热应激对小鼠相关神经行为学影响

本研究旨在观察34℃条件下不同时长的热刺激对小鼠神经行为学影响及在此条件下小鼠血液生理指标的具体变化。选择40只8周龄小鼠，平均分为4组，每组10只。分组后将小鼠分别置于34℃环境下进行时长0、2、4、6 h的热刺激。刺激结束后立刻对小鼠进行旷场和高架十字迷宫试验，观察并记录小鼠5 min内运动情况，并采取小鼠血液样本对其血液生理指标进行检测。结果显示：与对照组相比，小鼠热刺激2 h组探索行为显著增加，而热刺激4 h组及热刺激6 h组小鼠焦虑样行为显著增加，探索行为减少；小鼠热刺激2 h组肾上腺素（EPI）、皮质醇（CORT）水平都呈时间依赖性增加，并且具有显著性；热刺激2、4、6 h组去甲肾上腺素（NE）水平均极显著增加，并在热刺激4 h时达到峰值，6 h时略有回落趋势；小鼠热刺激4 h组促肾上腺皮质激素释放激素（CRH）水平极显著增加，6 h时略有回落趋势。综上表明，34℃热刺激2 h时对小鼠自发运动和探索行为有促进作用，小鼠自发运动和探索行为随着刺激时长的增加，被显著抑制，焦虑样行为显著增加，表现出时间依赖性，并提示小鼠热刺激后情绪和行为异常可能由中枢神经系统进行调控。     

The α2A‐adrenoceptor subtype plays a key role in the analgesic and sedative effects of xylazine

Xylazine, the classical α₂‐adrenoceptor (α₂‐AR) agonist, is still used as an analgesic and sedative in veterinary medicine, despite its low potency and affinity for α₂‐ARs. Previous pharmacological studies suggested that the α_2A‐AR subtype plays a role in mediating the clinical effects of xylazine; however, these studies were hampered by the poor subtype‐selectivity of the antagonists used and a lack of knowledge of their bioavailability in vivo. Here, we attempted to elucidate the role of the α_2A‐AR subtype in mediating the clinical effects of xylazine by comparing the analgesic and sedative effects of this drug in wild‐type mice with those in α_2A‐AR functional knockout mice using the hot‐plate and open field tests, respectively. Hippocampal noradrenaline turnover in both mice was also measured to evaluate the contribution of α_2A‐AR subtype to the inhibitory effect of xylazine on presynaptic noradrenaline release. In wild‐type mice, xylazine (10 or 30 mg/kg) increased the hot‐plate latency. Furthermore, xylazine (3 or 10 mg/kg) inhibited the open field locomotor activity and decreased hippocampal noradrenaline turnover. By contrast, all of these effects were abolished in α_2A‐AR functional knockout mice. These results indicate that the α_2A‐AR subtype is mainly responsible for the clinical effects of xylazine.     

The combined effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and the phytoestrogen genistein on steroid hormone secretion,AhR and ERβ expression and the incidence of apoptosis in granulosa cells of medium porcine follicles

Low doses of endocrine disrupting chemicals (EDCs) used in combination may act in a manner different from that of individual compounds. The objective of the study was to examine in vitro effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 100 pM) and genistein (500 nM) on: 1) progesterone (P₄) and estradiol (E₂) secretion (48 h); 2) dynamic changes in aryl hydrocarbon receptor (AhR) mRNA and protein expression (1, 3, 6, 24 and 48 h); 3) dynamic changes in estrogen receptor β (ERβ) mRNA and protein expression (1, 3, 6, 24 and 48 h); and 4) induction of apoptosis in porcine granulosa cells derived from medium follicles (3, 6 and 24 h). TCDD had no effect on P₄ or E₂ production, but potentiated the inhibitory effect of genistein on P₄ production. In contrast to the individual treatments which did not produce any effects, TCDD and genistein administered together decreased ERβ and AhR protein expression in granulosa cells. Moreover, the inhibitory effect of TCDD on AhR mRNA expression was abolished by genistein. The treatments did not induce apoptosis in the cells. In summary, combined effects of low concentrations of TCDD and genistein on follicular function of pigs differed from that of individual compounds. The results presented in the current paper clearly indicate that effects exerted by low doses of EDCs applied in combination must be taken into consideration when studying potential risk effects of EDCs on biological processes.     

