Impaired mammary gland T cell population during early lactation in hypoprolactinemic lactation-deficient rats

MACKERN-OBERTI JP; VALDEZ SR; VARGAS ROIG LM; JAHN GA

REPRODUCTION

BIOSCIENTIFICA LTD

Lugar: Bristol; Año: 2013 vol. 146 p. 233 - 242

1470-1626

Mammary stroma is composed of various cell types, among them migratory leukocytes. Although mammary antibody secreting cells have been extensively studied, reports focusing on mammary T cells are scarce. It is thought that the recruitment mechanism of leukocytes to the mammary gland (MG) are controlled by pregnancy- and lactation-specific stimuli. But whether PRL modulates the T cell population in MG is still unknown. Our aim was to study the relationship between prolactin (PRL) levels and T and B cells in early lactation (L2, day 2 postpartum) and mid lactation (L12). In order to investigate if PRL is associated to homing events to MG, female Sprague Dawley (SD) and SD derived desmoglein 4-/- hairless (phenotype with lactation deficit, OFA hr/hr) rats were sacrificed at estrus, pregnancy and postpartum, and blood, MG and corpora lutea were obtained to perform FACS, Real Time PCR, histological and RIA studies. Serum PRL levels were lower in OFA hr/hr than in SD at early lactation. MG of OFA hr/hr rats showed less secretory material compared to SD. FACS analysis showed lower percentage of MG CD3+ cells in OFA hr/hr compared to SD rats on L2 and L12. OFA hr/hr rats showed higher absolute numbers of circulating CD3+ cells compared to SD on L2 but not on L12. These results show that MG T cell population is affected in early lactating OFA hr/hr rats and strongly suggest that serum PRL levels may be involved in mammary homing T cell events, probably helping antibody secreting cells and protecting the gland during lactation development.