OBJECTIVETo investigate the treatment for scarred vocal folds by transplanting human amniotic epithelial cells (hAECs)and injecting collagenase as well as hyaluronic acid (HA) for the intervention of the extracellular matrix(EMC), to observe the growth, distribution of hAECs and to assess the abilities of them for scarred vocal fold regeneration.

METHODSThe lamina propria was injured by localized resection in thirty-eight vocal folds of twenty rabbits. hAECs were isolated from human amnion and marked by Lenti-GFP. After the formation of vocal fold scarring, hAECs were transplanted into ten vocal folds, collagenase and HA were injected into ten vocal folds, all three were injected into ten vocal folds, none were injected into eight vocal folds, and two normal vocal folds were used as control. At 1 month and 2 months after the transplanting, the survival, the distribution and the cytoactive of hAECs were examined by immunofluorescence method. Meanwhile, at 1 month, 2 months, 3 months and 6 months after the operation, HE staining was performed for histopathological research, Masson trichrome staining and immunohistochemical staining were used for collagen and fibronectin respectively.

RESULTSAfter implanted into the scarred vocal folds, hAECs could survive in vocal fold lamina propria for two months. The immunofluorescence analysis showed the cytoactive of hAECs.Six months postoperatively, compared with that in the normal vocal folds, collagen in the untreated scarred vocal folds more increased and disorderly distributed; the changes in other three groups were between the two groups above, but the group injected with all of hAECs, collagenase and HA was better than other two groups. Besides, the mean density of fibronectin in the scarred untreated control group was more significantly increased than that in the normal vocal folds; the changes in other three groups were between the two groups above, but the group injected with all of hAECs, collagenase and HA was better than other two groups.

CONCLUSIONThe transplanting of hAECs and the interventions of EMC by injecting collagenase as well as HA have better abilities in rabbit scarred vocal fold reparation and regeneration by promoting ECM secretion, rational distribution and part ordering arrangement.