山羊妊娠早期胎儿胎盘血管形成及相关基因的表达

旨在探究大足黑山羊妊娠早期胎儿胎盘血管发育、分布和血管生成相关因子表达状况,并对血管生成相关因子表达之间和血管发育进行相关性分析。本研究随机选取15只8月龄、体格相近、身体健康的国家级畜禽遗传资源—大足黑山羊青年母羊,经同一种公羊自然交配后(以末次配种当天记为0 d),经剖腹产手术采集妊娠第20、25和30天的胎儿和胎儿胎盘以及经屠宰采集妊娠第45和60天的胎儿和胎儿胎盘作为研究对象,通过免疫组化法评估胎盘血管发育和分布情况,采用qRT-PCR技术检测主要血管生成相关基因的mRNA表达水平,分析血管生成相关基因之间以及与胎盘血管发育分布的相关性。结果显示,胎儿体重和体长随着妊娠的进行逐渐增加,且血管内皮细胞阳性率处于较高水平(26%)。山羊胎儿胎盘毛细血管总面积/组织区域面积(CAD)逐渐升高;毛细血管总数/单位组织区域面积(CND)在妊娠25～30 d增加,30～60 d降低,毛细血管总面积/毛细血管根数(APC)呈相反趋势;毛细血管总周长/单位组织区域面积(CSD)无显著变化。妊娠早期胎儿胎盘VEGFA的表达量随着妊娠的进行逐渐升高,且与血管分布存在一定的相关性,其受体FLT1和KDR表达量呈先增高后降低的趋势,分别在30和45 d达到峰值。血管生成相关基因ANGPT1/2及其受体TEK和FGF2及其受体FGFR2的表达均在妊娠30 d时较高。综上表明,在妊娠30 d前,胎儿胎盘主要通过毛细血管形成分支促进血管面积的增加;而在30～60 d,主要通过单位血管的增粗促进血管面积的增加,并且血管生成相关基因的表达在妊娠30 d时较高,这可能和子叶开始形成有关。山羊妊娠早期胎儿胎盘中VEGFA可能通过其受体结合与其他血管生成因子共同作用调控胎儿胎盘血管形成。     

大足黑山羊妊娠不同阶段胎盘线粒体相关基因的表达

胎盘在母体-胎儿间物质交换时发挥着重要作用,而其物质交换动力来自胎盘线粒体通过氧化磷酸化产生ATP。为探讨随着动物妊娠阶段的持续,线粒体相关基因的表达量变化,本研究采用RT-PCR技术检测大足黑山羊妊娠20,25,30,60,90和120d胎盘线粒体COXIV、SDHA、PGC-1α、NRF-1和TFAM基因的相对表达量。结果显示,随着大足黑山羊妊娠持续,胎盘子叶和子宫阜线粒体被检测的5项基因相对表达量均呈现先升高后降低、再缓慢变化的趋势。尤其在妊娠25d时相对表达量均达到高峰,但妊娠30d时相对表达量急剧下降。在胎盘子叶组织中COXIV、SDHA和NRF-1的相对表达量分别由0.84,1.53和1.06,降至0.09,0.32和0.22,差异显著(P0.05);在子宫阜中COXIV、SDHA和PGC-1α的相对表达量分别由0.50,4.36和1.36降至0.11,0.84和0.48,差异极显著(P0.01)。妊娠60d后,在胎盘子叶组织中,这些基因相对表达量不断升高;在子宫阜,相对表达量呈递减趋势,但差异均不显著(P0.05)。相关性分析结果显示,子宫阜组织中线粒体相关基因的表达与胎儿及胎盘生长发育指标如胎儿重、胎儿长、胎盘重、胎盘效率、子叶个数和子叶直径呈显著负相关(P0.05);而子叶组织中线粒体相关基因的表达与胎儿长和子叶直径显著性相关(P0.05),但与胎儿重、胎盘质量、胎盘效率和子叶个数无显著相关性(P0.05)。     

