Abstract
Abstract Background: There are divergences in the literature regarding the experimental model (Wistar-WIS or Wistar Kyoto-WKY) to be used as a Spontaneously Hypertensive Rat (SHR) control. The characterization of these models in terms of cardiovascular parameters provides researchers with important tools at the time of selection and application in scientific research. Objective: The aim of this study was to evaluate the use of WIS and WKY as a Spontaneously Hypertensive Rat (SHR) control by assessing the long-term behavior of blood pressure and cardiac structure and function in these strains. Methods: To this end, WIS, WKY, and SHR underwent longitudinal experiments. Blood pressure and body mass were measured every two weeks from the 8th to the 72nd. Echocardiographic analysis was performed in all groups with 16, 48, and 72 weeks of life. After having applied the normality test, the Two-Way ANOVA of repeated measures followed by the Tukey post hoc test was used. A significance level of 5% was established. Results: The WIS group showed higher body mass (p<0.05), while the WKY and SHR presented higher body mass variation over time (p<0.05). SHR exhibited increased values of systolic, diastolic, and mean blood pressure when compared to WKY and WIS, whereas the WKY generally showed higher values than WIS (p<0.05). Regarding the cardiac function, SHR showed reduced values, while the WKY presented an early decrease when compared to WIS with aging (p<0.05). Conclusion: WIS is a more suitable normotensive control for SHR than WKY in experiments to test blood pressure and cardiac structure and function.
Highlights
Between the 8th and the 20th weeks, Wistar Kyoto rats (WKY) presented a higher body mass when compared to Spontaneously Hypertensive Rat (SHR)
It was observed that WKY presented higher variation than Wistar rats (WIS) at 12th - 16th, 24th - 30th, 34th - 44th, and 60th - 64th weeks
WIS showed pressure values that were more consistent with those expected for normotensive rats; and 2) WKY presented earlier reductions in cardiac function when compared to WIS
Summary
Experimental animals are usually applied in the study of human health and disease, including the use of rodents as experimental models for the investigation of biological phenomenon similar to those observed in humans.[1,2,3] Among them, the SHR is widely used as a model for the investigation of essential hypertension.[3,4,5] For those working with these experimental animals, it is obvious and mandatory to adopt a control group in their experiments.In this way, two experimental strains are nowadays used as SHR’s controls, namely Wistar rats (WIS)[6,7,8] or Wistar Kyoto rats (WKY).[4,5,9] It is a well-known fact that WKY was the SHR background and most used strain as SHR control in scientific research.[8,10,11] the WIS strain has been used.[4,5,9,12] some previous studies have pointed out limitations in the use of both strains.[13,14,15,16,17,18]. Experimental animals are usually applied in the study of human health and disease, including the use of rodents as experimental models for the investigation of biological phenomenon similar to those observed in humans.[1,2,3] Among them, the SHR is widely used as a model for the investigation of essential hypertension.[3,4,5] For those working with these experimental animals, it is obvious and mandatory to adopt a control group in their experiments.
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