Effects of DDPH on HECCM-induced proliferation and immunophenotypes of the pulmonary vascular pericytes.

In order to study the effects of 1-(2, 6-dimethylphenoxy)-2-(3, 4-dimethoxyphenylethylamino) propane hydrochloride (DDPH) on proliferation and immunophenotypes of newborn rat pulmonary vascular pericytes induced by hypoxic endothelial cell conditioned medium (HECCM) from porcine pulmonary arteries, the cultured pericytes were divided into 4 groups according to the endothelial cell conditioned medium (ECCM) used: normoxic ECCM (NECCM) group, NECCM + DDPH group, HECCM group and HECCM + DDPH group. Cell culture, immunocytochemical staining, image analysis and flow cytometric method were used to investigate the effects of HECCM and DDPH on the expression of alpha-smooth muscle actin (alpha-SM-Actin) antigen, CD34 antigen, S-100 antigen and proliferating cell nuclear antigen (PCNA) and cell cycle in pericytes. The results showed that the alpha-SM-Actin antigen in the pericytes in HECCM group was stronger positively expressed than in the other three groups, but CD34 antigen and S-100 antigen were negatively expressed. The expression of alpha-SM-Actin antigen, CD34 antigen and S-100 antigen was positive in the groups of NECCM, NECCM + DDPH and HECCM + DDPH; The expression of alpha-SM-Actin and PCNA in HECCM group was 1.32 times (P < 0.01) and 1.24 times (P < 0.05) that in NECCM group, 1.30 times (P < 0.01) and 1.21 times (P < 0.05) that in HECCM + DDPH group, respectively. The percentage of the cells in the GO-G1 phase in the HECCM group was lower by 11.7% and 9.1%, in S phase higher by 5.6% and 4.2%, in G2-M phase higher by 6.1% and 4.9% than in the groups of NECCM, HECCM + DDPH, respectively. The inhibitory rate of DDPH on the increased alpha-SM-Actin and PCNA syntheses in pericytes induced by HECCM were 23.4% and 17.1% respectively. The inhibitory rate on the increased pericytes from GO-G1 phase to S phase was 8.3%. These results suggest that DDPH can directly inhibit pericytes from proliferation and immunophenotypical transformation of smooth muscle-like cells induced by HECCM.