| Objective:Through the whole animal experiment and occupational epidemiological investigation method, discussed the nano calcium carbonate might poison mechanism from two aspects of oxidative damage and inflammatory reaction.Methods:(1) Animal experiment:About100SD rats of ten weeks old, half male and half female with20rats in every group, were selected and divided randomly into blank control group, micron calcium carbonate group(200mg/kg) and nano-calcium carbonate groups which were divided into low(12.5mg/kg), middle(50mg/kg) and high(200mg/kg) three groups. Every rat was infected in nasal cavity which was five times a week for12weeks. Infected the last time, kill rat after24hours, take the heart, liver, spleen, lung, kidney, and brain tissue,"We detected the contents of malondialdehyde(MDA), total antioxidant capacity (T-AOC), high sensitivity c reactive protein (hsCRP), Fibrinogen, interleukine-6(IL-6), interleukine-8(IL-8), tumor necrosis factor a (TNF-α) in serum. And the contents of glutathione(GSH) and MDA in viscera tissue. The GSH was measured by colorimetric method, MDA was measured by associates, T-AOC was measured by colorimetric method, inflammatory cytokine levels were measured by ELISA method.(2) Population survey:119workers from a nano-calcium carbonate plant of Shanxi were selected for this study,90workers of whom as the exposure group;29administrative personal as the control group, were involved in our study. We detected the contents of (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD),(MDA), nitric oxide (NO) in serum and8-hydroxy deoxyguanosine (8OHdG) in urine. The MDA was measured by thiobarbituric acid method, SOD was measured by hydroxylamine method, NO was measured by nitrate reduction method, GSH, GSH-Px was measured by colorimetric method,8-OhdG and inflammatory cytokine levels were measured by ELISA method.Results:(1) Animal experiment:Single factor variance analysis results indicate that the content of MDA to the infected dose of nano calcium carbonate group in serum, are larger than the control group and micron calcium carbonate infected group, and the content of MDA was as the increased dose that is on the overall decline. Compared with control group and micron calcium carbonate infected group, the infected low dose of group was statistically significant (P<0.05); In the lung tissue, the content of MDA was as the increased dose that is on the overall rise to the infected dose of nano calcium carbonate group. Compared with control group, the infected dose of three groups were statistically significant (P<0.05). the infected same dose of nano and micron group differences are significant (P<0.05). The content of GSH in the lung tissue to the infected dose of nano calcium carbonate were lower than the control group and micron calcium carbonate infected group, and the difference had statistically significant (P<0.05). after pairwise comparison, we can found that compared with control group and the infected dose of micron calcium carbonate group, the infected dose of three groups were statistically significant (P<0.05); In liver tissue, the content of GSH was as the increased dose that is on the overall decline to the infected dose of nano calcium carbonate group. Compared with control group, the infected middle dose of group was statistically significant (P<0.05); In kidney tissue, the content of MDA was as the increased dose that is on the overall rise to the infected dose of nano calcium carbonate group. Compared with control group, the infected high dose of group was statistically significant (P<0.05), the infected same dose of nano and micron group differences are significant (P<0.05); In the myocardial tissue, compared with control group and micron calcium carbonate infected group, the contents of MDA and GSH were no difference statistically significant (P>0.05); In the brain, compared with control group and micron calcium carbonate infected group, the contents of MDA and GSH were no difference statistically significant (P>0.05); Compared with control group, the contents of hsCRP, Fibrinogen were as the increased dose that is on the overall rise(P>0.05), The contents of IL-6, IL-8, TNF-α were as the increased dose that is on the overall decline(P>0.05).(2) Population survey:The Rank and inspection showed that all indicators, including GSH-Px, SOD,8-OHdG, GSH, in exposure group had a decline tendency when compared with control group, and the difference of GSH was statistically significant (P<0.05). MDA and NO levels in the exposure group had a rising trend (P>0.05). In addition, multiple linear regression analysis showed GSH level in serum was negatively correlated with exposing and smorking. And the content of hsCRP, Fibrinogen, IL-8and TNF-α in the exposure was lower than the control group, while IL-6is higher than the control group, there was no statistically significant difference (P>0.05).Conclusion:1. Nano-calcium carbonate could cause a certain degree of oxidative damage to the body.2. The chronic of Nanometer calcium carbonate infected lung tissue to rat oxidative damage is the most serious, followed by the liver and kidney might also cause a certain degree of oxidative damage, but found no oxidative damage to the heart and brain tissue.3. The body exposure to nano calcium carbonate that the indicator of inflammatory cytokines has no significant difference in serum. So the toxic mechanism of nanometer calcium carbonate might have nothing to do with the inflammatory response. |
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