大足黑山羊妊娠不同阶段胎盘组织线粒体酶活性和超微结构变化

山羊的胎盘属于子叶型胎盘,胎盘子叶性状和结构与山羊繁殖性能具有较强的相关性。胎盘子叶组织线粒体发挥正常功能是保证胎儿生长发育,进而维持正常妊娠的关键。本试验采用大足黑山羊妊娠60,90,120d的胎盘和胎儿组织为研究对象,检测胎盘子叶及胎儿心、肝、脾、肺、肾组织的线粒体细胞色素C氧化酶(CCO)、琥珀酸脱氢酶(SDH)、Ca++-Mg++-ATP酶和Na+-K+-ATP酶的活性变化,并通过透射电镜技术观测胎盘子叶组织线粒体的形态结构。结果发现,胎盘子叶及胎儿心、肝、脾、肺、肾的线粒体CCO、SDH及ATP酶的活性都有随着妊娠时间的增加而显著提高的趋势,且在妊娠90~120d的上升趋势高于妊娠60~90d,表明妊娠中后期的胎儿生长发育所需要的能量较多;在同一妊娠阶段,胎盘子叶线粒体酶活性均高于胎儿各组织,且差异显著(P<0.05),说明胎盘子叶是妊娠过程中的重要部位,胎儿组织器官在发育过程中存在先后顺序,并且与该器官的功能作用有关;透射电镜观察发现,随着妊娠时间的增加胎盘线粒体数量增多,密度增大且主要聚集在子叶绒毛附近,这体现了胎盘子叶的营养交换作用。     

山羊妊娠早期胎盘滋养层细胞TET1、MMPs与TIMPs的表达规律

TET1的去甲基化作用对胎盘功能具有重要调控作用,胎盘滋养层分泌的基质金属酶(matrix metalloproteinase,MMPs)使其具有迁移和侵袭功能,保证了滋养层细胞正常侵入子宫内膜建立妊娠,但滋养层细胞TET1、MMPs及TIMPs在山羊妊娠早期胎盘滋养层细胞中的表达规律未知。因此,本试验取妊娠20,25,30,45和60 d大足黑山羊胎盘滋养层,利用荧光定量PCR技术检测并分析了MMP2和MMP9、TIMP1和TIMP2基因相对表达规律,观察TET1和MMP9在各时期胎盘滋养层中的分布规律。结果显示,除20,25 d外,MMP9的表达量均高于MMP2,在30和60 d差异显著(P0.05),45 d时差异达到极显著(P0.01);除20 d外,TIMP1的表达量均高于TIMP2,且在30,45 d时具有显著性差异(P0.05)。免疫组化染色结果发现TET1在细胞核和细胞质中均有表达,MMP9则主要分布于细胞质和细胞膜,且两者表达变化存在一定相似性。结果表明,山羊妊娠25～60 d,可能由MMP9和TIMP1主要调控胎盘滋养层细胞迁移和侵袭,且在该过程中,TET1可能通过影响MMP9的表达,进而影响山羊胎盘滋养层细胞迁移和侵袭。     

enJSRV及其受体HYAL2在妊娠蒙古绵羊胎盘组织中的表达

为了探究enJSRV及其受体HYAL2在妊娠蒙古绵羊的发育过程和肺腺瘤病的致瘤过程中的作用,运用TaqMan实时荧光定量PCR和组织原位杂交技术对其在不同妊娠时期（30、50、70、90、110、130d）蒙古绵羊胎盘的表达规律和分布定位进行了研究。荧光定量PCR结果显示,enJSRV及其受体HYAL2在蒙古绵羊胎盘组织的不同妊娠时期均有表达,通过SPSS统计学分析可以看出,妊娠蒙古绵羊胎盘组织中enJSRV基因的表达于90d时达到高峰,之后开始下降,直至妊娠130d表达量最低,且enJSRV与其受体HYAL2mRNA之间亦无线性相关性。原位杂交结果显示,enJSRV及其受体HYAL2mRNA在妊娠30、50、130d蒙古绵羊胎盘的腺上皮细胞、肉阜、胎盘绒毛叶、间质及滋养外胚层中均有阳性信号表达。enJSRV及其受体HYAL2在不同妊娠时期蒙古绵羊胎盘组织的表达规律和分布定位揭示其在胎盘的形成过程中可能发挥重要作用,且可通过干扰enJSRV的侵入而影响肺腺瘤病的发生。     

