Andrade Luis P, Rhind Stewart M, Rae Michael T, Kyle Carol E, Jowett Jamie, Lea Richard G
Instituto Politécnico de Castelo Branco, Escola Superior Agraria, Quinta Sr.ª Mércules, Castelo Branco, 6001-909, Portugal.
J Negat Results Biomed. 2013 Jan 8;12:2. doi: 10.1186/1477-5751-12-2.
The aim of this study was to determine the effects of maternal undernutrition on ovine fetal testis morphology and expression of relevant histological indicators. Maternal undernutrition, in sheep, has been reported, previously, to alter fetal ovary development, as indicated by delayed folliculogenesis and the altered expression of ovarian apoptosis-regulating gene products, at day 110 of gestation. It is not known whether or not maternal undernutrition alters the same gene products in the day 110 fetal testis.
Mature Scottish Blackface ewes were fed either 100% (Control; C) or 50% (low; L) of estimated metabolisable energy requirements of a pregnant ewe, from mating to day 110 of gestation. All pregnant ewes were euthanized at day 110 and a sub-set of male fetuses was randomly selected (6 C and 9 L) for histology studies designed to address the effect of nutritional state on several indices of testis development. Sertoli cell numbers were measured using a stereological method and Ki67 (cell proliferation index), Bax (pro-apoptosis), Mcl-1 (anti-apoptosis), SCF and c-kit ligand (development and apoptosis) gene expression was measured in Bouins-fixed fetal testis using immunohistochemistry.
No significant differences were observed in numbers of Sertoli cells or testicular Ki67 positive cells. The latter were localised to the testicular cords and interstitium. Bax and Mcl-1 were localised specifically to the germ cells whereas c-kit was localised to both the cords and interstitium. SCF staining was very sparse. No treatment effects were observed for any of the markers examined.
These data suggest that, unlike in the fetal ovary, maternal undernutrition for the first 110 days of gestation affects neither the morphology of the fetal testis nor the expression of gene products which regulate apoptosis. It is postulated that the effects of fetal undernutrition on testis function may be expressed through hypothalamic-pituitary changes.
本研究旨在确定母体营养不足对绵羊胎儿睾丸形态及相关组织学指标表达的影响。先前有报道称，绵羊母体营养不足会改变胎儿卵巢发育，在妊娠110天时表现为卵泡发生延迟以及卵巢凋亡调节基因产物表达改变。目前尚不清楚母体营养不足是否会改变妊娠110天胎儿睾丸中的相同基因产物。
将成熟的苏格兰黑脸母羊从交配至妊娠110天期间，按照怀孕母羊估计代谢能需求的100%（对照组；C）或50%（低营养组；L）进行饲养。所有怀孕母羊在妊娠110天时实施安乐死，并随机选取一部分雄性胎儿（6只C组和9只L组）进行组织学研究，以探讨营养状态对睾丸发育的几个指标的影响。使用体视学方法测量支持细胞数量，并采用免疫组织化学法检测在Bouin氏固定的胎儿睾丸中Ki67（细胞增殖指数）、Bax（促凋亡）、Mcl-1（抗凋亡）、SCF和c-kit配体（发育和凋亡）基因的表达。
支持细胞数量或睾丸Ki67阳性细胞数量未观察到显著差异。后者定位于睾丸索和间质。Bax和Mcl-1特异性定位于生殖细胞，而c-kit定位于睾丸索和间质。SCF染色非常稀少。在所检测的任何标志物中均未观察到处理效应。
这些数据表明，与胎儿卵巢不同，妊娠前110天母体营养不足既不影响胎儿睾丸的形态，也不影响调节凋亡的基因产物的表达。据推测，胎儿营养不足对睾丸功能的影响可能通过下丘脑-垂体的变化表现出来。
