Histologic changes of lung tissue in each group. Microphotographs of morphological changes of lung tissues (original magnification × 200). Hematoxylin and eosin staining:control: control group. LPS: LPS injury group. L: LPS + low-dose NaHS group. M: LPS + middle-dose NaHS group. H: LPS + high-dose NaHS group. In comparison, the LPS injury group showed diffuse edema in alveolar spaces and interstitium of the lung, hemorrhage, severe inflammatory cell infiltration and serous exudation in the alveolar space, and thickened interbular septa. These changes were lightly mitigated in the LPS + low-dose NaHS group, and were significantly mitigated in LPS + middle-dose NaHS group and high-dose NaHS group.