Inflammatory and morphological changes in the colon reflect early aging induced by D-galactose in rats

Aging leads to a decline in function and structural changes. To mimic these processes, D-galactose (D-Gal) administration is widely used as a pro-aging model in animal studies due to its reproducibility and practicality. In this study, D-Gal was administered via intraperitoneal injection to induce aging in rats. This study aimed to investigate age-related changes in colon function and structure in an animal model through histological analysis and immunohistochemical assessment of aging biomarkers. Twelve-week-old male Sprague Dawley rats were divided into control and GAL groups. The functional test was performed by measuring the colon transit time duration and faecal output amount. Structural analysis was performed by histological examination using hematoxyllin-eosin staining and immunohistochemistry against p16Ink4A and lamin B1 antibodies. Colon transit time in the GAL group was significantly faster, but fecal pellet output and body weight in the GAL group had lower values. Microscopic examination revealed significant differences (p = 0.00) between the GAL and control groups. The GAL group exhibited mild epithelial (score 1) and muscle tissue damage (score 2), along with leukocyte infiltration (score 3). The immunohistochemistry results showed a significant difference in the GAL group (p < 0.05) for p16Ink4A and lamin B1 antibodies, which confirmed the ongoing aging process. Mild structural and functional changes, accompanied by significant inflammation, suggest that the D-Gal-induced aging model accelerates colon aging.