Abstract:
Llama reproductive physiology is unique when compared with other livestock species. Llamas carry 95-98% of all pregnancies in the left uterine horn. It is believed that there is a physiological difference between the uterine horns that contributes to this phenomenon. This study examined the uterine environment for protease and protease inhibitors, specifically, matrix metalloproteases (MMP) and tissue type (tPA) and urokinase type plasminogen activators (uPA) and their respective inhibitors. Llama uterine fluid was collected non-surgically from luteal phase pregnant and non pregnant females on days 7, 9, and 11 post-copulation. Uterine fluid was collected a single time from follicular phase (non-ovulatory) females. Fluid was assayed for protein concentration and corrected to 1 mg/mL. Proteases were detected with 10% polyacrylamide gel electrophoresis copolymerized with gelatin for MMP detection or casein and human plasminogen for PA detection. The gels were then analyzed for changes in relative percent of detected proteases.Both MMPs and PAs were detected. There was no difference due to day, reproductive status or uterine horn for high molecular mass MMPs. Low molecular mass MMPs differed for the luteal phase females due to the combined interaction of day x status and day x status x side. There were multiple interactions for the various molecular mass categories of PA/PAls. The changes that occurred in protease percentages are consistent with embryonic migration, maternal recognition of pregnancy and preparation for implantation of the embryo. Furthermore, the evidence revealed in this study suggests that there is a physiological difference due to reproductive status, day and uterine horn, which may support evidence as to why pregnancies are carried in the left uterine horn
