TY - JOUR
T1 - Role of transplanted bone marrow cells in development of rotator cuff muscle fatty degeneration in mice
AU - Klomps, Lawrence V.
AU - Zomorodi, Naseem
AU - Kim, H. Mike
PY - 2017/12
Y1 - 2017/12
N2 - Background Rotator cuff muscle fatty degeneration after a chronic tendon tear is an irreversible pathologic change associated with poor clinical outcomes of tendon repair, and its exact pathogenesis remains unknown. We sought to investigate the role of transplanted bone marrow cells in the development of fatty degeneration, specifically in adipocyte accumulation, using a mouse model. Methods Fourteen mice were divided into 2 bone marrow chimeric animal groups: bone marrow transplantation (BMT) group and reverse BMT group. For the BMT group, C57BL/6J wild-type mice underwent whole body irradiation followed by BMT into the retro-orbital sinus from green fluorescent protein (GFP)-transgenic donor mice. For the reverse BMT group, GFP-transgenic mice received BMT from C57BL/6J wild-type donor mice after irradiation. The supraspinatus tendon, infraspinatus tendon, and suprascapular nerve were surgically transected 3 weeks after transplantation. The rotator cuff muscles were harvested 13 weeks after transplantation for histologic analysis and GFP immunohistochemistry. Results On histologic examination, both groups showed substantial fatty degeneration, fibrosis, and atrophy of the cuff muscles. The BMT group showed no noticeable GFP immunostaining, whereas the reverse BMT group showed significantly stronger GFP staining in most adipocytes (P < .001). However, both groups also showed that a small number of adipocytes originated from transplanted bone marrow cells. A small number of myocytes showed a large cytoplasmic lipid vacuole resembling adipocytes. Conclusions This study's findings suggest that most adipocytes in fatty degeneration of the rotator cuff muscles originate from sources other than bone marrow–derived stem cells, and there may be more than 1 source for the adipocytes.
AB - Background Rotator cuff muscle fatty degeneration after a chronic tendon tear is an irreversible pathologic change associated with poor clinical outcomes of tendon repair, and its exact pathogenesis remains unknown. We sought to investigate the role of transplanted bone marrow cells in the development of fatty degeneration, specifically in adipocyte accumulation, using a mouse model. Methods Fourteen mice were divided into 2 bone marrow chimeric animal groups: bone marrow transplantation (BMT) group and reverse BMT group. For the BMT group, C57BL/6J wild-type mice underwent whole body irradiation followed by BMT into the retro-orbital sinus from green fluorescent protein (GFP)-transgenic donor mice. For the reverse BMT group, GFP-transgenic mice received BMT from C57BL/6J wild-type donor mice after irradiation. The supraspinatus tendon, infraspinatus tendon, and suprascapular nerve were surgically transected 3 weeks after transplantation. The rotator cuff muscles were harvested 13 weeks after transplantation for histologic analysis and GFP immunohistochemistry. Results On histologic examination, both groups showed substantial fatty degeneration, fibrosis, and atrophy of the cuff muscles. The BMT group showed no noticeable GFP immunostaining, whereas the reverse BMT group showed significantly stronger GFP staining in most adipocytes (P < .001). However, both groups also showed that a small number of adipocytes originated from transplanted bone marrow cells. A small number of myocytes showed a large cytoplasmic lipid vacuole resembling adipocytes. Conclusions This study's findings suggest that most adipocytes in fatty degeneration of the rotator cuff muscles originate from sources other than bone marrow–derived stem cells, and there may be more than 1 source for the adipocytes.
UR - http://www.scopus.com/inward/record.url?scp=85028385510&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85028385510&partnerID=8YFLogxK
U2 - 10.1016/j.jse.2017.06.032
DO - 10.1016/j.jse.2017.06.032
M3 - Article
C2 - 28869071
AN - SCOPUS:85028385510
SN - 1058-2746
VL - 26
SP - 2177
EP - 2186
JO - Journal of Shoulder and Elbow Surgery
JF - Journal of Shoulder and Elbow Surgery
IS - 12
ER -