Group Housing of Male Mice Causes a Significant Decrease in Day to Night Changes in Mean Arterial Pressure and are Indicative of the Development of Hypertension and Cardiovascular Disease

Abstract

Changes in day to night time mean arterial pressure (MAP) predict hypertension and cardiovascular diseases. When there is a decrease in day ‐ night time MAP changes, the chances of hypertension and cardiovascular diseases increase significantly. Our hypothesis is that socialization of male mice causes a decrease in the day ‐ night time changes in MAP and heart rate (HR). Male mice, 6 – 8 weeks of age, were implanted with a biotelemetry device from Data Sciences (male mouse in a single cage) or TSE (multiple male mice in a single cage). Day and Night MAP for Data Science mice were 131 ± 0.5 and 157 ± 1.5 mmHg, respectively. Day and Night MAP for TSE mice were 114 ± 7.0 and 124 ± 3.6 mmHg, respectively. The change in day and night MAP were 26 ± 2.2 mmHg in Data Science and 8.4 ± 4.0 mmHg in TSE mice. Day and Night time HR for Data Science mice were 482 ± 6 bpm and 505 ± 5.4 bpm, respectively. The change in day and night time HR were 36 ± 6 bpm in Data Science and 51 ± 12 bpm in TSE mice. Data Science mice had a higher MAP than TSE mice, the change in day ‐ night time MAP was less than TSE mice. The change in day and night time HR was also less in Data Science mice. Therefore, socialization of mice decreases day to night change in MAP and is indicative of hypertension and cardiovascular diseases.