A comparison of the changes in the non-neuronal cell populations of the superior cervical XXXX following decentralization and axotomy.

@entity21 @entity4700 @entity528 @entity22577
Transecting the axons of neurons in the adult superior cervical ganglion (SCG; axotomy) results in the survival of most postganglionic neurons, the influx of circulating monocytes, proliferation of satellite cells, and changes in neuronal gene expression. In contrast, transecting the afferent input to the SCG (decentralization) results in nerve @entity528 and elicits a different pattern of gene expression. We examined the effects of decentralization on macrophages in the SCG and compared the results to those previously obtained after axotomy. Monoclonal antibodies were used to identify infiltrating ( @entity22577 +) and resident ( @entity4700 +) macrophages, as well as macrophages expressing MHC class II molecules (OX6+). Normal @entity21 contained @entity4700 + cells and OX6+ cells, but few infiltrating macrophages. After decentralization, the number of infiltrating @entity22577 + cells increased in the SCG to a density about twofold greater than that previously seen after axotomy. Both the densities of @entity4700 + and OX6+ cells were essentially unchanged after decentralization, though a large increase in OX6+ cells occurred after axotomy. Proliferation among the ganglion's total non-neuronal cell population was examined and found to increase about twofold after decentralization and about fourfold after axotomy. Double-labeling experiments indicated that some of these proliferating cells were macrophages. After both surgical procedures, the percentage of proliferating @entity4700 + macrophages increased, while neither procedure altered the proliferation of @entity22577 + macrophages. Axotomy, though not decentralization, increased the proliferation of OX6+ cells. Future studies must address what role(s) infiltrating and/or resident macrophages play in regions of decentralized and axotomized neurons and, if both are involved, whether they play distinct roles.
