Decellularized Nerve Scaffold in a Rat Model of Extensive Peripheral Nerve Damage

The aim of the study was to develop a modified protocol for rat sciatic nerve decellularization and evaluate its efficacy in a rat model of an extensive peripheral nerve defect.

The study described a modified detergent-enzymatic decellularization protocol to create a decellularized nerve scaffold. A decellularization process (24 h) included the sequential treatment of a rat sciatic nerve with the solutions of trypsin-versene, 1% Triton X-100, 4% sodium deoxycholate, phosphate-buffered saline, and pancreatic DNase I. We modelled an extended defect of the sciatic nerve (15±2 mm), and Wistar rats were implanted with autografts or decellularized nerve scaffolds. The nerve recovery was assessed on day 90 after implantation using an immunohistochemistry analysis of the total count of nerve fibers, intact motor fibers, and myelinated fibers.

The results of the histological examination and DAPI staining showed the complete destruction and washing of nuclear material to preserve the nerve structure after decellularization. The DNA content in the decellularized scaffolds was 48.17±4.25 ng/mg of tissue, while in the native nerve it was 221.51±1.36 ng/mg. The analysis of the tissue response to the decellularized scaffold subcutaneously implanted demonstrated the absence of macrophages. Histology revealed a moderate number of intact nerve fibers in the orthotopically implanted decellularized scaffold (835.6 [804.2; 866.0] per 1 mm² of tissue) compared to the autograft (1284.1 [1190.5; 1316.0] per 1 mm² of tissue). The decellularized scaffold implantation resulted in an increase in the number of small myelinated fibers and the restoration of motor and sensory nerve fibers.

The use of detergent-enzymatic decellularization of the rat sciatic nerve demonstrated high efficacy, which was confirmed by the absence of nuclear material with the nerve histological structure preserved. The presence of the sufficient number of Schwann cells 3 months after implantation and the perineurium formation are the positive characteristics when assessing the nerve decellularization protocol efficacy. Thus, the decellularized nerve scaffold is a promising replacement of autografts to treat extensive defects of peripheral nerves.