The peripheral nervous system is able to regenerate after injury, and regeneration is associated with the expression of many genes and proteins. MicroRNAs are evolutionarily conserved, small, non-coding RNA molecules that regulate gene expression at the level of translation. In this paper, we focus on the identification and functional annotation of novel microRNAs in the proximal sciatic nerve after rat sciatic nerve transection. Using Solexa sequencing, computational analysis, and quantitative reverse transcription PCR verification, we identified 98 novel microRNAs expressed on days 0, 1, 4, 7, and 14 after nerve transection. Furthermore, we predicted the target genes of these microRNAs and analyzed the biological processes in which they were involved. The identified biological processes were consistent with the known time-frame of peripheral nerve injury and repair. Our data provide an important resource for further study of the role and regulation of microRNAs in peripheral nerve injury and regeneration.
LI ShiYingYU BinWANG YongJunYAO DengBingZHANG ZhanHuGU XiaoSong
To find a promising alternative to neurons or schwann cells (SCs) for peripheral nerve repair applications,this study sought to isolate stem cells from fetal rat dorsal root ganglion (DRG) explants.Molecular expression analysis confirmed neural stem cell characteristics of DRG-derived neurospheres in terms of expressing neural stem cell-specific genes and a set of well-defined genes related to stem cell niches and glial fate decision.Under the influence of neurotrophic factors,bFGF and NGF,the neurospheres gave rise to neurofilament-expressing neurons and S100-expressing Schwann cell-like cells by different pathways.This study suggests that a subpopulation of stem cells that reside in DRGs is the progenitor of neurons and glia,which could directly induce the differentiation toward neurons,or SCs.
Objective To prepare and identify a polyclonal antibody against rat myostatin and investigate myostatin expression in the rat atrophic gastrocnemius muscle after tibial nerve crush. Methods The purified fusion protein was used as antigen to immunize rabbits for the preparation of polyclonal antibody. The polyclonal antibody of the protein was measured by enzyme linked immunosorbent assay （ELISA）, western-blot and immunochemistry. Myostatin protein expression levels in normal and atrophic gastrocnemius muscle were detected by western-blot and immunochemistry assays. Results The GST-myostatin had a purity of 96% and possessed high titer and specificity. The level of myostatin in gastrocnemius muscle significantly increased one week after tibial nerve crush, reached the peak on day 14, and then returned to normal level on day 28. Conclusion We have successfully made antiserum of rat myostatin and found that the expression level of myostatin protein in the gastrocnemius after tibial nerve crush-induced atrophy was time-dependent. This study provides an experimental basis to clarify the possible role of myostatin during skeletal muscle atrophy.
