Table 3.

Collagen-based antiscarring agents.

Reference	Method to Induce Scar Formation	Agent	Animal and Nerve Model	Analyses	Results
Colonna et al., 2019 [16]	Section + suture	Collagen sheath derived from an acellular hypoallergenic dermal matrix (OrACELL)	Female Wistar Rat Median nerve	-Functional evaluation (grasping test) (every two months) -Histology on nerve and surrounding tissue and morphometric analysis (Toluidine Blue) (7 months)	Axon diameter was higher in the treated group. No significant differences in the functional test were observed.
Lee et al., 2014 [76]	Section + suture	Collagen-based film (NeuraGen)	Male Wistar Rat Sciatic nerve	-Electrophysiological evaluation (12 weeks) -Wet muscle weight (12 weeks) -Histology on nerve and surrounding tissue and morphometric analysis (Toluidine Blue) (12 weeks)	Reduction of scar in microscopical analysis, although the scar-decreasing effect of bioabsorbable nerve wrap did not translate into a better motor nerve recovery.
Mathieu et al., 2012 [47]	Section + suture	Collagen membrane and vein wrapping	Female Wistar Rat Sciatic nerve	-Gross evaluation (Petersen’s classification) (12 weeks) -Histology on nerve and surrounding tissue (Masson’s trichrome—extraneural and intraneural fibrosis, foreign body reaction)	The collagen membrane was effective in reducing neural scar formation. Autologous vein wrapping also showed a favorable effect in this indication despite less successful histological outcomes.
Kim et al., 2010 [75]	Section + suture	Collagen wrap	Sprague–Dawley Rat Sciatic nerve	-Gross evaluation (Petersen’s classification) (3 months) -Histology on nerve and surrounding tissue and morphometric analysis (Toluidine Blue) (3 months)	Significant reduction of inner epineurium thickness in the treated group.
Isla et al., 2003 [13]	Section + suture or repair with silastic tube	ADCON/TN	Male Wistar Rat Ulnar nerve	-Gross evaluation (4-point qualitative Scale) (3 months) -Histology on nerve, surrounding tissue and muscle (H&E, Masson’s trichrome) (3 months)	Significant reduction of fibrosis. No differences in terms of fiber density.
Palatinsky et al., 1997 [23]	Scratch; a second neurolysis performed 4 weeks later	ADCON/TN (applied after the second neurolysis)	Sprague Dawley Rat Sciatic nerve	-Gross evaluation (4-point qualitative Scale) (4 and 8 weeks) -Histology on nerve and surrounding tissue (H&E, Masson’s trichrome, phenylenediamine staining) (4 and 8 weeks)	Significant reduction of composite score (macroscopical evaluation). No statistical difference in axons diameter.
Petersen et al., 1996 [27]	External neurolysis, abrasive injury on muscle and nerve, section + suture	ADCON/TN	Lewis’s Albino Rat Sciatic nerve	-Gross Evaluation (Petersen’s classification) (4 and 6 weeks) -Electrophysiological evaluation (4 and 6 weeks) -Histology on nerve and surrounding tissue (H&E, silver stain, van Gieson’s stain, Toluidine blue for morphometric analysis) (4 and 6 weeks)	Significant reduction of scar tissue; no differences in morphometrical analysis.