Related Experiment Video
Updated: Jun 4, 2026
Facial Nerve Surgery in the Rat Model to Study Axonal Inhibition and Regeneration
Published on: May 5, 2020
Effect of neurotrophic factor, MDP, on rats' nerve regeneration
A A Fornazari1, M R de Rezende, R Mattar
1Laboratório de Microcirurgia, Instituto de Ortopedia e Traumatologia, Hospital das Clínicas, Universidade de São Paulo, SP, Brasil. adrienfornazari@ig.com.br
Abstract:
Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.
Insights
The neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) enhanced median nerve regeneration in rats, improving functional recovery. MDP-treated rats showed superior grasp function compared to controls, despite no significant histological differences.
Area of Science:
- Neuroscience
- Regenerative Medicine
- Immunology
Background:
- Median nerve injury can lead to significant functional deficits.
- Nerve repair techniques aim to restore function, but outcomes vary.
- The role of immune modulators like N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) in nerve regeneration is under investigation.
Purpose of the Study:
- To evaluate the immune-modulating effects of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration.
- To compare the efficacy of different nerve repair methods, including the addition of MDP.
Main Methods:
- Male Wistar rats underwent median nerve repair using sutures alone (S), sutures with fibrin tissue adhesive (SF), or sutures with FTA and MDP (SFM).
- Functional recovery was assessed weekly for 12 weeks using the grasp test.
- Histological analysis quantified myelinated fiber number and diameter to calculate regeneration and diameter change indices.
Main Results:
- MDP administration (group SFM) significantly improved grasp function by week 8 compared to sutures alone (group S).
- By week 12, MDP-treated rats demonstrated superior grasp function compared to both sutures alone (S) and sutures with FTA (SF) groups.
- While functional recovery was enhanced with MDP, histological analysis revealed no significant differences between the groups.
Conclusions:
- N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) significantly enhances functional recovery after median nerve repair in rats.
- MDP's benefits appear to be functional rather than structural, as evidenced by histological data.
- Further research into MDP's mechanisms may offer new therapeutic strategies for nerve regeneration.
