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[Histomorphology and histocompatibility of acellular nerve prepared by different methods].

OBJECTIVE
To observe the histomorphology and the biocompatibility of acellular nerve prepared by different methods, to provide the experimental evidence for the selection of preparation of acellular nerve scaffold.


METHODS
Forty-eight adult Sprague Dawley rats, male or female, weighing 180-220 g, were selected. The sciatic nerves were obtained from 30 rats and were divided into groups A, B, and C (each group had 20 nerves). The acellular sciatic nerves were prepared by the chemical methods of Dumont (group A), Sondell (group B), and Haase (group C). The effect to remove cells was estimated by the degree of decellularization, degree of demyelination, and integrity of nerve fiber tube. The histocompatibility was observed by subcutaneous implant test in another 18 rats. Three points were selected along both sides of centre line on the back of rats, and the points were randomly divided into groups A1, B1, and C1; the acellular nerve of groups A, B, and C were implanted in the corresponding groups A1, B1, and C1. At 1, 2, and 4 weeks after operation, the rats were sacrificed to perform the general observation and histological observation.


RESULTS
The histomorphology: apart of cells and the dissolved scraps of axon could be seen in acellular never in the group A, and part of Schwann cell basilar membrane was broken. In group B, the cells in the acellular never were not removed completely, the Schwann cell basilar membrane formed bigger irregular hollows, part of the Schwann cell basilar membrane was broken obviously. But in the group C, the cells were completely removed, the Schwann cell basilar membrane remained intactly. Group C was better than group A and group B in the degree of decellularization, degree of demyelination, integrity of nerve fiber tube and total score, showing significant differences (P < 0.05). The subcutaneous implant test: there were neutrophils and lymphocytes around the acellular nerve in 3 groups at 1 week after implant. A few of lymphocytes were observed around the acellular nerve in 3 groups at 2 weeks after implant. The inflammation was less in groups A1, B1, and C1 at 4 weeks after implant, part of the cells grew into the acellular nerve and arranged along the Schwann cell basilar membrane. The reaction indexes of the inflammation cells in group A1 and group B1 were higher than that in group C1 at 1, 2, and 4 weeks after implant, showing significant differences (P < 0.01), but there was no significant difference between group A1 and group B1 (P > 0.05).


CONCLUSION
The acellular sciatic nerves prepared by Haase method has better acellular effect and the histocompatibility than those by the methods of Dumont and Sondell.