A balance of apoptosis and proliferation of the satellite cells in the rat dorsal root ganglia after dorsal rhizotomy
| Authors | |
|---|---|
| Year of publication | 2004 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Molecular Histology |
| MU Faculty or unit | |
| Citation | |
| Field | Morphological specializations and cytology |
| Keywords | TUNEL Ki-67 satellite cells dorsal root ganglion |
| Description | A peripheral axotomy has been shown to cause satellite cell reactions (proliferation, apoptosis, morphological and biochemical changes) in corresponding dorsal root ganglia (DRG). However, only scarce information is available about the reaction of satellite cells to the central axotomy (rhizotomy). Therefore, we have investigated apoptosis and proliferation of the rat DRG cells after dorsal rhizotomy. Thirty six adult rats with dorsal rhizotomy (L1, L2) were left to survival for 2, 4 and 8 weeks and twelve intact rats were used as control. Cryostat sections through axotomized and intact ganglia were incubated for immunohistochemical identification of apoptosis (TUNEL) and proliferation (Ki-67). Satellite cells were identified by immunohistochemical reaction for S-100 protein and their nuclei were counterstained with Hoechst 33342. The sections were digitalized and analyzed using image analysis system (Lucia - G). The neurons were divided into three types according to diameter of their bodies; A (40-75 Ým), B (25-40 Ým) and C (Ź 24.9 Ým). The mean number of satellite cells surrounding each type of neurons was determined. Apoptosis and proliferation were evaluated by means of following criteria: mean percentage of neurons surrounded by TUNEL+ or Ki-67+ satellite cells in individual type of neurons and mean percentage of TUNEL+ or Ki-67+ satellite cells surrounding each type of neurons. No significant changes of total number of satellite cells surrounding individual types of neurons were found up to 8 weeks of survival. The number of TUNEL+ and Ki-67+ satellite cells significantly increased to 4 weeks, but 8 weeks from rhizotomy the positive cells slightly decreased. The largest differences in both increase and decrease of TUNEL+ as well as Ki-67+ satellite cells were detected around C - type of neurons. Simultaneous elevation or diminution of amount of TUNEL+ and Ki-67+ satellite cells following dorsal rhizotomy suggest that both apoptosis and proliferation of the cells are balanced to keep their constant amount around individual types of neurons. |
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