Effects of different injection methods of propofol anesthesia on the behavior and electroencephalography recording in mice

Propofol is commonly used in mice studies on the mechanism of general anesthesia. The administration routes of propofol include intraperitoneal injection, single tail vein injection, and continuous tail vein pumping. The aim of this study is to compare the effects of the three injection methods on the behavior and electroencephalography (EEG) recording in mice. Mice were divided into an intraperitoneal injection group, a single tail vein injection group, and a continuous tail vein pumping group according to the propofol administration route. The indexes for observation were: time of loss of righting reflex (LORR), time of resumption of righting reflex (RORR), and change in the number of EEG spindle waves during anesthesia. The LORR and RORR were detected again after 1 week to determine the repeatability of the three administration routes. Death and behavioral change after anesthesia recovery in mice were recorded in the three groups. For propofol administration in mice, intraperitoneal injection induced long-duration anesthesia, but the depth of anesthesia was shallow and there was a risk of anesthesia accidents. A small dose of propofol administered through a single tail vein can induce loss of consciousness but the LORR time was not recorded, hence the metrics during induction of anesthesia were not investigated. Continuous tail vein pumping produced stable behavior and EEG recording during anesthesia induction and recovery in mice, and the individual difference was small. Continuous tail vein pumping is an ideal administration route for studying the mechanism of loss of consciousness of propofol anesthesia in mice, which could provide reference data for future mice experiments using propofol.