Figure 2: The left lung histological slices of SD rats from groups of the control, PQ treatment, and PQPDTC treatment. In A1 (light micrographs of lung sections stained with hematoxylin and eosin (HE) from control), evidencing a normal pulmonary structure without evidence of alveolar collapse, vascular congestion, or cellular infiltrations. In B1(PQ group on the 3rd day HE), the capillary vessel of alveolar wall dilation, congestion in lungs, hemorrhagic lung, and alveolar epithelium detached, edema, and infiltration of inflammatory cell around bronchia can be visible. In B2 (PQPDTC group on the 3rd day HE), a slight decrease in the alveolar space can be observed as well as the existence of several infiltrative vacuolated cells in the interstitial and in the alveolar space. In C1 (PQ group on the 7th day HE), the lungs showed an accumulation of mixed inflammatory cells in the alveolar region and confluent areas of marked interstitial thickening. In C2 (PQPDTC group on the 7th day HE), there was a slight change. In A2 (MASSON from control group), relatively little collagen accumulation can be observed in control group. In D1 (PQ group on the 14th day MASSON) and E1 (PQ group on the 21st day MASSON), Masson's Trichrome staining showed collagen accumulation, broadened alveolar wall and patchy collagen deposition within the expanded interstitium in some areas. In D2 (PQPDTC group on the 14th day MASSON) and E2 (PQPDTC group on the 21st day MASSON), a slight collagen accumulation can be visible.