BDNF和TRKB蛋白在妊娠期山羊子宫和胎盘的表达

为探讨脑源性神经营养因子(BDNF)及其受体酪氨酸激酶受体B(TRKB)在妊娠期山羊子宫和胎盘中的表达情况,本实验分别于妊娠15、25、65 d采集子宫和胎盘样品,免疫组织化学方法分析BDNF和TRKB蛋白的分布情况。结果表明:妊娠15 d时,BDNF和TRKB蛋白在子宫内膜上皮和腺上皮细胞中强表达,BDNF在肌层弱表达,而TRKB强表达;妊娠25 d和65 d时,2种蛋白在子宫内膜上皮和腺上皮细胞中维持强表达,同时在胎儿绒毛膜滋养层细胞中表达强烈;与妊娠15 d相比,妊娠25 d和65 d时2种蛋白均在浅层子宫腺强烈表达,深层子宫腺弱表达。综上可知,随着妊娠的进行,BDNF和TRKB蛋白的表达情况也发生变化,提示BDNF对山羊妊娠活动有一定的调节作用,与妊娠期山羊子宫和胎盘的组织结构变化相关联,可能通过与其受体TRKB的特异性结合来实现其功能。     

大足黑山羊胎盘子叶性状和结构及其与繁殖性能的相关性

收集79窝(单羔,n=21,G1;双羔,n=47,G2;三羔,n=11,G3)大足黑山羊正常分娩后胎盘及繁殖性能数据,比较不同产羔类型胎盘子叶承载效率(窝初生重与子叶总面积之比)、子叶密度(子叶个数与胎盘质量之比)、子叶面积和子叶组织学结构、绒毛超显微结构,并且分析子叶性状和结构及其与繁殖性能的相关性。结果表明,大足黑山羊随产羔数增加,胎盘子叶承载效率和子叶总面积极显著增加(P0.01),G1、G2和G3组子叶承载效率分别是(5.70±2.50),(9.23±3.90),(8.15±3.33)g·cm-2,子叶总面积分别为(501.57±124.25),(546.34±197.78),(735.85±194.28)cm2;子叶密度极显著性降低(P0.01),G1、G2和G3组分别是(0.38±0.18),(0.26±0.10),(0.21±0.08)n·g-1,子叶总数无显著性差异(P0.05);由组织学结构观察发现,随着产羔数增加,胎盘子叶内血管数量增多,密度增大,绒毛形状变宽变大,密集程度增加,表面褶皱更丰富。相关性分析表明,产羔数和窝初生重与胎盘质量、子叶总面积、子叶承载效率呈极显著正相关(P0.01)。研究发现山羊胎盘子叶面积与子叶承载效率相互联系;胎盘子叶组织结构及绒毛结构与山羊产羔数有显著性相关。     

川中黑山羊和雷州山羊大小卵泡转录组学分析

试验旨在通过比较两个品种山羊大小卵泡的mRNA表达图谱来挖掘影响山羊卵泡发育的基因,为进一步阐述山羊卵泡发育机制提供数据基础。使用氯前列醇钠对川中黑山羊和雷州山羊进行同期发情处理,屠宰后采集卵巢并在体视显微镜下分离单个卵泡（大卵泡>6 mm;小卵泡<3 mm）,提取卵泡组织总RNA进行RNA-seq,利用生物信息学方法检测mRNA表达谱,筛选差异基因,并对其进行GO功能、KEGG通路富集分析。结果显示,川中黑山羊大小卵泡差异基因共4 451个,雷州山羊2 355个,二者共有差异基因1 771个。分析筛选出两个品种共有（INHBA、INHA、CYP19A1、KITLG、LHCGR和STAR）及各自特有（IGFBP6、BMP6和BMPR2）的已报道与卵泡发育相关的基因,此外还筛选出可能与这两种山羊繁殖性能相关的基因（GADD45B、TC2N和MSMO1）。GO功能分析显示,两个品种共有差异基因主要与各种物质的跨膜转运活性有关;KEGG通路分析显示,类固醇生成、细胞因子受体相互作用和cAMP信号通路在两个品种中均存在显著变化。类固醇生成过程中细胞色素P450代谢差异可能是川中黑山羊高产仔数的一个潜在因素。本研究结果为进一步探究山羊卵泡发育的基因功能及不同山羊品种繁殖性能差异提供参考。     

