title: Endogenous IL-11 is pro-inflammatory in acute methylated bovine serum albumin/interleukin-1-induced (mBSA/IL-1)arthritis.
abstract: OBJECTIVE
  To evaluate the role of interleukin-11 (IL-11) in acute mBSA/IL-1-induced inflammatory arthritis.
  
  
  METHODS
  IL-11 was administered via intra-articular (IA) injection into knee joints of C57BL/6 mice and joint histology was assessed. The mitogenic response to IL-11 was measured in wild-type (WT) synovial fibroblasts. IL-1 was used as a comparator in both the studies. The severity of acute methylated bovine serum albumin (mBSA)/IL-1 arthritis was determined in WT and IL-11 receptor null (IL-11Ra1-/-) mice. In parallel experiments, a neutralising antibody to IL-11 was administered to WT mice throughout this model.
  
  
  RESULTS
  IA injections of IL-11 resulted in mild-to-moderate joint inflammation which was less than that due to IA IL-1. IL-11 had a dose-dependent mitogenic effect on WT synovial fibroblasts (P<0.01). mBSA/IL-1 acute arthritis was reduced in IL-11Ra1-/- versus WT mice (histological arthritis score: 10.1+/-0.5 versus 12.8+/-0.7, respectively; P=0.01). Administration of an IL-11 neutralising antibody to WT mice reduced mBSA/IL-1 acute arthritis scores compared to control antibody (10.6+/-0.7 versus 13.3+/-0.6, respectively; P=0.02).
  
  
  CONCLUSIONS
  These data demonstrate that endogenous IL-11 exerts relatively mild but consistent pro-inflammatory effects in acute inflammatory arthritis.
authors.affiliation: Reid Rheumatology Laboratory, Division of Autoimmunity and Transplantation, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia.
authors.forename: Peter K K
authors.initials: PK
authors.lastname: Wong
authors.forename: Ian K
authors.initials: IK
authors.lastname: Campbell
authors.forename: Lorraine
authors.initials: L
authors.lastname: Robb
authors.forename: Ian P
authors.initials: IP
authors.lastname: Wicks
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000503:physiopathology*; D007375:Interleukin-1 / Q000008:administration & dosage*; D017370:Interleukin-11 / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008934:Mitogens / Q000502:physiology; D012710:Serum Albumin, Bovine / Q000008:administration & dosage*
chemical_list: D007375:Interleukin-1; D017370:Interleukin-11; D008934:Mitogens; C029180:methylated bovine serum albumin; D012710:Serum Albumin, Bovine