Physiology and Endocrinology 2

摘要

Nerve growth factor-β (NGF) is a seminal plasma protein that inducesovulation and has a luteotrophic effect in camelids, but little is knownregarding the interactions of seminal plasma-derived NGF on the preovulatoryfollicle in the bovine species. Our objectives were to assessthe effects of purified bovine NGF on steroidogenesis and angiogenicmarkers in the bovine pre-ovulatory follicle. Two Holstein heifers weresynchronized, and ovariectomy was performed via colpotomy when apre-ovulatory follicle >12 mm was present. The pre-ovulatory folliclewas excised from the ovary, fluid was aspirated, and the remainingtissue was dissected. The theca interna with adherent granulosa cellswas peeled from the theca externa and surrounding stromal tissue andcut into small pieces (average weight: 5.3 ± 0.7 mg). The follicle tissuepieces (n = 24) were incubated in 0.5 mL of Eagle’s MEM culturemedium supplemented with 1% l-glutamine, 1% nonessential aminoacids, 1% penicillin-streptomycin, 1% insulin-transferrin-selenium,10% fetal bovine serum, 40 ng/mL cortisol, 4 ng/mL LH, and 4 ng/mLFSH. Culture wells were either supplemented with 100 ng/mL NGF (n= 12) or left as an untreated control (n = 12). Medium was withdrawnand replaced with fresh medium at 3, 6, 12, 24, 48, and 72 h of cultureand frozen at −80°C for hormone analysis and follicle tissue pieceswere frozen to measure steroidogenic and angiogenic gene expressionusing qPCR. A general linear mixed model with repeated measures forhormone data and Kruskal-Wallis rank sum test for non-parametric datawere performed. Treatment with NGF increased testosterone and (P <0.01) and steroidogenic enzyme 17β-hydroxysteroid dehydrogenase(P = 0.04) in the follicle wall extracts. There was no effect of NGF onprogesterone and estradiol (P ≥ 0.14) or other steroidogenic enzymes(P ≥ 0.31). Treatment with NGF reduced (P = 0.02) fibroblast growthfactor 2 (Fgf-2) but did not alter other angiogenic factors (P ≥ 0.44).In conclusion, NGF affected steroidogenesis increasing testosteroneproduction and reduced Fgf-2, a marker of cell remodeling.