Preconceptional paternal caloric restriction of high-fat diet-induced obesity in Wistar rats dysregulates the metabolism of their offspring via AMPK/SIRT1 pathway

Abstract

Background: Obesity is a metabolic syndrome where allelic and environmental variations together determine the susceptibility of an individual to the disease. Caloric restriction (CR) is a nutritional dietary strategy recognized to be beneficial as a weight loss regime in obese individuals. Preconceptional parental CR is proven to have detrimental effects on the health and development of their offspring. As yet studies on maternal CR effect on their offspring are well established but paternal CR studies are not progressing. In current study, the impact of different paternal CR regimes in diet-induced obese male Wistar rats (WNIN), on their offspring concerning metabolic syndrome are addressed.

Methods: High-fat diet-induced obese male Wistar rats were subjected to caloric restriction of 50% (HFCR-I) and 40% (HFCR-II) and then they were mated with normal females. The male parent's reproductive function was assessed by sperm parameters and their DNMT's mRNA expression levels were also examined. The offspring's metabolic function was assessed by physiological, biochemical and molecular parameters.

Results: The HFCR-I male parents have shown reduced body weights, compromised male fertility and reduced DNA methylation activity. Further, the HFCR-I offspring showed attenuation of the AMPK/SIRT1 pathway, which is associated with the progression of proinflammatory status and oxidative stress. In line, the HFCR-I offspring also developed altered glucose and lipid homeostasis by exhibiting impaired glucose tolerance & insulin sensitivity, dyslipidemia and steatosis. However, these effects were largely mitigated in HFCR-II offspring. Regarding the obesogenic effects, female offspring exhibited greater susceptibility than male offspring, suggesting that females are more prone to the influences of the paternal diet.

Conclusion: The findings highlight that HFCR-I resulted in paternal undernutrition, impacting the health of offspring, whereas HFCR-II largely restored the effects of a high-fat diet on their offspring. As a result, moderate caloric restriction has emerged as an effective weight loss strategy with minimal implications on future generations. This underscores the shared responsibility of fathers in contributing to sperm-specific epigenetic imprints that influence the health of adult offspring.

Keywords: Male fertility; Metabolic disorders; Paternal caloric restriction; SIRT1 and AMPK..

Fig. 1

Effect of caloric restriction in high-fat diet-induced obese on fertility of male parents. (a) Body weights (b) Testes weights. (c) Gonadal Fat weights. (d) Testosterone levels. (e) Representative photomicrograph (40X) of sperm morphology of male parents stained with H & E where➝ triangle headed arrow indicate the decapitation, ▶ pointed triangle indicate seperated head, ↣ inward arrow indicates bent tail. (f) Representative photomicrograph (40X) of testis histology of male parents. (g) Sperm parameters. (h) Testes DNA methylation gene transcripts. Data was presented as mean ± SEM where statistically significance of *P < 0.05; **P < 0.01; ***P < 0.001 vs. controls. All the groups were analysed using one-way ANOVA with Dunnett’s post hoc test

Fig. 2

Effect of paternal caloric restriction on offspring signaling molecules. (a) Gene expression of energy metabolism pathways in the male offspring. (b) Gene expression of energy metabolism pathways in the female offspring. (c) Gene expression of the transcriptional factors involved in energy metabolism in the male offspring. (d) Gene expression of transcriptional factors involved in energy metabolism in the female offspring. Data was presented as mean ± SEM where statistically significance of *P < 0.05; **P < 0.01; ***P < 0.001 vs. controls. All the groups were analysed using one-way ANOVA with Dunnett’s post hoc test

Fig. 3

Effect of paternal caloric restriction on offsprings body weights . (a) Birth weights of male offspring. (b) Birth weights of female offspring. (c) Postweaning energy intake in the male offspring. (d) Postweaning energy intake in the female offspring. (e) Postweaning body weights in the male offspring. (f) Postweaning body weights in the female offspring. Data was presented as mean ± SEM where statistically significance of *P < 0.05; **P < 0.01; ***P < 0.001 vs. controls. All the groups were analysed using one-way ANOVA with Dunnett’s post hoc test

Fig. 4

Effect of paternal caloric restriction on offsprings anthropometric measures. (a) FER of male offspring. (b) FER of female offspring. (c) BMI of male offspring. (d) BMI of female offspring. (e) DEXA measurements of the male offspring. (f) DEXA measurements of the female offspring. Data was presented as mean ± SEM where statistically significance of *P < 0.05; **P < 0.01; ***P < 0.001 vs. controls, All the groups were analysed using one-way ANOVA with Dunnett’s post hoc test

Fig. 5

Effect of paternal caloric restriction on offsprings lipid metabolism. (a & b) Representative photomicrographs (40X) of liver histology of of male and female offspring respectively where ▶ pointed triangle indicate presence of lipid droplets. (c) Lipid profiles of the male offspring. (d) Lipid profiles of the female offspring. (e) Lipogenesis and lipid oxidation gene expression in the male offspring. (f) Lipogenesis and lipid oxidation gene expression in the female offspring. Data was presented as mean ± SEM where statistically significance of *P < 0.05; **P < 0.01; ***P < 0.001 vs. controls. All the groups were analysed using one-way ANOVA with Dunnett’s post hoc test

Fig. 6

Effect of paternal caloric restriction on offsprings insulin sensitivity. (a) Fasting insulin of male offspring. (b) Fasting insulin of female offspring. (c) OGTT of male offspring. (d) OGTT of female offspring. (e) AUC & HOMA scores of male offspring. (f) AUC & HOMA scores of female offspring. (g) Glycolysis & gluconeogenesis enzymes gene expression in the male offspring. (h) Glycolysis enzymes & gluconeogenesis gene expression in the female offspring. Data was presented as mean ± SEM where statistically significance of *P < 0.05; **P < 0.01; ***P < 0.001 vs. controls. All the groups were analysed using one-way ANOVA with Dunnett’s post hoc test