Effects of quinestrol and levonorgestrel on populations of plateau pikas, Ochotona curzoniae, in the Qinghai-Tibetan Plateau

BACKGROUND: Plateau pikas ( Ochotona curzoniae , Hodgson, 1858) are viewed as a pest in the Tibetan Plateau meadow ecosystem when their population densities are high. Traditional culling using rodenticides often poses a high risk to non‐target species and even to humans. In this study, an investigation was made of the infertility effects of quinestrol (E), levonorgestrel (P) and a combination of the two (EP, ratio E:P = 1:2) on plateau pikas during 2007 and 2008. RESULTS: Treatment with E or EP significantly decreased the pregnancy rate of female pikas in 2007. In 2008, there was a cross‐year effect that still suppressed male reproduction in treated groups. Treatment with E obviously reduced the reproduction of pikas but not their population abundance in 2007; the reduction in population size was significant in 2008. CONCLUSIONS: Single baiting of quinestrol in early breeding season reduced the reproduction and population size of pikas throughout 2007. The effect of infertility lasted into the next breeding season through a cross‐year effect, which resulted in a significant reduction of population size in 2008. Quinestrol is a very promising non‐lethal approach to managing pika populations; however, several factors need to be investigated further to improve the practicality of this method. Copyright © 2012 Society of Chemical Industry     

N,N- 二甲基甲酰胺对炔雌醚不育作用和适口性的影响

【目的】明确添加高效、安全的助剂 N,N- 二甲基甲酰胺 (N,N-Dimethylformamide,DMF) 对提高不 育剂炔雌醚（Quinestrol）药饵的不育效果,以及改善炔雌醚药饵对鼠类适口性的作用。【方法】试验设 3 个处理组, 分别投喂三组小鼠空白饵料（C 组）、炔雌醚药饵（T1 组）和 DMF- 炔雌醚药饵（T2 组）,计算饵料消耗量。 将 3 个处理组的雄、雌鼠合笼 7 d,记录雌鼠怀孕及产仔情况。高效液相色谱法检测不同配制的药饵中炔雌醚的 分布浓度。【结果】T1 和 T2 组对雄、雌鼠体重均有显著影响,且 T1 和 T2 组雄鼠肾脏器官鲜重分别低于 C 组 16.4% 和 19.7%。炔雌醚对雌性小鼠繁殖抑制作用明显,T1 和 T2 组雌鼠产仔率降低至 C 组的 37.5% 和 25.0%, 产仔数仅为 C 组的 35.0% 和 11.1%。DMF 对炔雌醚药饵适口性改善作用不明显,高效液相色谱法检测药饵中药 物的分布浓度结果表明,T2 组的糙米中炔雌醚的含量为 T1 组的 1.5 倍;DMF 提高了炔雌醚在糙米中的渗透, 从而增加了小鼠的药物摄入量。【结论】DMF 可快速有效溶解炔雌醚,并增强其在糙米中的渗透力,提高炔雌 醚药饵的抗生育作用,有望开发为具有良好应用前景的不育剂配方。     

疏肝益阳胶囊对炔雌醚诱导大鼠生精紊乱和氧化应激的缓解作用

笔者拟探讨疏肝益阳胶囊(SGYY)对炔雌醚(QES)诱导大鼠生精紊乱和氧化应激的缓解作用及机制。将20只8周龄雄性SD大鼠随机分为4组,适应饲养1周后,进行药物灌胃处理,对照组:0.1mL生理盐水+0.1mL橄榄油;SGYY组:100 mg·kg-1 SGYY;QES组:0.1 mg·kg-1 QES;QES+SGYY组:0.1 mg·kg-1 QES+100mg·kg-1 SGYY。QES溶于橄榄油;SGYY溶于生理盐水;每天1次,连续2周。处理结束后,取睾丸、附睾、精囊腺和前列腺称重、测量长径与短径,并制备睾丸组织切片,通过HE染色,观察睾丸生精小管组织结构、生精细胞比例的变化;通过免疫组织化学方法检测睾丸生精细胞PCNA表达,Tunel法检测细胞凋亡;分离血浆,检测睾酮含量变化。取睾丸匀浆检测抗氧化酶活性。结果显示,QES处理后大鼠生殖器官的质量显著下降,附睾的精子数量显著减少;生精小管的面积、直径、生精上皮的高度和生精细胞数量均显著减少。而且,生精细胞的PCNA表达和血浆睾酮含量明显下降,Tunel阳性细胞数明显增加。睾丸SOD、GSH-Px和T-AOC活性显著下降,MDA含量显著升高。SGYY增加生殖器官质量、精子数量、睾丸睾酮含量、增殖的生精细胞数量和抗氧化酶活性,降低了MDA含量和Tunel的表达。结果表明,SGYY通过改善抗氧化功能、抑制氧化应激及促进睾酮分泌等途径增加了生精细胞数量并提高睾丸的生精功能。     

Recovery of fertility in quinestrol‐treated or diethylstilbestrol‐treated mice: Implications for rodent management

Fertility control is an alternative strategy to traditional culling for the management of rodent pests. Previous studies have demonstrated that quinestrol is a potential contraceptive for male rodents, but the recovery of fertility in quinestrol‐treated rodents has not been evaluated. This study used C57BL/6J mice to evaluate the recovery rate of male fertility after the administration of quinestrol. Diethylstilbestrol (DES), a non‐steroid estrogenic compound, was used for comparison. Different groups of mice were treated with 1 mg/kg quinestrol, 1 mg/kg DES, or castor oil separately for 7 days. These mice were then killed on days 8, 22 and 50 respectively. Our results indicated that the weight of epididymides and seminal vesicles decreased significantly on days 8 and 22 in quinestrol/DES‐treated mice, with extensive histological changes in the seminiferous tubules. Sperm concentrations in the cauda epididymal fluid were significantly reduced on days 8 and 22 in both quinestrol and DES treatment groups and on day 50 for the DES, but not the quinestrol group. Further analysis revealed that DES‐treated mice exhibited a higher proportion of abnormal sperm accumulation in the epididymis, indicating that the normal sperm transportation to the cauda epididymis was blocked. Our results indicate that the anti‐fertility effects on male mice given quinestrol were of shorter duration than for those receiving DES at the dose of 1 mg/kg body weight.     

