Galanin in adjuvant arthritis in the rat.
OBJECTIVE
To study the concentration changes of galanin in the ankles and spinal cord and to detect the distribution of galanin in different tissues in arthritic rats.


METHODS
Adjuvant arthritis was induced by intradermal injection of Mycobacterium butyricum in Freund's incomplete adjuvant at the base of the tail. The concentrations of galanin were measured by radioimmunoassay (RIA) and the distributions of galanin were detected by immunoelectron microscopy (iEM).


RESULTS
Measurements were taken on Day 28 after injection. RIA results showed that the concentration of galanin was significantly lower in the ankles and spinal cords of rats with adjuvant arthritis compared to controls. Our iEM results showed a heterogeneous distribution of galanin labelling in different cells and tissue compartments. In arthritic rats, we observed decreased galanin labelling in the sciatic nerve and in macrophage-like cells in the synovial membrane and increased labelling in monocyte lineage cells, polymorphonucleated lineage cells in the bone marrow, fibroblasts in the periosteum, osteoclasts and osteocytes, and lower labelling in osteoblasts compared to controls.


CONCLUSIONS
Galanin is involved in the response to inflammation in adjuvant arthritis and might play a role in the regulation of inflammation and nociception. These findings are in accordance with a biological role of galanin in the development of inflammatory arthritis.
Qinyang
Wu
W
Department of Orthopaedic Surgery and the Clinical Research Centre, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden. quinyang.wu@cfss.ki.se
Hultenby
Kjell
K
Adlan
Elhassan
E
Lindgren
J Urban
JU
D000818:Animals; D000843:Ankle Joint / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D001169:Arthritis, Experimental / Q000378:metabolism*; D002908:Chronic Disease; D005260:Female; D019004:Galanin / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D009619:Nociceptors / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011917:Rats, Inbred Lew; D013116:Spinal Cord / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure
D019004:Galanin