Inhibition of neprilysin with sacubitril without RAS blockage aggravates renal disease in Dahl SS rats

Figures

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  Figure 1.. Experimental protocol and basic endpoint parameters. (A) A schematic representation of the experimental protocol. Dahl SS rats were allowed to acclimate for one week on a 0.4% NaCl diet before being swapped to a HS diet for 21 days. GFR was measured, OPs were installed before the HS challenge, and then GFR and BP were measured on day 20. Animals were euthanized and a kidney flush procedure was performed on day 21; kidneys, hearts, and blood plasma were harvested. NS, normal salt diet; HS, high salt diet; GFR, glomerular filtration rate measurements; BP, blood pressure measurement; OP, osmotic pump. (B) Endpoint kidney-to-total body weight ratios. (C) Endpoint systolic BP. One-way ANOVA was used for statistical analysis. P values are shown for comparisons where p < .05.

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  Figure 2.. Sacubitril’s effects on the heart. (A) Endpoint heart-to-total body weight ratios. (B) Histological characterization of cardiac tissue using Masson trichrome staining. Representative images of cardiac tissues from experimental rats isolated at the end point of the experimental protocol [high-salt diet, upon administration of vehicle (VEH) or sacubitril (SCB)]. One-way ANOVA was used for statistical analysis. p values are shown for comparisons where p < .05.

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  Figure 3.. Histological characterization of renal damage with Masson trichrome staining. (A) Representative images of cortical and medullary renal tissues from experimental rats isolated at the end point of the experimental protocol [high-salt diet, upon administration of vehicle (VEH) or sacubitril (SCB)]. The first column shows scans of coronal midsections of kidneys stained with Masson trichrome; fibrotic tissue appears blue. The second and third columns demonstrate representative images taken in the cortexes and medulla, respectively. (B and C) graphs summarizing the analysis of percentage of fibrosis (B) and protein cast scoring (C). a.u., arbitrary units. Two-way ANOVA with Tukey post-hoc was used for significance comparisons. Each point on the graphs denotes data obtained from one image, with 16 images being taken per kidney: 10 from each cortex, and 6 from each medulla. p values are shown for comparisons where p < .05.

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  Figure 4.. Characterizations of glomerular function and damage. (A) Start vs endpoint glomerular filtration rates (GFR). (B) Representative FITC-inulin clearance curves from conscious freely moving rats injected with FITC-inulin. (C) Glomerular injury as determined by scoring individual glomeruli for damage; each point is an average of 100 randomly scored glomeruli per kidney. Images are representatives of glomeruli from Masson trichrome stained tissues, from VEH and SCB animals. Two-way ANOVA with Tukey post-hoc was used for significance comparisons. p values are shown for comparisons where p < .05.