Effects of disturbed liver growth and oxidative stress of high-fat diet-fed dams on cholesterol metabolism in offspring mice

Abstract

Background/objectives: Changes in nutritional status during gestation and lactation have detrimental effects on offspring metabolism. Several animal studies have shown that maternal high-fat diet (HFD) can predispose the offspring to development of obesity and metabolic diseases, however the mechanisms underlying these transgenerational effects are poorly understood. Therefore, we examined the effect of maternal HFD consumption on metabolic phenotype and hepatic expression of involved genes in dams to determine whether any of these parameters were associated with the metabolic outcomes in the offspring.

Materials/methods: Female C57BL/6 mice were fed a low-fat diet (LFD: 10% calories from fat) or a high-fat diet (HFD: 45% calories from fat) for three weeks before mating, and during pregnancy and lactation. Dams and their male offspring were studied at weaning.

Results: Dams fed an HFD had significantly higher body and adipose tissue weights and higher serum triglyceride and cholesterol levels than dams fed an LFD. Hepatic lipid levels and mRNA levels of genes involved in lipid metabolism, including LXRα, SREBP-2, FXR, LDLR, and ABCG8 were significantly changed by maternal HFD intake. Significantly lower total liver DNA and protein contents were observed in dams fed an HFD, implicating the disturbed liver adaptation in the pregnancy-related metabolic demand. HFD feeding also induced significant oxidative stress in serum and liver of dams. Offspring of dams fed an HFD had significantly higher serum cholesterol levels, which were negatively correlated with liver weights of dams and positively correlated with hepatic lipid peroxide levels in dams.

Conclusions: Maternal HFD consumption induced metabolic dysfunction, including altered liver growth and oxidative stress in dams, which may contribute to the disturbed cholesterol homeostasis in the early life of male mice offspring.

Keywords: Cholesterol metabolism; high-fat diet; liver; offspring; oxidative stress.

Fig. 1. Effects of maternal HFD consumption on body weight of dams.

Body weights were measured at baseline, mating, postpartum day (PP) 3 and PP20. Data are presented as mean ± SEM (LFD: n = 7, HFD: n = 5). ^*Significantly different from the LFD group (P < 0.05 by Student's t-test).

Fig. 2. Effects of maternal HFD consumption on serum and hepatic biochemical parameters of dams.

(A) Serum glucose, triglyceride, total cholesterol, HDL-cholesterol, ALT, and protein levels. (B) Hepatic triglyceride and cholesterol levels. Data are presented as mean ± SEM (LFD: n = 7, HFD: n = 5). ^*Significantly different from the LFD group (P < 0.05 by Student's t-test).

Fig. 3. Effects of maternal HFD consumption on hepatic mRNA levels of genes involved in (A) triglyceride metabolism, (B) cholesterol metabolism, and (C) lipoprotein transport in dams.

Relative mRNA expression was analyzed by real-time PCR and normalized to RPL19 as endogenous control. Data are presented as mean ± SEM (LFD: n = 7, HFD: n = 5). ^*Significantly different from the LFD group (P < 0.05 by Student's t-test).

Fig. 4. Effects of maternal HFD consumption on liver growth and proliferation of dams.

(A) Total liver DNA and protein contents. Data are presented as mean ± SEM (LFD: n = 7, HFD: n = 5). ^*Significantly different from the LFD group (P < 0.05 by Student's t-test). (B) Representative immunoblots of hepatic PCNA and cleaved caspase-3. Each protein was normalized to HSC70.

Fig. 5. Effects of maternal HFD consumption on oxidative stress and inflammation of dams.

(A) Serum and hepatic TBARS levels. (B) Hepatic mRNA levels of p40phox and HO-1. (C) Serum MCP-1 levels and hepatic mRNA levels of MCP-1. Relative mRNA expression was analyzed by real-time PCR and normalized to RPL19 as endogenous control. Data are presented as mean ± SEM (LFD: n = 7, HFD: n = 5). ^* Significantly different from the LFD group (P < 0.05 by Student's t-test).

Fig. 6. Effects of maternal HFD consumption on serum biochemical parameters of male offspring.

(A) Serum glucose, triglyceride, total cholesterol and ALT levels. Data are presented as mean ± SEM (LFD-O: n = 10, HFD-O: n = 7). ^* Significantly different from the LFD-O group (P < 0.05 by Student's t-test). (B) Correlation between offspring serum cholesterol levels and the relative liver weight of dams. (C) Correlation between offspring serum cholesterol levels and hepatic TBARS levels of dams.

Fig. 7. Effects of maternal HFD consumption on hepatic PCNA, β-catenin, and cleaved caspase-3 protein levels of male offspring.

Representative immunoblot of each protein was normalized to HSC70.

Fig. 8. Effects of maternal HFD consumption on hepatic mRNA levels of genes involved in cholesterol metabolism of male offspring.

Relative mRNA expression was analyzed by real-time PCR and normalized to RPL19 as endogenous control. Data are presented as mean ± SEM (LFD-O: n = 10, HFD-O: n = 7). ^* Significantly different from the LFD-O group (P < 0.05 by Student's t-test).