Ethanol prevents development of destructive arthritis

Abstract

Environmental factors are thought to play a major role in the development of rheumatoid arthritis. Because the use of ethanol is widespread, we assessed the role of ethanol intake on the propensity to develop chronic arthritis. Collagen type II-immunized mice were given water or water containing 10% (vol/vol) ethanol or its metabolite acetaldehyde. Their development of arthritis was assessed, as well as the impact of ethanol on leukocyte migration and activation of intracellular transcription factors. Mice exposed daily to this dose of ethanol did not display any liver toxicity, and the development of erosive arthritis was almost totally abrogated. In contrast, the antibody-mediated effector phase of collagen-induced arthritis was not influenced by ethanol exposure. Also, the major ethanol metabolite, acetaldehyde, prevented the development of arthritis. This antiinflammatory and antidestructive property of ethanol was mediated by (i) down-regulation of leukocyte migration and (ii) up-regulation of testosterone secretion, with the latter leading to decreased NF-kappaB activation. We conclude that low but persistent ethanol consumption delays the onset and halts the progression of collagen-induced arthritis by interaction with innate immune responsiveness.

Fig. 1.

Development of arthritis in DBA/1 mice immunized with CII and supplied with 10% ethanol or water. (A and B) Frequency (A) and severity (B) of arthritis in mice followed for 5–6 weeks after immunization. Values from two experiments were pooled. The ethanol-drinking group contained 26 mice, and the water-drinking group contained 27 mice except on day 42, when both groups contained 12 mice. Statistical evaluation was made by using the χ² test or the Mann–Whitney U test. Bold lines indicate medians. (C) Histological signs of synovitis and erosivity in CII-immunized DBA/1 mice 6 weeks after the start of ethanol drinking. A histological scoring system was used to evaluate synovial hypertrophy and degradation of cartilage and bone. Scores were set as follows: 1, mild; 2, moderate; and 3, severe synovitis and joint damage. Each group contained 12 mice. (D Left) Micrograph of heavily inflamed tarsal joints from a CII-immunized DBA/1 mouse that drank water only for 6 weeks. Note frequent bone and cartilage erosions. (Right) Micrograph of histologically apparently intact tarsal joints from a CII-immunized DBA/1 mouse that was provided with 10% ethanol in drinking water. Hematoxylin/eosin staining was used. B, Bone; C, cartilage; E, erosion of bone and cartilage; J, joint cavity; P, pannus tissue formation; S, synovial tissue. (Scale bar: 100 μm.) (E) Weight development in DBA/1 mice after immunization with CII. The ethanol-drinking group contained 26 mice and the water-drinking control group contained 27 mice on days 21–35. Each group contained 12 mice on day 42. Statistical evaluation was made by using the Mann–Whitney U test.

Fig. 2.

Ex vivo production of MCP-1 (A), MIP-1α (B), TNF-α (C), and IL-6 (D) by spleen cells from NMRI mice drinking 10% ethanol (open bars) or water (light gray bars) for 2 months. In vitro production of MCP-1 (A), MIP-1α (B), TNF-α (C), and IL-6 (D) by spleen cells of naive NMRI mice after incubation with 0.1% and 0.5% ethanol. Statistical evaluation was made by using Student's t test. Values are presented as mean ± SEM. P value of ≤0.05 was considered N.S.

Fig. 3.

Migration of peritoneal leukocytes from NMRI mice, supplied with either 10% ethanol in drinking water or water alone for 8 weeks. Seven separate experiments were performed. Statistical evaluation was made by using the Mann–Whitney U test. Bars show the mean value.

Fig. 4.

The reduction of NF-κB (A) and AP-1 (B) nuclear activity in the ethanol-drinking mice. NMRI mice were exposed in vivo to a continuous intake of 10% ethanol during a period of 8 weeks. Spleen cell cultures of ethanol-drinking and water-drinking control mice were stimulated with Con A (1.25 μg/ml). Nuclear extracts were prepared after 2 h of stimulation. EMSA was performed by using probes specific to the NF-κB and AP-1 binding sites, and after 20 min at room temperature the complexes were resolved by electrophoresis through a 2.5% polyacrylamide gel. In vivo exposure of mice to ethanol resulted in a significant reduction of NF-κB (A) and AP-1 (B) expression in the nuclei.

Fig. 5.

Impact of ethanol drinking on bone mineral density. (A Right) Ethanol drinking decreases in vivo demineralization of trabecular bone by down-regulation of arthritis. (Left) Nonarthritic mice did not show any changes in bone mass as a function of ethanol consumption. Statistical evaluation was made by using the Mann–Whitney U test. (B) pQCT scans of one representative mouse from each group. Nonarthritic mice were represented by NMRI mice, and arthritic mice were represented by DBA/1 mice immunized with CII. Trabecular BMD was determined with a metaphyseal scan at a point 3% of the length of the femur from the growth plate, and the inner 45% of the area was defined as the trabecular bone compartment. (I) Nonarthritic mouse provided with 10% ethanol in drinking water (pQCT value of 367.7 mg/cm³). (II) Nonarthritic mouse drinking plain water (pQCT value of 398.8 mg/cm³). (III) Arthritic mouse provided with 10% ethanol in drinking water (pQCT value of 280.4 mg/cm³). (IV) Arthritic mouse drinking plain water (pQCT value of 119.1 mg/cm³). The gradient bar shows the density of the bone, from 0 (gray) to 750 (white) mg/cm³. (Scale bar: 1 mm.)