Serum levels of tau protein increase according to the severity of the injury in DAI rat model.

Keisuke Tomita,Taka-Aki Nakada,Shigeto Oda,Taku Oshima,Rui Kawaguchi

doi:10.12688/f1000research.21132.1

Keisuke Tomita, Taka-Aki Nakada + Show 3 more

Open Access

https://doi.org/10.12688/f1000research.21132.1

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Journal: F1000Research	Publication Date: Jan 20, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: Chiba University

Abstract

Traumatic brain injury (TBI) in the form of diffuse axonal injury (DAI) is difficult to diagnose in the early phase of the injury. Early diagnosis of DAI may provide opportunity for developing treatment and management strategies. Tau protein has been demonstrated to increase in the early phase of TBI with high diagnostic accuracy in patients with DAI. We tested the biological plausibility of tau protein using a rat DAI model by evaluating the association between serum tau levels and the severity of brain injury.DAI was induced in animals using the Marmarou model.After a survival of 60 minutes, rats were anesthetized and sacrificed after obtaining blood samples (5ml) from the heart. Eighteenratswereemployedin the present studyand were randomly subjected to sham-operated control (n=4), mild DAI (n=7), and severe DAI (n=7). Of seven severe DAI rats, two rats that had focal injury caused by skull fracture were excluded in the measurement of tau protein level. The serum levels of tau protein in the rat DAI model were found to increase significantly and consistently according to the severity of the injury.Rats with DAI showed significantly higher serum levels of tau protein compared to sham rats; the severe DAI rats had higher levels of tau than moderate DAI and sham rats (sham vs. mild, P=0.02; mild vs. severe, P=0.02). In conclusion, serum tau protein levels may be useful as a biomarker for diagnosing and estimating the severity of DAI in the early phase.

Highlights

Traumatic brain injury (TBI) in the form of diffuse axonal injury (DAI) is difficult to diagnose with computed tomography (CT) scans, due to the minimal effect on the anatomical structure of the brain in the early phase of the injury
Of seven severe DAI rats, two rats that had focal injury caused by skull fracture were excluded in the measurement of tau protein level
The serum tau protein levels increased according to the severity of the injury, which was consistent with our results despite the difference in the injury model[13]

Summary

Introduction

Traumatic brain injury (TBI) in the form of diffuse axonal injury (DAI) is difficult to diagnose with computed tomography (CT) scans, due to the minimal effect on the anatomical structure of the brain in the early phase of the injury. Apart from imaging diagnostic techniques, biomarkers may be useful in diagnosing DAI and predicting its severity. Tau protein has been demonstrated to increase in the early phase of TBI with high diagnostic accuracy in patients with DAI4. Blood tau protein level has been reported to increase in concussion and chronic traumatic encephalopathy[5,6], and it has been reported that there is an association with severity. We tested the biological plausibility of tau protein using a rat DAI model by evaluating the association between serum tau levels and the severity of brain injury

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