Figure 7.

Effects of CBS on HRV Power Spectral Analysis and PA Sympathetic Tone in Monocrotaline-Induced PAH Rats

As shown by the representative immunohistochemistry photomicrographs, tyrosine hydroxylase (TH)–positive nerve bundles were localized mainly in adipose and connective tissue around the pulmonary artery (PA) trunk and adjacent right PA (RPA) and left PA (LPA) (A, B). The black arrow indicates the TH-positive nerve bundle, and the blue arrow indicates the PA (A). The bottom row image (B) is an enlarged version of the black dotted box in the top-row image (A). Scale bars,100 μm (A) and 20 μm (B). Representative anatomical image of the PA trunk and its bifurcations in rats (D). Short-term power spectral analysis of heart rate variability (HRV) showed that PAH rats had a significant reduction in total power (TP) and low-frequency (LF) and high-frequency (HF) power and an increase in LF/HF ratio compared with control animals, but the decreases of TP and HF power, as well as the increase in LF/HF ratio in PAH rats, were partially reversed by a 4-week CBS intervention (C). CBS reduced the area of TH-positive nerve bundles around the PA trunk and bifurcations in PAH rats (E). In C, n = 6 to 9 for each group; in E, n = 3 to 6 for each group. Values are mean ± SEM. #P < 0.05 vs con-sham, ##P < 0.01 vs con-sham, and ###P < 0.001 vs con-sham; ∗P < 0.05 vs PAH-sham and ∗∗P < 0.01 vs PAH-sham; &P < 0.05 vs con-CBS by 1-way analysis of variance followed by Tukey or Tamhane T2 post hoc test or Kruskal-Wallis test followed by Dunn post hoc test. MPA = main pulmonary artery; other abbreviations as in Figure 1.