The Therapeutical Effect Of Sodium Tanshinone IIA Sulphonate On Hypoxic Pulmonary Hypertension Rats

Hypoxic pulmonary hypertension (HPH) is a respiratory system disease characterized by a progressive elevation of pulmonary artery pressure and pulmonary vascular resistance, ultimately resulting in severe right ventricular (RV) failure and death.This disease has no obvious causes and the treatments are still limited, expensive, and often associated with significant side effects. Sodium tanshinone IIA sulphonate (STS), a derivative of tanshinone II A, is isolated from the root of Salvia miltiorrhiza known as Danshen in China.Injection of STS was successfully used for cardiac diseases but the exact mechanisms are poorly understood. To date, researches have indicated that Salvia miltiorrhiza has showed properties such as anti-tumor, anti-inflammation, anti-proliferation, and anti-reduced-oxidation etc. Clinical statistics data also suggest that Salvia miltiorrhiza extract such as STS imposes a helpful effect on the PAH patients by diminishing the increased pulmonary arterial pressure. However, the underlying mechanisms which it exhibits its beneficial effect on the treatment of HPH are not well defined. And limited information is available on the effect of STS on HPH in rat models. So we set up chronic HPH rats models to explore the effect and the mechanisms of STS on HPH.Objective1. To clear the effects of STS on the change of pulmonary hemodynamics and morphology in the chronic HPH rats model.2.To prove the regulation effects of STS on the contraction and relaxation of pulmonary artery rings from chronic HPH rats.3.To verify whether STS can inhibit proliferation and induce apoptosis, upgrade Kv2.1 expression and depress oxidative stress.Methods1. The animal model of hypoxic pulmonary hypertension was established by exposing the rats to hypobaric hypoxia environment for 3 weeks. All male SD rats were randomly divided into four groups: normoxia group, normoxia + STS group, hypoxia group and hypoxia + STS group.2. Right ventricular peak systolic pressure (RVPSP) and mean carotid artery pressure (mCAP) were examined by catheterization, right ventricular hypertrophy index (RVHI) was calculated. The lung specimens were examined by light microscope to study morphological analysis, and to calculate the ratio of pulmonary arterial thickness between vessel wall and vessel radius (WT%), and the ratio of pulmonary arterial area between wall and all vessel (WA%).3. Make manufacture the pulmonary artery rings from all groups respectively to study the response to the cumulative concentration SNP, NE and Kcl, and prove that STS can reversal the dysfunction of contraction and relaxation in pulmonary artery rings from chronic HPH rats.4. Detcet the rate of PCNA, Brdu and TUNEL positive cells by immunohistochemistry, and analyze the Kv2.1 expression by immunohistochemistry and RT-PCR respectively. Meanwhile, SOD, MDA and H₂O₂ in lung homogenate were measured.ResultsThe RVPSP in hypoxia group were (6.28±0.59) kPa, which was significantly higher than that in normoxia group (2.81±0.49) kPa; the RVPSP in hypoxia + STS group reduced to (4.7±0.56) kPa, which had significant difference compared with hypoxia group. At the same time, the mCAP was of no difference in all groups. Histological studied showed that there were congestion, edema, the sequestration of inflammatory cells and the small pulmonary artery vessel wall were thickened and the vessel lumina were deflated in lung tissues in hypoxia group, which were significantly alleviated by STS treatment.The WA%, the WT% and the RV/ (LV + S) % in hypoxia group were (87.24±2.71)%, (77.75±2.18)% and (35.703±2.95)% respectively, which were significantly higher than that in normoxia group [(52.53±2.43)%, (33.21±1.64)% and (26.79±1.86)%]; the WA%, the WT% and the RV/ (LV + S) % in hypoxia + STS group reduced to (72.06±3.84)%, (61.79±3.10)% and (32.371±2.296)%, which had significant difference compared with hypoxia group.NE (10^-7 - 10^-6 mol/L) or Kcl (20 -40mM) induced contraction of pulmonary artery rings in a concentration-dependent manner. The tension to NE and Kcl was significantly raised in hypoxia group (P < 0.05); STS could inhibit the pulmonary artery rings constraction induced by hypoxia (P < 0.05). There were no differences in higher concentration of NE or Kcl among groups. SNP induced relaxation of pulmonary artery rings also in a concentration-dependent manner. The sensitivity of pulmonary artery rings from the chronic HPH rats to SNP was significantly decreased (P < 0.05), while STS can improve the sensitivity decreased by hypoxia (P < 0.05). Simultaneously, there ware no distinctions on above-mentioned parameters in normoxia + STS group and normoxia group.The express of PCNA and Brdu significantly increased in the pulmonary artery from chronic HPH rats (P < 0.05), and decreased in STS treatment rats (P < 0.05).The express of TUNEL striking weakened in the pulmonary artery from chronic HPH rats (P < 0.05), and strengthened in STS treatment rats (P < 0.05). Hypoxia depressed the express of Kv2.1 in pulmonary artery (P < 0.05), while STS could upgrade the express of Kv2.1 (P < 0.05).The content of MDA and H₂O₂ in hypoxia group were increased (P < 0.01), but the content of SOD in hypoxia group was decreased (P < 0.01). STS treatment could upgrade the content of SOD (P < 0.01), and. inhibit MDA and H₂O₂ (P < 0.01). At the same time, there ware no differences on above-mentioned parameters in normoxia + STS group and normoxia group.ConclusionThis research proved that STS can significantly impove the changes of pulmonary hemodynamics and morphology, reversal the RV/ (LV+S) % induced by hypoxia. These effects of STS correlate with regulating the function of contraction and relaxation in pulmonary artery, inhibiting proliferation and inducing apoptosis of pulmonary arterial smooth muscle cells, up regulating Kv2.1pression and depressing oxidative stress. This research may provide a new theoretacal evidence for STS using to thrapy HPH in clinical.