炔雌醚暴露对幼年小鼠睾丸发育及增殖细胞核抗原、半胱氨酸蛋白酶-3表达的影响

This experiment was aimed to study the effect of quinestrol on the expression of PCNA and Caspase-3 in spermatogenic cells of juvenile mice. 4-week old male mice were randomly divided into four groups. Mice in the control group were injected intraperitoneally with olive oil alone and mice in the experiment groups were injected intraperitoneally with octylphenol resolved in olive oil at 1, 10, 100 mg/kg doses respectively for 1 week (once a day). The testes were immediately removed for weighing and serial cross-sections that were used for histological examination when the mice were 8-week-old. The expressions of PCNA and Caspase-3 in spermatogenic cells were determined by immunohistochemical method. The results showed that the thickness of the convoluted seminiferous tubule decreased, cellular deranged, cell layers decreased and intercellular space increased. Meanwhile, there were a large number of abnormal shedding of spermatocytes and round spermatids, but few elongated spermatids and spermatozoa. The expression of PCNA extremely significantly decreased and the expression of Caspase-3 extremely significantly increased as quinestrol dose increased (P＜0.01). Quinestrol caused male reproductive function injury through inhibiting proliferation and promoting apoptosis in spermatogenic cells by regulating the expression of associated proteins.     

Fertility control of Rattus nitidus using quinestrol: effects on reproductive organs and social behavior

Fertility control has been identified by studies in the laboratory and the field as a more appropriate and long‐term control strategy for rodent pests than lethal control. In this study, we investigated the effects of quinestrol on mass of reproductive organs and on social behaviors in female and male Himalayan field rats (Rattus nitidus). A total of 16 adult females and 16 adult males were randomly assigned to 4 groups. One male and one female group were fed rice with 0.005% quinestrol by weight for 7 days, and another 2 groups were fed rice only. After 7 days, rats were assigned to 10 min dyadic encounters between groups, and investigation, aggression, defense and attack latency were quantified. All animals were killed on day 10, and reproductive organs were dissected and weighed. Dyadic encounter data showed that there were obvious changes in social behaviors of quinestrol‐treated rats. Quinestrol significantly inhibited the investigative behavior of quinestrol‐treated males toward control females in Rattus nitidus, but seldom affected investigation between control males and quinestrol‐treated females. Aggression of control females toward quinestrol‐treated males was higher than that of quinestrol‐treated females, and defense of quinestrol‐treated males toward control females was more remarkable than that of control males. Quinestrol remarkably decreased wet masses of epididymis and spermotophore in males and ovaries in females, but had no effect on wet masses of testes and uteri after quinestrol treatment. These results indicate that the anti‐fertility effects of quinestrol on R. nitidus are attributed to not only suppressing reproductive organs but also impacting social behaviors associated with territory defense and mate choice.     

两种不育剂药饵对黄毛鼠的适口性比较

鼠药的适口性是决定鼠害控制效果的关键因素之一。采用单只饲喂法,以稻谷为基饵,分别测定了0.005%炔雌醚和米非司酮药饵对黄毛鼠的适口性。结果表明,黄毛鼠对炔雌醚药饵平均摄食系数显著低于米非司酮;雌雄鼠对炔雌醚和米非司酮药饵的摄食差异显著。炔雌醚显著降低了雌雄鼠对药饵的摄食量,且雄鼠摄食量少于雌鼠。米非司酮提高药饵对雌鼠的适口性,但不影响对雄鼠的适口性;黄毛鼠在处理时间内对药饵的摄食量存在显著变化,雌雄鼠第1 d对炔雌醚药饵和基饵摄食量无显著差异,第2、3 d对炔雌醚药饵摄食量显著少于基饵;雌鼠第1 d对米非司酮药饵和基饵摄食无显著差异,第2、3 d取食药饵显著多于基饵,雄鼠在用药第1 d即表现出对米非司酮药饵的偏好,但随后2 d对基饵和药饵摄食量差异不显著。0.005%米非司酮的稻谷对黄毛鼠具有很好的适口性,而炔雌醚药饵配制有待改善,如增加香味剂、甜味剂等提高其适口性。     

2种不育剂和1种抗凝血剂对藏北草原高原鼠兔的控制效果

2012年4月至2013年4月在藏北草原进行了炔雌醚、莪术醇和增效敌鼠钠盐控鼠试验。均配制成青稞药饵,投放药饵后第20、75和350天进行控效调查。结果显示:炔雌醚具杀灭高原鼠兔作用,20d校正灭效达72.24%,对成年雌雄鼠繁殖器官均能起到明显损坏作用,且适口性最好;增效敌鼠钠盐控鼠效果最好,20d校正灭效达94.46%;莪术醇也有一定效果,75d幼体比最低,总体看,3种药物均具有一定控制效果,有一定实际应用潜力,但还需进一步试验验证其控鼠效果。