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目的 :缺氧能否通过影响血管平滑肌细胞血管活性肽的自分泌功能而参与缺氧性肺动脉高压的发生尚不明确 ,本实验在培养的新生小牛肺动脉平滑肌细胞(PASM)上探讨内皮素 1(ET 1)自分泌在其中的作用。方法 :采用3H TdR掺入研究PASM增殖 ,放免测定和斑点杂交技术研究ET 1的分泌和表达。结果 :无氧培养(0 %O2)24h使新生小牛肺动脉平滑肌细胞(PASM)的3H TdR掺入与常氧组相比增加42.3 %(P<0.001) ,ETA受体拮抗剂BQ123(10 -6mmol/L)使常氧培养的PASM的3H TdR掺入降低47 %(P<0.01) ,但对缺氧培养条件下PASM的3H TdR掺入无显著影响。采用放免测定发现 ,缺氧培养3～48h导致PASM的ET 1分泌降低非常显著(P<0.01)。斑点杂交显示 ,缺氧同样抑制PASM的ET 1的mRNA表达(P<0.01)。结论 :ET 1参与常氧情况下PASM增殖的调节 ,而与缺氧引起的PASM过度增殖无关 ,缺氧可通过抑制PASM的ET 1mRNA的表达而抑制ET 1的合成和分泌。
OBJECTIVE: Whether hypoxia can participate in the pathogenesis of hypoxic pulmonary hypertension by affecting the autocrine function of vasoactive peptides in vascular smooth muscle cells is not yet clear. In this study, we investigated the effects of endothelin-1 on cultured neonatal pulmonary artery smooth muscle cells (PASM) (ET 1) autocrine in which role. Methods: 3H - thymidine incorporation was used to study the secretion and expression of ET 1 by PASM proliferation, radioimmunoassay and dot blot hybridization. Results: 3H TdR incorporation of neonatal calf pulmonary artery smooth muscle cells (PASM) increased by 42.3% (P <0.001) compared with normoxia group under anaerobic culture (0% O2) for 24 h, while ETA receptor antagonist BQ123 6 mmol / L) decreased the incorporation of 3H TdR by 47% (P <0.01) in PASM cultured in normoxic condition, but did not affect 3H TdR incorporation in PASM under hypoxia condition. Using radioimmunoassay, it was found that the decrease of ET 1 secretion in PASM caused by hypoxia for 3 ~ 48h was significant (P <0.01). Dot blotting showed that hypoxia also inhibited ET1 mRNA expression in PASM (P <0.01). CONCLUSION: ET 1 is involved in the regulation of PASM proliferation under normoxia, but not with hypoxia-induced hyperplasia of PASM. Hypoxia inhibits the synthesis and secretion of ET 1 by inhibiting the expression of ET 1 mRNA in PASM.