A method for reducing animal use whilst maintaining statistical power in electrophysiological recordings from rodent nerves

Laura R Rich,Jonathan A Patrick,Margaret A Hamner,Bruce R Ransom,Angus M Brown

doi:10.1016/j.heliyon.2020.e04143

Laura R Rich, Jonathan A Patrick + Show 3 more

Open Access

https://doi.org/10.1016/j.heliyon.2020.e04143

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Journal: Heliyon	Publication Date: Jun 1, 2020
Citations: 2	License type: cc-by

Affiliation: University of Nottingham, University of Washington

Abstract

The stimulus evoked compound action potential, recorded from ex vivo nerve trunks such as the rodent optic and sciatic nerve, is a popular model system used to study aspects of nervous system metabolism. This includes (1) the role of glycogen in supporting axon conduction, (2) the injury mechanisms resulting from metabolic insults, and (3) to test putative benefits of clinically relevant neuroprotective strategies. We demonstrate the benefit of simultaneously recording from pairs of nerves in the same superfusion chamber compared with conventional recordings from single nerves. Experiments carried out on mouse optic and sciatic nerves demonstrate that our new recording configuration decreased the relative standard deviation from samples when compared with recordings from an equivalent number of individually recorded nerves. The new method reduces the number of animals required to produce equivalent Power compared with the existing method, where single nerves are used. Adopting this method leads to increased experimental efficiency and productivity. We demonstrate that reduced animal use and increased Power can be achieved by recording from pairs of rodent nerve trunks simultaneously.

Highlights

Application of the suction electrode technique to record the stimulus evoked compound action potential (CAP) from rodent nerve trunks was introduced in the late 1980s (Baker et al, 1987; Kocsis et al, 1986) and subsequently adopted to assess the damage incurred by central white matter as a result of metabolic insult (Fern et al, 1994; Ransom and Fern, 1997; Stys et al, 1992)
We demonstrate that reduced animal use and increased Power can be achieved by recording from pairs of rodent nerve trunks simultaneously
This difference can be more accurately reported as the relative standard deviation (RSD), which is the coefficient of variation (S/x) expressed as a percentage

Summary

Introduction

Application of the suction electrode technique to record the stimulus evoked compound action potential (CAP) from rodent nerve trunks was introduced in the late 1980s (Baker et al, 1987; Kocsis et al, 1986) and subsequently adopted to assess the damage incurred by central white matter as a result of metabolic insult (Fern et al, 1994; Ransom and Fern, 1997; Stys et al, 1992). In more recent studies both optic nerves have been placed in the same superfusion recording chamber and paired sets of stimulating and recording electrodes used to acquire CAPs from both nerves simultaneously (Hamner et al, 2011). This method has obvious advantages in studies such as investigations into the effects of ischaemic pre-conditioning on subsequent CAP recovery in optic nerves exposed to oxygen glucose deprivation (OGD), where surgical occlusion of the blood supply to one optic nerve was compared with its untreated partner nerve (Hamner et al, 2015)

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