Development of gender differences in DBA/2Cr mouse kidney morphology during maturation

Area of Science:

• Nephrology
• Developmental Biology
• Comparative Anatomy

Background:

• Recent studies have identified sex-based differences in adult mouse kidney morphology.
• The developmental trajectory and underlying mechanisms of these sexual dimorphisms during maturation remain largely uncharacterized.

Purpose of the Study:

• To investigate the developmental processes that lead to sex-based differences in mouse kidney morphology during maturation.
• To establish a detailed timeline of morphological changes in the developing mouse kidney between males and females.

Main Methods:

• Longitudinal morphometric analysis of DBA/2Cr mouse kidneys at multiple ages (20, 30, 50, 60, 70, 90, 120, and 150 days).
• Measurement of total kidney weight, kidney weight to body weight ratio, renal corpuscle dimensions, and proximal tubule cellular characteristics.

Main Results:

• Male mice exhibited significantly larger total kidney weight and kidney-to-body weight ratios starting at 50 days of age.
• Sexual dimorphisms in renal corpuscle morphology (parietal layer shape, diameter) and proximal tubule characteristics (cell nuclei number, vacuolar structures, PAS-positive granules) emerged progressively from 50 days onwards.
• Specific differences included a higher percentage of cuboidal parietal layers in males (≥70 days), larger corpuscle diameter in males (≥90 days), and increased proximal convoluted tubular cell nuclei in females (≥90 days).

Conclusions:

• This study provides the first comprehensive description of the developmental emergence of sex-based differences in mouse kidney morphology.
• The findings highlight distinct developmental pathways contributing to sexual dimorphism in kidney structure and function.
• Understanding these developmental differences is crucial for interpreting sex-specific kidney phenotypes and diseases.