Groenewald H B
Department of Anatomy, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Onderstepoort J Vet Res. 1993 Sep;60(3):197-204.
Mortalities due to digestive disturbances occur in homozygous grey and white lambs after they have reached weaning age. Milk-filled, distended rumens, due to malfunctioning of the oesophageal groove, are found 24 h after birth. Scanning electron microscopical studies revealed that milk caused sloughing of the luminal cells in the forestomachs of the affected lambs, while no sloughing of cells was apparent in control black lambs. The purpose of this study was to compare the ultrastructure of the forestomach mucosa of grey, white and black Karakul lambs; to determine whether the sloughing of luminal cells was evident in sections; and, if possible, to find a reason for the desquamation of the cells. Samples of the forestomach of grey, white and black Karakul lambs were prepared routinely for electron microscopy and studied with a Phillips electron microscope. In all the lambs the mucosa of the forestomach was a stratified squamous epithelium consisting of a stratum basale, stratum spinosum and stratum corneum. In the grey and white lambs the luminal cells of the stratum corneum were electron dense, non-nucleated and vacuolated. Sloughing of luminal cells was observed. In the black lambs no sloughing of cells was evident and the luminal cells were moderately electron-dense, nucleated elements. Desquamation of the luminal cells in the affected lambs revealed the underlying layer with its exposed desmosomal attachment sites. This explained the differences in the appearance of the luminal cells in the three groups of lambs as revealed by the scanning electron microscope.
纯合的灰色和白色羔羊在达到断奶年龄后会因消化功能紊乱而死亡。出生后24小时可发现，由于食管沟功能异常，瘤胃充满乳汁且膨胀。扫描电子显微镜研究显示，乳汁导致患病羔羊前胃腔面细胞脱落，而对照的黑色羔羊未见细胞脱落。本研究的目的是比较灰色、白色和黑色卡拉库尔羔羊前胃黏膜的超微结构；确定切片中是否明显存在腔面细胞脱落；如果可能，找出细胞脱屑的原因。将灰色、白色和黑色卡拉库尔羔羊的前胃样本常规制备用于电子显微镜检查，并使用飞利浦电子显微镜进行研究。在所有羔羊中，前胃黏膜均为复层鳞状上皮，由基底层、棘层和角质层组成。在灰色和白色羔羊中，角质层的腔面细胞电子密度高、无核且有空泡。观察到腔面细胞脱落。在黑色羔羊中，未见细胞脱落，腔面细胞为中等电子密度的有核细胞。患病羔羊腔面细胞的脱屑显示出其下方带有暴露的桥粒附着位点的层。这解释了扫描电子显微镜所揭示的三组羔羊腔面细胞外观的差异。
