Characteristics of cytokines in regeneration of injured peripheral nerves

Abstract Background Cytokines are essential cellular modulators of a variety of physiological and pathological activities, including peripheral nerve repair and regeneration. However, the molecular changes of these cellular mediators during peripheral nerve regeneration are not well clarified. The study is aimed to discover critical cytokines for the regenerative process of injured peripheral nerves. Methods The sequencing data of the injured nerve stumps and the dorsal root ganglia (DRGs) of Sprague-Dawley (SD) rats subjected to sciatic nerve (SN) crush injury was analyzed to determine expression patterns of genes coding for cytokines. PCR experiments were used to validate the accuracy of sequencing data. Results A total of 46, 52, and 54 upstream cytokines were differentially expressed in SNs at 1 day, 4 days, and 7 days after nerve injury. And a total of 25, 28, and 34 upstream cytokines were differentially expressed in DRGs at these time points. The expression patterns of some essential upstream cytokines were displayed in a heatmap and validated by PCR experiment. Bioinformatic analysis of these differentially expressed upstream cytokines after nerve injury demonstrated that inflammatory and immune responses were significantly involved. Conclusions In summary, the findings provided an overview of the dynamic changes of cytokines in SNs and DRGs at different time points after rat nerve crush injury, elucidated the biological processes of differentially expressed cytokines, especially the important roles in inflammatory and immune responses during peripheral nerve repair and regeneration, and thus might contribute to identification of potential treatments for peripheral nerve repair and regeneration.