Cyanoacrylate in nerve repair: transient cytotoxic effect

Cyanoacrylate adhesive has been suggested as an alternative to suturing when repairing severed peripheral nerves. The authors examined the cytotoxic effect of ethyl-cyanoacrylate on the human neuroblastoma cell line SH-SY5Y and compared it with the effects of butyl-cyanoacrylate (Histoacryl®), an adhesive approved for skin closure. Ethyl-cyanoacrylate or butyl-cyanoacrylate was applied in confluent SH-SY5Y cultures. Immediately, at 24 h and at 7, 14, 21 and 28 days, cultures were photographed and analysed digitally. At corresponding intervals, cell death was quantified using a 51Cr release assay. In cultures exposed to ethyl-cyanoacrylate or butyl-cyanoacrylate, cell death was observed predominantly in conjunction with the adhesive, causing a halo devoid of cells. Surviving cells showed neurodegenerative properties with loss of neuritis and reduction of body size up to 3 days post exposure. The inhibition halo diminished over time in both groups and at 28 days cells reached the margin of the adhesive in the ethyl-cyanoacrylate group. 51Cr assay indicated significant cell death in exposed cultures, which rapidly decreased during the first 14 days. No significant differences were found between the adhesives. This study demonstrates that ethyl-cyanoacrylate and butyl-cyanoacrylate have a transient cytotoxic effect, which may explain the promising results when using cyanoacrylate for nerve repair.