Objective: To study the effect of calcium-sensing receptor (CaSR) agonists and antagonists on the expression of CaSR in neonatal mice with persistent pulmonary hypertension (PPHN), and to clarify the role of CaSR in neonatal mice with PPHN.
Methods: Forty-nine neonatal mice were randomly divided into four groups: control (n=10), hypoxia (PPHN; n=11), agonist (n=13), and antagonist (n=15). The mice in the PPHN, agonist, and antagonist groups were exposed to an oxygen concentration of 12%, and those in the control group were exposed to the air. The mice in the agonist and antagonist groups were intraperitoneally injected with gadolinium chloride (16 mg/kg) and NPS2390 (1 mg/kg) respectively once daily. Those in the PPHN and the control groups were given normal saline daily. All the mice were treated for 14 consecutive days. Hematoxylin and eosin staining and immunohistochemistry were used to observe the changes in pulmonary vessels. Laser confocal microscopy was used to observe the site of CaSR expression and measure its content in lung tissues. qRT-PCR and Western blot were used to measure the mRNA and protein expression of CaSR in lung tissues.
Results: Compared with the control group, the PPHN group had significant increases in the pulmonary small artery wall thickness and the ratio of right to left ventricular wall thickness (P<0.05), which suggested that the model was successfully prepared. Compared with the control group, the PPHN group had a significant increase in the mRNA and protein expression of CaSR (P<0.05), and the agonist group had a significantly greater increase (P<0.05); the antagonist group had a significant reduction in the mRNA and protein expression of CaSR (P<0.05).
Conclusions: CaSR may play an important role in the development of PPHN induced by hypoxia in neonatal mice.
目的: 探讨钙敏感受体（CaSR）激动剂及抑制剂在新生小鼠持续性肺动脉高压（PPH）模型中对CaSR的表达影响，明确其在新生小鼠PPH模型中的作用。
方法: 将49只新生小鼠随机分为对照组（n=10）、PPH组（n=11）、激动剂组（n=13）和抑制剂组（n=15）；将PPH组、激动剂组和抑制剂组小鼠暴露在12%的氧浓度中，对照组小鼠暴露在空气中。激动剂组和抑制剂组每日分别给予GdCl3（16mg/kg）、NPS2390（1mg/kg）腹腔注射1次，低氧组和对照组每日以生理盐水替代，共持续14d。采用苏木精-伊红染色和免疫组化检测肺血管的变化；采用激光共聚焦技术观察CaSR在新生小鼠肺组织中的表达位置及含量；qRT-PCR技术检测新生小鼠肺组织中CaSRmRNA表达；Western blot法检测新生小鼠肺组织中CaSR蛋白的表达。
结果: 与对照组相比，PPH组肺小动脉血管壁厚度（WT%）及右心室与左心室壁厚度比（RV/LV）均较对照组明显增大（P < 0.05），模型验证成功。与对照组相比，PPH组CaSR mRNA和蛋白表达水平明显增加（P < 0.05），激动剂组表达水平增加更加明显（P < 0.05），而抑制剂组表达减少（均P < 0.05）。
结论: CaSR参与了低氧诱导的新生小鼠PPH，可能发挥重要作用。