression of p53,Bax and bcl-2 gene was detected by real-time PCR,the protein expression of p53,Bax and bcl-2 was assessed by immunohistochemical SABC and the cell apoptosis of HELF was detected by flow cytometry(FCM),in a 6-well plate and cultured for 48 hours,which was exposed to different doses(0,3,9,15mmol/L)NaAsO2 for 24 hours.Results The p53 gene mRNA expression level of p53 group(0.51±0.29)was lower than that of the normal group and PC group [ (1.00 ± 0.20), (1.32 ± 0.26), all P < 0.05 ]. The p53 protein expression level of p53 group(4.10 ± 1.20) was lower than the PC group and normal group[ (8.00 ± 1.63), (7.90 ± 1.79), allP < 0.05]. In p53 group, PC group, normal group exposed to 0,3,9,15 mmol/L NaAsO2 doses, the apoptotic rate [(0.57 ± 0.28)%, (22.91 ± 4.86)%, (40.05 ± 3.93)%, (44.87 ± 3.58)%; (0.65 ± 0.24)%, (14.09 ± 3.49)%,(20.31 ± 3.66)%, (32.42 ± 3.63)%; (0.56 ± 0.25)%, (12.14 ± 3.70)%, (19.61 ± 3.63)%, (30.43 ± 2.83)%], Bax mRNA expression level[(12.73 ± 3.96), (25.12 ± 6.42), (104.96 ± 26.77), (154.04 ± 30.52); (14.63 ± 3.57),(36.75 ± 3.67), (272.26 ± 66.11), (846.12 ± 243.36); (14.75 ± 5.65), (37.22 ± 11.27), (278.51 ± 37.42),(861.67 ± 369.29) ], Bax protein expression level [ ( 15.07 ± 0.83 ) %, ( 23.79 ± 3.99 ) %, (38.51 ± 1.58 ) %, (53.86 ±1.74)%;(15.43 ± 1.45)%,(36.11 ± 1.37)%, (56.86 ± 1.97)%, (76.09 ± 2.01)%; (15.20 ± 1.03)%,(35.25 ±1.09)%, (55.56 ± 2.17)%, (74.48 ± 2.85)% ] was respectively increased in a dose-dependent manner with the increased concentration of NaAsO2(all P < 0.05). The bel-2 mRNA expression level [ (443.00 ± 244.47), (156.79 ±53.18), (62.13 ± 13.66), (23.10 ± 6.44); (420.55 ± 110.77), (48.15 ± 10.02), (14.91 ± 6.53), (7.54 ± 2.62);(577.75 ± 123.22), (49.68 ± 10.11), (12.41 ± 1.28), (7.22 ± 1.89)], bcl-2 protein expression level[(47.20 ±3.77)%, (41.80 ± 2.94)%, (36.00 ± 2.36)%, (29.00 ± 2.91)%; (45.90 ± 4.15)%, (35.70 ± 2.77)%, (29.80 ±2.78)%, (24.80 ± 2.66)% ; (46.70 ± 3.47)%, (36.20 ± 2.90)%, (30.10 ± 3.21)%, (25.10 ± 2.28)% ] wasdecreased in a dose-dependent manner with the increased concentration of NaAsO2(all P < 0.05 ). In 3,9,15 mmol/L NaAsO2, apoptotic rate of p53 group, mRNA expression of bcl-2, protein expression of bcl-2 was higher than that ofnormal group and PC group, respectively (all P < 0.05), but mRNA expression of Bax, protein expression of Bax was respeetivelylower than that normal group and the PC group(P < 0.05 ). Conclusion p53 gene reduced the apoptosis induced by NaAsO2 in HELF, possibly by changing the apoptosis pathway.