Reproductive Toxicity Of Chlormequat To Mice

This paper makes a systematic study on the toxic effects of chlormequat (CQ) on thereproductive function of parental mice and the development of embryo and offspring.Moreover, a rapid method for analyzing trace level of CQ in tissues of mice by LC-MS/MSwas developed, which provided an approach for the study of accumulation and distribution ofCQ in various tissues of mice.144ICR mice were randomly divided into4groups,including a control group (aquadestillata) and three experimental groups,20mg/kg,60mg/kg,180mg/kg,0.02ml/g throughgavage, once a day,36in each group, female and male ratio was2:1. CQ was administered for28days before mating, and14days after mating to male mice,14days before mating tofemale mice, half of pregnant mice were sacrificed to investigate the growth and developmentof embryos, another half of female mice were continuing to the offsprings weaning, andobserved the offspring until weaning.(1) The F₀mice were weighted, the organs coefficients,sperm kinematic parameters, biochemical indexes and pathological change were determined.(2) The skeletal and organ anomalies and the growth of fetus were observed. The offspringswere weighted, the organs coefficients and the pathological change were determined and thelitter size was counted.(3) A LC-MS/MS method to determine CQ in tissues of mice wasdeveloped. The mobile phase and sample preparation were optimized.(4) Based on themethod, the concentration of CQ in tissues of male mice (180mg/kg) at different time after thelast administration were determined. The concentration of CQ in tissues of female mice afteradministration were also determined. The results were as follows:(1) Compared with the control group, the male mice body weight of high experimentalgroups were lower significantly (P＜0.05), the testis coefficient of high group was highersignificantly (P＜0.05), the sperm counts of medium and high groups were lowersignificantly (P＜0.05), and the sperm motility rate of high group was lower significantly (P＜0.05); the activities of AKP and LDH in testis of high group were higher significantly (P＜0.05), the activity of SOD in testis of medium and high group were higher significantly (P＜0.05); histopathologic studies showed that the germ epithelial thinning, the number ofspermatogencic cell decreasing, the leydig cells decreasing, the structure of hepatic lobulesdisordered, congestion in cetral vein, necrosis of liver cells, thickness in alveolar walls,congestion in pulmonary capillary, thickness in renal tubular walls, stenosis of lumen, theglomeruli swelling and kind of congestion. (2) The litter size of high group was significantly lower than that of control (P＜0.05).The weight of weaning offspring of medium and high groups were significantly lower thanthat of control (P＜0.05).(3) A rapid method for analyzing trace level of CQ in tissues of mice by LC-MS/MS wasdeveloped. The quantification was performed using a matrix-matched calibration curve whichwas linear in the range of the0.05-100μg/L. The average recovery of CQ in spiked meatsamples was86.4-94.7%at2,20and200μg/kg and the relative standard deviation (RSD)was less than5.7%.The limit of quantification (LOQ) was0.1μg/kg.(4) Chlormequat was distributed in various tissues and organs of mice after intragastricadministration, and the highest level was detected in muscle, followed by liver and renal.Besides, chlormequat was distributed and accumulated in testis.The results demonstrated that exposure to CQ can cause reproductive, embryonic anddevelopmental toxicity to mice. Liver and renal excretion were the major ways of eliminationof CQ. CQ can be distributed and accumulated in various organs of mice after a littlelong-term exposure and eliminated slowly.