gms | German Medical Science

Introduction: The replacement of soft tissue remains a challenging field in reconstructive surgery. A promising alternative is seen with the idea of creating bioartificial musculoskeletal tissue out of primary muscle cells. However, the poor cell survival of transplanted myoblasts is limiting the development of full-thickness transplantable constructs. To optimize this, studies with different matrices, growing factors and vascularisation of the bioartificial tissues (BAT) are carried out with more or less improvement. Furthermore, granulocytes intake to BATs seems to be another barrier for impaired cell survival. Therefore in this study we were focused on the effect of immunocompromising therapy on transplanted myoblasts within a 3-dimensional vascularised BAT.

Material and Methods: Myoblasts were harvested from 5 days old male Wistar rats as described by Bach et al1. For further in vivo monitoring with bioluminescence the cells were transfected with a vector containing the sequence of Luciferase. After further expansion, the myoblasts (4 x 106) were seeded inside an in vivo bioreactor chamber placed within in the abdominal wall of 4 weeks old male Wistar rats using the epigastric artery as central core vessel and fibrin glue as matrix as described before2. The in vivo monitoring of the transplanted myoblasts was assessed by bioluminescence on day 0, 1, 3 and 7.

Immunocomprimising therapy was induced with daily administration of cyclosporine with a dosage of 5mg/kg bodyweight starting one day prior to surgery in group 1 (n=4). The same procedure was carried out in the control group (n=3) but without immunocomprimising therapy. Atfer explantation of the bioartificial tissue on day 7 histomorphological staining (H/E) as well as immunofluorescence (Myo-D) was performed.

Results: The bioluminescence followup monitoring of the Luciferase-transfected and in vivo transplanted myoblasts showed an increase of the signals from day 0 to day 7 in the group of the immunocompromised Wistar rats (5.09 x 107 photons/sec and 1.33 x 108 photons/sec). However, the signals in the control group decreased (2.18 x 108 photons/sec and 4.17x106 photons/sec) and therefore demonstrating a significant beneficial effect on day 7 with cyclosporine therapy (p

Discussion: Immunocompromising therapy with cyclosporine has a beneficial effect on the cell survival of transplanted myoblasts in vivo and might therefore lifting musculoskeletal tissue engineering one step closer to clinical practice. Further studies need to be carried out to prove the long-term effect as well as the effect on different transplanted cell types other than myoblasts.