BISPHENOL A MODIFIES MILK LIPID CONCENTRATION AND FATTY ACID PROFILE IN PERINATALLY EXPOSED LACTATING RATS

ALTAMIRANO G ; MARRA C; GOMEZ A; DELCONTE M; LUQUE EH; MUÑOZ-DE-TORO M; KASS L

Congreso; 1º Congresso Latino Americano de Toxicologia Clínico-Laboratorial; 2014

Milk synthesis requires the coordination of many biochemical processes in the mammary gland. Milk nutritional value is mainly attributable to fat and protein fractions. Diet and the environment are variables that influence milk fatty acid (FA) composition. Bisphenol A (BPA), a widespread endocrine disrupting chemical, has been shown to impair metabolism and induce obesity in rodents. Perinatal exposure to BPA also modifies milk yield and milk protein composition in lactating rats. Objective: Evaluate whether BPA modifies the synthesis, composition and/or profile of FA in the lactating mammary gland of perinatally exposed animals. Material and Methods: BPA (0, 0.6 or 52 µg/kg/day) was administered in the drinking water of F0 rats from gestational day 9 until weaning. F1 females were bred. On lactation day 2 (LD2), mammary gland samples were obtained. On LD10, mammary gland, milk and blood samples were collected. The mRNA expression of mammary fat globule membrane proteins and FA synthesis key enzymes was quantified. FA profile and lipid content were analyzed in milk. Serum levels of glucose, cholesterol and triglycerides were measured. Results: On LD2, a decreased mRNA expression of butyrophilin and xanthine oxidoreductase was observed in BPA-exposed groups whereas adipophilin (ADPH) mRNA levels were reduced only in BPA0.6 animals. In contrast, on LD10, the ADPH mRNA expression was increased in BPA52 F1 dams. On LD2, no alterations were observed in the mRNA expression of the enzymes involved in FA synthesis; whereas on LD10, stearoyl-CoA desaturase 2 was up-regulated in BPA52 F1 dams. Glucose, cholesterol and triglyceride serum levels were similar among groups. However, in milk both triglyceride and phospholipid concentrations were lower in BPA0.6 F1 dams than in controls. In contrast, in the BPA52 F1 lactating dams the proportion of milk FA and triglyceride concentration were higher. Moreover, BPA52 F1 dams produced milk with higher saturated FA concentration than BPA0.6 and control F1 animals. C18:1(n-9) as well as C18:2(n-6) and C20:3(n-6) FA were increased in BPA52 F1 animals and decreased in BPA0.6 F1 dams compared to control rats. Arachidonic acid, by contrast, was higher in BPA0.6 and lower in BPA52 F1 animals than in control dams. The increase in milk fat content and the differences in milk FA profile exhibited by BPA52 F1 dams were associated with a higher body weight gain of the BPA52 F2 pups during lactation. Conclusion: Perinatal exposure to BPA not only modified milk protein composition but FA synthesis and milk FA profile. Moreover, the body weight gain of the BPA F2 offspring was increased suggesting that, in mammals, BPA obesogenic effects might also be indirect, through altering milk nutritional value.