GFAP immunoreactivity and transcription in trigeminal and dental tissues of rats and transgenic GFP/GFAP mice

✍ Scribed by Margaret R. Byers; Takeyasu Maeda; Angus M. Brown; Ruth E. Westenbroek

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 1006 KB
• Volume: 65
• Category: Article
• ISSN: 1059-910X
• DOI: 10.1002/jemt.20130

✦ Synopsis

Abstract

Sensory mechanisms in teeth are not well understood and may involve pulpal–neural interactions. Tooth cells that proliferate in vitro have polyclonal immunoreactivity (IR) for glial fibrillary acidic protein (GFAP), growth‐associated protein (GAP‐43), and vimentin, plus glial‐like ion channels. Here, we analyzed GFAP‐IR patterns in dental and trigeminal tissues of rats, for comparison with green fluorescent protein (GFP) associated with GFAP transcription in transgenic mice, in order to better characterize glial‐like cells in dental tissues. Astrocytes, ganglion satellite cells, and epineurial Schwann cells were demonstrated by anti‐GFAP antibodies and GFP‐GFAP, as expected. Odontoblasts did not stain by any of these methods and cannot be the glial‐like cells. Fibroblasts and undifferentiated mesenchymal cells in pulp had polyclonal GFAP‐IR and vimentin‐IR, while nerve fibers reacted only with polyclonal antibody. Some Schwann cell subtypes in trigeminal nerve and oral mucosa were positive for GFP and for polyclonal anti‐GFAP, but not for monoclonal antibody. In pulp almost all Schwann cells were unstained, but many Schwann cells in periodontal ligament had polyclonal GFAP‐IR. These results show greater heterogeneity for Schwann cells than expected, and suggest that the glial‐like pulp cells are fibroblasts and/or undifferentiated mesenchymal cells or stem cells. We also found that polyclonal GFAP revealed intermediate filaments in preterminal sensory nerve fibers, thereby providing a useful marker for that neural subregion. GFP transcription by some Schwann cell subtypes in oral mucosae and trigeminal nerve, but not trigeminal root was a novel finding that reveals more complexity in peripheral glia than previously recognized. Microsc. Res. Tech. 65:295–307, 2004. © 2005 Wiley‐Liss, Inc.