2.3. CCl4-Induced Acute Liver Injury and Sample Collection

The solution of CCl₄ (Sigma-Aldrich, St. Louis, MO, USA) and olive oil (Sigma-Aldrich) at a ratio of 1 : 1 and dose of 3 mL/kg body weight was administered intraperitoneally (i.p.) in a single dose. Control mice were administered an i.p. injection of an equal volume of olive oil (3 mL/kg) only. Next, 5 × 10⁵ MSCs in 100 μL of phosphate-buffered saline (PBS) or 100 μL of PBS were injected into the mice via the caudal vein 6 h after CCl₄ administration.

The mice were anesthetized by i.p. injection of 4% chloral hydrate (Sangon Biotech, Shanghai, China) at a dose of 10 μL/g body weight, and blood samples were drawn from the inferior vena cava at 48 h, 1 week (w), and 2 w after CCl₄ administration. Following exsanguination, the liver, small intestinal segments, and cecum and colon contents were precisely dissected and harvested, snap frozen in liquid nitrogen, and stored at -80°C until further analysis. Portions of the liver and ileum were immediately fixed in 10% neutral buffered formalin for histopathologic examination.