Alanyl-glutamine has no effect on epidural fibrosis in a post-laminectomy rat model

Abstract

Epidural fibrosis following spinal surgery is common, and subsequent reoperations are more technically challenging with higher complication rates. A safe and effective therapeutic solution to this difficult clinical problem has yet to be realized. Previous research has demonstrated the effectiveness of alanyl-glutamine in reduction of peritoneal adhesions in a rat abdominal sepsis model. I hypothesized that alanyl-glutamine may be similarly efficacious in minimizing epidural fibrosis in a rat laminectomy model.

Rats were randomized into three groups: no surgery, laminectomy/normal saline and laminectomy/alanyl-glutamine (1g/kg). The surgical groups underwent a lumbar laminectomy with instillation of either normal saline or alanyl-glutamine into the peridural space. Thirty days after surgery, the rats were euthanized and the spinal columns prepared for histological evaluation. A blinded veterinary pathologist and a less experienced student independently graded the extent and maturity of epidural fibrosis.

The laminectomy model was an effective model for epidural fibrosis formation. Rats that underwent laminectomy demonstrated significant fibrosis compared to control animals (p<0.001). However, there was no significant difference in histological grade of fibrosis between normal saline and alanyl-glutamine treatment groups (p=0.83).

Based on this study, alanyl-glutamine does not appear to have an effect in reducing epidural fibrosis at a histological level. It is possible that alanyl-glutamine may have an effect that is not detectable using this model, in which case further studies with a more sensitive model may be indicated. Resources may be better used elucidating the mechanism by which glutamine acts to reduce adhesions in the peritoneal model and further studies exploiting those mechanisms can be designed.