title: Proliferative cell nuclear antigen (PCNA) expression in the intestine of Salmo trutta trutta naturally infected with an acanthocephalan.
abstract: BACKGROUND
  Changes in the production of proliferating cell nuclear antigen (PCNA), a 36 kd protein involved in protein synthesis, within intestinal epithelia can provide an early indication of deviations to normal functioning. Inhibition or stimulation of cell proliferation and PCNA can be determined through immunohistochemical staining of intestinal tissue. Changes in the expression of PCNA act as an early warning system of changes to the gut and this application has not been applied to the fields of aquatic parasitology and fish health. The current study set out to determine whether a population of wild brown trout, Salmo trutta trutta (L.) harbouring an infection of the acanthocephalan Dentitruncus truttae Sinzar, 1955 collected from Lake Piediluco in Central Italy also effected changes in the expression of PCNA.
  
  
  METHODS
  A total of 29 brown trout were investigated, 19 of which (i.e. 65.5%) were found to harbour acanthocephalans (5-320 worms fish-1). Histological sections of both uninfected and infected intestinal material were immunostained for PCNA.
  
  
  RESULTS
  The expression of PCNA was observed in the epithelial cells in the intestinal crypts and within the mast cells and fibroblasts in the submucosa layer which is consistent with its role in cell proliferation and DNA synthesis. The number of PCNA-positive cells in both the intestinal epithelium and the submucosa layer in regions close to the point of parasite attachment were significantly higher than the number observed in uninfected individuals and in infected individuals in zones at least 0.7 cm from the point of parasite attachment (ANOVA, p < 0.05).
  
  
  CONCLUSIONS
  An infection of the acanthocephalan D. truttae within the intestinal tract of S. t. trutta effected a significant increase in the number of PCNA positive cells (mast cells and fibroblasts) at the site of parasite attachment when compared to the number of positive cells found in uninfected conspecifics and in tissue zones away from the point of parasite attachment.
authors.affiliation: Department of Biology & Evolution, University of Ferrara, St. Borsari 46, 44123 Ferrara, Italy.
authors.forename: Bahram Sayyaf
authors.initials: BS
authors.lastname: Dezfuli
authors.forename: Luisa
authors.initials: L
authors.lastname: Giari
authors.forename: Alice
authors.initials: A
authors.lastname: Lui
authors.forename: Samantha
authors.initials: S
authors.lastname: Squerzanti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Castaldelli
authors.forename: Andrew Paul
authors.initials: AP
authors.lastname: Shinn
authors.forename: Maurizio
authors.initials: M
authors.lastname: Manera
authors.forename: Massimo
authors.initials: M
authors.lastname: Lorenzoni
mesh_terms: D000049:Acanthocephala / Q000302:isolation & purification*; D000818:Animals; D005347:Fibroblasts / Q000737:chemistry; D005393:Fish Diseases / Q000469:parasitology* / Q000473:pathology; D006374:Helminthiasis, Animal / Q000469:parasitology* / Q000473:pathology; D007150:Immunohistochemistry; D007411:Intestinal Diseases, Parasitic / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D007413:Intestinal Mucosa / Q000473:pathology; D007558:Italy; D008407:Mast Cells / Q000737:chemistry; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis*; D012487:Salmonidae / Q000469:parasitology*
chemical_list: D018809:Proliferating Cell Nuclear Antigen