Oncolytic reovirus synergizes with chemotherapeutic agents to promote cell death in canine mammary gland tumor

The oncolytic effects of reovirus in various cancers have been proven in many clinical trials in human medicine. Oncolytic virotherapy using reovirus for canine cancers is being developed in our laboratory. The objective of this study was to examine the synergistic anti-cancer effects of a combination of reovirus and low doses of various chemotherapeutic agents on mammary gland tumors (MGTs) in dogs. The first part of this study demonstrated the efficacy of reovirus in canine MGTs in vitro and in vivo. Reovirus alone exerted significant cell death by means of caspase-dependent apoptosis in canine MGT cell lines. A single injection of reovirus impeded growth of canine MGT tumors in xenografted mice, but was insufficient to induce complete tumor regression. The second part of this study highlighted the anti-tumor effects of reovirus in combination with low doses of paclitaxel, carboplatin, gemcitabine, or toceranib. Enhanced synergistic activity was observed in the MGT cell line treated concomitantly with reovirus and in all the chemotherapeutic agents except toceranib. In addition, combining reovirus with paclitaxel or gemcitabine at half dosage of half maximal inhibitory concentration (IC₅₀) enhanced cytotoxicity by activating caspase 3. Our data suggest that the combination of reovirus and low dose chemotherapeutic agents provides an attractive option in canine cancer therapy.     

Fetal and lactational exposure to the no-observed-adverse-effect level (NOAEL) dose of the neonicotinoid pesticide clothianidin inhibits neurogenesis and induces different behavioral abnormalities at the developmental stages in male mice

Recently, it has been reported that neonicotinoid pesticides (NNs) are transferred from mother to child and are assumed to affect the next generation, but the behavioral effects of NN exposure at different developmental stages have not been investigated. We exposed mice to no-observed-adverse-effect level (NOAEL) doses of clothianidin (CLO) during the fetal and lactational period, and then evaluated the neurobehavioral effects in juvenile and adult mice. Significant increases in anxiety-like behavior and locomotor activity were observed in juveniles and adults, respectively, and neuronal activity and neurogenesis in the hippocampal dentate gyrus were affected in both stages. These results suggest that fetal and lactational exposure to CLO may inhibit neurogenesis and cause different behavioral abnormalities at different developmental stages.     

Experimental chemotherapy against canine mammary cancer xenograft in SCID mice and its prediction of clinical effect

The effectiveness of 6 antitumor agents has been evaluated for canine mammary gland tumor (CMG-6) serially transplanted into severe combined immunodeficiency (SCID) mice. CMG-6 diagnosed as a solid carcinoma was subcutaneously transplanted into SCID mice and six antitumor agents were intravenously given to the mice as a single injection. The effectiveness was evaluated by Treatment group/Control group percent (T/C %) and statistical significance determined by Mann-Whitney's U-test in tumor volume. The minimum effective doses (MEDs; mg/kg) of mice were as follows; cyclophosphamide (CPM) 65, doxorubicin (DXR) 6, cisplatin (CDDP) 5, vincristine (VCR) 1.6, vinblastine (VLB) more than 5.5, 5-fluorouracil (5-FU) 105. Clinical effects of the drugs were predicted based on area under the curve (AUC) of dogs given a clinical dose (AUCdog)/AUC of mice given a MED (AUCmouse) ratios from published references. The AUC ratios were as follows; CPM 2.24, DXR 0.19, CDDP 1.20, VCR 0.04, VLB <1.24 and 5-FU 1.15. Drugs indicating more than 1.0 in AUCdog/AUCmouse ratio were CPM, CDDP and 5-FU, and would be suggested as effective in the original patient with CMG-6. The combination chemotherapy using clinically equivalent doses in CDDP and CPM, which were the two highest values in AUCdog/AUCmouse ratio by single agent therapy, was performed and shown to have additional effects as compared to the responsiveness of each agent against CMG-6.     

