The effect of seminal plasma ?-NGF on follicular fluid hormone concentration and gene expression of steroidogenic enzymes in llama granulosa cells.
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ABSTRACT: BACKGROUND:Nerve growth factor (?-NGF) from llama seminal plasma has been described as a potent ovulatory and luteotrophic molecule after intramuscular or intrauterine infusion in llamas and alpacas. We tested the hypothesis that systemic administration of purified ?-Nerve Growth Factor (?-NGF) during the preovulatory stage will up-regulate steroidogenic enzymes and Vascular Endothelial Growth Factor (VEGF) gene expression in granulosa cells inducing a change in the progesterone/estradiol ratio in the follicular fluid in llamas. METHODS:Experiment I: Female llamas (n?=?64) were randomly assigned to receive an intramuscular administration of: a) 50??g gonadorelin acetate (GnRH, Ovalyse, Pfizer Chile SA, Santiago, Chile, n?=?16), b) 1.0?mg of purified llama ?-NGF (n?=?16), or c) 1?ml phosphate buffered saline (PBS, negative control group, n?=?16). An additional group of llamas (n?=?16) were mated with a fertile male. Follicular fluid and granulosa cells were collected from the preovulatory follicle at 10 or 20?h after treatment (Time 0?=?administration of treatment, n?=?8/treatment/time point) to determine progesterone/estradiol concentration and steroidogenic enzymes and VEGF gene expression at both time points. Experiment II: Granulosa cells were collected from preovulatory follicles from llamas (n?=?24) using ultrasound-guided transvaginal follicle aspiration for in vitro culture to determine mRNA relative expression of Steroidogenic Acute Regulatory Protein (StAR) and VEGF at 10 or 20?h (n?=?4 replicates) and progesterone secretion at 48?h (n?=?4 replicates) after LH or ?-NGF treatment. RESULTS:Experiment I: There was a significant increase in the progesterone/estradiol ratio in mated llamas or treated with GnRH or purified ?-NGF. There was a significant downregulation in the mRNA expression of Aromatase (CYP19A1/P450 Arom) for both time points in llamas mated or treated with GnRH or llama purified ?-NGF with respect to the control group. All treatments except ?-NGF (20?h) significantly up regulated the mRNA expression of 3-beta-hydroxysteroid dehydrogenase (HSD3B) whereas the expression of StAR and Side-Chain cleavage enzyme (CYP11A1/P450scc) where significantly up regulated only by mating (20?h), or ?-NGF at 10 or 20?h after treatment. VEGF was up regulated only in those llamas submitted to mating (10?h) or treated with purified ?-NGF (10 and 20?h). Experiment II: Only ?-NGF treatment induced an increase of mRNA abundance of StAR from llama granulosa cells at 20?h of in vitro culture. There was a significant increase on mRNA abundance of VEGF at 10 and 20?h of in vitro culture from granulosa cells treated with ?-NGF whereas LH treatment increases VEGF mRNA abundance only at 20?h of in vitro culture. In addition, there was a significant increase on progesterone secretion from llama granulosa cells 48?h after LH or ?-NGF treatment. CONCLUSIONS:Systemic administration of purified ?-NGF from llama seminal fluid induced a rapid shift from estradiol to progesterone production in the preovulatory follicle. Differences in gene expression patterns of steroidogenic enzymes between GnRH and mated or ?-NGF-treated llamas suggest local effects of seminal components on the preovulatory follicle.
SUBMITTER: Valderrama XP
PROVIDER: S-EPMC6647067 | biostudies-literature | 2019 Jul
REPOSITORIES: biostudies-literature
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