氯氰菊酯和甲基对硫磷混配对大鼠内分泌和免疫系统的影响——II.联合作用

Effects of mixed cypermethrin and methylparathion on endocrine hormone levels and immune functions in rats: II. interaction

目的探讨农药氯氰菊酯(Cyp)和甲基对硫磷(MP)混配对大鼠生殖激素、甲状腺激素和免疫功能的联合作用。方法健康2月龄Wistar大鼠80只,按3×2析因设计随机分为8组(雌雄各4组)。以1/30LD50剂量隔日灌胃1次,即0,Cyp8·0mg/kgbw,MP0·23mg/kgbw,Cyp8·0+MP0·23mg/kgbw,连续30天,对照组用色拉油。测量大鼠体重增长,脏器湿重;用放射免疫法测定血清生殖激素指标促黄体生成激素(LH)、促卵泡成熟激素(FSH)、雌二醇(E2)和睾酮(T);甲状腺激素指标(T3、T4和TSH);以及免疫指标IgG和IgA,取血测定淋巴细胞转化率、中性粒细胞吞噬率。结果氯氰菊酯和甲基对硫磷混配对大多数指标为相加作用,但对卵巢和肾脏重量、淋巴细胞转化率和血清IgA为拮抗作用;对雌二醇的联合作用则有性别差异:对雌鼠为协同作用,两种农药能分别使雌鼠血清雌二醇升高1·44倍或1·21倍;而对雄鼠则为相加作用,氯氰菊酯可使雄鼠E2值增加64·64%。结论氯氰菊酯和甲基对硫磷混配可对大鼠生殖激素、甲状腺激素和免疫功能产生联合作用,雌二醇是较敏感的指标。

Objective To study interaction of mixed pesticides cypermethrin and methyl parathion on reproductive hormones, thyroid hormones, and immune functions in rats. Methods Eighty 2-month old Wistar rats （40 male and 40 female） were divided randomly by body weight into 8 groups. The dose 1/30 LD50 were chosen for the single or combined exposure representing respective doses of 0, cypermethrin 8.0mg/kg bw, methylparathion 0.23 mg/kg bw, and 1/30 LD50 cypermethrin plus 1/30 LD50 methylparathion. The control group received vehicle solvent only. All groups were force-fed every two days for 30 days. Body weight gain and organ weights were determined. Serum levels of IgG and IgA, reproductive hormones [ luteinizing hormone （ LH ）, follicle stimulating hormone （ FSH ）, estradiol （ E2 ）, and testosterone], as well as the thyroid hormones [ triiodothyronine （T3 ）, tetraiodothyronine （T4 ）, and thyroid stimulating hormone （TSH） were measured using radioimmunoassay （RIA）. In addition, two immunological parameters （rate of neutrophil phagocytosis, rate of lymphocyte transformation ] were being measured in blood samples. Results The most of index indicated addictive interaction, while the effects on relative weights of ovaries and adrenals, IgA and rate of lymphocyte transformation were antagonistic. It was of interest that the effect on estradiol was synergistic interaction in female rats, whereas it was addictive interaction in male rats, whose estradiol level could be increased 64.64% by cypermethrin exposure. Conclusion Our results showed that exposure to cypermethrin and methyl parathion mixture at 1/30 LD50 dose had interaction on endocrine hormone levels, and immune functions in rats. Estradiol was very sensitive, the mixture can enhance estradiol level both in male and female rats.