Effects of lithium chloride on endogenous neural stem cells in rats after spinal cord injury

Qifei XU; Chusong ZHOU; Anmin JIN; Xiaoyong LAN

ABSTRACT

BACKGROUND:

For treatment of spinal cord injury, exogenous neural stem cell transplantation still faces many problems.Thus, the strategy of supplementary treatment of activating exogenous neural stem cells has been a hot focus.It has been found that lithium chloride can significantly inhibit differentiation and promote proliferation of neural stem cells, whose effects are correlated to Wnt signal pathway.

OBJECTIVE:

To investigate the effect of lithium on endogenous neural stem cells after spinal cord injury in rats.DESIGN, TIME AND

SETTING:

The randomized controlled animal study was performed at the Central Laboratory, Zhujiang Hospital from March to August 2008.MATERIALSA total of 55 adult female Wistar rats were assigned into normal control group(n=5), simple injury group(n=25), and lithium chloride group(n=25).Lithium chloride was purchased from Guanghua, Guangzhou, China.

METHODS:

In the simple injury group and lithium chloride group, rat models of acute spinal cord injury at T10 segment were made by Allens method.From 1 hour following model induction, rats in the lithium chloride group received 3 mmol/kg per day lithium chloride through intraperithoneal injection.Samples were directly obtained.In the simple injury group, rats received an equal volume of saline.Rats in the normal control group were left intact.24 hours before samples were obtained, rats in each group were intraperitoneally injected with Brdu solution for labeling, once every 8 hours, totally 3 times.Spinal cord at 5 mm from the center of damage region received Brdu, catenin immunohistochemistry.MAIN OUTCOME

MEASURES:

BrdU-positive cell number and area of catenin-positive expression were measured.

RESULTS:

There were a few Brdu-positive cells and less expression of catenin in the center canal and adventitia of spinal cord in the normal control group.Many Brdu-positive cells and a little expression of catenin were found in gray matter and ependyma of injury area in the simple injury group 24 hours after model induction, which reached the peak at 1 week, and declined gradually at 2 weeks.Just a few Brdu-positive cells and little expression of catenin existed at 4 weeks.Compared with the simple injury group, there was no difference in Brdu-positive cells and the expression of catenin at 24 hours following model induction in the lithium chloride group.There were more Brdu-positive cells and the expression of catenin in the center canal and adventitia of spinal cord at 1 week(P