Morphological study on the collaterals developed by one axon during peripheral nerve regeneration

Figures & data

Figure 1. Illustration of surgical procedures. 1/2 Proximal tibial nerve segment was served as father nerve to repair the distal nerve stump using biodegradable chitin conduits with a gap of 1 mm.

Table I. Comparison of myelinated axon numbers for all groups.

Group	PT	MT	DT	RDP	Amplifying ratio	TFI
Sham control	7302 ± 1121	7218 ± 1324	7423 ± 1218	–	–	− 9.1 ± 2.7
Experimental	7414 ± 1039	3756 ± 604	6879 ± 1023	1.97	1.83	− 48.6 ± 6.8

Values are expressed as the mean ± standard deviation. All data above were received 4 months after operation. PT: Proximal Tibial Nerve; MT: Medial Tibial Nerve (Donor nerve); DT: Distal Tibial Nerve (regenerated nerve); R_DP: Ratio of distal nerve stump endoneurial tube numbers to proximal donor nerve axon numbers; Amplifying ratio: ratio of distal regenerative myelinated axon numbers to that of the proximal donor axons (n = 6).

Figure 2. Electrophysiological recordings of the compound muscle action potential of gastrocnemius muscles 4 months after operation. The motor NCV of the tibial nerve in the sham control group was 49.5 ± 4.9 m/s (A) while the value of the distal tibial nerve segment in the experimental group was 27.8 ± 5.3 m/s (B).

Figure 3. Histological sections through the reconstructed nerves 4 months after surgery. A: The proximal part of the tibial nerve (normal tibial nerve). B: The distal part of the tibial nerve was repaired with 1/2 number of proximal donor axons (regenerated tibial nerve).

Figure 4. Myelinated nerve fiber isolated from the tibial nerve. A: single fiber isolated from the tibial nerve in sham control group; B: Regenerated fiber at the site of suture with biodegradable chitin conduits. A myelinated axon sprouts collateral branches at the node of Ranvier. (Observed with light microscopy working at 100× magnification).