| Objective: Pulmonary fibrosis is a chronic interstitial lung disease,the early pathological changes of alveolitis,with prolonged,ultimately developing pulmonary fibrosis, result in progressively loss of lung function.The prognosis is very poor. The etiology and pathogenesis of interstitial lung disease is still unknown.Resentely,studies suggested that disordered coagulation system may be involved in developmenting of pulmonary fibrosis in patients with interstitial lung disease.This study aimed to observe the changes of protein C,APC-PCI of bronchoalveolar lavage Fluid in Bleomycin-induced lung fibrosis in rats,PCⅢin serum, to investigate the changes of protein C system and the impact on contributing to the excessive procoagulation activity and developmenting of pulmonary fibrosis.Methods: 48 healthy Sprague-Dawley male rats(provided by Center Experiment Animal of Hebei province) weighing 230g±10g were randomly divided into control group and Bleomycin(BLM) group,24 rats in each group.After intraperitoneal injection of anesthesia by 10% Chloral hydrate(5mg/kg),under sterile operation ,made the neck incision,exposed the bronchi.Lung fibrosis induced by intratracheal injection BLMA5(5mg/kg), on days 3,7,14 and 28,six rats were killed randomly from each group at each point. The control group animals were treated under the same conditions in the same way to the intratracheal injection of normal saline. On days 3,7,14 and 28,six rats were killed randomly from each group at each point.Rats were sacrificed with abdominal aorta depletion method,collected serum and stored at﹣70℃for later testing the content of PCⅢ. Left lung was lavaged by 4℃saline,after which the BALF was trifuged and stored at﹣70℃.The contents of PC,APC-PCI in BALF were measured.The inferior of right lung tissues were preserved in 10% formalin for histologic interpretation,HE staining was used to investigate alveolitis.Masson staining was used to investigate the extent of collagen deposition.To be classified by the method of Szapiel for studying the development alveolitis and lung fibrosis.The date were analyzed using the SPSS system.Results:1 The changs of protein C contents in bronchoalveolar lavage fluid in rats:The contents of protein C was no significant difference in control group(P>0.05). In BLM group,the levels of protein C in BALF became declined from 3rd,3.966±0.684,and on day 7 the difference were the most obvious, 1.423±0.799,there were both significant differences versus control group(P<0.01).On day 14,the contents showed an increasing tendency comprared with 7th,5.085±0.728,the difference was also significant versus control group.Accompanied with the time the content of protein C went on upregulating on day 28, 6.031±0.574, the differences were no significant(P>0.05).2 The changs of APC-PCI complex contents in bronchoalveolar lavage fluid:The contents of APC-PCI was no significant difference in control group(P>0.05). In BLM group,the levels of protein C in BALF became declined from 3rd,55.855±8.555,and the differences were the most significant on day 7,31.971±8.296,there were both significant differences versus control group(P < 0.05,P < 0.01).On day 14,the contents showed an increasing tendency comprared with 7th,58.608±6.599,the differences were also significant versus control group.Accompanied with the time the contents of protein C went on upregulating on day 28, 69.348±9.313, the difference were no significant(P>0.05).3 The changs of the contents of typeⅢprocollagen in Serum:The contents of PCⅢwere no difference in control group(P>0.05). In BLM group,the level of PCⅢin BALF had a little increase,but had no significant diffeence compared with control group from 3rd,31.804±5.155,and the difference were more significant on day 7, 44.208±7.299,there were significant differences versus control group(P<0.01).On day 14,the contents showed a declining tendency comprared with 7th, 33.941±4.384,the difference was also significant versus control group (P<0.05). Accompanied with the time the contents of protein C went on declining on day 28, 30.239±6.811, the difference were no significant(P > 0.05).And the levels of PCⅢwere negatively correlation with the levels of protein C.The levels of PCⅢwere also negatively correlation with the levels of APC-PCI.Conclusions:1 Excessive procoagulant activity exists in pulmonary interstitial fibrosis. In the alveolitis,the anticoagulation activity was declined in BALF;In the lung fibrosis,it was not obviously change.That is,the change of coagulation activity mainly exists in the alveolitis stage.2 The change of coagulation activity in the alveolar space and lung interstitium may play a relevant role in the pathogenesis of pulmonary fibrosis. Decreased PC level and increased typeⅢprocollagen level were observed, showed that impairment of PC pathway was the reason for the excessive procoagulant activity and may promote pulmonary fibrosis.These results confirm that disordered coagulation and fibrinolysis system appeared to contribute to the development of pulmonary fibrosis. |
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