Activated Vitamin D3 and Pro-activated Vitamin D3 Attenuate Induction of Permanent Changes Caused by Neonatal Estrogen Exposure in the Mouse Vagina

Exposure of mice to a high dose of estrogens including diethylstilbestrol (DES) during the neonatal period modifies the developmental plan of the genital tract, which leads to various permanent changes in physiology, morphology and gene expression. These changes include development of an abnormal vaginal epithelium lined with hyperplastic mucinous cells accompanied by Tff1 gene expression in mice. Here, the influence of vitamin D on the direct effect of estrogen on the developing mouse vagina was examined. The mid-vagina of neonatal mice was cultured in a serum-free medium containing estradiol-17β (E₂) and various concentrations of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D) ex vivo and then was transplanted under the renal capsule of ovariectomized host mice for 35 days. Exposure to E₂ alone caused the vaginal tissue to develop estrogen-independent epithelial hyperplasia and to express TFF1 mRNA, while addition of a low nanomolar amount of 1,25(OH)₂D added at the same time as E₂ to the culture medium attenuated the effects of estrogen. Expression of vitamin D receptor was also evident in the neonatal mouse vagina. Interestingly, addition of 25-hydroxyvitamin D₃, a pro-activated form of vitamin D, at the micromolar level was found to be potent in disrupting the developmental effects of E₂, while cholecalciferol was not at least at the dose examined. Correspondingly, expression of Cyp27B1, a kidney-specific 25-hydroxyvitamin D hydroxylase, was evident in the neonatal mouse vagina when examined by RT-PCR. In addition, simultaneous administration of 1,25(OH)₂D successfully attenuated DES-induced ovary-independent hyperplasia in the vagina in neonatal mice in vivo. Thus, manipulation of vitamin D influenced the harmful effects of estrogens on mouse vaginal development.     

Reduction of isoflurane MAC by fentanyl or remifentanil in rats

Objective The main objective of the study was to determine the effects of three different infusion rates of fentanyl and remifentanil on the minimum alveolar concentration (MAC) of isoflurane in the rat. A secondary objective was to assess the cardiovascular and respiratory effects of the two opioid drugs. Animal population Thirty‐seven male Wistar rats were randomly allocated to one of six treatment groups. Material and methods For all treatment groups anaesthesia was induced with 5% isoflurane in oxygen using an induction chamber. A 14‐gauge catheter was used for endotracheal intubation, and anaesthesia was maintained with isoflurane delivered in oxygen via a T‐piece breathing system. A baseline determination of the minimum alveolar concentration of isoflurane (MAC_ISO) was made for each animal. Fentanyl (15, 30, 60 µg kg^?1 hour^?1) or remifentanil (60, 120, 240 µg kg^?1 hour^?1) were infused intravenously into a previously cannulated tail vein. Thirty minutes after the infusion started, a second MAC_ISO (MAC_ISO+drug) was determined. The carotid artery was cannulated to monitor the arterial pressure and to take samples for arterial gas measurements. Cardiovascular (heart rate and arterial pressure) and respiratory (respiratory rate and presence/absence of apnoea) effects after opioid infusion were also recorded. Results Fentanyl (15, 30, 60 µg kg^?1 hour^?1) and remifentanil (60, 120, 240 µg kg^?1 hour^?1) similarly reduced isoflurane MAC in a dose‐dependent fashion: by 10% at lower doses, 25% at medium doses and by 60% at higher doses of both the drugs. Both opioids reduced the respiratory rate in a similar way for all doses tested. No episodes of apnoea were recorded in the remifentanil groups, while administration of fentanyl resulted in apnoea in three animals (one at each dose level). The effects on the cardiovascular system were similar with both drugs. Conclusions We conclude that the intraoperative use of remifentanil in the rat reduces the MAC of isoflurane, and that this anaesthetic sparing effect is dose‐dependent and similar to that produced by fentanyl at the doses tested. Clinical relevance The use of remifentanil during inhalant anaesthesia in the rat can be considered an intravenous alternative to fentanyl, providing similar reduction in isoflurane requirements. Due to its rapid offset, it is recommended that alternative pain relief be instituted before it is discontinued.     

钼对小鼠后代肾脏的损伤作用

为探讨长期钼暴露对子代小鼠肾功能的影响,采用2月龄清洁级小鼠60只(雌雄比2∶1),随机分为4组(每组10只雌鼠,5只雄鼠),雌雄分开饲养。饮水中加入不同剂量Na2MoO4.2H2O组成空白对照组、低钼组(100mg/L)、中钼组(200mg/L)和高钼组(400mg/L),4周后雌雄合笼饲养,待其产仔。妊娠期和哺乳期母鼠仍按原分组给予不同剂量的钼。仔鼠断奶后,同样按原分组给予不同剂量的钼。饲养8周后,再从每组后代中随机选取雌性小鼠10只和雄性小鼠5只合笼饲养,待其产仔。如此反复,使小鼠繁殖4代。选取第3代(F2)、第4代(F3)小鼠眼球摘除法采血并分离血清,测定血清肌酐和尿素氮。采集肾脏测定微核率和肾组织切片。结果表明,当饮水中Na2MoO4.2H2O达到200mg/L以上时,可显著增加后代小鼠肾细胞微核率(P<0.05)和血清肌酐浓度(P<0.05),降低血清尿素氮含量(P<0.05)。说明钼制剂可对小鼠后代肾脏产生损伤作用。     

