Protein restriction in the rat negatively impacts long-chain polyunsaturated fatty acid composition and mammary gland development at the end of gestation.
OBJECTIVE
Maternal nutrition during gestation is critical for mammary gland cell proliferation and differentiation and development of optimal delta-6 (Δ6D) and delta-5 (Δ5D) desaturase and elongase 2 and 5 (Elovl 2 and 5) activity for synthesis of the long chain polyunsaturated fatty acids (LC-PUFAs), arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, important for normal fetal and neonatal brain development. We hypothesized that maternal low protein diet (LPD) impairs mammary gland preparation for lactation and PUFA synthesis. The aim of the study was to evaluate consequences of maternal LPD on mammary gland structure and development and expression of enzymes responsible for LC-PUFA production.


METHODS
Pregnant rats were assigned to control or protein restricted, isocaloric diet (R). At 19 days gestation, mammary gland tissue was removed for histological analysis and lipid, AA, EPA and DHA determination by gas chromatography. Gene transcription was quantified by RT-PCR and protein by Western blot.


RESULTS
In R mothers, mammary gland lobuloalveolar development was decreased and showed fat cell infiltration. Δ6D, Δ5D, and Elovl 5 mRNA were lower in R, whereas protein levels measured by Western blot were unchanged. This is the first report that detects mammary gland desaturase and elongase protein. Although Elovl 2 mRNA was not detectable by RT-PCR, Elovl 2 protein was not different between groups. AA and DHA were lower and EPA undetectable in the mammary gland of R mothers.


CONCLUSIONS
Maternal LPD decreased late gestation mammary gland lobuloalveolar development and LC-PUFAs. Protein restriction negatively impacts maternal mammary gland development prior to lactation.
Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán," Mexico City, Mexico; Posgrado en Ciencias Biomédicas, Facultad de Medicina, UNAM, Mexico City, Mexico.
Claudia J
CJ
Bautista
Guadalupe L
GL
Rodríguez-González
Nimbe
N
Torres
Rogelio
R
Hernández-Pando
Victoria
V
Ramírez
Maricela
M
Rodríguez-Cruz
Peter W
PW
Nathanielsz
Elena
E
Zambrano
D000123:Acetyltransferases / Q000032:analysis; D000273:Adipose Tissue / Q000201:enzymology*; D000818:Animals; D018753:Diet, Protein-Restricted / Q000009:adverse effects*; D044943:Fatty Acid Desaturases / Q000032:analysis; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007774:Lactation / Q000502:physiology; D042361:Mammary Glands, Human / Q000254:growth & development*; D039382:Maternal Nutritional Physiological Phenomena / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014481:United States
D005231:Fatty Acids, Unsaturated; D044943:Fatty Acid Desaturases; D000123:Acetyltransferases; C531219:elongase-2, rat
Low protein; Mammary gland; Pregnancy and LC–PUFAs