OBJECTIVEPresent study aimed at further comprehensive functional, histomorphometrical and immunohistochemical assessment of peripheral nerve regeneration using rat sciatic nerve transection model.

METHODSThe 10-mm rat sciatic nerve gap was created in rats. In control group nerve stumps were sutured to adjacent muscle and in treatment group the gap was bridged using an inside-out vein graft. In sham-operated group the nerve was manipulated and left intact. All animals underwent walking track analysis test 4, 8, and 12 weeks after surgery. Subsequently, muscle mass measurement was performed to assess reenervation, histological examination to observe the sciatic nerve regeneration morphologically and immunohistochemistry to detect Schwann cells using anti S-100. Results were analyzed using a factorial ANOVA with two between-subjects factors. Bonferroni test for pairwise comparisons was used to examine the effect of treatments.

RESULTSFunctional analysis of myelinated nerve fibers showed that nerve function improved significantly in the time course in treatment group. However, quantitative morphometrical analysis of myelinated nerve fibers showed that there was no significant difference between 8 and 12 weeks in treatment group. Muscle weight ratio was bigger and weight loss of the gastrocnemius muscle was ameliorated by inside-out vein grafting. The position of positive immunohistochemical reactions further implied that regenerated axons and Schwann cell-like cells existed after vein grafting was performed, and was accompanied by the process of myelination and structural recovery of regenerated nerves.

CONCLUSIONFunctional analysis of peripheral nerve repair is far more reliable than quantitative morphometrical analysis.

Animals ; Immunohistochemistry ; Male ; Nerve Regeneration ; Rats ; Recovery of Function ; S100 Proteins ; analysis ; Sciatic Nerve ; physiology ; surgery ; Veins ; transplantation

OBJECTIVETo evaluate the potential effects of uncultured adipose-derived stromal vascular fraction on tendon healing.

METHODSTwenty five adult male New Zealand white rabbits weighing 2.5-3.0 kg were used. Five rabbits were used as donors of adipose tissue and the rest were divided into control and treatment groups. The injury model was completed by unilateral tenotomy through the middle one third of deep digital flexor tendon. Immediately after suture repair, either fresh stromal vascular fraction from enzymatic digestion of adipose tissue or placebo was intratendinously injected at tendon stumps in treatment and control groups, respectively. Immobilization with cast was continued for two weeks after surgery. Animals were sacrificed at eight weeks after surgery and tendons underwent histological, immunohistochemical, and mechanical evaluations. Statistical analyses of quantitative and qualitative data were assessed using one-way analysis of variance and Mann-Whitney U-test, respectively.

RESULTSHistological evaluations demonstrated superior fibrillar linearity and continuity, and decreased vascularity in treatment group indicated improved organization and remodeling of neotendons. Immunohistochemistry de- monstrated a significant increase in collagen I expression in treatment group. Ultimate load and energy absorption capacity were both significantly increased in cell-treated repairs compared with controls.

CONCLUSIONThe present study shows that intratendinous injection of uncultured adipose-derived stromal vascular fraction results in improved structural and mechanical properties of tendon repairs and it could be an effective modality for treating tendon injury.

Animals ; Biomechanical Phenomena ; Disease Models, Animal ; Orthopedic Procedures ; Rabbits ; Reconstructive Surgical Procedures ; Tendon Injuries ; surgery ; Tendons ; Wound Healing