Maternal protein restriction differentially alters the expression of AQP1, AQP9 and VEGFr-2 in the epididymis of rat offspring

Marilia Martins Cavariani,Wellerson Rodrigo Scarano,Dhrielly Natalia Pereira,Luiz Gustavo De Almeida Chuffa,Patricia Fernanda Felipe Pinheiro,Raquel Fantin Domeniconi,Talita De Mello Santos

doi:10.3390/ijms20030469

Marilia Martins Cavariani, Wellerson Rodrigo Scarano + Show 5 more

Open Access

https://doi.org/10.3390/ijms20030469

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Abstract

Background: Maternal protein restriction causes sperm alterations in the offspring, most of which are associated with epididymal functions. Because fluid reabsorption/secretion dynamics in the epididymal environment play important roles in the process of sperm maturation and concentration, we investigated the effects of maternal protein restriction on the expression of aquaporins (AQP1 and AQP9), vascular endothelial growth factor (VEGFa), and its receptor VEGFr-2 in different stages of postnatal epididymal development. Methods: Pregnant rats were divided into groups that received normoprotein (17% protein) and low-protein diets (6% protein) during gestation and lactation. After weaning, male rats only received the standard diet and were euthanized at the predetermined ages of 21, 44 and 120 days. Results: Maternal protein restriction decreased AQP1 and AQP9 expression in the initial segment and caput epididymis compared to the increased expression of these proteins observed in the corpus and cauda at all ages. Although protein restriction reduced the microvasculature density (MVD) on postnatal day (PND) 21 and 44, the MVD was unaltered on PND 120. Conclusions: Maternal protein restriction changed the structure or function of the offspring’s epididymis, specifically by affecting fluid dynamics and vasculogenesis in important stages of epididymis development.

Highlights

The developing fetus depends on the mother and the maternal environment to supply their nutritional needs
Maternal protein restriction during gestation and lactation caused a slight increase in testosterone levels on postnatal day (PND) 21 (111%; p > 0.05; Figure 1A(I))
At PND 44, the animals exhibited a significant decrease in circulating testosterone levels (a 0.43-fold reduction compared with the normoprotein (NP) group; Figure 1A(II)) and the PND120 animals exhibited a nonsignificant decrease in the levels of this steroid hormone (0.81-fold reduction compared with the NP group) (Figure 1 A(III))

Summary

Introduction

The developing fetus depends on the mother and the maternal environment to supply their nutritional needs. Adequate protein intake is recommended to ensure that the additional nitrogen demands of both mother and fetus are met since an increase in protein turnover to meet the requirements for rapid embryo growth occurs at this stage [9] Based on these findings, the protein restriction model is one of the most well-characterized models of early growth restriction [6,10,11]. Few epidemiological and experimental studies have examined the effects of a maternal low-protein diet on the male reproductive function compared to studies of the metabolic disturbances This experimental model causes sperm alterations in male offspring, most of which are associated with epididymal functions, such as sperm motility, viability, and concentration [12,13,14,15]. Conclusions: Maternal protein restriction changed the structure or function of the offspring’s epididymis, by affecting fluid dynamics and vasculogenesis in important stages of epididymis development

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