Seventy-two male Wistar rats were randomly divided into control group, PQ
poisoning group, and
Xuebijing intervention group, with 24 rats in each group.
Pulmonary fibrosis was induced by single gavage at the dosage of 50 mg/kg of PQ, while 1 mL of distilled water was given by gavage in control group.
Xuebijing injection at the dosage of 4 mL/kg were given intraperitoneally at 30 minutes after exposure to PQ in
Xuebijing group, and it was repeated every 12 hours; same amount of physiological saline was given intraperitoneally in PQ group and control group. The experiment lasted for 14 days. Six rats in each group were sacrificed on 1, 3, 7, 14 days, respectively, after insult, and 30 minutes after the last intervention. The lung tissues were harvested, the changes in pathology in lung tissue and the degree of
pulmonary fibrosis were observed with optical microscope with
hematoxylin-
eosin (HE) staining and Masson
stain. The ultrastructure changes in lung tissues were observed with transmission electron microscopic, and the content of
hydroxyproline (HYP) in the lung tissue was determined by alkaline hydrolysis. The expression of mitochondrial fusion
protein 2 (Mfn2) was determined by Western Blot.
RESULTS: (1) HE staining: in PQ group,
inflammation was most marked on the 3rd day. On the 7th day, exudates in the alveoli started to be organized, and hypertrophic fibroblasts were seen to secrete slim
collagen fibers, and
fibrosis could be seen in alveoli. On the 14th day, intensive
hyperplasia of fibroblasts could be observed, and the alveolar structure was destroyed and collapsed, with deposition of
collagen deposited with formation of
pulmonary fibrosis. At the same time, pathologic changes were milder in
Xuebijing group than those in PQ group. (2) Masson staining: the degree of
inflammation in alveoli and
pulmonary fibrosis were less marked in
Xuebijing group than those of PQ group on the 14th day. (3) Under the transmission electron microscopy, it was found that the mitochondria of lung tissue cells was relatively less in number on the 14th day in PQ group, and the majority of them underwent degeneration, swelling and damage. Basement membrane became folded, alveoli were collapsed, and
fibrosis was obvious. These changes were less serious in
Xuebijing group. (4) Content of HYP: contents of HYP in lung tissues on the 3rd day in PQ group and
Xuebijing group were significantly higher than those in control group (743.3±50.2 μg/g, 718.1±34.0 μg/g vs. 665.8±6.6 μg/g, both P<0.05), it then increased gradually, but the contents of HYP in
Xuebijing group were significantly lower on the 7th day and 14th day than those in PQ group (790.5±23.8 μg/g vs. 876.7±42.0 μg/g, 812.9±72.3 μg/g vs. 931.3±33.0 μg/g, both P<0.05). (5) Expression of Mfn2: the expression of Mfn2 in control group was relatively lower. The expression of Mfn2 in PQ group was increased gradually under stress, but its rate was low. The expression of Mfn2 (A value) in
Xuebijing group was significantly higher than that in PQ group on the 1st day (0.731±0.035 vs. 0.618±0.029, P<0.05), and it was elevated steadily, reaching the peak on the 7th day (0.732±0.037 vs. 0.669±0.034, P<0.05), but it was lower than that of PQ group on the 14th day (0.708±0.034 vs. 0.765±0.041, P<0.05).
CONCLUSIONS: