Differential gene expression and alternative splicing of survivin following mouse sciatic nerve injury.

Study Design: In vivo studies using an axotomy model in adult male Naval Medical Research Institute mice.

Objective: Survivin, a unique member of the inhibitor of the apoptosis (IAP) protein family, is expressed during embryonal development, but is undetectable in terminally differentiated cells and tissues. Owing to the vital role of survivin in cellular proliferation and apoptotic cell death, and also to the necessity of treatment of the nervous system injuries, we have monitored survivin gene expression as well as its alternative splicing changes at different time points within injured mouse sciatic nerves.

Setting: Department of Genetics, School of Basic Sciences, Tarbiat Modares University, Tehran, Iran.

Methods: The sciatic nerves of adult male Naval Medical Research Institute mice were transected and the expression of survivin was examined in the distal and proximal parts of the dissected nerves as well as in the corresponding segments within the spinal cord of the animals, using semi-quantitative RT-PCR and immunohistochemistry.

Results: Survivin is not expressed in undamaged sciatic nerves, but, after sciatic nerve injury, it is gradually upregulated in proximal and distal parts of the dissected nerve (P<0.05). Survivin140 is the main variant expressed after injury, accompanied by a low expression of survivin40 (P<0.05). There was no expression of the survivin121 variant after injury.

Conclusions: Survivin is differentially expressed and spliced in damaged nerve and spinal cord. Future works on the manipulation of expression and/or the splicing of survivin could decipher the potential effects of survivin variants on the regeneration of nerve and/or spinal cord injuries.