川中黑山羊和雷州山羊大小卵泡转录组学分析

试验旨在通过比较两个品种山羊大小卵泡的mRNA表达图谱来挖掘影响山羊卵泡发育的基因,为进一步阐述山羊卵泡发育机制提供数据基础。使用氯前列醇钠对川中黑山羊和雷州山羊进行同期发情处理,屠宰后采集卵巢并在体视显微镜下分离单个卵泡(大卵泡6 mm;小卵泡3 mm),提取卵泡组织总RNA进行RNA-seq,利用生物信息学方法检测mRNA表达谱,筛选差异基因,并对其进行GO功能、KEGG通路富集分析。结果显示,川中黑山羊大小卵泡差异基因共4 451个,雷州山羊2 355个,二者共有差异基因1 771个。分析筛选出两个品种共有(INHBA、INHA、CYP19A1、KITLG、LHCGR和STAR)及各自特有(IGFBP6、BMP6和BMPR2)的已报道与卵泡发育相关的基因,此外还筛选出可能与这两种山羊繁殖性能相关的基因(GADD45B、TC2N和MSMO1)。GO功能分析显示,两个品种共有差异基因主要与各种物质的跨膜转运活性有关;KEGG通路分析显示,类固醇生成、细胞因子受体相互作用和cAMP信号通路在两个品种中均存在显著变化。类固醇生成过程中细胞色素P450代谢差异可能是川中黑山羊高产仔数的一个潜在因素。本研究结果为进一步探究山羊卵泡发育的基因功能及不同山羊品种繁殖性能差异提供参考。     

大足黑山羊的饲养与管理

随着畜牧业的发展,大足黑山羊的养殖规模有所增加。大足黑山羊是一种经过培育和挑选而形成的优质黑山羊,通常饲养规模较小。大足黑山羊的原产地是重庆大足区。由于该地农业经济较为发达,气候宜人,具有大量的牧草资源,因此适合山羊生长。大足黑山羊在全国的山羊养殖中属于产羔率最高的,其羊肉的品质相较于其它品种也较高,因此大足黑山羊具有很高的研究与经济价值,受到了相关部门的特别关注。本文主要对大足黑山羊的特性进行分析,阐述了大足黑山羊的饲养管理及疾病防疫。     

Quantitative expression and immunohistochemical detection of glucose transporters, GLUT1 and GLUT3 in the rabbit placenta during successful pregnancy

Glucose is essential for the development of the fetus. We address here the quantitative expression and immunohistochemical localization of glucose transporter (GLUT1 and GLUT3) in the rabbit placenta during successful pregnancy. Blood glucose level showed a significant decrease at the gestation period in comparison with non-pregnancy. Maternal serum glucose was gradually increased according to fetal development. Quantitative RT-PCR results showed that expression of GLUT1 was significantly increased from day 13 to day 18, while GLUT3 mRNA level was significantly decreased during the same periods. Western blot analysis demonstrated that GLUT1 protein did not change significantly in the placenta during pregnancy when compared to non-pregnant uteri. Immunohistochemistry indicated that distribution of GLUT1 was observed mainly to the surface of the outer trophoblasts, whereas GLUT3 mainly localized to the basal site of the inner trophoblasts and fetal blood vessels. These results suggest that glucose is transported through GLUT1 from the maternal blood stream for use as a placental fuel and for further transport through GLUT3 to the fetal circulation, thus signifying the distinct anatomical localization of GLUT1 and GLUT3 in the rabbit placenta during successful pregnancy.     

