BACKGROUND: Avascular necrosis of the femoral head occurs in the hip joints at high load-bearing areas, it is a special form of aseptic bone necrosis. Bone marrow-derived mesenchymal stem cells may have an excellent repair effect for the necrosis of femoral head. OBJECTIVE: To understand bone marrow mesenchymal stem cell transplantation for treatment of early avascular necrosis of the femoral head, and to lay a foundation for further study. METHODS: Taking avascular necrosis of femur head, femur head necrosis, osteonecrosis, bone marrow mesenchymal stem cells, mesenchymal stem cells, multipotent stem cells in English as search terms, Pubmed database from January 2000 to April 2009 was retrieved; Taking avascular necrosis and bone marrow mesenchymal stem cells in Chinese as search terms, CNKI database from January 1989 to April 2009 was searched, Literatures were limited to English and Chinese languages. Inclusive criteria: Study of the biological characteristics and functions of bone marrow mesenchymal stem cells, the etiology and pathology of avascular necrosis of femoral head, bone marrow mesenchymal stem cell transplantation for treatment of avascular necrosis; Exclusive criteria: duplication of documents. RESULTS AND CONCLUSION: More than 800 literatures were screened out by computer search, according to inclusive and exclusive criteria, 38 documents of which were involved for analysis. Marrow mesenchymal stem cells can differentiate into chondrocytes, osteocytes and dipocytes under suitable cultural condition. With the development of stem cell engineering, marrow mesenchymal stem cell transplantation becomes an effective method for repairing osteonecrosis. This article describes the cause and the pathology of avascular necrosis of the femoral head, analyzes the theory basis for the treatment of avascular necrosis of the femoral head with marrow mesenchymal stem cell, and verifies its effect through comparing both animal and clinical experiments of this aspect at home and abroad, with the hope of seeking a better treatment.

BACKGROUND:Bone marrow mesenchymal stem cell(BMSC) transplantation is one of the developmental directions in the treatment of femoral head necrosis. In recent years, the use of superparamagnetic iron oxide (SPIO) nanoparticles labeled target cells traced by MRI imaging method has become the focus of the study.
OBJECTIVE:To observe the in vivo MRI tracking and the curative effects of SPIO-labeled BMSC transplantation on rabbit femoral head necrosis.
METHODS:SPIO-labeled BMSCs, unlabeled BMSCs, and normal saline were injected in situ into the necrotic femoral head of rabbits. Fol owing MRI dectection, the image changes of transplanted BMSCs marked by SPIO were observed among the three scanning sequences of SE T2WI, FSE T2WI and GRE T2*WI. Meanwhile, the area percentage of newly formed bone trabecula in the defect samples under high power lens were observed and calculated for statistical analysis.
RESULTS AND CONCLUSION:In situ celltransplantation group showed the emerging and extinctive time of the decreased-signal region was different among the three scanning sequences of SE T2WI, FSE T2WI and GRE T2*WI. It was found that the decreased-signal region of the MRI scanning sequences was the target of the present experiment. No obvious signal change occurred in the control side. After 6 weeks of transplantation, the area percentage of newly formed bone trabecula in the defect samples showed no difference in SPIO-labeled and unlabeled BMSC transplantation groups (P>0.05), but it was higher than that in the control side (P<0.01). The SPIO-labeled BMSCs and unlabeled BMSCs are shown to have the same effects in the treatment of femoral head necrosis. The SPIO-labeled BMSCs can be observed obviously by MRI detection in vitro.