Stress During Lactation: A Hidden Link to Offspring Bone Health.

Area of Science:

• Developmental Biology
• Bone Biology
• Stress Physiology

Background:

• Early-life resource limitation can significantly impact child health and development.
• Chronic early-life stress (CES) is a potential factor affecting long-term health outcomes.
• Understanding the effects of CES on bone development is crucial for identifying potential interventions.

Purpose of the Study:

• To investigate the effects of a limited bedding and nesting (LBN) model of CES on postnatal bone development, mineralization, and microarchitecture in rats.
• To assess changes in bone parameters at various postnatal developmental stages (PND 10, 21, and 35).
• To explore the underlying molecular mechanisms by analyzing gene expression changes.

Main Methods:

• A rat model of CES was established using limited bedding and nesting (LBN).
• Offspring were assessed at postnatal day (PND) 10, 21, and 35 for tibial length, bone mineral density (BMD), bone mineral content (BMC), and bone area (BMA) using DXA.
• Bone microarchitecture was analyzed using microcomputed tomography (μCT).
• Transcriptome analysis of lumbar vertebrae was performed to examine gene expression changes.

Main Results:

• CES significantly reduced tibial length at PND 10 and 35.
• By PND 21, CES led to reduced tibial BMC and BMA, indicating impaired bone mineral accumulation.
• μCT revealed altered cortical bone microarchitecture in tibiae and changes in vertebral bone structure.
• Transcriptome analysis showed differential gene expression related to immune response and cellular repair at PND 21.

Conclusions:

• CES disrupts bone development, including length, mineralization, and microarchitecture, in a stage-dependent manner.
• Altered gene expression in immune and cellular repair pathways may mediate the negative effects of CES on bone health.
• Longitudinal studies and interventions are needed to mitigate CES impacts on bone health from infancy to adulthood.