Expression and localization of NO synthase isoenzymes (iNOS and eNOS) in development of the rabbit placenta

Nitric oxide synthase (NOS) is a key regulator of angiogenesis and embryogenesis in the mammalian reproductive process. Here, we attempted to clarify the expression and localization of inducible and endothelial NOS (iNOS and eNOS) in the developing rabbit placenta. Real-time RT-PCR analysis indicated that iNOS mRNA was significantly upregulated till the complete development of the placenta (d18), and then significantly decreased at the end of fetal growth stage (d28) during successful pregnancy. The eNOS mRNA was also enhanced in the pregnant uteri and gradually decreased near the term of pregnancy. Western blot analysis also showed elevation of the iNOS and eNOS protein levels during the course of successful pregnancy till the functional maturation of the placenta (d18). Immunohistochemical study revealed distinct localizations of iNOS along the radial arteries and eNOS at the spiral arteries and arterial sinuses in the developing placenta. This may reflect that iNOS and eNOS participate in pregnancy success through placentation-specific vascular formation and by supporting adequate blood circulation in the rabbit placenta.     

BMP4调控睾丸支持细胞增殖的初步研究

旨在研究BMP4对睾丸支持细胞增殖的调控。本试验选取0、1、2和3月龄组的健康大足黑山羊公羊各3只,采集睾丸支持细胞,每次试验均设3个生物学重复和3次技术重复,通过体外培养、细胞免疫荧光、基因干扰、过表达、qPCR和Western blotting等技术对BMP4是否通过Id2对山羊睾丸支持细胞进行调控以及它们的调控关系进行验证。结果发现,BMP4在2月龄组大足黑山羊睾丸支持细胞中的表达量极显著高于0、1月龄组（P<0.01）;在一定范围内,随着BMP4浓度的增加睾丸支持细胞的增殖活性有所增强,BMP4浓度为200 ng·mL^-1时其增殖能力最强（P<0.05）;干扰BMP4后,细胞增殖活力显著下降（P<0.05）,但在72 h后回到正常水平（P>0.05）,PCNA的表达极显著降低（P<0.01）,表明干扰BMP4后细胞的增殖能力受到限制,细胞增殖指数测定结果进一步说明,干扰BMP4后细胞的增殖能力受到限制;过表达BMP4后,Id2基因表达水平极显著增加（P<0.01）,表明BMP4对Id2具有正向调控作用;相对过表达BMP4再干扰Id2试验组,干扰Id2试验组的PCNA基因的表达水平显著降低（P<0.05）,这进一步证明BMP4可以调控该基因和蛋白表达。综上所述,山羊睾丸支持细胞的增殖活力在一定范围内与BMP4的浓度呈正相关;且BMP4能够正向调控Id2的表达,并通过促进Id2的表达进而促进支持细胞的增殖。本研究为阐明BMP4调控山羊睾丸支持细胞的分子机制和生理功能提供了基础。     

猪胎盘营养转运相关基因在不同妊娠期的表达

【目的】探究不同妊娠时期猪胎盘的氨基酸、葡萄糖、脂肪酸转运体的表达模式。【方法】选择15头遗传背景、产仔数接近的杜洛克2~4胎经产健康母猪平均分为3组,所有母猪发情后使用相同公猪精液进行人工授精,在妊娠第40天(D40)、65天(D65)和95天(D95)通过麻醉分别取出每组母猪子宫,快速打开子宫分离出每个胎儿的胎盘组织,提取胎盘组织总RNA并反转录合成cDNA,利用合成的引物进行普通PCR扩增,用2.0%琼脂糖凝胶检测扩增产物。采用实时荧光定量PCR检测并比较3个时期胎盘中氨基酸、葡萄糖、脂肪酸转运体相关基因mRNA相对表达水平。【结果】PCR检测结果显示,氨基酸转运体相关基因(SLC7A1、SLC7A2、SLC7A3、SLC7A4、SLC7A10、SLC1A3、SLC1A5、SLC38A10、SLC36A1)、葡萄糖转运体相关基因(SLC2A1、SLC2A2、SLC2A3、SLC2A10、SLC2A12、SLC2A13)及脂肪酸转运体相关基因(FATP1、FATP2、FATP3、FATP4、FABP3、FABP5、FABP7、CD36)的片段长度均与预期相符。实时荧光定量PCR结果显示,在氨基酸转运体中,D65胎盘中SLC7A4、SLC7A10、SLC38A10基因表达水平显著高于D40胎盘(P＜0.05),而SLC7A2基因表达水平显著低于D40胎盘(P＜0.05),且D65胎盘的SLC1A3和SLC7A4基因表达水平均显著低于D95胎盘(P＜0.05);在葡萄糖转运体中,D65和D95胎盘的SLC2A3和SLC2A13基因表达水平显著高于D40胎盘(P＜0.05),D95胎盘的SLC2A1、SLC2A2和SLC2A12基因表达水平显著低于D65胎盘(P＜0.05);在脂肪酸转运体中,D65胎盘的FATP2、FATP4、FABP3、FABP5、FABP7和CD36基因表达水平显著高于D40胎盘(P＜0.05),而FATP1、FATP4和CD36基因表达水平显著低于D95胎盘(P＜0.05)。【结论】在猪妊娠过程中,胎盘中SLC7A10、SLC38A10、SLC7A4、SLC2A3、FATP1、FATP4、FABP5、CD36等基因可能是影响胎儿生长发育的重要营养转运基因。     

