Expression of the insulin-like growth factor (IGF) system in the bovine oviduct at oestrus and during early pregnancy

Abstract

Early mammalian embryo development in vitro can be enhanced by co-culture with oviductal cells and by the addition of insulin-like growth factors (IGFs). This study examined the expression patterns of the oviductal IGF system in cattle in relation to the number of days after oestrus and the presence or absence of embryos. Oviducts were collected from: (i) 66 nulliparous heifers on day 3, day 6 or day 16 after insemination and from (ii) ten non-pregnant, lactating cows on day 0 or day 1 of the oestrous cycle. Oviducts were coiled, frozen whole and sectioned for in situ hybridization. Expression patterns of mRNAs encoding IGF-I, IGF-II, type 1 IGF receptor (IGF-1R), and the IFG binding proteins (IGFBP)-1, -3 and -5 were determined from autoradiographs. Separate measurements were made for the mucosa and muscle layers of the infundibulum, ampulla and isthmus. None of the parameters measured differed between heifers with or without the presence of an embryo. mRNAs encoding IGF-I and IGF-1R were present in the mucosa and muscle of all three oviductal regions, and the highest value of IGF-I mRNA was measured in heifers on day 3. IGF-II mRNA was expressed predominantly in the muscle wall. IGFBP-1 mRNA was not detectable, whereas mRNAs encoding IGFBP-3 and -5 were expressed in both the muscle and mucosa. IGFBP-3 expression was higher in cows on day 0 and day 1 of the oestrous cycle than in heifers on day 3, day 6 and day 16 after insemination. A peak of IGFBP-5 expression was reached on day 6. Locally or systemically produced IGFs, regulated by IGFBPs, may act directly on the embryo or indirectly via modulation of oviductal secretions and muscular activity to influence the success of early embryo development.

Human fallopian tube epithelium co-culture with murine ovarian follicles reveals crosstalk in the reproductive cycle

“…In vitro cultured murine follicles were engineered to secrete hormones in a manner that phenocopied the reproductive cycle (Skory et al, 2015) and were used to stimulate a physiological response in primary human fallopian tube tissue. In the co-culture system, the factors produced by the follicles during growth, ovulation and luteinization impacted fallopian tissue morphology and protein secretion, such as OVGP1, IGF1, VEGF-A and IL8, producing similar results to in vivo observations (Palter et al, 2001;Pushpakumara et al, 2002;Lam et al, 2003;Briton-Jones et al, 2004). In order to understand whether the dynamic changes of these factors in the reproductive cycle generated by the murine follicle were due to the steroid hormones, stepwise exogenous estrogen and progesterone were used to mimic the menstrual cycle steroid hormone patterns in our coculture system.…”

“…Oviduct-specific glycoprotein 1 [OVGP1], produced by fallopian secretory cells, positively influences the capacitation of sperm and its motility prior to fertilization (Erickson-Lawrence et al, 1989;Verhage et al, 1997). Insulin-like growth factor 1 [IGF1] is one of the growth factors produced by the secretory epithelium cells, and cyclic changes in IGF1 concentration during the menstrual cycle are critical to embryonic development (Carlsson et al, 1993;Schmidt et al, 1994;Stevenson and Wathes, 1996;Pushpakumara et al, 2002;Swangchan-Uthai et al, 2011). Vascular endothelial growth factor A [VEGF-A] is a potent mitogen for vascular endothelium and can stimulate vascular permeability.…”

Hyaluronan and hyaluronidase, which is better for embryo development?

“…IGF1 is linked to embryo development. IGF1 is locally produced by the oviduct (Pushpakumara, et al 2002) and the uterus (Robinson, et al 2000) and can affect embryos though its receptors on the embryo. The bovine embryo can respond to IGF1 treatment in vitro and improved development to the blastocyst stage was demonstrated in many studies (see Block, et al 2011 for review).…”

Characterisation of endometrial gene expression and metabolic parameters in beef heifers yielding viable or non-viable embryos on Day 7 after insemination

“…While the oviductal environment has an important role in early embryonic development (Pushpakumara, et al 2002;Wolf 2003, Fenwick et al 2008) the main focus of this study was on the uterine component that affects early embryonic development. Alterations in the local uterine microenvironment can be one of the potential factors contributing to the subfertility in these heifers.…”