Effect of local administration of cyclosporine A on pe- ripheral nerve regeneration in a rat sciatic nerve transec- tion model

Objective： To assess the effect of cyclosporine A （CsA） loaded in chitosan conduit on bridg- ing the sciatic nerve defects in a rat model. Methods： A 10 mm sciatic nerve defect was bridged using a chitosan conduit filled with 10 μl carrier-drug dilu- tion （10 pg/L CsA）. In control group, the conduit was filled with the same volume of carrier dilution alone. The regene- rated fibers were studied 4, 8 and 12 weeks after surgery. Results： The functional study confirmed faster recov- ery of the regenerated axons in treatment group than control group （P〈0.05）. There was statistically significant differ- ence of the gastrocnemius muscle weight ratios between treatment and control groups （P〈0.05）. Morphometric indi-ces of regenerated fibers showed that the number and diam- eter of the myelinated fibers in CsA-treated animals were significantly higher than those in control group. In immunohistochemistry, the location of reactions to S-100 in CsA group was clearly more positive than control group. Conclusion： CsA loaded in a chitosan conduit results in improvement of functional recovery and quantitative mor- phometric indices of sciatic nerve. It is easily available with- out any complications compared with its systemic administration.