Abstract: Objective To investigate the effects of a chitosan product on scarring and adhesion after never injury in laminectomy in rats. Methods 48 male Sprague-Dawley rats were divided into group A and group B, and carried laminectomy of L4-5, and injured the right spinal nerve roots. The normal saline was smeared on the operation field in the group A, while the chitosan product was smeared in the group B. The adhesion was assessed with Rydell score 1 (groups A1/B1), 2 (groups A2/B2) and 4 (groups A3/B3) weeks after operation, while the spinal nerves were observed with HE staining and Masson staining, and the adhesion was assessed with Nussbaum score. The complete blood count and the series of blood chemistries and enzymes for liver and kidney functioning were measured. Results The Rydell scores of adhesion was I grade in group A1, II grade in A2 and III grade in A3, while was 0 grade in B1, 0 grade in B2 and II grade in B3. The scar and adhesion contact more loosely in the group B than in the group A, and the Nussbaum score was less in the group B than in the group A at the same time (P<0.05). The complete blood count and the series of blood chemistries and enzymes for liver and kidney functioning were in normal. Conclusion This chitosan product can prevent the formation of epidural scar and adhesion around the spinal and the nerve roots after laminectomy, with little toxicity and side effects.

Key words: chitosan, laminectomy, nerve roots, scar, adhesion, rats