Evaluation of polymeric aligned NGCs and exosomes in nerve injury models in diabetic peripheral neuropathy condition

Peripheral nerve injuries in diabetic patients are challenging due to the limited regenerative nerve tissue capacity and additional tissue impairment due to diabetes. Here, we have developed a therapeutic approach for treating traumatic peripheral nerve injuries after diabetic neuropathy. We designed and evaluated the potential of nerve guiding scaffold and stem cell-derived exosomes in the repair of the nerve injuries after diabetic peripheral neuropathy (DPN). For that, polyurethane-based nerve conduits were fabricated by electrospinning technique. Further, in its lumen, aligned chitosan-collagen (1.5% w/v) cryogels were synthesized for developing porous nerve guidance channels (NGCs). Bone marrow stem cell-derived exosomes were isolated and characterized by transmission electron microscopy and CD-9 marker analysis. The developed NGCs have highly aligned porous architecture, as illustrated by the scanning electron microscopy and microCT imaging. In-vitro cell culture experiments showed Neuro2a cells growth and alignment along the porous channels on the chitosan-collagen cryomatrix. The in-vivo analysis was carried by developing two different traumatic sciatic nerve injury models in DPN rats, i.e., nerve crush injury and a nerve transection injury model. The exosomes were delivered via nerve conduits and direct transplantation in case of a crush injury model. In the case of nerve transection injury, exosomes loaded NGCs were implanted at the injury site. The regeneration was analyzed for nerve functionality and morphological assessment. The results showed improvement in the electrophysiological parameters such as nerve conduction velocity, compound muscle action potential, and sciatic nerve morphology after the treatment compared to the non-treated control. Also, the gastrocnemius muscle showed recovery in weight and morphology after treatment. The study demonstrated the role of the PUAO conduits, NGCs, and BMSCs exosomes in clinically challenging nerve injuries and paved the way for its application as a potential therapeutic approach.