Fig. 1. In vitro inhibition of TNF-α secretion by G-Rb1 in RA chondrocytes. Chondrocytes were stimulated with 1 ng/ml IL-1β (A) or 0.2 μg/ml LPS (B) in the presence of various concentrations of G-Rb1 for 24 h. The release of TNF-α was measured in the culture supernatant using ELISA. IC50 of G-Rb1 were calculated for TNF-α inhibition by IL-1 (C) or LPS (D). denotes < 0.05, denotes < 0.01 compared to control(in the absence of G-Rb1). The data represent the mean ± S.D. of duplicate experiment from at least 2 donors.

Fig. 2. Suppression of disease onset and progression of collagen-induced arthritis (CIA) by G-Rb1. Mice were divided into 3 separate groups of 10 and treatment group was treated orally once a day with G-Rb1 (1.25 and 2.5 mg/kg of body weight) for 18 consecutive days starting at day 22 after the first immunization. The arthritis index was calculated as the sum of the measurements for the four paws of each animal. The data represent the mean ± S.E. of 10 mice in each group. P < 0.05,versus control, by the use of the Mann–Whitney Utest.

Fig. 3. Suppression of joint inflammation and TNF expression in CIA joints. On day 40 after the first immunization, mice were sacrificed and the left hind paws were fixed, decalcified, embedded in paraffin, and sectioned. Right, Tissues were stained with H and E (A) and safranin O (B), respectively. Each section was blindly scored by two independent observers as described in Materials and methods. Left, the mean ± S.E. histologic scores of each group are plotted as bar graphs; original magnification, × 200. Representative staining from each group of 10 mice is shown. P < 0.01,versus control, by use of the Mann–Whitney Utest. (C) Hind paw sections from control or G-Rb1-treated CIA mice on day 40 after CIA induction were immunostained with the anti-TNF-α antibody, as described in Materials and methods. The sections were counterstained with hematoxylin; original magnification, × 200. Representative staining of 10 mice from each group is shown.

In vitro inhibition of TNF-α secretion by G-Rb1 in RA FLS and PBMCs

Parentheses indicate the stimuli for TNF-α induction.

Values are pg/ml.

Data are representative of duplicate experiments from at least 3 different donors.