Morphometric analysis of the intergenerational effects of protein restriction on nephron endowment in mice

Parental nutritional status is crucial in shaping offspring's kidney development. However, the association between a protein-restrictive diet and its intergenerational impact on kidney development remains unclear.

We conducted multigenerational morphometric measurements to investigate the effects of parental protein deprivation on offspring kidney development across four generations. F0 mice were divided into two groups and fed a normal protein diet (NPD) or a low-protein diet (LPD) for three weeks before mating and continued these diets throughout gestation and lactation. Body weight (BW), kidney weight (KW), KW/BW ratio, nephron counts, and blood pressure were assessed in F1 pups. To examine paternal effects, we bred CD1 females on an NPD with males on an LPD. BW, KW, KW/BW, and nephron counts were measured at P20. To measure the transgenerational effect of parental LPD on kidney development, F1 offspring (from parents on LPD) were fed NPD upon weaning. These F1 offspring were bred at 6 weeks of age to produce F2, F3 and F4 generations. Kidney metrics were evaluated across generations.

The average body weight of P0 pups from parents on NPD was 1.61g, while pups from parental LPD weighed an average of 0.869g, a decrease of 54 % (p = 6.9e-11, Wilcoxon test). F1 from parental LPD have significantly smaller kidneys than the control, with an average combined kidney weight of 0.0082g versus 0.0129g, a 37 % decrease (p = 3.2e-02, Wilcoxon test). P20 BW and KW remained low in LPD offspring. These effects persisted for 4 generations (F1 to F4) with an average glomerular count reduction of roughly 20 %. F3 and F4 showed wider variability in glomerular counts but were not statistically significant compared to controls.

Both maternal and paternal LPD significantly affected offspring nephron endowment. Our study underscores the complex nature of nutritional transgenerational effects on kidney development, emphasizing the importance of both maternal and paternal dietary impacts on kidney development and the developmental origin of adult disease.