Synergism between albumin, bicarbonate and cAMP upregulation for cholesterol efflux from ram sperm.
Reproduction
; 160(2): 269-280, 2020 08.
Article
en En
| MEDLINE
| ID: mdl-32460237
ABSTRACT
Compared to other mammalian species, ram spermatozoa are difficult to capacitate in vitro. Dibutyryl cAMP (db-cAMP) and the phosphodiesterase (PDE) inhibitors, caffeine and theophylline (cAMP up-regulators), must be added to traditional capacitation media (containing bicarbonate, calcium and BSA) to elicit a capacitation response. In this exploratory study, we assessed whether bicarbonate was still required for ram spermatozoa if cAMP is up-regulated by the addition of db-cAMP and PDE inhibitors and what role BSA plays in cholesterol efflux under these conditions. In this study, the validated BODIPY-cholesterol assay was used for the first time in ram spermatozoa to quantify cholesterol efflux by tracking the loss of BODIPY-cholesterol from the sperm plasma membrane using flow cytometry. The results show that under cAMP up-regulated conditions, an increase in membrane fluidity and tyrosine phosphorylation of sperm proteins remain as bicarbonate-dependent processes. In fact, the supplementation of bicarbonate under these conditions was necessary to further enhance cAMP production in ram spermatozoa, which correlated with the presence of these capacitation-related processes. When BSA was supplemented with cAMP up-regulators (as well as bicarbonate), there was a loss of approximately 20-23% of BODIPY-cholesterol (79.5 ± 30.5% to 76.9 ± 12.3% remaining from 10 min), indicating that BSA is essential for mediating cholesterol efflux in ram spermatozoa as measured by the BODIPY-cholesterol assay. The current study identifies the functional relationship between bicarbonate, BSA and cAMP up-regulators that is required to support capacitation-related processes in ram spermatozoa, specifically cholesterol efflux.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Capacitación Espermática
/
Espermatozoides
/
Bicarbonatos
/
Albúmina Sérica Bovina
/
Calcio
/
Colesterol
/
AMP Cíclico
/
Sinergismo Farmacológico
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Reproduction
Asunto de la revista:
MEDICINA REPRODUTIVA
Año:
2020
Tipo del documento:
Article
País de afiliación:
Australia