Comparison of three different strategies to treat sciatic nerve regeneration: an experimental study

Abstract

Purpose: To compare the effect of vein conduit filled with adipose tissue stem cells (ASC) on peripheral nerve injury regeneration.

Methods: We analyzed 30 male Wistar rats surgically submitted to a 5-mm gap on the sciatic nerve. Then, the animals were divided into three groups: nerve autografting (AG, n=10), autogenous inverted glycerol-conserved vein (VG, n=10), and autogenous inverted glycerol-conserved vein + ASC (VASCG, n=10). The study endpoints were neuromotor functional analysis, gastrocnemius muscle weight, and sciatic nerve graft histomorphometry analysis. In the histologic analysis, we added a control group (naïve nerve).

Results: Regarding functional analysis (Walking tract- score), the findings at week 3 showed a difference between the AG and the VG (-96.6 vs. -59.6, p=0.01, respectively) and between the VG and the inverted vein + VASCG (-59.9 vs. -88.92, p=0.02). At week 12, this study showed a difference between the AG and the VG (-64.8 vs. -47.3, p=0.004, respectively), and also a difference between the VG and the VASCG (-47.3 vs. -57.4, p=0.02, respectively). There was no difference in the histomorphometry analysis (nerve diameter, Schwann cells counting). The gastrocnemius muscles on the intervention side were more atrophic when compared to the gastrocnemius muscles on the control side.

Conclusions: Our results suggested better functional recovery in the inverted vein group when compared to control group, and inverted vein + ASC group.

Figure 1. Inversion of the vein graft process. (a) With the two tips catheterizing the lumen of the vein, the microsurgical titanium instrument (microsurgical forceps with angulated tips) was introduced all the way to the other end of the tubular structure (vein). (b) Clamping of one of the faces of the vein. (c) Reversing the vein inside out with the aid of an auxiliary microsurgical forceps with straight tips. (d) Result of the graft vein inversion process with the adventitia facing the lumen of the graft, and the endothelium facing the outside.

Figure 2. AG: autograft group; VG: inverted vein group; VASCG: inverted vein + ASC group. Methods adopted in the experimental surgeries.

Figure 3. Arrows: effective axons myelinated with Schwann cells (nuclei) in their periphery revealing neuronal regeneration in the vein conduit group. Transverse section with Masson’s trichrome staining under a Nikon E200 microscope (40x).