A modified D-galactose-induced aging rat model with low-dose intraperitoneal ozone: Redox, functional, and skin...

Aging impairs quality of life, making experimental models essential to evaluate interventions that modulate age-related changes. This study aimed to characterize a modified D-galactose-induced aging model and explore the effects of intermittent low-dose ozone exposure on redox balance and functional outcomes. Twenty-seven 12-week-old male Wistar rats were randomly assigned to healthy, aging (D-galactose induction), and ozone-treated (D-galactose + ozone) groups. Plasma and skin MDA levels, SOD activity, and GSH levels were measured colorimetrically. Physical performance was assessed using physical health score, morbidity proportion, body weight, muscle strength (hanging test), hair regrowth, and skin structure (Hematoxylin-Eosin and Masson's trichrome staining). Compared with healthy rats, the aging group showed increased plasma MDA levels (p = 0.007), MDA/SOD ratios (p = 0.005), and MDA/GSH ratios (p = 0.016). In ozone-treated rats, plasma MDA and MDA/SOD tended to decrease compared with aging rats, while GSH tended to increase. In the skin, redox markers were comparable across groups, except for a significantly lower MDA/SOD ratio in the ozone-treated group (p = 0.043) compared with the aging group. D-Galactose induction reduced physical health (p = 0.017), increased morbidity, and tended to reduce body-weight gain and hanging ability. Ozone-treated rats showed improved physical health (p = 0.041), lower morbidity, accelerated hair regrowth, and preserved skin structure, particularly dermal firmness and collagen thickness (p = 0.013). The modified D-galactose model partially induced redox imbalance and functional deterioration, whereas intermittent low-dose ozone exposure tended to restore redox homeostasis, preserve physical health, accelerate hair regrowth, and maintain the skin structure without inducing supraphysiological effects.