Repairing bone defects using human bone marrow mesenchymal stem cells transfected with insulin like growth factor-1 in nude mice

Haibin ZHOU; Qirong DONG; Xiaozhong ZHOU; Zugen ZHENG

ABSTRACT

BACKGROUND:

Insulin-like growth factor-1(IGF-1) is an important regulator in osteoblasts proliferation,differentiation and matrix synthesis,which participates in the process of fracture healing and repairing.

OBJECTIVE:

To investigate the potential bone regeneration effect of human bone marrow mesenchymal stem cells(MSCs) transfected into IGF-1 retroviruses vector on bone defects repairing. DESIGN,TIME AND

SETTING:

A controlled observation experiment was performed between March 2004 and May 2005 at the Laboratory Animal Center of Soochow University. MATERIALSMSCs were transfected into IGF-1 retroviruses vector in vitro and combined with demineralized bone matrix(DBM) .

METHODS:

Fifteen BalB/C nude mice were prepared for 8 mm calvarial defects models and divided into 3 groups by number table method,with 5 animals in each group. DBM transfected with IGF-1 and DBM transfected with vector were implanted into the defect in MSCs cells transduced with IGF-1 and vector groups,respectively. There was no other intervention in the blank control group. The implants were harvested and evaluated by histological examination at 4 weeks after model preparation. MAIN OUTCOME

MEASURES:

①The mRNA expression of IGF-1 was analyzed by RT-PCR and Western Blot. ②The complexes of cells and DBM were analyzed by scanning electron microscope(SEM) at days 3 and 6 after co-culture. ③Gross observation of the calvarial defects models. ④Osteogenic activity of the implants was evaluated by hematoxylin-eosin staining at weeks 4 after model preparation.

RESULTS:

①There were mRNA and protein expression of IGF-1 in MSCs cells transduced with IGF-1 vector. ②SEM showed that there were plenty of cells adhered to surface of DBM,and grew into inner part at the 3 days after co-culture with IGF-1,which secreted much collagen fibers at days 6. The count of adherent cells and collagen fiber was smaller in the vector group at each time points. ③No obvious inflammatory reaction could be seen in each group at 4 weeks after model preparation. Compared with vector control,abundant new bone and blood vessel formation occurred in the calvarial defects treated with DBM/IGF-1,and no new bone formation in the blank control groups. ④Results of hematoxylin-eosin staining showed that grafts in the MSCs cells transduced with IGF-1 group was combined closely with calvarial defects,new bone and vessel could be found. There were few bone-like materials formation in vector group,and no defects in control group were repaired.

CONCLUSION:

The composites of IGF-1 transfected MSCs and DBM has good effect in repairing calvarial defects.