Advanced maternal age induces fetal growth restriction through decreased placental inflammatory cytokine expression and immune cell accumulation in mice

Advanced maternal age is a risk factor for female infertility, and placental dysfunction is considered one of the causes of pregnancy complications. We investigated the effects of advanced maternal aging on pregnancy outcomes and placental senescence. Female pregnant mice were separated into three groups: young (3 months old), middle (8–9 months old), and aged (11–13 months old). Although the body weights of young and middle dams gradually increased during pregnancy, the body weight of aged dams only increased slightly. The placental weight and resorption rate were significantly higher, and live fetal weights were reduced in a maternal age-dependent manner. Although mRNA expression of senescence regulatory factors (p16 and p21) increased in the spleen of aged dams, mRNA expression of p16 did not change and that of p21 was reduced in the placenta of aged dams. Using a cytokine array of proteins extracted from placental tissues, the expression of various types of senescence-associated secretory phenotype (SASP) factors was decreased in aged dams compared with young and middle dams. The aged maternal placenta showed reduced immune cell accumulation compared with the young placenta. Our present results suggest that models using pregnant mice older than 8 months are more suitable for verifying older human pregnancies. These findings suggest that general cellular senescence programs may not be included in the placenta and that placental functions, including SASP production and immune cell accumulation, gradually decrease in a maternal age-dependent manner, resulting in a higher rate of pregnancy complications.     

Streptozotocin-induced diabetes decreases placenta growth factor (PlGF) levels in rat placenta

The placenta produces several growth factors, including placenta growth factor (PlGF), which are essential for placenta growth and fetal growth. Diabetic pregnancy induces the abnormal placental growth and fetal development. This study investigated whether diabetes in pregnant rats induces changes in PlGF expression in the placenta. Diabetes was induced by a single intravenous injection of streptozotocin (35 mg/kg body weight) on day 0 of pregnancy, blood and tissue samples were collected on day 20 of pregnancy. In the diabetic group, maternal body weight and fetal weight significantly decreased compared to controls. RT-PCR and Western blot analyses showed that expression of PlGF was significantly decreased in placenta by streptozotocin treatment. Immunohistochemical study showed that the positive signal of PlGF in trophoblast cells was decreased in the diabetic group compared to controls. These findings demonstrate the decline of PlGF in the placenta in diabetic pregnancy.     

Effect of early gestational undernutrition on angiogenic factor expression and vascularity in the bovine placentome

