Peripheral nerve allografts stored in green tea polyphenol solution

Background. We previously demonstrated the successful 1 -month storage of peripheral nerve segments in a green tea polyphenol extract. We investigated whether this method could reduce the donor-host immune reaction associated with peripheral nerve allotransplantation. Methods. Sciatic nerve segments (20 mm long) were harvested from Dark Agouti (DA) rats, stored in polyphenol solution (1 mg/mL) for I month, and transplanted into recipient major histocompatibility complex- mismatched Lewis rats to bridge 15-mm-long sciatic nerve gaps (polyphenol-treated allograft group). The controls were an isograft group (nerve segments harvested from Lewis rats were immediately transplanted into Lewis rats), a polyphenol-treated isograft group (nerve segments harvested from Lewis rats were treated by polyphenol in the same method and transplanted into Lewis rats), and a fresh allograft group (nerve segments harvested from DA rats were transplanted into Lewis rats without storage). To investigate the origins of the cells in the transplanted nerves, sciatic nerve segments harvested from the male DA rat donors were transplanted into female Lewis rat recipients; genomic DNA was extracted from each nerve segment and amplified by polymerase chain reaction using primers specific for the rat sex-determining region of the Y-chromosome (Sry). Results. Nerve regeneration in the polyphenol-treated allograft group was similar to that in the isografted group. Sry-specific bands were detected in all samples in the sex-mismatched polyphenol-treated allograft specimens despite their major histocompatibility complex incompatibility. Conclusions. Storage in green tea polyphenol solution can reduce both ischemic damage to nerve tissue and donor-host immune reactions after allotransplantation.