A distinct subset of submucosal mast cells undergoes hyperplasia following neonatal maternal separation: a role in visceral hypersensitivity?
- N P Hyland1,2,
- M Julio-Pieper2,
- S M O’Mahony2,3,
- D C Bulmer3,
- K Lee3,
- E M Quigley2,4,
- T G Dinan2,5,
- J F Cryan1,2,6,6
- 1Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland
- 2Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- 3Immuno-Inflammation CEDD, GlaxoSmithKline Medicines Research Centre, Stevenage, UK
- 4Department of Medicine, University College Cork, Cork, Ireland
- 5Department of Psychiatry, University College Cork, Cork, Ireland
- 6School of Pharmacy, University College Cork, Cork, Ireland
- Dr J F Cryan, School of Pharmacy, Cavanagh Pharmacy Building, University College Cork, Cork, Ireland; j.cryan{at}ucc.ie
We recently read with great interest the article published by Barreau et al (Gut 2008;57:582–90) who report, as one of their primary findings, mast cell hyperplasia and increased colonic rat mast cell protease II (RMCPII) activity following neonatal psychological stress. The authors also persuasively demonstrate a potential role for mast cell-derived nerve growth factor in contributing to increased colonic neural density in this model. In the study we describe here, using a related maternal separation procedure1 we also observed mast cell hyperplasia. However, this was restricted to the colonic submucosa and characterised by RMCPII immunoreactivity and predominantly blue or blue/red positive cells following Alcian blue/safranin staining, without an associated change in mucosal mast cell (MMC) number.
Maternal separation was carried out using a protocol previously described by our group and known to induce a number of behavioural and gastrointestinal (GI) effects,1 and adult male animals, at least 11 weeks of age, were used in subsequent studies. To identify mast cells we used sheep anti-RMCP II (1:500; Moredun, Midlothian, UK) and Alcian blue (1% in 0.7 mol/l HCl)/safranin (0.5% in 0.125 mol/l HCl) staining. Analysis of colonic supernatants for RMCPII release was carried out using an enzyme-linked immunosorbent assay (ELISA; Moredun).
Similarly to Barreau et al we identified extensive RMCPII positive staining along the crypt mucosa axis (non-separated (NS), 49.5 (SEM 3.7) mast cells/mm2, n = 10, maternally separated (MS), 53.1 (SEM 2.5) mast cells/mm2, n = 15, p>0.05) in rat colon; though …
