Comparative study on functional effects of allotransplantation of bone marrow stromal cells and adipose derived stromal vascular fraction on tendon repair: a biomechanical study in rabbits

Tendon never returns to its complete biological and mechanical properties after repair. Bone marrow and, recently, adipose tissue have been used as sources of mesenchymal stem cells which have been proven to enhance tendon healing. In the present study, we compared the effects of allotransplantation of bone marrow derived mesenchymal stromal cells [BMSCs] and adipose derived stromal vascular fraction [SVF] on tendon mechanical properties after experimentally induced flexor tendon transection. In this experimental study, we used 48 adult male New Zealand white rabbits. Twelve of rabbits were used as donors of bone marrow and adipose tissue, the rest were divided into control and treatment groups. The injury model was a unilateral complete transection of the deep digital flexor tendon. Immediately after suture repair, 4×106 cells of either fresh SVF from enzymatic digestion of adipose tissue or cultured BMSCs were intratendinously injected into tendon stumps in the treatment groups. Controls received phosphate-buffered saline [PBS]. Immobilization with a cast was continued for two weeks after surgery. Animals were sacrificed three and eight weeks after surgery and tendons underwent mechanical evaluations. The differences among the groups were analyzed using the analysis of variance [ANOVA] test followed by Tukey's multiple comparisons test. Stromal cell transplantation resulted in a significant increase in ultimate and yield loads, energy absorption, and stress of repairs compared to the controls. However, there were no statistically significant changes detected in terms of stiffness. In comparison, we observed no significant differences at the third week between SVF and BMSCs treated tendons in terms of all load related properties. However, at the eighth week SVF transplantation resulted in significantly increased energy absorption, stress and stiffness compared to BMSCs. The enhanced biomechanical properties of repairs in this study advocates the application of adipose derived SVF as an excellent source of multipotent cells instead of traditional BMSCs and may seem more encouraging in cell-based therapy for tendon injuries

Testicular biohistochemical alterations following experimental varicocele in rats

The exact pathophysiology of testicular degeneration, following varicocele has not been completely understood yet. The current study was designed to determine the effect of varicocele on germinal epithelium [GE] cytoplasmic biohistochmical alterations. To follow-up this study, left varicocele was induced in test groups. Non-varicocelized rats were served as control-sham [n=6]. Following 4, 6 and 8 months, right and left testes were dissected out and the blood serum sample was taken. The GE cytoplasmic carbohydrate, lipid accumulation, lipase and alkaline-phosphates [ALP] ratios were analyzed. Serum levels of LH, FSH and testosterone were measured. Observations demonstrated that in varicocele-induced rats, the spermatogenesis cell lineage exhibited lower number of cells with periodic acid shift positive cytoplasm, higher number of cells with lipid and ALP positive stained cytoplasm in comparison to control animals. Lipase enzyme decreased by the time in the test animals. In varicocelized groups the number of Leydig cells decreased in to 2.25 +/- 0.41 and 1.16 +/- 0.75 per one mm[2] in left and right testicles respectively after 8 months, and these cells demonstrated an ALP positive feature. In test groups, the serum levels of LH and FSH reduced into 1.12 +/- 0.01 and 2.03 +/- 0.05 ng/ml respectively after 8 months. Although testosterone level diminished by the time in the test animals, and this decreasing was significant [p=0.031] after 8 months [3.08 +/- 0.10 ng/ml]. Our results suggest that following varicocele induction major alterations occur in GE, which may lead to loss of GE cells physiological function and ultimately result in fertility problems

Adipose-derived stromal vascular fraction improves tendon healing in rabbits / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the potential effects of uncultured adipose-derived stromal vascular fraction on tendon healing.</p><p><b>METHODS</b>Twenty 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.</p><p><b>RESULTS</b>Histological 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.</p><p><b>CONCLUSION</b>The 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.</p>