title: Neurological function following intra-neural injection of fluorescent neuronal tracers in rats.
abstract: Fluorescent neuronal tracers should not be toxic to the nervous system when used in long-term labeling. Previous studies have addressed tracer toxicity, but whether tracers injected into an intact nerve result in functional impairment remains to be elucidated. In the present study, we examined the functions of motor, sensory and autonomic nerves following the application of 5% Fluoro-Gold, 4% True Blue and 10% Fluoro-Ruby (5 μL) to rat tibial nerves via pressure injection. A set of evaluation methods including walking track analysis, plantar test and laser Doppler perfusion imaging was used to determine the action of the fluorescent neuronal tracers. Additionally, nerve pathology and ratio of muscle wet weight were also observed. Results showed that injection of Fluoro-Gold significantly resulted in loss of motor nerve function, lower plantar sensibility, increasing blood flow volume and higher neurogenic vasodilatation. Myelinated nerve fiber degeneration, unclear boundaries in nerve fibers and high retrograde labeling efficacy were observed in the Fluoro-Gold group. The True Blue group also showed obvious neurogenic vasodilatation, but less severe loss of motor function and degeneration, and fewer labeled motor neurons were found compared with the Fluoro-Gold group. No anomalies of motor and sensory nerve function and no myelinated nerve fiber degeneration were observed in the Fluoro-Ruby group. Experimental findings indicate that Fluoro-Gold tracing could lead to significant functional impairment of motor, sensory and autonomic nerves, while functional impairment was less severe following True Blue tracing. Fluoro-Ruby injection appears to have no effect on neurological function.
authors.affiliation: School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, Jiangsu Province, China ; Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Hu
authors.affiliation: Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, Jiangsu Province, China ; Department of Hand Surgery, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, Jiangsu Province, China ; Department of Hand Surgery, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, Jiangsu Province, China ; School of Medicine, Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, Jiangsu Province, China ; School of Medicine, Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Tianwen
authors.initials: T
authors.lastname: Gu
authors.affiliation: School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, Jiangsu Province, China ; Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Gu
authors.affiliation: Department of Hand Surgery, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Gu
keywords: Fluoro-Gold; Fluoro-Ruby; True Blue; grants-supported paper; neural regeneration; neurological function; neuronal tracing; neuroregeneration; peripheral nerve injury; tracer toxicity