The effects of anesthesia on measures of nerve conduction velocity in male C57Bl6/J mice

Abstract

Animal models, particularly mice, are used extensively to investigate neurological diseases. Basic research regarding animal models of human neurological disease requires that the animals exhibit hall mark characteristics of the disease. These include disease specific anatomical, metabolic and behavioral changes. Nerve conduction velocity (NCV) is the predominant method used to assess peripheral nerve health. Normative data adjusted for age, gender and height is available for human patients; however, these data are not available for most rodents including mice. NCV may be affected by animal age and size, body temperature, stimulus strength and anesthesia. While the effects of temperature, age and size are documented, the direct and indirect effects of anesthesia on NCV are not well reported. Our laboratory is primarily concerned with animal models of diabetic neuropathy (DN) and uses NCV to confirm the presence of neuropathy. To ensure that subtle changes in NCV are reliably assayed and not directly or indirectly affected by anesthesia, we compared the effects of 4 commonly used anesthetics, isoflurane, ketamine/xylazine, sodium pentobarbital and 2-2-2 tribromoethanol on NCV in a commonly used rodent model, the C57Bl6/J mouse. Our results indicate that of the anesthetics tested, isoflurane has minimal impact on NCV and is the safest, most effective method of anesthesia. Our data strongly suggest that isoflurane should become the anesthetic of choice when performing NCV on murine models of neurological disease.

Figure 1

The recording/stimulating electrodes in the tail (yellow dots) are placed 30 mm apart. In the sciatic nerve, the recording electrode is placed in the dorsum of the foot (b, red dots) and the stimulating electrode in the ankle and sciatic notch (a, red dots). A reference electrode is placed 5 mm distal from the recording/stimulating electrodes.

Figure 2

The effects of anesthesia on cardiopulmonary function (heart rate, arterial oxygen saturation and respiratory rate). All parameters were measured under anesthesia in mice 24 weeks of age and within 5 min of anesthesia. * = p < 0.05