Open AccessAlexa Fluor 488-conjugated cholera toxin subunit B optimally labels neurons 3–7 days after injection into the rat gastrocnemius muscle
Author(s) -
Bai Wei,
Jingjing Cui,
Jia Wang,
Dongsheng Xu,
Shuang Wu,
Yating Guo,
Yuxin Su,
Yihan Liu,
Yuqing Wang,
Xiang-Hong Jing
Publication year - 2022
Publication title -
neural regeneration research/neural regeneration research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.93
H-Index - 38
eISSN - 1876-7958
pISSN - 1673-5374
DOI - 10.4103/1673-5374.337055
Subject(s) - cholera toxin , alexa fluor , retrograde tracing , motor neuron , anatomy , biology , neuroscience , central nervous system , chemistry , spinal cord , endocrinology , physics , quantum mechanics , fluorescence
Neural tract tracing is used to study neural pathways and evaluate neuronal regeneration following nerve injuries. However, it is not always clear which tracer should be used to yield optimal results. In this study, we examined the use of Alexa Fluor 488-conjugated cholera toxin subunit B (AF488-CTB). This was injected into the gastrocnemius muscle of rats, and it was found that motor, sensory, and sympathetic neurons were labeled in the spinal ventral horn, dorsal root ganglia, and sympathetic chain, respectively. Similar results were obtained when we injected AF594-CTB into the tibialis anterior muscle. The morphology and number of neurons were evaluated at different time points following the AF488-CTB injection. It was found that labeled motor and sensory neurons could be observed 12 hours post-injection. The intensity was found to increase over time, and the morphology appeared clear and complete 3-7 days post-injection, with clearly distinguishable motor neuron axons and dendrites. However, 14 days after the injection, the quality of the images decreased and the neurons appeared blurred and incomplete. Nissl and immunohistochemical staining showed that the AF488-CTB-labeled neurons retained normal neurochemical and morphological features, and the surrounding microglia were also found to be unaltered. Overall, these results imply that the cholera toxin subunit B, whether unconjugated or conjugated with Alexa Fluor, is effective for retrograde tracing in muscular tissues and that it would also be suitable for evaluating the regeneration or degeneration of injured nerves.