Establishment of dose-response relationships in BALB/c mice, using Brucella cell surface protein and lipopolysaccharide

A study was conducted to determine the immune (increased antibody) and protective (reduced colony-forming units) responses induced in mice by a: (i) single vaccinal inoculation, using various concentrations of Brucella cell surface protein (BCSP) or lipopolysaccharide (LPS); (ii) primary inoculation, using various concentrations of BCSP, followed by a secondary inoculation, using a standard concentration of BCSP; and (iii) primary inoculation, using 1 concentration of BCSP or LPS, followed by a secondary inoculation, using various concentrations of BCSP or LPS. Four weeks after the primary inoculation, mice were challenge exposed with approximately 1 x 10(4) colony-forming units of Brucella abortus strain 2308 and all mice were euthanatized at 6 weeks. Reduced splenic weights and reduced colony-forming units in the spleens of vaccinated mice, compared with nonvaccinated mice, were the criteria of protection. Increase in serum IgM and IgG was defined as immunity. Both BCSP and LPS induced protective and immune responses that were proportional to the dose given up to an optimal limit. However, concentrations higher than optimal decreased the protective and immune responses. This was true for mice given either 1 or 2 vaccinal inoculations. Enhanced secondary protective responses were seen only when suboptimal doses were used in the primary inoculation. Excessive or optimal doses in the secondary inoculations prevented or obscured the protectiveness and immunity by primary inoculations. The protective effects appeared to be additive when suboptimal doses were used in the primary and secondary inoculations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ivermectin impairs sexual behavior in sexually naïve, but not sexually experienced male rats

Ivermectin (IVM) is an antiparasitic drug, widely used in domestic animals. In mammals, IVM act as a GABA agonist. This neurotransmitter has an important role in the regulation of sexual behavior. Thus, this study sought to investigate the effects of various medically relevant doses IVM on the sexual behavior of male rats. In particular, we also wished to examine if previous sexual experience modulated responses to IVM. In the first experiment, the sexual behavior of inexperienced male rats was analyzed after they received 0.2, 0.6, 1.0 or 2.0 mg/kg IVM, 15 min prior to behavioral testing. In the second experiment, the effects of four previous sexual experiences on IVM treated rats (1.0 or 2.0 mg/kg, 15 min prior to the 5th session) were assessed. The standard therapeutic dose (0.2 mg/kg) did not impair the sexual behavior of inexperienced male rats. At a more concentrated dose (0.6 mg/kg), which is still within the therapeutic range, the appetitive phase of sexual behavior of inexperienced male rats was impaired. Likewise, 1.0 mg/kg impaired the appetitive phase. Previous sexual experience blocked almost entirely this sexual impairment, suggesting that previous sexual experience exerts a positive effect in attenuating the sexual impairment produced by IVM treatment. Therefore, the standard therapeutic dose of IVM can be used without producing side effects on sexual behavior. Use of more concentrated therapeutic doses is not recommended during reproductive periods, unless the animals have had previous sexual experience.     

胸腺肽对雄性小鼠血清激素水平的影响

为探讨胸腺肽对雄性小鼠血清激素水平的影响,采用放射性免疫分析法和生化法测定注射不同剂量胸腺肽1月龄、3月龄雄性小鼠血清中促黄体生成素(LH)、睾酮(T)、促甲状腺激素(TSH)、胰岛素(INS)和血糖水平.结果显示,1月龄雄性小鼠注射胸腺肽后LH和T水平均升高,其中高剂量组显著升高(P<0.05);TSH水平升高,其中...     

