Amelioration of type II collagen induced arthritis in rats by treatment with thymulin.
OBJECTIVE
To investigate the effects of thymulin (serum thymic factor + Zn2+) in collagen induced arthritis (CIA) in rats.


METHODS
SD rats were immunized with bovine type II collagen plus Freund's incomplete adjuvant, and thymulin was administered intraperitoneally on the first day of first immunization. We determined the level of serum thymulin by rosette inhibition assay. Effects of thymulin on CIA rats were estimated by measuring the extent of hind paw edema, the level of serum anti-type II collagen antibody, and changes in histopathological features of the affected joints.


RESULTS
Serum thymulin levels in CIA rats were significantly lower than in untreated rats. Thymulin diminished hind paw swelling and onset of arthritis compared with control rats. The serum anti-type II collagen antibody level was also reduced by thymulin. Histopathological examination showed inhibition of granulation tissue and new bone formation after injection of thymulin.


CONCLUSIONS
Our results suggest thymulin plays a significant role in the onset and development of CIA in rats. Our data indicate thymulin may be therapeutically effective in preventing the development of rheumatoid arthritis.
Aono
H
H
Research and Development Division, Santen Pharmaceutical Co., Ltd., Osaka, Japan.
Morishita
M
M
Sasano
M
M
Okamoto
M
M
Okahara
A
A
Nakata
K
K
Mita
S
S
D000818:Animals; D001168:Arthritis / Q000097:blood / Q000139:chemically induced / Q000517:prevention & control*; D003094:Collagen / Q000097:blood / Q000633:toxicity; D004487:Edema / Q000139:chemically induced; D006614:Hindlimb / Q000187:drug effects / Q000473:pathology; D007074:Immunoglobulin G / Q000032:analysis; D007596:Joints / Q000187:drug effects / Q000473:pathology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013935:Thymic Factor, Circulating / Q000378:metabolism / Q000494:pharmacology*; D013950:Thymus Gland / Q000187:drug effects / Q000473:pathology
D007074:Immunoglobulin G; D003094:Collagen; D013935:Thymic Factor, Circulating