Effects of porcine luteal cell coculture on the development and quality of in vitro-produced embryos.

Coculture of gametes or embryos with somatic cells can improve in vitro conditions and support embryonic development. The corpus luteum is a transient ovarian endocrine gland that produces progesterone, a hormone essential for the maintenance of pregnancy. This study evaluated the effect of coculturing in vitro-produced porcine embryos with a monolayer of porcine luteal cells (PLC) on embryo development and quality. PLC were obtained by mechanical and enzymatic dissociation of corpora lutea collected from slaughterhouse ovaries of diestrous sows, and passage-1 cells were used. PLC were characterized by immunostaining for 3β-hydroxysteroid dehydrogenase. Presumptive zygotes in vitro produced were cultured for the first 2 days either with a different concentration of PLC monolayer or without cells (control). Coculture with 20000 PLC/mL significantly increased cleavage rates but did not affect blastocyst formation. This concentration also increased the number of cells per blastocyst compared with the control and 60000 PLC/mL. Furthermore, coculture with 10000 and 20000 PLC/mL significantly reduced the apoptosis index. Progesterone levels were higher at the onset of coculture and decreased over time. In conclusion, coculture with a PLC monolayer can improve porcine embryo quality in a concentration-dependent manner and may be applicable to other species. Progesterone is a possible mediator of the observed improvement in embryo quality.