The aim of this study was to quantify immune cell populations within the cow corpus luteum (CL) throughout the oestrous cycle in order to investigate whether these cells could be involved in controlling luteal function, particularly around the time of luteolysis. Six CL were collected from each of four stages of the oestrous cycle and were identified on the basis of their gross appearance, for preliminary immunohistochemical studies. Immune cell populations and MHCII expression varied throughout the oestrous cycle. In particular, the number of macrophages, T-lymphocytes (CD5+, CD4+) and MHCII expression was significantly higher in late stage CL (after luteolysis) compared to all other stages. To study in more detail the cellular events associated with luteolysis, the oestrous cycles of 19 cows were synchronised. CL were collected between days 16 and 20 of the following oestrous cycle. A significant increase in the number of T-lymphocytes (CD5+, CD8+) was detected in CL collected from day 16 onwards, compared to days 13-14. This increase occurred prior to functional luteolysis. Artificially-induced luteolysis was then assessed as a potential model for further studies around luteolysis. CL collected 6, 12, and 24 hours after luteolysis induced using a single injection of 25mg PGF<SUB>2α</SUB> had undergone dramatic structural regression which bore little resemblance to events during normal luteolysis and so this model was rejected. The role of endogeoous PGF<SUB>2α</SUB> in inducing the influx of T-lymphocytes was then investigated. Production of PGF<SUB>2α</SUB> was inhibited in 12 cows between days 15 and 18 of the oestrous cycle and artificially replaced in six of the cows for 24 hours before collection of the CL on day 18. The number of macrophages was significantly lower in all animals in which PGF<SUB>2α</SUB> was inhibited compared to control animals but T-lymphocyte numbers were not significantly altered.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:640502 |
| Date | January 1998 |
| Creators | Anderson, Lesley A. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/29760 |
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