表皮生长因子对水牛胚胎体外发育及凋亡的影响

为了探讨表皮生长因子(EGF)对水牛早期胚胎体外发育及凋亡的影响,通过收集屠宰场卵巢卵母细胞进行体外成熟和体外受精,将假定的受精卵置于含不同浓度EGF(0,25,50和100 ng/mL)的培养液中培养,检查分裂率和囊胚发育率,用细胞凋亡试剂盒(Annexin-V-FluosStaining kit)试剂染色,统计囊胚细胞凋亡率和坏死率。结果表明:50 ng/mL EGF组的孵化囊胚率显著高于对照组(P<0.05),该组细胞凋亡率和坏死率显著低于对照组(P<0.05)。100 ng/mL EGF的卵裂率、囊胚率、D7囊胚率和孵化囊胚率显著低于对照组和其他试验组(P<0.05)。细胞凋亡率和坏死率显著高于其他各组(P<0.05)。提示:一定浓度的EGF可提高囊胚孵化率,并可抑制胚胎细胞的凋亡。     

饲粮中添加表皮生长因子对蛋鸡卵巢形态学、激素含量及凋亡因子表达的影响

【目的】试验旨在研究饲粮中添加不同剂量表皮生长因子(epidermal growth factor;EGF)对蛋鸡卵巢形态学、激素含量及凋亡因子表达的影响;为探明EGF促进蛋鸡卵巢的生长发育提供一定的理论依据。【方法】选用240只260日龄体重相近、健康的白来航高产蛋鸡;随机分为4个处理组;每组5个重复;每个重复12只鸡。对照组(Con)蛋鸡饲喂不添加EGF的基础饲粮;3个试验组(LG、MG、HG)蛋鸡分别在基础饲粮中添加200、400及800 mg/kg EGF。预试期7 d;正试期42 d。每个重复取2只蛋鸡;采集血液和组织样品;测量卵巢、输卵管、卵泡的重量;统计卵泡分级的数量;测定血清中促黄体激素(LH)、促卵泡素(FSH)、雌二醇(E₂)和孕酮(P₄)含量;并利用实时荧光定量PCR和Western blotting测定卵巢中凋亡因子Bcl-2和Caspase-3的表达量。【结果】与Con组相比;①饲粮中添加不同剂量EGF对蛋鸡卵巢重、卵巢指数和白卵泡数量均有显著影响(P＜0.05);但各组卵巢在形态上无明显变化。②LG、MG、HG组蛋鸡血清中LH、FSH和E₂水平均显著升高(P＜0.05);LG、MG组蛋鸡血清中P₄水平显著升高(P＜0.05)。③LG、MG组蛋鸡卵巢中Bcl-2基因相对表达量均显著升高(P＜0.05);LG、MG、HG组蛋鸡卵巢中Bcl-2蛋白相对表达量均显著升高(P＜0.05);LG、MG组蛋鸡卵巢组织中Caspase-3基因相对表达量均显著降低(P＜0.05);MG、HG组蛋鸡卵巢组织中Caspase-3蛋白相对表达量均显著降低(P＜0.05)。【结论】在本试验条件下;饲粮中添加不同剂量EGF在一定程度上可促进卵巢生殖激素分泌和卵泡发育;有效抑制细胞凋亡进而改善蛋鸡生产性能。EGF在白来航高产蛋鸡饲粮中的推荐添加量为400 mg/kg。     

Does the tumour microenvironment alter tumorigenesis and clinical response in transmissible venereal tumour in dogs?

The canine transmissible venereal tumour (CTVT) is a transmissible cancer that is spread naturally between dogs, with the ability to develop and evade the immune system, despite strict immune surveillance of the host. Furthermore, molecular signalling between cells of the immune system and the tumour microenvironment appear to influence the behaviour and development of the tumour. Thus, this study aimed to quantify the expression of genes related to the immune system such as IL‐6, IFN‐γ, and TGF‐β, as well as angiogenic factors (VEGF, CXCR4), in CTVT cells in vivo and in vitro (primary culture), correlating with the clinical response of the animals treated with vincristine. As expected, the most prevalent subtype was plasmacytoid cells, although lymphocytic cells were also found, indicating the possibility of polyclonality. When we compared the gene expressions of IFN‐γ and IL‐6, we mostly found low expression, concluding that MHC expression was probably not occurring in tumour cells, and no activation of immune cells to eliminate the tumour. The TGF‐β gene was normal in the majority of animals but demonstrated decreased expression in vincristine resistant animals, leading to the hypothesis that the concentration of tumour‐derived TGF‐β was affecting and even suppressing the real TGF‐β expression, favouring tumour proliferation and progression in these cases. VEGF expression was extremely high, demonstrating its angiogenic role in tumour growth, while CXCR4 was decreased, possibly because of CTVT’s low metastatic potential. Thus, we concluded that the tumour microenvironment, together with the immune system of the host, influences CTVT, presumably altering its tumorigenesis and the animal’s clinical response to treatment.     

Energy requirements of puppies of two different breeds for ideal growth from weaning to 28 weeks of age

To ensure an optimal growth is crucial in raising healthy dogs, especially in large and giant breeds. Dogs with a moderate growth velocity tend to have lesser problems with developmental orthopaedic diseases than those with forced or maximum weight gain. In this study, the energy needs of growing dogs from two different breeds (Beagles as a medium‐size breed and Foxhound crossbreds as a large‐size breed) to ensure a growth development as recommended by the National Research Council (NRC) were determined at the age of 6–28 weeks. After weaning at the age of 6 weeks, the food rations sufficient to meet the energy requirements of each individual puppy were adjusted every other day according to growth level, guaranteeing a development consistent with the recommended weight curve for the respective breed size. The food and therefore energy intake of the puppies was registered daily; it ranged from 0.72 to 2.34 times the maintenance requirements with little effect of age. During the whole period, however, there was a consistent breed difference: Foxhound‐Boxer‐Ingelheim Labrador crossbreds (FBIs) had higher energy intakes expressed as multiples of maintenance than Beagles, suggesting that during the major period of growth, the energy requirement is not a function of age. Adult Beagles and FBIs showed similar differences in energy requirements as already during growth as shown in this study. This indicates that breed differences in energy requirements have already to be taken into account during growth. On the other hand, the results showed clearly lower energy needs for growth in these two different breeds than recommended in the NRC.     

孕激素诱导的生长激素与犬的乳腺肿瘤

乳腺肿瘤是犬的最常见的肿瘤,约占母犬肿瘤总数的一半;乳腺肿瘤约有一半是恶性肿瘤,发生转移的比率很高。犬乳腺肿瘤的发病原因还不很明确,它的形成都受哪些因子调节还未完全确定。孕激素能够诱导乳腺组织生成并蓄积生长激素,使乳腺增生,最终导致犬乳腺肿瘤的形成。在此过程中,雌激素受体、孕激素受体、生长激素结合蛋白和生长激素受体在乳腺癌的形成、发展中起关键作用。从内分泌的角度对犬乳腺肿瘤发病机理作了简单综述,以期为激素治疗乳腺肿瘤提供一些理论依据。