Evaluation of the effect of mating, intrauterine deposition of raw seminal plasma or seminal plasma purified β-NGF on endometrial vascularization in llamas

The aim of this study was to evaluate the endometrial vascularization area (EVA) of both uterine horns in llamas subjected to different intrauterine treatments resembling physiological conditions after a single mating. Llamas with a growing follicle (≥8 mm) were randomly assigned to: a) single mating with a fertile male (mating; positive control; n = 6); b) intramuscular administration of 50 μg of gonadorelin acetate plus an intrauterine infusion of 4 ml of PBS (GnRH; negative control; n = 4); c) intrauterine infusion of 4 ml of raw llama seminal plasma (SP; n = 4) or d) intrauterine infusion of 10 mg of β-NGF purified from llama semen diluted in 4 ml of PBS (spβ-NGF; n = 6). Females in GnRH, SP and NGF group received 50% of treatment volume into each horn by guiding an insemination pipet through the cervix. Ovaries were examined by ultrasonography every 12 h until Day2 (Day 0 = Day of treatment) to determine ovulation. Power-Doppler ultrasonography evaluation of EVA in a cross-section of the middle segment of each horn was conducted at 1 h before and 1, 3, 6, 12 and 24 h (intensive evaluation) and 2, 4, 6 and 8 days (long-term evaluation) after treatment administration. Serial EVA data was analyzed as a 2-by-2 factorial design for repeated measures using the MIXED procedure. The analysis included main effects of treatment (mating, SP, spβ-NGF or GnRH), uterine horn (left vs right), time, and their interactions. According to the 2 by 2 analysis there was no effect of uterine horn on EVA during the first 24 h and from Day 2 to Day 8 after treatment; therefore, data were grouped based on treatment type regardless of uterine horn for both periods of observation. Thus, EVA was affected by time (P