| Objective: The research and application of plant growth regulator is one of the main measurements of increasing production and over production in agriculture in the new century. Phthalanillic acid is one of the new plant growth regulators and widely used in agriculture in recent years. Because it belongs to low toxicity pesticide, the reports of the health hazard of phthalanillic acid have been rare so far at home and abroad. And the toxicity effect on the immune system has not been reported. Based on BALB/c mice as animal model in the experiment, we assessed the immunotoxicity of phthalanillic acid through three respects, including immune organs, immune cells and immune molecules. At the same time, we preliminarily studied the oxidative damage on main immune organs, including the spleen and thymus. Our aim was to offer scientific reference to proper usage of phthalanillic acid and to protect the health of famers and workers. To explore whether phthalanillic acid has effects on BALB/c mice immune system. To further provide scientific reference for immunotoxicity and mechanism of phthalanillic acid. And to find sensitive index of immunological effects and offer experimental data for toxicological safety evaluation.Methods: 1. 60 BALB/c mice were randomly divided into four groups. The mice in control group were given soybean oil. The mice were given phthalanillic acid at dose of 30mg/kg, 100mg/kg and 300mg/kg through gavage respectively for continuous 28 days. There were 15 mice per group. Observe the activity of mice during the contamination. After 24 hours of the last contamination, collect blood by pick out theeyeball to analyze. 2.Execute and dissect the mice to weigh the main organs and calculate the organ coefficient. Do histopathological examination on thymus and spleen. 3.Prepare cell suspension of thymus and spleen respectively to analyze cell multiplication of lymphocyte. 4.Prepare tissue homogenate to measure the content of IL-4 and IFN-?. 5.Use the method of TBA to measure the content of MDA. DTNB reaction was used to measure the level of GSH-Px. And Test the activity of T-SOD by hydroxylamine assay method.Results: 1.Results of general toxicity: The color of spleens in high-dose group was darken and the volume increased. The organ coefficient of high-dose group(0.38±0.04)% was bigger than that in control group(0.29±0.03)%. There was no different between other dose groups and control group. The level of WBC, HGB and PLT in blood: The level of WBC(3.55±1.63)*109/L in high-dose group was lower than that in the control group(4.49±1.20)*109/L. The level of PLT(455.54±81.37)*109/L in high-dose group was also lower than that in the control group(531.87±93.92)*109/L, P < 0.05. 3. Pathological alteration: As the result of HE dyeing showed, there was no obvious changes in the pathology of thymus. Compared with control group, there was an amount of inflammatory cell infiltration in the pathology of spleen in middle-dose group and high-dose group. There was trabecular venous distention in high-dose group. 2. Lymphocytes proliferation test: The reproductive capacity of thymus T cells induced by Con A in high-dose group(0.084±0.004) was lower than that in control group(0.112±0.012). The reproductive capacity of spleen T cells induced by Con A in middle-dose group and high-dose group(0.125±0.047,0.125±0.031) was lower than that in control group(0.174±0.050), P < 0.05. The reproductive capacity of thymus and spleen B cells induced by LPS in every group was almost same. 3. The content of IFN-? and IL-4: The levels of immune factors of IFN-? andIL-4(843.31±14.81 pg/ml and 1174.44±7.32 pg/ml) in thymus were both significantly higher than that in control group(P < 0.05). There were no apparent difference of IFN-? and IL-4 in spleen in every group. Compared with the contral group, the ratio of IFN-? and IL-4 was different in low-dose group, but the ratio in high-dose group was undifferentiated. 4.The results of oxidative indexes:(1)The content of MDA in spleen in the dose group of 100 mg/kg and 300 mg/kg was higher than that in the control group.(2)Compared with the control group, the activity of T-SOD was not obviously changed.(3)The activity of GSH-Px in high-dose group(292.43±61.66) U/mgport was lower than that in control group(197.21±78.27) U/mgport. There were differences between thymus and spleen in the oxidative system.Conclusion: From our experiment, we knew that 100 mg/kg phthalanillic acid could make the spleen injury. 300 mg/kg phthalanillic acid could inhibit the multiplication of T cells in thymus and spleen. 30 mg/kg phthalanillic acid could rise the level of immune factor IFN-? and IL-4 in thymus. We could conclude that the subacute exposure to phthalanillic acid made BALB/c mice immunologic injury to varying degrees and disturbed the balance of oxidative-antioxidant system. From that we knew the phthalanillic acid has immunotoxicity effects on organism and oxidative stress may be the toxic mechanism. By comprehensive assessments on immune organs, immune cells and immune factors, we found that immune factors were the most sensitive index. |
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