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双酚A(BPA)是广泛存在的雌激素样化学物质.在啮齿类动物中,BPA可以由母体快速传递给胎儿,围产期脑和神经系统对环境的变化非常敏感.为了探讨围产期BPA暴露对探究行为的影响,分别给不同组别的处于围产期的母鼠口服2 μg/(kg·bw)和200 μg/(kg·bw)BPA,待雄性小鼠达70日龄时进行新笼子行为检测.结果表明,雄性小鼠的探究水平增加,其中,BPA200组小鼠的探究能力显著提高,虽然BPA2组小鼠的探究能力没有达到显著提高,但是与对照组雄鼠相比,BPA2组小鼠的探究频次也呈增多趋势.说明围产期BPA暴露可以增加雄鼠的探究能力,而且这种影响可能是剂量依赖式的. 相似文献
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为探究母鼠妊娠期暴露双酚A(BPA)对子代成年雌性小鼠生殖损伤作用及DNA甲基转移酶(DNMT)基因表达量的影响,将120只妊娠母鼠随机分为6组,每组20只。各组分别在母鼠孕0.5～17.5 d内按0、2.5、5、10、20、40 mg·(kg·d)~(-1)剂量灌胃BPA。每组随机选取10只子代成年(56 d)雌鼠,麻醉后处死,收集血液、子宫和卵巢;统计子鼠成年时子宫和卵巢指数;HE染色观察子代雌鼠卵巢的组织形态学变化;放射性免疫法检测子代雌鼠血清中卵泡刺激素(FSH)、黄体生成素(LH)、雌二醇(E_2)和孕酮(P_4)水平;酶联免疫吸附法(ELISA)检测子代雌鼠卵巢内雌激素受体α(ERα)、雌激素受体β(ERβ)的含量;实时荧光定量PCR法检测子代雌鼠卵巢内ERα、孕酮受体(PgR)、DNMT1、DNMT3A和DNMT3B mRNA转录水平。结果显示,BPA显著降低子代雌鼠血清FSH、LH、E_2和P_4水平,显著提高子代雌鼠卵巢ERα和ERβ含量,显著降低子代雌鼠卵巢ERα、PgR和DNMT mRNA的转录水平(P0.05或P0.01)。BPA暴露子代小鼠成年时卵巢和子宫指数增大,HE染色观察卵巢实质发生萎缩,初级和次级卵泡数量增加。本研究表明,妊娠期暴露BPA可促进成年子鼠卵巢产生卵泡,显著降低生殖激素的含量及活性,显著增加卵巢激素受体的含量,抑制卵巢激素受体和DNMT的转录,对子代产生生殖损伤。 相似文献
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雌性动情状态和雄性等级对布氏田鼠社会行为的影响 总被引：3，自引：3，他引：0
在雄性竞争条件下,不同动情雌性布氏田鼠与雄鼠之间行为观察表明:(1)雌鼠动情状态下,优势雄鼠的攻击、自我修饰行为以及交配频次与交配时间均显著高于从属雄鼠,并具有交配优先权;优先被动情雌性选择交配。而从属雄鼠则表现出更频繁的上跳(逃跑或亢奋)行为。(2)当雌鼠处于非动情状态下,雌鼠与优势雄鼠间的相互嗅问行为频次显著高于雌鼠与从属鼠;优势鼠对雌鼠和从属雄鼠的攻击行为频次均显著高于从属鼠对雌鼠和优势雄鼠的攻击;从属鼠也表现出频繁的上跳行为。(3)在与不同雌鼠动情状态下共栖时,从属雄鼠对动情雌鼠的攻击行为频次显著高于对非动情雌鼠;优势雄鼠和从属雄鼠,与非动情雌鼠的友好行为频次均高于雌鼠;与非动情状态雌鼠共栖,雄鼠之间的友好行为频次显著高于动情雌鼠状态。(4)雌鼠动情状态和雄鼠等级会影响雌雄鼠之间的相互行为,动情雌鼠优先与优势雄鼠交配。 相似文献
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[目的]通过围产期暴露于双酚A,探讨其对C57BL/6J小鼠成年后社会性以及性行为产生的影响.[方法]让处于围产期的母鼠口服200 μg/(kg·bw)BPA,待雄性小鼠70日龄时进行异性社会互作行为检测.[结果]发现BPA处理的雄鼠对异性刺激鼠亲密行为无明显变化;但是和对照组相比,BPA处理的雄鼠爬胯行为明显减少.[结论]表明围产期BPA暴露减弱了雄鼠的性行为. 相似文献
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《中国兽医学报》2019,(12):2422-2428
