1994 Fiscal Year Final Research Report Summary
Cytological analysis of and strategy for retarded nerve regeneration in aging animals
| Project/Area Number |
05834012
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
老化(加齢)
|
|---|
| Research Institution | YOKOHAMA CITY UINVERSITY |
|---|
Principal Investigator |
KOMIYAMA Atsushi Yokohama City Uinversity School of Medicine, Department of Neurology, Assistant Professor, 医学部, 講師 (00170382)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Keywords | aging animals / nerve regeneration / Schwann cells / wallerian degeneration / cell proliferation / macrophages |
|---|
| Research Abstract |
Although regeneration of myelinated fibers after nerve-crush was shown to be retarded in aging animals, the factors of this retardation remains to be determined. To test the hypothesis that Schwann cell dysfunction with aging process was at least in part responsible for the retarded response, we investigated proliferative responses of Schwann cells in the mouse sciatic nerves after nerve-transection at 2 and 24-29 months of age. As assessed by thymidine incorporation for 24h in culture (Komiyama and Suzuki, 1992a, 1994), Schwann cells from young adult nerves proliferated rapidly within day 1 post-transection and reached a peak at day 3. However, division rate of Schwann cells from aging mouse remained at the level about one tenth of Schwann cells from young adult mouse. The number of macrophages recruited in the distal stump was also smaller in the aging nerves than in the young adult nerves. When Schwann cells from the sciatic nerves of aging mouse were maintained in the media supplemented with 15% FBS,the rate of proliferation reached one half of that of young adult mouse during an 8 day period in culture. The results of our study suggest that Schwann cell proliferation is impaired in the injured nerves of aging mouse partly because of their limited capacity to proliferate. This difference in vivo and in vitro proliferative capacity of Schwann cells may be related to the paucity of macrophage migration in the endoneural space of injured nerves of aging mice.
|
