Microvascularization and angiogenic activity of equine corpora lutea throughout the estrous cycle

Abstract

Corpus luteum growth and endocrine function are closely dependent on the formation of new capillaries. The objectives of this study were to evaluate (i) tissue growth and microvascular development in the equine cyclic luteal structures; (ii) in vitro angiogenic activity of luteal tissues in response to luteotrophic (LH, PGE 2 ) and luteolytic (PGF 2␣ ) hormones and (iii) to relate data to luteal endocrinological function. Our results show that microvascular density was increased in the early and mid luteal phase, followed by a fall in the late luteal phase and a further decrease in the corpus albicans. Hyperplasia of luteal tissue increased until the mid luteal phase and it was followed by tissue regression. Luteal explants were cultured with no hormone added, or with PGF 2␣ , LH, PGE 2 , LH + PGE 2 or LH + PGF 2␣ . Media conditioned by equine luteal tissue from different stages of the luteal phase were able to stimulate mitogenesis of bovine aortic endothelial cells (BAEC), suggesting the presence of angiogenic activity. No difference was observed among luteal structures on their mitogenic capacity, for any treatment used. Nevertheless, Late-CL conditioned-media with PGF 2␣ showed a significant decrease in BAEC proliferation (p < 0.05) and LH + PGF 2␣ a tendency to reduce mitogenesis. Thus, prostaglandin F 2␣ may play a role on vascular regression of the CL during the late luteal phase in the * Corresponding author. Tel.: +351 213652859; fax: +351 213652889. -mail address: gmlfdias@fmv.utl.pt (G. Ferreira-Dias Ferreira-Dias et al. / Domestic Animal Endocrinology 30 (2006) [247][248][249][250][251][252][253][254][255][256][257][258][259] mare. These data suggest that luteal angiogenesis and vascular regression in the mare are coordinated with the development of non-vascular tissue and might be regulated by many different factors. E

Testicular angiogenic activity in response to food restriction in rabbits

“…Vascular density was assessed as the percentage of the area occupied by blood vessels with respect to the entire area of each micrograph (Ferreira-Dias et al 2001. For each animal, vascular area was considered as the mean value of the area of blood vessels assessed for that animal (Ferreira-Dias et al 2006). The mean number of testicular blood vessels was also evaluated for each animal, on the same 28 randomly selected fields used for vascular area determinations.…”

“…Briefly, these BAEC (2!10 4 cells/ml) were allowed to attach to the bottom of a 24-well culture plate (Nucleon-Nunc, Ballerup, Denmark) for 24 h, in a tissue incubator (Biosafe EcoIntegra Biosciences; 37 8C, 5% CO 2 , 95% air; Ferreira- Dias et al 2006). Samples of testicular conditioned media were added in triplicate wells at a final concentration of 30% (30% conditioned media by the samples C70% DMEM), and incubated for another 72 h. Afterward, in order to assess BAEC proliferative response, the number of these cells in each well was determined using a Neubauer chamber under the light microscope (Olympus CK40), and further compared with negative controls (with no testicular tissue).…”

“…Samples of testicular conditioned media were added in triplicate wells at a final concentration of 30% (30% conditioned media by the samples C70% DMEM), and incubated for another 72 h. Afterward, in order to assess BAEC proliferative response, the number of these cells in each well was determined using a Neubauer chamber under the light microscope (Olympus CK40), and further compared with negative controls (with no testicular tissue). The percentage of BAEC proliferation in media conditioned by testes was calculated with respect to negative controls, which were considered 100% of cell mitogenesis (Ferreira-Dias et al 2006).…”

“…Physiological angiogenesis in the adult is mostly restricted to the female reproductive tract during the ovarian/uterine cycle (Reynolds et al 1992, Augustin et al 1995, Ferreira-Dias et al 2006, Roberto da Costa et al 2007, and to the male reproductive tract during gonadal recrudescence in seasonal breeders (Mayerhofer et al 1989). However, neovascularization is also present in adult life in conditions such as tissue repair or regeneration during healing of wounds or fractures, or in the re-establishment of blood flow, playing an essential role in the transport of oxygen and nutrients (Reynolds et al 1992.…”

Seasonal Changes in Luteal Progesterone Concentration and mRNA Expressions of Progesterone Synthesis-related Proteins in the Corpus Luteum of Mares

“…The mares used in the present study weighed approximately 1,000 kg and were expected to have a high BCS. After midsagittal sectioning, the CLs were classified as being in the early, mid and regressed luteal stages (n=3-6/stage) by macroscopic observation of the CL and follicles as described previously [16,17]. Briefly, the early CL had a corpus hemorrhagicum; the mid CL had a solid, although trabeculated, appearance; and the regressed CL was straw colored and associated with follicles > 35 mm in diameter.…”