Investigating Alterations in Caecum Microbiota After Traumatic Brain Injury in Mice

Summary

Presented here is a protocol to induce diffuse traumatic brain injury using a lateral fluid percussion device followed by the collection of the caecum content for gut microbiome analysis.

Abstract

Increasing evidence shows that the microbiota-gut-brain axis plays an important role in the pathogenesis of brain diseases. Several studies also demonstrate that traumatic brain injuries cause changes to the gut microbiota. However, mechanisms underlying the bidirectional regulation of the brain-gut axis remain unknown. Currently, few models exist for studying the changes in gut microbiota after traumatic brain injury. Therefore, the presented study combines protocols for inducing traumatic brain injury using a lateral fluid percussion device and analysis of caecum samples following injury for investigating alterations in the gut microbiome. Alterations of the gut microbiota composition after traumatic brain injury are determined using 16S-rDNA sequencing. This protocol provides an effective method for studying the relationships between enteric microorganisms and traumatic brain injury.

Introduction

Traumatic brain injury (TBI) is a global public health problem and the leading cause of death and disability in young adults^1,2. TBI causes many deaths every year, and survivors experience a variety of physical, psychiatric, emotional, and cognitive disabilities. Therefore, TBI is a heavy burden to a patient's family and societal resources. TBI involves both the primary brain injury that occurs at the time of trauma and any secondary brain injuries that develop hours to months following initial injury. Secondary brain injury is mediated by several biochemical cascades, which are not only detrimental to the bra....

Protocol

All procedures performed were approved by the Experimental Animal Ethics Committee of Zhejiang University. All instruments and materials used in surgery are sterile. The TBI proceudre takes about 20 minutes.

1. Animal care

1. Use 5- to 6-week-old male C57BL/6J mice (20-25 g of weight) in this experiment.
2. Maintain mice on a 12 h/12 h light/dark cycle, and make sure they receive food and water ad libitum. Provide the same amounts of food and water to both the sham and TBI.......

Discussion

Presented here is a simple and efficient protocol to determine changes in cecal microbiota after TBI in mice. Induction of brain injury and collection of caecum content samples are critical parts of the protocol.

Despite researchers having studied the changes of gut microbiota following TBI, the brain injury used in these studies were CCI-⁸ and weight drop/impact-induced models⁹. However, the CCI model mostly replicates brain contusion, and the w.......

Materials

Name	Company	Catalog Number	Comments
DNA isolation kit	QIAGEN	51604	For fast purification of genomic DNA from stool samples
Gene analysis service	GENEWIZ		Gene analyse service
Heating pad	Shanghai SAFE Biotech Co.	TR-200	heating pad
Injector	The First Affiliated Hospital, School of Medicine, Zhejiang University		injector
LFPI device	Virginia Commonwealth University	FP302	LFPI device
Micro cranial drill	RWD Life Science	78061	Micro cranial drill
Povidone Iodine	The First Affiliated Hospital, School of Medicine, Zhejiang University		Povidone Iodine