The histological study of germ cell genesis in mongolian ovine fetal ovary

Using the method of histological routine,histological structure of 37-99 day-old ovine fetal ovaries were studied.When the sheep embryo is 37 days old,it can be distinguished female or male from external appearance.About 37-51 d,the quantity of oogonia grows rapidly and the synplasma-like oogonia can be found in this stage.About 55-76 d,much of the syncytium-like cell group is found in the ovary.The un-typical primordial follicle is found in the ovary cortices from 58 d.The typical primordial follicle is found in deep layer of the ovary cortices from 73 d;and on the 81 d,the number of primordial follicles increases.Primary follicles are found in deep layer of cortices at 99 d.In contrast to mature oocytes,the germ cells are active cell-growing and dividing,changing shape and even migrating within the fetal ovary,hence more changes at this development stage.Our observations provide the morphometric and apoptosis aspects of sheep fetus ovary and evidence that apoptosis in the sheep fetus ovary is associated with germ cells.