Fig. 2.

Skin elasticity as measured using a micro-tensiometer following 12 weeks of treatment. Treatment groups include: Young, naïve rats receiving 0.9% saline via subcutaneous injection daily; Old, rats receiving 600 mg/kg D-galactose via subcutaneous injection to induce aging; Old+4189, aged rats treated with Limosilactobacillus fermentum USM 4189 (1×10¹⁰ CFU/d) via oral administration; Old+metformin, aged rats treated with metformin (300 mg/kg/d) via oral administration. Results are expressed as the mean±SE; n=6. Statistical analysis was conducted using an independent t-test.