Transplantation of human amnion prevents recurring adhesions and ameliorates fibrosis in a rat model of sciatic nerve scarring

[Display omitted] Peripheral nerve fibrosis and painful adhesions are common, recurring pathological sequelae following injury. In this study, vital human amnion (hAM), an increasingly interesting biomaterial for regenerative medicine, was investigated as a novel therapy. hAM was first analyzed in vitro regarding its anti-adhesive characteristics. Then, the reflected region of hAM which was identified as more suitable, was transplanted into female Sprague Dawley rats with recurring sciatic nerve scarring (n = 24) and compared with untreated controls (n = 30) at one, four and twelve weeks. Immune response and fibrosis were investigated by (immuno)histochemical analysis. Nerve structure was examined and function determined using electrophysiology and gait analysis. Here we identified strongly reduced adhesions in the hAM-treated rats, displaying a significant difference at four weeks post transplantation compared to untreated controls (p = .0052). This correlated with the in vitro cell attachment test on hAM explants, which demonstrated a distinctly limited ability of fibroblasts to adhere to amniotic epithelial cells. Upon hAM transplantation, significantly less intraneural fibrosis was identified at the later time points. Moreover, hAM-treated rats exhibited a significantly higher sciatic functional index (SFI) after four weeks compared to controls (p