Establishment of inflammatory model induced by Pseudorabies virus infection in mice

BackgroundPseudorabies virus (PRV) infection leads to high mortality in swine. Despite extensive efforts, effective treatments against PRV infection are limited. Furthermore, the inflammatory response induced by PRV strain GXLB-2013 is unclear.ObjectivesOur study aimed to investigate the inflammatory response induced by PRV strain GXLB-2013, establish an inflammation model to elucidate the pathogenesis of PRV infection further, and develop effective drugs against PRV infection.MethodsKunming mice were infected intramuscularly with medium, LPS, and different doses of PRV-GXLB-2013. Viral spread and histopathological damage to brain, spleen, and lung were determined at 7 days post-infection (dpi). Immune organ indices, levels of reactive oxygen species (ROS), nitric oxide (NO), and inflammatory cytokines, as well as levels of activity of COX-2 and iNOS were determined at 4, 7, and 14 dpi.ResultsAt 10⁵–10⁶ TCID₅₀ PRV produced obviously neurological symptoms and 100% mortality in mice. Viral antigens were detectable in kidney, heart, lung, liver, spleen, and brain. In addition, inflammatory injuries were apparent in brain, spleen, and lung of PRV-infected mice. Moreover, PRV induced increases in immune organ indices, ROS and NO levels, activity of COX-2 and iNOS, and the content of key pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon-γ and MCP-1. Among the tested doses, 10² TCID₅₀ of PRV produced a significant inflammatory mediator increase.ConclusionsAn inflammatory model induced by PRV infection was established in mice, and 10² TCID₅₀ PRV was considered as the best concentration for the establishment of the model.     

Uptake of manganese from manganese–lysine complex in the primary rat intestinal epithelial cells

This study was conducted to compare the differences of the uptake of Mn from Mn–lysine complex (MnLys) and MnSO₄ and to determine the potential mechanisms of the uptake of Mn from MnLys. We first established the primary rat intestinal epithelial cell culture model and used it to determine the uptake of Mn from different Mn sources. The MnLys increased (p < 0.001) Mn uptake when compared to MnSO₄. The uptake of Mn decreased (p < 0.05) with added Fe concentration increasing in the medium regardless of Mn source. The MnLys decreased (p < 0.01) Mn²⁺ efflux transporter ferroportin 1 (FPN1) mRNA level, but did not influence (p > 0.06) Mn²⁺ influx transporter DMT1 mRNA expression when compared to MnSO₄. The results above indicated that the increase of Mn accumulation for MnLys at least partly was due to the decrease of Mn efflux by reduced FPN1 expression. The N‐ethylmaleimide, as an l ‐lysine transport system y⁺ inhibitor, decreased (p < 0.001) the uptake of Mn from MnLys, but did not affect (p > 0.10) the uptake of Mn from MnSO₄. The cycloheximide, as an l ‐lysine transport system b^0,+ activator, increased (p < 0.001) the uptake of Mn from MnLys, whereas also did not influence the uptake of Mn from MnSO₄. The MnLys increased (p < 0.01) the system y⁺ member cationic amino acid transporter (CAT) 1, and system b^0,+ components rBAT and b^0,+AT mRNA expression when compared to MnSO₄. These results suggested that the uptake of Mn from MnLys complex might be transported by CAT1 and system b^0,+, which was different from ionized Mn²⁺ uptake pathway. In conclusion, the uptake of MnLys complex not only might be absorbed as Mn²⁺, but also appeared to be transported through CAT1 and system b^0,+ in the primary rat intestinal epithelial cells.     

蜂王浆冻干粉对衰老小鼠抗氧化能力的影响

试验旨在探讨蜂王浆冻干粉(lyophilized royal jelly,LRZ)对D-半乳糖致衰老模型小鼠的抗氧化作用。以昆明种小鼠为研究对象,按体重随机分为正常对照组、模型对照组和低、中、高剂量（170、340、510 mg/kg）蜂王浆冻干粉组。除正常对照组外,其余各组小鼠每天颈背部皮下注射160 mg/kg D-半乳糖0.2 mL,正常对照组注射等量的生理盐水。试验组小鼠每天灌胃0.3 mL LRZ水溶液,对照组小鼠灌胃等量的蒸馏水,试验期49 d。测定血清、脑和肝脏组织匀浆中超氧化物岐化酶（SOD）、过氧化氢酶（CAT）的活力及丙二醛（MDA）的含量。结果表明,D-半乳糖致衰小鼠SOD活力和CAT活力均明显下降,MDA含量明显上升,与正常小鼠比较差异显著(P＜0.05);340、510 mg/kg LRZ可以提高小鼠血清、脑、肝脏组织中的SOD和CAT活性,降低MDA含量,与衰老模型组相比有显著性差异(P＜0.05)。说明LRZ能显著提高亚急性衰老小鼠的抗氧化能力,具有量效关系。     

