Effect Of Calcium-Sensitive Receptors On Caveolin-1,Endothelial Nitric Oxide Synthase And Nitric Oxide In Neonatal Mice With Persistent Pulmonary Hypertension

Objective:To study the effect of calcium-sensitive receptors?CaSR?on the expression of Caveolin-1?Cav-1?,endothelial nitric oxide synthase?eNOS?and the concentration of nitric oxide?NO?in a neonatal C57BL/6mouse model of persistent pulmonary hypertension?PPH?.Methods:Sixty SPF neonatal C57BL/6 mice were mated with the ratios of female and male 1:2.When the weight of female mouse was over 2 g,it was considered to be pregnant,and the pregnant mice were placed in the cages alone,free to drink and eat.After the pregnant mice delivering,eighty neonatal mice were randomly divided into Control,PPH,Agonist and Antagonist groups.Pups of the Control group were exposed to normoxic air with an oxygen concentration of 21%.Pups of the PPH,agonist and antagonist groups were exposed to 12%hypoxic oxygen.The agonist and antagonist groups were intraperitoneally injected with a CaSR agonist?GdCl₃,16 mg/kg?and a CaSR antagonist?NPS-2390,1 mg/kg?,respectively,while the PPH and control groups were intraperitoneally injected with normal saline instead.All mice were treated for 14days.Alveolar development and pulmonary vessels were assessed by hematoxylin-eosin staining?H&E?.The protein and mRNA expression of Cav-1 and eNOS and their localization in lung tissues were determined by Western blot,qRT-PCR and immunohistochemistry.The levels of brain natriuretic peptide?BNP?and NO in lung homogenate were determined using ELISA.Results:1)Compared with the control group,the PPH and agonist groups showed significant increases in alveolar mean linear intercept,wall thickness of pulmonary arterioles,right to left ventricular wall thickness ratio?RV/LV?and BNP concentration,but a significant reduction in radial alveolar count?P<0.05?.The antagonist group had significant improvements in all the above indices except RV/LV compared with the PPH and agonist groups?P<0.05?.2)Compared with those in the control group,the protein and mRNA expression of Cav-1 and eNOS were significantly increased in the PPH group and increased more significantly in the agonist group,but were significantly reduced in the antagonist group?P<0.05?.3)Compared with those in the control group,NO concentration was significantly increased in the PPH group and increased more significantly in the agonist group,but were significantly reduced in the antagonist group?P<0.05?.Conclusion CaSR plays an important role in the development of PPH in neonatal mice,possibly by increasing Cav-1,eNOS expression and NO concentration.