An inhalation anaesthesia approach for neonatal mice allowing streamlined stereotactic injection in the brain

Abstract

Investigating brain function requires tools and techniques to visualise, modify and manipulate neuronal tissue. One powerful and popular method is intracerebral injection of customised viruses, allowing expression of exogenous transgenes. This technique is a standard procedure for adult mice, and is used by laboratories worldwide. Use of neonatal animals in scientific research allows investigation of developing tissues, and enables long-term study of cell populations. However, procedures on neonatal mice are more challenging, due to the lack of reliable methods and apparatus for anaesthesia of these animals. Here, we report an inhalation-based protocol for anaesthesia of neonatal (P0-2) mice, and present a custom 3D-printed apparatus for maintenance of anaesthesia during surgical procedures. This approach significantly enhances animal welfare and facilitates wider and simpler use of neonatal rodents in scientific research. Our optimised method of anaesthesia enables a rapid method of stereotactic injection in neonatal mice for transduction of brain tissue. We demonstrate this procedure for targeted labelling of specific brain regions, and in vivo modification of tissue prior to organotypic culture. This anaesthetic approach can be readily employed by any laboratory, and will enable safer use of neonatal rodents across a diverse spectrum of scientific disciplines. HighlightsO_LIDevelopment of inhalation-based anaesthesia for early postnatal (P0-2) mice C_LIO_LI3D-printed mould allows anaesthetic maintenance for neonatal surgery C_LIO_LIImproved mouse welfare through reliable neonatal inhalation anaesthesia C_LIO_LIRapid procedure for brain transduction of mouse litter in under 2 hours C_LI