饲粮高铁对肉仔鸡十二指肠黏膜铁转运载体基因表达及组织微量元素含量的影响

本试验旨在研究饲粮铁含量对肉仔鸡组织重要微量元素铁、锰、铜、锌含量及十二指肠黏膜主要铁转运载体基因表达的影响,探讨铁对肉仔鸡微量元素吸收和代谢的影响及其机制。将336只1日龄商品代罗斯308肉公雏按照体重随机分成4个组,每组6个重复,每个重复14只鸡。对照组饲喂不额外添加铁的基础饲粮(实测铁含量为78 mg/kg),铁添加组分别饲喂以七水硫酸亚铁(FeSO_4·7H_2O)形式添加100、250或500 mg/kg铁的试验饲粮(实测铁含量分别为166、308和579 mg/kg)。试验期21 d。各组试鸡分别于7、14和21日龄屠宰分析肝脏、心脏、胰腺、十二指肠黏膜和胫骨灰中铁、锰、铜、锌含量及十二指肠黏膜中二价金属转运蛋白(DMT1)和膜铁转运蛋白(FPN1)mRNA表达水平。结果表明:1)500 mg/kg铁添加组1~7日龄和8~14日龄的平均日增重显著低于其他3组(P0.10),250和500 mg/kg铁添加组1~7日龄的平均日采食量显著低于其他2组(P0.10)。2)饲粮铁含量对肉仔鸡7、14、21日龄的血浆总铁结合力以及全血血红蛋白浓度(7日龄除外)和红细胞压积均无显著影响(P0.10),但显著影响7、14和21日龄血浆铁含量和铁饱和度(P0.10),二者均随饲粮铁含量增加而升高。3)7和14日龄心脏及7、14和21日龄肝脏、十二指肠黏膜、胰腺和胫骨灰铁含量均随饲粮铁含量的增加而升高,7、14和21日龄十二指肠黏膜、胰腺和胫骨灰锰含量均随饲粮铁含量的增加而降低;饲粮添加铁显著降低7日龄胰腺锌含量(P0.10),但对其他日龄胰腺和各日龄其他所测组织锌含量以及各日龄所测各组织铜含量均无显著影响(P0.10)。4)饲粮铁含量显著影响7、14和21日龄十二指肠黏膜DMT1和FPN1 mRNA表达水平(P0.10),各日龄DMT1和FPN1mRNA表达水平均随饲粮铁含量的增加而降低。以上结果提示,高铁饲粮可能通过调控十二指肠黏膜DMT1和FPN1基因的表达降低锰和锌在肠道的吸收,进而减少锰和锌在组织中的沉积。     

Behavioral and physiological responses of striped field mice (Apodemus agrarius) to predator odor

Predation risk is one of the most important selective forces in nature and has significant effects on the behavior and physiology of prey individuals. Prey species have evolved several different traits to reduce and avoid this predation pressure. This research aimed to determine the behavioral and physiological responses of striped field mice to predator risk. In the present study, we compared the agonistic behavior in male and female striped field mice (Apodemus agrarius Pallas, 1771) of the same sexes under the odor derived from a male Himalayan weasel (Mustela sibirica). Dyads were subjected to 5 min staged encounters in neutral arenas once a week for 3 weeks during which agonistic and social behaviors were recorded and fecal hormone concentrations were determined using pre‐column derivatization and high performance liquid chromatography methods. Furthermore, we also tested the effects of weasel odor on the adrenal glands. The results showed that: (i) male striped field mice did not exhibit any change in body weight and physiological characteristics but their aggressive behavior changed over time, and (ii) females responded to predation risk by significantly decreasing body mass and through increases in fecal cortisol levels and adrenal gland indices. These data show significant sex differences in the body weight, adrenal gland indices and fecal cortisol levels of striped field mouse under predation risk.     

Effect of Intravenous Administration of Cobalt Chloride to Horses on Clinical and Hemodynamic Variables

Background

Cobalt chloride (CoCl₂) is administered to racehorses to enhance performance. The purpose of this study was to evaluate the clinical, cardiovascular, and endocrine effects of parenterally administered CoCl₂.

