Effects of stromal cells derived factor-1/CXCR4 on migration of human bone marrow mesenchymal stem cells toward ischemic brain region

Jie ZHU; Zhujuan ZHOU; Zili GONG; Jian ZHENG

ABSTRACT

BACKGROUND:

Recent research has shown that transplanted bone marrow mesenchymal stem cells(BMSCs) migrate to the injured regions and exert their therapeutic effects in cases of intracranial trauma, stroke, inflammation and degenerative disease.The specific mechanisms involved in their migration to lesions are still to be fully elucidated.

OBJECTIVE:

To explore the effects of stromal cells derived factor-1(SDF-1) and its receptor CXCR4 on the migration of transplanted BMSCs to ischemic brain lesions.DESIGN, TIME AND

SETTING:

The cytological in vivo study was performed at the Central Laboratory, Xinqiao Hospital, Third Military Medical University of Chinese PLA from February 2008 to February 2009.MATERIALSBone marrow samples were obtained from normal or primary affection non-involved bone marrow patients aged 15-40 years at the Department of Hematology, Xinqiao Hospital, Third Military Medical University of Chinese PLA.A total of 72 healthy male Sprague Dawley rats aged 3-4 months were supplied by the Experimental Animal Center, Research Institute of Surgery, Third Military Medical University of Chinese PLA.

METHODS:

Human BMSCs were isolated by combination of gradient centrifugation and different adherent time method.The transient middle cerebral artery occlusion(MCAO) was induced using intraluminal vascular occlusion in 54 rats, based on the method described by Nagasawa et al.The remaining 18 rats served as sham operation group, only inserted with thread for 10 mm depth.At 2, 4 and 8 days after cerebral ischemia, the expression of SDF-1 in the ischemic brain was determined by real time RT-PCR and immunohistochemistry in 9 rats from either group.The remaining 36 rat models of cerebral ischemia/reperfusion were equally and randomly assigned into a cell transplantation and solution control groups.1 mL human BMSCs(2?109/L cells) or 1 mL phosphate buffered saline were slowly infused through the caudal vein at 24 hours following reperfusion.MAIN OUTCOME

MEASURES:

CXCR4 mRNA and protein expression in human BMSCs was determined.SDF-1 mRNA and protein expression following ischemia/reperfusion were detected.Migration of transplanted human BMSCs into the damaged region was observed through immunohistochemistry.

RESULTS:

RT-PCR showed that human BMSCs were positive for CXCR4 mRNA.Immunocytochemistry revealed that CXCR4 mainly expressed in cell membrane and cytoplasm of human BMSCs.At 2, 4 and 8 days following cerebral ischemia/reperfusion, SDF-1 mRNA levels showed an increased tendency, and showed significant difference compared with the sham operation group(P