| Objective To investigate the role of tissue factor(TF),autophagy and their interactions during chronic thromboembolic pulmonary hypertension(CTEPH) pathogenesis in a rat model.Methods The rats were randomly divided into a Sham group(n=45) and experimental group(n=45). The rats were further divided into three subgroups according to the time after the experimental procedures: 1-week subgroup(n = 15), 2-week subgroup(n = 15), and 4-week subgroup(n = 15). In experimental group,autologous blood clots were repeatedly injected into the right jugular vein of rats to induce animal model of CTEPH; The procedure in the Sham group was the same as in the experimental group except that the rats were injected with 0.9% Na Cl instead of autologous blood clots. Repeating injecting the clots or Na Cl 1 week, 2 weeks and 4 weeks later after the first injection, mean pulmonary arterial pressure(m PAP)was detected, histopathology and vessel wall area/total area( WA/TA) were measured. The plasma TF antigen concentration and activity were detected by the method of enzyme-linked immuno sorbent assay(ELISA)and TF by the CHROMOGENIC activity assay kit, respectively. TF, Beclin-1 and LC3 B antigen expression in the pulmonary artery were detected by immunohistochemistry. TF, Beclin-1, and LC3 B m RNA and protein expression in the pulmonary artery were detected by reverse transcription polymerase chain reaction(RT-PCR)and western blot, respectively.Results The m PAP and WA/TA ratio in the experiment group increased significantly(P<0.05)compared with the sham operation group(18.97±3.87 mm Hg vs. 14.4±2.66 mm Hg, 21.89±4.22 mm Hg vs. 13.9±2.82 mm Hg, 25.17±4.74 mm Hg vs. 14.1±3.12 mm Hg, P<0.05, respectively;46.67±8.50 vs. 31.2±6.25, 49.06±8.82 vs. 30.1±6.01, 54.03±10.26 vs. 32.8±6.83, P<0.05, respectively). The plasma TF concentration in the 1-week, 2-week, and 4-week subgroups in the experimental group increased significantly compared with the sham operation group(134.89±49.39 pg/ml vs. 83.24±21.90pg/ml, P <0.05; 159.92±67.07pg/ml vs. 82.45±22.76pg/ml, P <0.05; and 174.90±53.38 pg/ml vs. 83.92±24.11pg/ml, P <0.05, respectively). Rat plasma TF activity was higher in the 1-, 2-, and 4-week subgroups in the experimental group than in the sham operation group(103.38±22.05 p M/ml vs. 62.62±16.06 p M/ml, P <0.05; 119.54±26.70 p M/ml vs. 60.15±17.23 p M/ml, P <0.05; and 117.12± 19.14 p M/ml vs. 61.87±16.69 p M/ml, P <0.05, respectively). The TF m RNA and protein expression levels of pulmnaruy arteries in the experiment group increased significantly(P <0.05, respectively)compared with the sham operation group. Beclin-1 and LC3 B m RNA and protein expression levels of pulmnaruy arteries were lower in the experiment group(P <0.05, respectively)compared with the sham operation group. The m PAP had a positive correlation with WA/TA ratio(r = 0.955, P <0.05). TF activity in the plasma of rats had a positive correlation with the WA/TA ratio(r = 0.972, P<0.05)and a positive correlation trend with m PAP(r = 0.914, P>0.05). Beclin-1 and LC3 B protein expression had a negative correlation with the WA/TA ratio(r =-0.963, P <0.05, r =-0.965, P<0.05, respectively). TF protein expression had a negative correlation with both Beclin-1 and LC3 B protein expression(r =-0.995, P <0.05, r =-0972, P <0.05, respectively).Conclusion A rat model of CTEPH can be established by introducing autologous blood clots into the pulmonary artery with injecting tranexamic acid. The WA/TA ratio and m PAP significantly increase in the rat CTEPH model. TF expression may increase and Beclin-1 and LC3 B expression may decrease in rat CTEPH model. TF, Beclin-1, and LC3 B may play a key role during CTEPH pathogenesis, especially on vascular remodeling. However, the detailed mechanisms underlying these processes warrant further investigation. |
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