[Expression of thrombospondin-1 in the lung of hypoxic pulmonary hypertension rats].

Objective: To investigate the expression of thrombospondin-1(TSP-1) in the lung of hypoxia-induced pulmonary hypertension rats.

Methods: Thirty male Wistar rats were divided into two groups, pulmonary hypertension group and control group. The mice in experimental group were exposed to isobaric hypoxia for 3 weeks, and those in control group were exposed to air. The pulmonary artery pressure was measured by right cardiac catheterization. The expression of TSP-1 and TGF-beta1 in the lungs of rats were measured by immunohistochemical staining. The histological sections of the lungs were examined using a computerized image analyzer.

Results: After the induction of hypoxia for 3 weeks, the rats had pulmonary artery pressure increased with the thickening of the wall and the narrowing of the lumen of pulmonary arterioles. In the experimental group, the mean pulmonary artery pressure (mPAP) was (2.86 +/- 0.39) kPa, the index of right ventricular hypertrophy RV/(LV+S) was (43.53 +/- 3.38)%, the ratio of vascular wall thickness/vascular external diameter (WA%) was (55.09 +/- 12.38)%, and the ratio of vascular wall area/total vascular area (WT%) was (35.24 +/- 11.2)%, which all were significantly increased in comparison with those of control group [mPAP (1.35 +/- 0.28) kPa, RV/(LV+S) (23.68 +/- 3.48)%, WT% (23.63 +/- 9.74)%, WA% (41.62 +/- 12.83)%, respectively. P < 0.05). The positive staining of TSP-1 (1.32 +/- 0.04 vs. 0.96 +/- 0.03) and TGF-beta1 (1.38 +/- 0.05 vs. 1.04 +/- 0.04) in the wall of pulmonary arteriole of the rats exposed to hypoxia were significantly stronger than those of control rats (P < 0.01).

Conclusion: The expression of TSP-1 appears to be increased in hypoxic pulmonary hypertension rats, which may contribute to the pathogenesis of hypoxic pulmonary vascular remodeling.