[The attractive effects of nerve regeneration chamber fluid and degenerated nerve segments on the growth and the migration of the cocultured dorsal root ganglion neuron].
OBJECTIVE
We intended in this study to investigate the neurotropic effects of regeneration chamber fluid (RCF) and the degenerated nerve segments from distal of the regeneration chamber on the dorsal root ganglion (DRG).


METHODS
The capillary model was first tested for its reliability to form concentration gradient with a dye being contained in the capillaries. The tissue culture in RCF test was divided into two groups each with 8 DRGs implanted in 8 dishes. RCF was contained in capillaries inserted down to the bottom of the dishes with their lower ends at a distance of about 1 mm to the DRGs in the experimental group, and DMEM media was contained in the control group. Segments of degenerated sciatic nerve from distal of the regeneration chamber were implanted with DRGs at a distance of about 0.5 - 1 mm in the coculturing experiment. DRGs were observed for the direction of the growth of the cells and the fibres.


RESULTS
While the capillary containing the dye was put down to the bottom of the culture dish coated with a piece of nylon pad, the red color slowly disseminated with heavier staining in the center and lighter staining in the peripheral portion. We believe this pattern of shade could simulate the concentration gradient of tropic factors in this model. There were significantly more nerve fibres growing from the DRGs towards the capillaries in 6 of the 8 dishes in the experimental group after 72 hours of culture. The tissue and nerve fibers grew evenly in the control group. 76.5% of all the nerve fibres were growing in the direction facing the degenerated nerve segments after 12 hours of coculturing, and only 33.3% of the nerve fibres growing in that direction in the control group. Cells from the DRGs migrated towards the degenerated nerve segments, yet they tended to avoid the normal nerve segments. The migration index of the cells was 0.98 in average in the coculturing experiment with the degenerated nerve segments, but only 0.43 in average with the normal nerve coculturing.


CONCLUSIONS
The capillary model was effective in studying the chemotactic growth of nerve tissue. RCF and the degenerated nerve segments had definite neurotropic effects on DRGs tissue.
Chen
J
J
Department of Orthopedics, General Hospital, People's Liberation Army, Beijing 100853, China.
Lu
S
S
Zhao
B
B
Yuan
X
X
D000818:Animals; D002642:Chick Embryo; D018920:Coculture Techniques; D005727:Ganglia, Spinal / Q000187:drug effects / Q000502:physiology*; D009410:Nerve Degeneration; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000473:pathology / Q000502:physiology; D018523:Tropism
D009414:Nerve Growth Factors