ABSTRACT
This study is to explore the activation of the Ca2+/CaM/CaN signal pathway in 5-HT-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and the inhibitory effect of m-nisoldipine (m-Nis) on this pathway. PASMCs were cultured with the explant technique. The proliferation of PASMCs was evaluated by MTT assay. Confocal microscopy was used to measure the change of [Ca2+]i. The mRNA expression of CaM and CaN was evaluated by RT-PCR and the activity of CaN was measured according to the instruction of kits. The results of MTT assay suggested that 5-HT (1 micromol x L(-1)) significantly induced the proliferation of rat PASMCs (P < 0.01), which was inhibited obviously by m-Nis (P < 0.05 or P < 0.01). Similarly, m-Nis inhibited 5-HT-induced elevation of [Ca2+]i (P < 0.01). The mRNA expression of CaM, CaN and the activation of CaN were also inhibited by m-Nis at different degrees (P < 0.05 or P < 0.01). Thus, the results of this study suggested that Ca2+/CaM/CaN signal pathway played an important role in 5-HT-induced proliferation of rat PASMCs, the inhibition of m-Nis on proliferation of rat PASMCs may be related to the blockage of Ca2+/CaM/CaN signal pathway by inhibiting the elevation of [Ca2+]i.
Subject(s)
Animals , Male , Rats , Antihypertensive Agents , Pharmacology , Calcineurin , Genetics , Metabolism , Calcium , Metabolism , Calcium Channel Blockers , Pharmacology , Calmodulin , Genetics , Metabolism , Cell Proliferation , Cells, Cultured , Myocytes, Smooth Muscle , Cell Biology , Metabolism , Nisoldipine , Pharmacology , Pulmonary Artery , Cell Biology , RNA, Messenger , Metabolism , Rats, Wistar , Serotonin , Pharmacology , Signal TransductionABSTRACT
Effect of new calcium antagonist m-nisoldipine (m-Nis) on MCT-induced PH in rats and its mechanisms were investigated. Rats were injected with a single dose (60 mg x kg(-1)) of MCT subcutaneously to induce PH. Pulmonary haemodynamic measurement and lung tissue morphological investigations were undertaken. The MDA production and SOD activity in the serum were tested. PCNA, ERK1 and p-ERK expressions were analyzed by Western blotting. The expressions of 5-HT and PCNA were observed with immunohistochemistry. Results suggested that the PAP, right ventricular index and the degree of muscularization of small pulmonary artery were elevated markedly in MCT group, which was attenuated by m-Nis treatment. A significant reduction in MDA production and an increase in the SOD activity in the serum were also observed in all three m-Nis groups. The number of PCNA and 5-HT positive smooth muscle cells increased significantly in MCT group, and m-Nis treatment attenuated the expression obviously. Western blotting results suggested that the protein expression of PCNA and the ratio of p-ERK/ ERK1 increased markedly in MCT group and decreased by m-Nis. In conclusion, m-Nis protected against MCT-induced PH by decreasing PAP, right ventricular index, PAMSCs proliferation and pulmonary artery remodelling, which may be related to the reduction of 5-HT and the suppression of the ERK/MAPK signal pathway.