A maternal "junk food" diet in pregnancy and lactation promotes nonalcoholic Fatty liver disease in rat offspring

Abstract

With rising obesity rates, nonalcoholic fatty liver disease is predicted to become the main cause of chronic liver disease in the next decades. Rising obesity prevalence is attributed to changes in dietary habits with increased consumption of palatable junk foods, but maternal malnutrition also contributes to obesity in progeny. This study examines whether a maternal junk food diet predisposes offspring to nonalcoholic fatty liver disease. The 144 rat offspring were fed either a balanced chow diet alone or with palatable junk foods rich in energy, fat, sugar, and/or salt during gestation, lactation, and/or after weaning up to the end of adolescence. Offspring fed junk food throughout the study exhibited exacerbated hepatic steatosis, hepatocyte ballooning, and oxidative stress response compared with offspring given free access to junk food after weaning only. These offspring also displayed sex differences in their hepatic molecular metabolic adaptation to diet-induced obesity with increased expression of genes associated with insulin sensitivity, de novo lipogenesis, lipid oxidation, and antiinflammatory properties in males, whereas the gene expression profile in females was indicative of hepatic insulin resistance. Hepatic inflammation and fibrosis were not detected indicating that offspring had not developed severe steatohepatitis by the end of adolescence. Hepatic steatosis and increased oxidative stress response also occurred in offspring born to junk food-fed mothers switched to a balanced chow diet from weaning, highlighting a degree of irreversibility. This study shows that a maternal junk food diet in pregnancy and lactation contributes to the development of nonalcoholic fatty liver disease in offspring.

Figure 1

Liver function tests and expression analysis. ALT, AST, ALP, and GGT levels in serum (A) and hepatic mRNA expression (B) in 10-wk-old rat offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation, and postweaning, respectively. CCC, Open bars; CCJ, cross-hatching; JJC, diagonal striping; JJJ, solid black. Results are mean ± sem. Different letters (a, b, c, d) on the graphs indicate statistical differences between nutritional groups by hierarchical two-way ANOVA followed by post hoc analyses (P < 0.05), whereas the absence of letters (i.e. serum GGT) indicates nonsignificance (P > 0.05); n = 36 offspring (18 males and 18 females) in each nutritional group (see text for details on statistical analysis).

Figure 2

Histological analysis. Representative H&E, Oil Red O, and Masson’s trichrome stains of livers from 10-wk-old rat offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation, and postweaning, respectively (magnification, ×400). Male and female JJJ offspring exhibit hepatocyte ballooning (H&E) with macrovesicular (arrowhead) and microvesicular (arrows) steatosis and a greater degree of steatosis (Oil Red O) but absence of fibrosis (Masson’s) compared with all other groups. Gender differences were not evident.

Figure 3

Glucose uptake and metabolic enzymes. Real-time PCR analysis of hepatic genes regulating glucose uptake, glycogenesis, glycogenolysis, and de novo lipogenesis in 10-wk-old rat offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation, and postweaning, respectively. CCC, Open bars; CCJ, cross-hatching; JJC, diagonal striping; JJJ, solid black; GK, glucokinase; GlySynt, glycogen synthase; GlyPho, glycogen phosphorylase. Results are indicative of favored glucose uptake and de novo lipogenesis in JJJ males compared with the CCC group. Results are mean ± sem. Different letters (a, b) on the graphs indicate statistical differences between nutritional groups by hierarchical two-way ANOVA followed by post hoc analyses (P < 0.05), whereas the absence of letters indicates nonsignificance (P > 0.05); n = 36 offspring (18 males and 18 females) in each nutritional group (see text for details on statistical analysis).

Figure 4

Insulin and IGF signal. Real-time PCR analysis of hepatic genes regulating the insulin/IGF signal in 10-wk-old rat offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation, and postweaning, respectively. CCC, Open bars; CCJ, cross-hatching; JJC, diagonal striping; JJJ, solid black. Results are suggestive of increased and decreased insulin/IGF signal in JJJ males and females, respectively, compared with the CCC group. Results are mean ± sem. Different letters (a, b) on the graphs indicate statistical differences between nutritional groups by hierarchical two-way ANOVA followed by post hoc analyses (P < 0.05), whereas the absence of letters indicates nonsignificance (P > 0.05); n = 36 offspring (18 males and 18 females) in each nutritional group (see text for details on statistical analysis).

Figure 5

Metabolic nuclear factors. Real-time PCR analysis of hepatic nuclear factors regulating lipid homeostasis in 10-wk-old rat offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation, and postweaning, respectively. CCC, Open bars; CCJ, cross-hatching; JJC, diagonal striping; JJJ, solid black. Results indicate sex differences in PPAR and LRH-1 expression in JJJ offspring. Results are mean ± sem. Different letters (a, b) on the graphs indicate statistical differences between nutritional groups by hierarchical two-way ANOVA followed by post hoc analyses (P < 0.05), whereas the absence of letters indicates nonsignificance (P > 0.05); n = 36 offspring (18 males and 18 females) in each nutritional group (see text for details on statistical analysis).

Figure 6

Lipid oxidation, oxidative stress response, inflammation, and fibrosis. Real-time PCR analysis of genes involved in oxidative stress, inflammation, and fibrosis in 10-wk-old rat offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation, and postweaning, respectively. CCC, Open bars; CCJ, cross-hatching; JJC, diagonal striping; JJJ, solid black. Results are suggestive of increased hepatic oxidative stress response in offspring born to junk food-fed mothers (JJC and JJJ groups) but no sign of inflammation or fibrosis. Results are mean ± sem. Different letters (a, b, c, d) on the graphs indicate statistical differences between nutritional groups by hierarchical two-way ANOVA followed by post hoc analyses (P < 0.05), whereas the absence of letters indicates nonsignificance (P > 0.05); n = 36 offspring (18 males and 18 females) in each nutritional group (see text for details on statistical analysis).