Protein malnutrition early in life increased apoptosis but did not alter the β-cell mass during gestation.

We evaluated whether early life protein restriction alters structural parameters that affect β-cell mass on 15th d and 20th d of gestation in control-fed pregnant (CP), non-pregnant (CNP), protein-restricted pregnant (LPP) and non-pregnant (LPNP) rats from the foetal to the adult life stage as well as in protein-restricted rats that recovered after weaning (RP and RNP). On the 15th d of gestation the CNP group had a higher proportion of smaller islets, whereas the CP group exhibited a higher proportion of islets larger than the median. The β-cell mass was lower in the low-protein group than in the recovered and control groups. Gestation increased the β-cell mass, β-cell proliferation frequency and neogenesis frequency independently of the nutritional status. The apoptosis frequency was increased in the recovered groups compared to that in the other groups. On the 20th d of gestation, a higher proportion of islets smaller than the median was observed in the non-pregnant groups, whereas a higher proportion of islets larger than the median was observed in the RP, LPP and CP groups. β-cell mass was lower in the low-protein group than in the recovered and control groups, regardless of the physiological status. The β-cell proliferation frequency was lower, whereas the apoptosis rate was higher in recovered rats compared to those in the low protein and control rats. Thus, protein malnutrition early in life did not alter the mass of β cells, especially in the first two thirds of gestation, despite the increase in apoptosis.