Proliferation of neural progenitor cell after chronic compressive injury of spinal cord

Shaowen ZHANG; Shuanke WANG; Cuifang WANG; Yayi XIA; Haihong ZHANG; Yuliang WANG; Zhengyi SUN

ABSTRACT

BACKGROUND:

There is still no affirmative conclusion on the proliferative characteristics and the sources of neural progenitor cells after chronic compressive injury of spinal cord in adult mammals and the effects of astrocytes in this process.

OBJECTIVE:

To investigate the proliferative characteristics and the sources of neural progenitor cell and the effects of astrocytes by means of analyzing the changes of expression of nestin and glial fibrillary acidic protein after chronic compressive injury of spinal cord and after decompression in adult rats.

DESIGN:

Completely randomized control trial.

SETTING:

Orthopaedics Research Institute, the Second Hospital of Lanzhou University.MATERIALS The experiment was completed in Orthopaedics Research Institute of the Second Hospital of Lanzhou University from March to October 2003. A total of 50 adult healthy Wistar rats were selected and randomly divided into normal control group, moderate chronic compressive spinal cord injury group (compressive mass occupied 40% of the diameter of spinal canal), severe compression group (compressive mass occupied 60% of the diameter of spinal canal). Three-day and 10-day decompression groups (depression after 24-hour severe compressive injury) with 10 in each group.MAIN OUTCOME

MEASURES:

① Grey value of positive expression of nestin in grey and white matter in spinal cord segment near compression (5 mm to the edge of compression) in rats of each group. ② Expression of glial fibrillary acidic protein in spinal cord of rats in each group.

RESULTS:

All the 50 rats entered experimental analysis. ①There were significant expressions of nestin in moderate compression group (white matter 235.33±6.48, grey matter 196.28±6.55), severe compression group (white matter 190.45±4.91, grey matter 173.15±5.98), 3-day decompression after severe compressive injury group (white matter 198.39±3.24, grey matter 180.38±4.51) and 10-day decompression group (white matter 202.55±3.54) (P ＜ 0.05), especially in severe compression group (P ＜ 0.01).Compared with the normal control group, the difference between the ex pression of nestin in grey matter and that in ependymal cells on the central canal of spinal cord in 10-day decompression group has no significance (P ＞ 0.05). ②Compared with normal control group, the expression of glial fibrillary acidic protein in spinal cord increased in each injury group,and the amount of positive cells of glial fibrillary acidic protein went up and cell soma was hypertrophic, and the processes became thicker and longer.

CONCLUSION:

There is neural progenitor cell proliferation in the early stage of chronic compressive injury of spinal cord and after decompression in adult rats. Astrocyte participates in proliferation and migration of neural progenitor cells and has important trophic and repair effects on spinal cord.