Timecourse of recovery after surgical intraperitoneal implantation of radiotelemetry transmitters in rats.

INTRODUCTION

Rats are used in drug safety because they satisfy regulatory guidelines, there is a large historical database, and their cardiovascular systems respond similarly to humans. The use of radiotelemetry offers a variety of advantages over non-invasive techniques. Implantation of telemetry devices for cardiovascular assessments in rats is not novel, but the time to recover from the surgery has not been reported. In order to assess this, mean arterial blood pressure (MAP), heart rate (HR), body temperature (BT), body weight (BW), food consumption (FC), activity, and general health were determined in male Sprague-Dawley rats for 2 weeks following surgery.

METHODS

Radiotelemetry transmitters (TL11M2-C50-PXT, Data Sciences International, St. Paul, MN) were implanted into the peritoneal cavity of 15 rats under isoflurane anesthesia; 11 rats were used in the study. Data were collected (500 Hz for 24 h) using PONEMAH Physiology Platform software (Gould Instruments, Inc, Valley View, OH, version 4.0) on days 3, 8 and 15 following surgery. Body weight and 24-h food consumption were recorded 1 day prior to surgery and on days 3, 8 and 15 post-surgery; general health was recorded daily.

RESULTS

MAP tended to be greater on day 3 (104+/-2 mmHg) than on days 8 or 15 (99+/-2 mmHg and 99+/-2 mmHg, respectively). By contrast, activity (arbitrary units) tended to be lower on day 3 (1.9+/-0.2) than on days 8 or 15 (2.9+/-1.2 and 3.0+/-1.0, respectively). HR ( approximately 460 bpm) and BT ( approximately 37.5 degrees C) remained constant throughout the study. FC on day 4 postsurgery was less than pre-surgery (16.7+/-6.6 g vs. 23.6+/-1.2 g) and returned by day 9 (23.6+/-5.4 g). BW on day 4 (295+/-20 g) was not different from presurgery (297+/-11 g) and the rats gained weight on subsequent days. There were no effects on overall appearance and behavior due to surgery.

DISCUSSION

It is concluded that male Sprague-Dawley rats recover from surgery and can be used approximately 1 week following intraperitoneal implantation of radiotelemetry transmitters with monitoring of body weight and food consumption.