Treatment with eCG Decreases the Vascular Density and Increases the Glandular Density of the Bovine Uterus

Abstract

The uterus plays an essential role in mammalian reproduction and is a target of several hormonal protocols used to improve fertility in cattle. Many studies highlighted the importance of eCG treatment following fixed-time artificial insemination in improving follicular growth, ovulation and pregnancy rates in cattle. Moreover, eCG has been implicated in angiogenesis, leading to important changes in uterine blood flow and vascularisation. However, there is still a lack of information regarding the specific alterations induced by eCG upon glandular and vascular characteristics of bovine uterus. To investigate the influence of eCG on: uterine thickness and area; uterine artery diameter and area; uterine vascular and gland density; and the expression of the VEGFA-system, the uteri of crossbred beef cows were collected. All cows were submitted to follicular wave emergence synchronization. On day four of protocol, cows submitted to superovulation (n = 6) received 2000 IU eCG, on day eight, after expected follicular deviation, cows submitted to stimulatory treatment (n = 5) received 400 IU eCG. Control cows (n = 5) did not receive eCG. On day five po cows were subjected to ultrassonographic evaluation and slaughtered for uterine tissue sampling on day six po. Uterine vessels and glands were quantified by the counting point stereological method. The VEGFA-system was localized in different cellular types, showing no qualitative or quantitative differences in the site of expression or the intensity of the positive signal among the groups. Vascular density was decreased in the endometrium of stimulated and myometrium of superovulated cows compared with the control ones, which showed higher vascular density in the myometrium and endometrium of the ipsilateral uterine horn. The uterine gland density was higher in superovulated compared with stimulated and control cows. Thus, we can infer that stimulatory or superovulatory treatments with eCG influence the vascular density in the endometrium and myometrium in cattle.

Lipid droplets in the ovine uterus during the estrous cycle: Effects of nutrition, arginine, and FSH

“…For example, in humans, gonadotropin treatment resulted in alterations of mRNA expression of receptors for steroids, and other hormones and growth factors in the endometrium, and in steroid serum concentrations [40,41,[77][78][79]. In cows, treatments with gonadotropins resulted in altered oocyte LD accumulation and blastocyst development, expression of genes that regulate metabolic activity of the embryo, serum profile of P4 and PG metabolites, milk E2 concentration, endometrial and embryonic gene expression, and uterine blood flow, secretory functions, morphology and vascular density [43][44][45][80][81][82][83][84]. In mice, some adverse effects of gonadotropin treatments on blastocyst and conceptus gene expression, fetal development and and lower implantation and pregnancy rates have also been demonstrated [85,86].…”

Equine Chorionic Gonadotropin Modulates the Expression of Genes Related to the Structure and Function of the Bovine Corpus Luteum

“…Angiogenin, in turn, interacts with endothelial and smooth muscle cells to induce a wide range of cellular responses including cell migration, invasion, proliferation, and formation of tubular structures [ 53 ]. As shown in earlier studies [ 21 , 54 ], neither stimulatory nor superovulatory protocols influenced the VEGF system mRNA and protein expression. In contrast to VEGF, ANGPT1 itself does not initiate endothelial network organization, but stabilizes networks initiated by VEGF, presumably by stimulating the interaction between endothelial and periendothelial cells.…”

“…Immunoperoxidase method was used to detect MMP-9, PRSS2, NOS2, ANG, ANGPT1, ADM and PLAU in 2 μm tissue sections prepared from on CL per cow using 3 section per CL for each animal per group to assure accuracy of description as already published [ 21 ]. The primary antibody ( Table 3 ) for each protein was diluted in PBS at the following dilutions: MMP-9 1:100; PRSS2 1:1000; NOS2 1:200; ANG 1:100; ANGPT1 1:200; ADM 1:1000; PLAU 1:300 and incubated for overnight at 4°C.…”

Impact of age and FSH treatment on follicular environment, folliculogenesis and endometrial histomorphometry in prepubertal gilts

“…Then, fragments were processed in a similar way as described above. Five different sections per animal were used and 20 sections between one and its next were discarded [25]. The images of tissue sections were obtained by an Olympus BX60 microscope at 4X and 10X magnification equipped with a digital camera (Olympus Q-Color 3™) using QCapture™ software.…”

“…Expression of the FSHR is detected in gonadal tissues (specifically, granulosa and Sertoli cells); however, FSHR can also be found in extra-gonadal tissues of reproductive tract [21][22][23]. In this context, it has been demonstrated that in ruminant and human species, FSH affects uterine functions by changes in endometrium transcriptome, vascular density and endometrial morphology [24][25][26][27][28]. In pigs, the presence of FSH receptor in endometrium of prepubertal gilts was recently described [22,29], evidencing an extra-gonadal action of FSH in this specie.…”