Fig. 3

H₂S improves pathological changes of lung tissues in BLM-induced mice (×200). a–j HE stain; k–o Masson stain. a–e 7-day group; f–o 42-day group; a, f, k In the control group, the lung tissues were transparent and bright; b, g, l In the 7-day and 42-day model group, points all exhibited obvious inflammatory cell infiltration, disordered structure, increased collagen deposition, and thickening of alveolar septa; c, h, m and d, i, n In the low and high dose treatment group, the above targets significantly improved. e, j, o Repeated injections of NaHS had no significant effect on pathological changes of lung tissues