The effect of early gestation maternal undernutrition followed by realimentation on placentomal vascular growth and angiogenic factor expression was determined in multiparous beef cows bred to the same bull. Cows gestating only female fetuses (n = 30) were fed in equal numbers to meet the NRC requirements (control) or were fed below the NRC requirements to lose BW (nutrient restricted; NR) from d 30 to 125 of gestation. After slaughter on d 125 of gestation, 10 control and 10 NR cows were necropsied. The remaining NR cows (n = 5) were then fed to achieve a BCS equal to their control group contemporaries (n = 5) by d 220 of gestation. All cows were fed the control diet from d 220 until 250 of gestation, when the remaining control and NR cows were slaughtered and necropsied. At necropsy, placentomes were fixed via perfusion of the caruncular and cotyledonary arteries to determine capillary vascular density. Cotyledonary (fetal placental) and caruncular (maternal placental) tissues also were snap-frozen in liquid nitrogen, and mRNA concentrations of vascular endothelial growth factor and its 2 specific receptors, fms-like tyrosine kinase and kinase insert domain containing receptor, as well as placental growth factor, were determined. There was no effect of diet or day of gestation on the percentage of proliferating caruncular cells. Although diet did not impact cotyledonary cellular proliferation, there was an increase (P < 0.05) in the percentage of proliferating cells on d 250 compared with d 125 of gestation. Nutrient restriction from d 30 to 125 increased (P < or = 0.10) placental mRNA concentrations of placental growth factor and fms-like tyrosine kinase; however, there was no alteration in vascularity. By d 250 of gestation, NR cows had increased (P < 0.05) caruncular capillary surface density and decreased (P < 0.05) cotyledonary capillary area density, capillary number density, and capillary surface density compared with control cows. Although nutrient restriction had little effect on placental vascularity by d 125, upon realimentation, alterations in vascularity became apparent by d 250 of gestation, suggesting a placental programming effect.     

Effect of nutrient intake during pregnancy on fetal and placental growth and vascular development

Remarkable diversity of size and health of offspring exists after normal pregnancies. When pregnancies are complicated by an extrinsic variable such as inappropriate maternal nutrition, birth weight and health of the neonate are substantially affected. The placenta is the organ through which respiratory gases, nutrients, and wastes are exchanged between the maternal and fetal systems. Thus, transplacental exchange provides for all the metabolic demands of fetal growth. Transplacental exchange is dependent upon uterine and umbilical blood flow, and blood flow rates are in turn dependent in large part upon vascularization of the placenta. Therefore, factors that influence placental vascular development will have a dramatic impact on fetal growth and development, and thereby on neonatal mortality and morbidity. Recent work from our laboratories has focused on the effects of nutrient intake during pregnancy on placental growth and vascular development. Both nutrient restriction of the adult dam and overnourishment of the adolescent dam during pregnancy suppress placental cell proliferation and vascularity. Furthermore, placental expression of angiogenic factors and their receptors, factors that are known to affect vascular growth, are perturbed by level of nutrition. Studies in this area will lead to improved methods to manage nutritionally-compromised pregnancies.     

