Figure 2.

Gabrb3^ECKO mice have abnormal cardiac pathology and hypertension. (a–c) Isolectin B4-labeled vessels were significantly reduced in Gabrb3^ECKO hearts, when compared to floxed controls (a, b). Vessel quantification depicted in (c); Data represent mean ± SD (n = 6, *P < 0.05; Student's t-test). (d, e) Co-labeling with Isolectin B4 (red) and GABRB3 (green) revealed expression of GABRB3 in Gabrb3^fl/fl vessels only (merged in yellow, white arrows, (d) and its lack thereof in Gabrb3^ECKO vessels (gray arrows, e). Prominent expression of GABRB3 was observed in cardiomyocytes in both groups (asterisk). (f, g) Validation of GABRB3 expression in cardiomyocytes by co-labeling with GABRB3 and α-ACTININ in Gabrb3^fl/fl and Gabrb3^ECKO mice. (h–k) Low (h, j) and high (i, k) magnification images of normal picrosirius red staining in Gabrb3^fl/fl cardiac tissue (h, i), and an increase in collagen deposition, observed in Gabrb3^ECKO cardiac tissue (j, k). (l-o) H & E staining shows wavy myocardial fibers (black arrows, m, o) with long ‘worm-like’ nuclei (red arrows, m, o) in Gabrb3^fl/fl cardiac tissue, which is not seen in controls (l, n). (p) No changes in heart rate were observed in Gabrb3^fl/fl and Gabrb3^ECKO mice. (q, r) A significant increase in systolic and diastolic blood pressure was observed in Gabrb3^ECKO mice versus Gabrb3^fl/fl mice. Data represent mean ± SD (n = 5, *P < 0.05, Student's t-test). Scale bars: (a), 100 μm (applies to b, h, j); d, 50 μm (applies to e, f, g, i, k, l-o).