Objectives

To describe the effects of weekly intravenous doses of CoCl₂ on Standardbred horses.

Animals

Five, healthy Standardbred mares.

Methods

Prospective, randomized, experimental dose‐escalation pilot. Five Standardbred mares were assigned to receive 1 of 5 doses of CoCl₂ (4, 2, 1, 0.5, or 0.25 mg/kg) weekly IV for 5 weeks. Physical examination, blood pressure, cardiac output, and electrocardiography (ECG) were evaluated for 4 hours after administration of the first and fifth doses. Blood and urine samples were collected for evaluation of cobalt concentration, CBC and clinical chemistry, and hormone concentrations.

Results

All mares displayed pawing, nostril flaring, muscle tremors, and straining after CoCl₂ infusion. Mares receiving 4, 2, or 1 mg/kg doses developed tachycardia after dosing (HR 60–126 bpm). Ventricular tachycardia was noted for 10 minutes after administration of the 4 mg/kg dose. Increases in systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) occurred after administration of all doses (4, 2, 1, 0.5, and 0.25 mg/kg). Profound hypertension was observed after the 4 mg/kg dose (SAP/DAP, MAP [mmHg] = 291–300/163–213, 218–279). Hemodynamics normalized by 1–2 hours after administration. ACTH and cortisol concentrations increased within 30 minutes of administration of all CoCl₂ doses, and cardiac troponin I concentration increased after administration of the 4 and 2 mg/kg doses.

Conclusions and Clinical Importance

The degree of hypertension and arrhythmia observed after IV CoCl₂ administration raises animal welfare and human safety concerns.     

增精宝对环磷酰胺致小鼠生精障碍保护作用的研究

为评价增精宝对雄性动物生精作用的影响,采用环磷酰胺致小鼠生精障碍为动物模型,考察不同剂量增精宝对环磷酰胺致小鼠生精障碍的保护作用。结果显示,高剂量组对小鼠的附睾、睾丸、储精囊和前列腺均有较显著的促进作用;低剂量组精子总密度和精子活率均差异显著(P<0.05);高剂量组精子活率差异显著(P<0.05);对小鼠睾丸各倍体生精细胞比例的影响,高剂量组小鼠睾丸生精小管较为饱满,管腔内存在大量精子,生精上皮较厚,可见各级生精细胞排列整齐,界膜明显,睾丸间质细胞排列整齐。结论表明,增精宝两种剂量均能够显著促进环磷酰胺导致小鼠生精障碍的保护作用,高剂量组对雄性小鼠的作用尤为显著。     

枸杞多糖对双酚A暴露小鼠生精细胞Caspase-3、Bcl-2和Bax蛋白表达的影响

研究枸杞多糖(LBP)对双酚A(BPA)暴露小鼠睾丸生精细胞中Caspase-3、Bcl-2和Bax凋亡蛋白表达的影响.将50只成年雄性昆明小鼠随机分为A、B、C、D、E共5组,每组10只.除正常对照组(A组)注射等量橄榄油外,其余4组小鼠分别腹腔注射20 mg·kg 1的BPA,连续7d,建立生精损伤模型.同时C、D、E组小鼠分别灌服7d不同剂量的LBP(50、100、200 mg·kg-1),正常对照组(A组)和模型组(B组)小鼠灌服等量生理盐水.制备组织切片观察睾丸组织病理学变化,免疫组化法测定睾丸组织Caspase-3、Bax和Bcl-2凋亡蛋白的表达.结果显示,BPA可极显著增加睾丸生精细胞Caspase-3和Bax的阳性细胞数量(P＜0.01),降低Bcl-2的表达(P＜0.05).补充不同剂量LBP后,Caspase-3的阳性表达均极显著低于模型组(P＜0.01).200 mg·kg-1 LBP组生精细胞Bax的阳性细胞数量极显著低于模型组(P＜0.01);Bcl-2的表达随LBP剂量的增加而提高,其中200 mg·kg1LBP组阳性表达极显著高于模型组(P＜0.01),Bcl-2/Bax比值也随着LBP剂量的增加而上升.结果表明,枸杞多糖通过调节凋亡相关基因的表达,抑制生精细胞凋亡,从而缓解双酚A引起的雄性生殖损伤.