Survival and migration of transplanted embryonic stem cells in the injured brain and spinal cord of mice

Lei SHI; Jianhua YANG; Changde LI; Jie MA; Yu WANG

ABSTRACT

BACKGROUND:

Embryonic stem cell (ESC) is a kind of highly undifferentiated totipotent cell. It can proliferate and maintain its totipotency in the system cultured in vitro. It is one of most promising stem cells in thetreatment of central nerve injury.

OBJECTIVE:

To observe the survival and migration of induced transplanted ESC in mice with spinal injury and hypoxic-ischemic encephalopathy.

DESIGN:

A completely randomized grouping design, controlled animal experiment.

SETTING:

Laboratory of Developmental Biology Research Center of Shanghai Second Medical University.MATERIALS Sixty C57/BL6J mice, of clean grade and either gender, aged 6 to 8 weeks (n =30) and 7 days (n =30)were provided by the Shanghai Experimental Animal Center, Chinese Academy of Sciences [Permission No, SCXK (hu)2003-0003]. This animal experiment was approved by Animal Ethics Committee. Mouse ESC strain S8, labeled LacZ marker gene (Provided by Shanghai Developmental Biology Research Center). X-gal dyeing reagent (Sigma Company).

METHODS:

This experiment was carried out in the laboratory of Shanghai Developmental Biology Research Center (Shanghai Key Laboratory) from October 2002 to December 2003. ① Experimental grouping of spinal injury Sixteen C57/BL6J successful mice models, aged 6-8 weeks, were randomized into 2 groups experimental group (n =8), in which, following right spinal semi-sectioning, derivated cell suspension for inducing the in vitro differentiation of ESC was injected at 1 cm away from injury through vertebral canal, and control group (n =8), in which, following right spinal semi-sectioning, phosphate buffer solution (PBS) was injected at the peripheral region of injury. ② Hypoxic-ischemic encephalopathy experimental grouping Sixteen successful C57/BL6J mice models, aged 7 days, were randomized into 2 groups experimental group (n =8), following ligation of right common carotid artery, mice were placed in the closed container containing 0.08 volume fraction of oxygen and 0.92 volume fraction of Nitrogen gas, and taken out 1.5 hours later; 3 μL ESCs were injected into the right cerebral ventricle at about 1 week, and control group (n =8), in which, the same amount of PBS was injected into the right cerebral ventricle. ③ At 12 weeks after transplantation, the survival and migration of induced ESCs labeled by Lac-Z in the spinal cord and brain were observed by zymologic method.MATN OUTCOME

MEASURES:

Survival and migration of ESCs in the central nervous system.

RESULTS:

①After being induced in vitro and transplanted to spinal injured region, ESCs differentiated into neural precursor cells. Neural precursor cells could survive in the injured region and migrate to 5 mm away from injured region.Immunohistochemistry proved that the neural precursor cells of transplanted ESCs could differentiate into neurons.Morphologically, it was proved that neural precursor cells-derived from ESCs could well integrate peripheral tissue. ② The induced ESCs were injected into the lateral cerebral ventricle of mice. Derived ESCs widely distributed in the injured hippocampal region, cerebral cortex ventricle choroid plexus, vascular endothelium and other regions, and integrated peripheral tissue, which were similar to adjacent cells in morphology, suggesting that induced ESCs also could survive for long time and far migrate.

CONCLUSION:

The induced ESC can survive and migrate in the host injured brain and spinal cord, and the migration of ESCs is more obvious in the brain than in the spinal cord.