Tissue & Cell · Nov 2026
Progressive renal remodeling during physiological aging in rats: Histological, Ultrastructural, and Immunohistochemical studies
By Abdel-Maksoud FM, Mokhtar EE, Ibrahim N et al.
Physiological aging is accompanied by gradual structural changes in the kidney, which may affect its architecture and function. The current study aimed to examine age-related morphological and ultrastructural changes in the rat kidney from adulthood to senescence. The study was carried out on male albino rats (n = 6 per group) from three age groups: 3 months (young adult), 1.5 years (middle-aged), and 2 years (old/senescent). Histological examination and electron microscopy were used to evaluate age-related structural and ultrastructural alterations. Immunohistochemical detection of Caspase-3, TNF-α, and LC3 was also performed to evaluate apoptosis, inflammation, and autophagy, respectively. The kidneys of 3-month-old rats exhibited well-preserved mature renal architecture, with intact renal corpuscles and renal tubules. With advancing age, progressive structural alterations became evident in the 1.5- and 2-year-old groups. These changes included widening of Bowman’s space, glomerular tuft atrophy and sclerosis, thickening of the glomerular basement membrane, tubular epithelial alterations, interstitial expansion, and increased collagen deposition. Immunohistochemically, Caspase-3 and TNF-α immunoreactivity was higher in 2-year-old rats than in 3-month-old rats, particularly in the renal tubules and glomeruli. LC3 immunoreactivity was also higher in old rats, which may reflect either increased autophagosome formation or impaired autophagic flux. Renal function was not assessed. These findings provide morphological and immunohistochemical evidence of progressive structural changes in the kidney from young adulthood to senescence.