Satellite cell proliferation in murine sensory ganglia in response to scarification of the skin

Satellite cells (SCs) ensheathe neuronal cell bodies of sensory ganglia and provide mechanical and metabolic support for neurons. In mice, grossly detrimental stimuli such as nerve crush or cut, or explant culture of ganglia induce proliferation of SCs. It is unknown whether SC proliferation occurs in response to the less severe trauma that might commonly occur in a physiological situation. Our aim was to determine the response of SCs to mild trauma, such as scratching the skin. SC proliferation, measured by bromodeoxyuridine (BrdU) uptake, and immune cells, measured by CD45 labelling, were quantified at various times during the 7 days after scarification or abrasion of flank skin. We show that minimal skin trauma, such as scarification or light abrasion, triggers proliferation of SCs. Sections of control mice nervous tissue show <10 BrdU(+) cells/ganglionic profile. In contrast, sections of traumatised mice show >50 BrdU(+) cells/ganglionic profile, even after simply scratching the skin. The lack of CD45(+) cells shows that the proliferating cells are not immune cells. We suggest that SCs in mice are a labile cell population able to proliferate rapidly in response to minimal nerve trauma. This finding has implications for the role of SCs in nervous system repair. (C) 2003 Wiley-Liss, Inc.