Impact of gestational stress on bone and body composition in Wistar rats after lactation

This research aimed to evaluate the impact of stress at the end of the pregnancy on bone health and body composition of Wistar rats after the breastfeeding period. The 90-day pregnant Wistar rats were divided into 2 groups (n=7/group): the stress group (SG) and the control group (CG). The stress protocol was carried out over 8 days, with 4 different types of stressor stimuli during the third week of pregnancy. Serum corticosterone, osteoprotegerin (OPG), nuclear factor kappa beta ligand (RANKL), calcium, and phosphorus were measured by an ELISA kit and body composition by the carcass technique. Bone mineral density, content, and area were measured in the femur by dual-energy X-ray absorptiometry, and the maximum force, breaking force, and elastic modulus were measured using a flexural test with a load cell (50 kgf). Results with P<0.05 were considered significant and data are reported as means±SD. Corticosterone was higher in SG (P=0.04), showing the effectiveness of the protocol, but no differences were observed in OPG, RANKL, calcium, phosphorus, and body composition. SG had lower bone mineral density (P=0.01) and lower maximum strength (P=0.04). Stress during the gestational period promoted deleterious effects on maternal bone health after the lactation period, shown by the reduction of bone mineral density and maximum strength, affecting bone quality; no difference was found in body composition.