Figure 4.

Hearts From TAC Animals With PVN OXT Neuron Activation Had Improved LV Function and Less Collagen III and IL-1β Expression Compared with Untreated TAC Animals

(A) Langendorff studies of excised hearts revealed that LVDP was significantly impaired in TAC animals (n = 5) compared with both Sham (n = 8) and PVN OXT treatment animals (n = 8). Contractility (B) and relaxation (C) measurements were calculated using the derivative of the LV pressure wave; both were significantly compromised in TAC animals (n = 5) compared with Sham animals (n = 8), whereas TAC + OXT animals (n = 8) did not significantly deviate from Sham. (D) Western-blot analysis revealed significant elevations in cardiac levels of IL-1β in TAC animals (n = 7) compared with PVN OXT treatment animals (n = 8) using a Student’s t-test, as Sham levels were negligible; IL-1β quantitation is relative to GAPDH. (E) Western-blot assays also revealed significant elevations in cardiac levels of the fibrosis marker, collagen III, in TAC animals (n = 7) compared with both Sham (n = 7) and PVN OXT-treated animals (n = 9); collagen III quantitation is relative to GAPDH and to Sham values. (F) Trichrome-stained histological sections indicate increased fibrosis in all disease groups compared with Sham, as well as greater right-ventricular wall thinning in TAC-untreated animals compared with PVN OXT-treated animals. Data were analyzed using a 1-way analysis of variance with Tukey’s post hoc test; ∗p < 0.05. GAPDH = glyceraldehyde-3-phosphate dehydrogenase; IL = inerleukin; LV = left ventricle; LVDP = left ventricle-developed pressure; PVN = paraventricular nucleus of the hyperthalamus; OXT = oxytocin; TAC = transascending aortic constriction.