Cellular proliferation rate, and IGFBP-2 and -3 and estradiol receptor alpha expression in the mammary gland of dairy heifers naturally infected with gastrointestinal nematodes during development

PERRI, A; DALLARD B; BARAVALLE C; LICOFF, N; FORMÍA N; ORTEGA HH; BECÚ-VILLALOBOS, D; MEJIA, ME; LACAU-MENGIDO, IM

JOURNAL OF DAIRY SCIENCE

AMER DAIRY SCIENCE ASSOC-ADSA

Lugar: Champaign, Illinois; Año: 2014 vol. 97 p. 4985 - 4996

0022-0302

Mammary ductal morphogenesis during prepubertyoccurs mainly in response to insulin-like growth factor-1(IGF-1) and estradiol stimulation. Dairy heifers infectedwith gastrointestinal nematodes have reduced IGF-1levels, accompanied by reduced growth rate, delayedpuberty onset, and lower parenchyma-stroma relationshipin their mammary glands. Immunohistochemicalstudies were undertaken to determine variations in celldivision rate, IGF-1 system components, and estradiolreceptors (ESR) during peripubertal development in themammary glands of antiparasitic-treated and untreatedHolstein heifers naturally infected with gastrointestinalnematodes. Mammary biopsies were taken at 20, 30,40, and 70 wk of age. Proliferating cell nuclear antigenimmunolabeling, evident in nuclei, tended to be higherin the parenchyma of the glands from treated heifersthan in those from untreated. Insulin-like growth factorbinding proteins (IGFBP) type 2 and type 3 immunolabelingwas cytoplasmic and was evident in stroma andparenchyma. The IGFBP2-labeled area was lower intreated than in untreated heifers. In the treated group,a maximal expression of this protein was seen at 40wk of age, whereas in the untreated group the labelingremained constant. No differences were observed forIGFBP3 between treatment groups or during development.Immunolabeling for α ESR (ESR1) was evidentin parenchymal nuclei and was higher in treated than inuntreated heifers. In the treated group, ESR1 peaked at30 wk of age and then decreased. These results demonstratethat the parasite burden in young heifers negativelyinfluence mammary gland development, affectingcell division rate and parameters related to estradioland IGF-1 signaling in the gland.