为探究母鼠妊娠期暴露双酚A(bisphenol A,BPA)对子代雌鼠生殖激素的影响及BPA与机体发生作用的分子机制。通过灌服不同剂量的BPA制造孕鼠BPA暴露模型,然后计算子代小鼠断乳时的死亡率、卵巢与子宫系数;放射免疫法检测血清中雌二醇(E_2)、孕酮(P_4)、卵泡刺激素(FSH)、黄体生成素(LH)水平;酶联免疫吸附试验(ELISA)检测血清雌激素受体α(ERα)、雌激素受体β(ERβ)含量;qPCR法检测卵巢DNA甲基转移酶1(Dnmt1),DNA甲基转移酶3A(Dnmt3A),DNA甲基转移酶3B(Dnmt3B),孕酮受体(PgR)及雌激素受体α(EsR1)mRNA表达。结果显示,子代雌鼠的相关指标与母鼠妊娠期BPA暴露存在非单调性剂量-反应关系;卵巢系数、E_2含量与BPA剂量呈现"U"型关系;子宫系数,血清P_4、FSH、LH水平,卵巢ERβ含量,卵巢Dnmt1、 Dnmt3A、 Dnmt3B mRNA相对转录水平与BPA剂量呈现"波浪式"关系;卵巢PgR、EsR1 mRNA相对转录水平与BPA剂量呈现"倒U"型关系;且BPA暴露组与空白组相比有极显著差异(P0.01)。这表明BPA可能通过增强子代雌鼠DNA甲基化酶的转录活性使生殖激素分泌紊乱,造成子代生殖损伤。 相似文献
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环境浓度三丁基锡对根田鼠体重及摄食相关行为的影响 《畜牧与饲料科学》2015,36(4):4-4
为了探究环境浓度三丁基锡（tributyltin,TBT）对根田鼠体重及摄食相关行为的影响,实验组使用1μg/mL的TBT按5μL/（g·BW）每3 d 1次进行灌胃;对照组使用等剂量生理盐水做相同处理,实验持续45 d。记录根田鼠体重,并计算其摄食量和饮水量（供给－剩余）;摄食、饮水和运动的持续时间和频次用录像记录。结果显示：TBT暴露下,雄性根田鼠的摄食频次和时间、饮水频次和时间仅在有限的几个时间点上显著高于对照组（P<0.05）;对雌性根田鼠摄食和饮水的频次和时间的影响不明显。TBT暴露下,雄性根田鼠仅在灌胃第3天时其运动时间显著高于对照组（P<0.05）、静止时间显著低于对照组（P<0.05）,而随着染毒时间的延长,两组之间再无显著性差异。与对照组相比,TBT暴露对雌雄根田鼠摄食量、饮水量和体重的影响均不明显。因此,环境浓度的三丁基锡对成体根田鼠的体重没有明显影响,但对其摄食相关行为有部分影响。 相似文献
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为探究菟丝子黄酮(CCFs)对母鼠妊娠期暴露双酚A(BPA)导致的子代成年雌鼠生殖损伤的缓解作用,将50只妊娠母鼠随机分为5组,即空白对照组、BPA模型组、BPA+低剂量CCFs组、BPA+中剂量CCFs组、BPA+高剂量CCFs组,每组10只,分别在孕1～17 d灌胃0.2 mL含有相应剂量药物的玉米油。待仔鼠出生56日龄时,每组随机选取10只子代成年雌鼠,收集血液和卵巢,统计各组成年雌鼠的卵巢指数;检测各组子代成年雌鼠血清中促性腺激素释放激素(GnRH)、卵泡刺激素(FSH)、黄体生成素(LH)的含量;检测每组卵巢组织中雌激素(E2)、孕酮(P4)、雌激素受体α(ERα)、雌激素受体β(ERβ)水平;检测卵巢组织活性氧(ROS)、超氧化物歧化酶(SOD)、丙二醛(MDA)活性;HE染色观察各组卵巢组织学改变;荧光定量PCR法检测卵巢组织Nrf2、NQO1、HO-1 mRNA的表达。结果显示,BPA模型组小鼠卵巢指数升高,GnRH、FSH、LH、E2和P4激素水平降低,卵巢组织中ER水平紊乱。BP... 相似文献
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《中国兽医杂志》2020,(2)
本研究旨在从毒性病理学角度探讨双酚A(BPA)暴露对青春期前雌性大鼠生殖器官发育的影响,为研究BPA雌激素样作用提供组织形态学依据。选用21日龄雌性大鼠,经不同浓度的BPA暴露后,检测大鼠脏器指数、血清雌二醇水平,观察子宫和卵巢形态结构。结果显示,BPA给予7 d后与对照组比较,BPA 180 mg/(kg·bw)组大鼠子宫和卵巢指数升高(P<0.05),血清雌二醇水平降低(P<0.05)。光镜观察发现,BPA试验组大鼠与对照组比较,子宫内膜增厚、内膜细胞形态改变,卵巢初级和次级卵泡数量增多。病理半定量分析结果表明,与对照组比较, BPA 180 mg/(kg·bw)组大鼠子宫内膜厚度、内腔面积及外腔直径、总卵泡数量有统计学差异(P<0.05)。表明BPA短期大剂量暴露可促进青春期前雌性大鼠子宫和卵巢发育,其作用存在明显的剂量依赖关系。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献
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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献