title: Systemic Administration of Granulocyte Colony-Stimulating Factor for Osteochondral Defect Repair in a Rat Experimental Model.
abstract: OBJECTIVE
  The objective of this study was to assess the effect of granulocyte colony-stimulating factor (G-CSF) on osteochondral defect repair in the rat knee.
  
  
  METHODS
  Twenty-six 12-week-old male Lewis rats were randomly divided into 2 groups. From day 0 to day 4, the G-CSF group received glycosylated G-CSF, and the control group received phosphate-buffered saline. A 1.5-mm diameter and 1.0-mm deep osteochondral defect was introduced in the patellar groove of the bilateral femur in all rats on day 4. The peripheral blood nucleated cells were counted for 14 days from the first day of injection, the appearance of the cartilage repair was observed histologically and macroscopically for 2, 4, 8, 12, and 24 weeks after surgery.
  
  
  RESULTS
  The number of peripheral blood leukocytes increased 3 days and returned to normal levels 7 days after the first injection. Compared with the control group, the G-CSF group had more fibrous and/or bony tissue at earlier points in time. The tissue repair rate, which is defined as the percentage of repaired osteochondral defects, was significantly higher in the G-CSF group 4 weeks after surgery. However, there were no significant differences in the cartilage repair rate and the modified Wakitani score between the 2 groups at each time point.
  
  
  CONCLUSIONS
  The defect filling was significantly better in the G-CSF group in the early phases. Our findings suggest that G-CSF may promote the repair of osteochondral defects by mediating an increase in the number of peripheral blood nucleated cells.
authors.affiliation: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Okano
authors.affiliation: Department of Health and Sports Sciences, Mukogawa Women's University, Hyogo, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Mera
authors.affiliation: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan ; Department of Health and Sports Sciences, Mukogawa Women's University, Hyogo, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Itokazu
authors.affiliation: Department of Orthopedic Surgery, Itabashi Chuo Medical Center, Tokyo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okabe
authors.affiliation: Center for Senile Degenerative Disorders (CSDD), Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Koike
authors.affiliation: Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Department of Health and Sports Sciences, Mukogawa Women's University, Hyogo, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Wakitani
keywords: bone repair; cartilage repair; granulocyte colony-stimulating factor (G-CSF); osteochondral defect; peripheral blood