母猪妊娠期不同能量水平对后代公猪生长性能、睾丸发育与免疫的影响

试验旨在研究母猪妊娠期能量水平对后代睾丸发育与免疫的影响及其作用机理。选取30头体重、背膘相近的7~9胎长白×约克夏（LY）经产母猪,按照体重和胎次随机分为2组,每组15个重复,每个重复1头母猪,从妊娠当天分别饲喂正常能量（CON）和低能量饲粮（LE,12.55 MJ/kg）,直到分娩,所有母猪哺乳期均饲喂同一饲粮。分娩后,分别从CON和LE组中挑选体重为平均体重±0.05 kg的后代公猪各15头,断奶后所有公猪按阶段饲喂相同饲粮,于仔猪120日龄时结束试验。记录公猪每个月的体重并计算阶段平均日增重和平均日采食量;采集28和120 d的血液进行血清生化指标和免疫相关细胞因子检测,采集28和120 d的睾丸进行睾丸细胞计数和睾丸免疫相关基因检测。结果表明,与对照组相比,LE组0~59 d平均日增重极显著降低（P<0.01）,28~89 d平均日采食量和0 d睾丸重显著降低（P<0.05）,28 d睾丸指数显著增加（P<0.05）;LE组0和120 d睾丸组织内间质细胞数目、120 d生殖细胞数目、28和120 d支持细胞数目均显著降低（P<0.05）;LE组血清中28 d甘油三酯（TG）和120 d睾酮（T）含量均极显著升高（P<0.01）、雌二醇（E₂）含量极显著降低（P<0.01）,TG、T和E₂含量均存在时间和能量的交互作用（P<0.01）;LE组血液中胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）的含量120 d时极显著降低（P<0.01）,低密度脂蛋白胆固醇（LDL-C）、TC、HDL-C三者均无时间和能量的交互作用（P>0.05）。随着公猪日龄增加,血液中白细胞介素-1α（IL-1α）、肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、免疫球蛋白（IgG）浓度均极显著增加（P<0.01）,其中TNF-α和IL-1β有能量和时间的交互作用。与对照组相比,LE组28 d时TNF-α含量显著降低（P<0.05）,120 d时IL-1β水平显著升高（P<0.05）。LE组28 d紧密连接蛋白1（ZO1）及0和28 d闭合蛋白（Occludin）基因相对表达量均显著降低（P<0.05）,28和120 d时连接黏附分子1（JAM1）基因相对表达量显著增加（P<0.05）。LE组0 d时CCL4基因和28 d时IL-1α基因相对表达量均显著降低（P<0.05）,0和120 d时趋化因子2（CCL2）基因及28 d时细胞间黏附分子1（ICAM1）和酪氨酸激酶2（JAK2）基因相对表达量均显著增加（P<0.05）。与对照组相比,28 d时Toll样受体1（TLR1）基因、0 d时肿瘤坏死因子受体超家族成员Ⅰ型（TNFRSF1A）基因相对表达量均显著降低（P<0.05）,0 d时B细胞κ轻肽基因增强子核因子抑制因子（NFKBIA）、IL-1β和干扰素（IFNG）基因相对表达量均显著增加（P<0.05）。综上所述,母猪妊娠期摄入12.55 MJ/kg能量水平饲粮可降低后代公猪日增重、平均日采食量和睾丸重;降低后代公猪睾丸内生殖细胞数量及免疫相关细胞因子和睾丸免疫相关基因的表达,从而对后代成年后的免疫能力和繁殖性能产生深远影响。     

干扰Smad3促进山羊脂肪细胞分化

旨在克隆山羊Smad3的基础上，明确其组织和细胞表达谱，最终阐明干扰Smad3基因对山羊肌内和皮下脂肪细胞分化的影响。本研究选用5只体况良好的1周龄简州大耳羊，空腹24 h后屠宰并采集相应组织和细胞进行试验。利用RT-PCR技术克隆山羊Smad3基因cDNA区序列并进行生物信息学分析，利用实时荧光定量PCR（real-time quantitative PCR，qPCR）技术检测Smad3基因的组织和细胞时序表达水平；并且合成靶向Smad3的siRNA，采用油红O染色从形态学上明确干扰Smad3对山羊前体脂肪细胞成脂分化的影响，利用qPCR检测干扰Smad3对脂肪细胞分化标志基因C/EBPα、C/EBPβ、LPL、SREBP1、AP2、PPARγ、Pref-1、KLF3、KLF4、KLF6、KLF7、KLF8、KLF9、KLF10和KLF15以及Smads相关基因Smad2、Smad4、Smad7和TGF-β1基因mRNA表达水平的影响，探讨可能的作用机制。结果，获得山羊Smad3基因1 449 bp，其中CDS区序列为1 278 bp，编码425个氨基酸；Smad3在山羊各组织中具有广泛表达特性，且在肾脏中的表达水平最高（P<0.01）；Smad3均在山羊肌内和皮下两种脂肪细胞诱导分化的36 h表达量最低，极显著低于在未分化前体脂肪细胞中的表达丰度（P<0.01）；干扰Smad3后发现显著促进了山羊肌内和皮下脂肪细胞中脂滴的聚集，且脂肪细胞分化标志基因、KLF3、KLF4、KLF8、KLF9、KLF10和KLF15的表达水平显著上升（P<0.05），Pref-1的相对表达水平极显著下降（P<0.01），同时干扰Smad3基因下调了Smad2、Smad4和Smad7基因的相对表达水平（P<0.05）。研究结果指出，干扰Smad3促进山羊脂肪细胞分化，且可能通过调控脂肪细胞分化标志基因C/EBPα、C/EBPβ、LPL、SREBP1、AP2、Pref-1、KLF3、KLF4、KLF8、KLF9、KLF10和KLF15等及协同Smad2、Smad4和Smad7的表达来实现的。