Objective To identify and screen the level of arthritis susceptibility in C3H murine strains known to be resistant to proteoglycan (aggrecan)–induced arthritis, and to measure and correlate various immunologic and inflammatory parameters with susceptibility to either arthritis or spondylitis in various C3H substrains. Methods Mice of 10 C3H substrains (subcolonies) were immunized with cartilage proteoglycan (aggrecan) for induction of arthritis. Animals were assessed for clinical symptoms, and the peripheral joints and spine were studied by histologic methods. Proteoglycan‐specific T cell responses (T cell proliferation and production of interleukin‐2 [IL‐2], interferon‐γ, and IL‐4) and the B cell response to lipopolysaccharide (LPS) were measured in spleen cell cultures. Serum levels of heteroantibodies and autoantibodies as well as various cytokines (IL‐6, IL‐10, IL‐12, and tumor necrosis factor α) and soluble CD44 were determined by enzyme‐linked immunosorbent assay. Results Immunization with cartilage proteoglycan induced severe arthritis in the C3H/HeJCr substrain (95–100% incidence), whereas the original parent mice of the C3H/HeJ colony were resistant to proteoglycan (aggrecan)–induced arthritis. Furthermore, the progressive polyarthritis that is characteristic in susceptible C3H/HeJCr mice was accompanied by progressive inflammation around the spine. In subsequent experiments, 10 different C3H colonies with largely identical genetic backgrounds (all originating from the National Institutes of Health or Jackson Laboratory) exhibited extreme differences in susceptibility. Although none of the laboratory findings, including LPS hyporesponsiveness, immunologic parameters, and inflammatory markers, showed a correlation with susceptibility or resistance in the C3H/HeJCr and C3H/HeJ substrains, respectively, significant differences were found when all arthritic C3H mice were compared with all nonarthritic animals, regardless of their substrain origin. Conclusion Because many of the C3H substrains lost arthritis susceptibility or acquired resistance, our results suggest that a preferred site for a mutation(s) in a gene(s) in a relatively upstream position of the inflammatory cascade is present. This is the first autoimmune model that exhibits extreme differences in arthritis susceptibility in the same murine strain, and is therefore a valuable tool for identification of arthritis‐susceptible (or arthritis‐suppressive) genes.

No abstract

Aims:  Low back pain (LBP), a common presenting problem in general practice in the United Arab Emirates (UAE), has received increasing attention in recent decades. We seek to investigate the prevalence of LBP and associated risk factors among people living in the typically hot, humid desert environment of the UAE. Methods:  A cross‐sectional questionnaire survey was conducted. The setting was the Primary Health Care (PHC) Clinics in Al‐Ain, UAE. The subjects were a multistage stratified sample of 1304 UAE nationals, 15–70 years of age, who attended PHC clinics for any reason. All subjects were invited to participate. The questionnaire used in the survey is a modified version of the Roland‐Morris scale for evaluating low back pain. The questionnaires were administered during face‐to‐face interviews conducted in Arabic by qualified nurses. Results:  Of the total 1304 subject, 1103 (84.5%) living in both urban and rural areas agreed to participate and responded to the study; 586 (53.1%) were men and 517 (46.9%) women. The mean ages and SD of the subjects were 34.9 ± 13.4 years for the men and 33.5 ± 11.8 years for the women. The prevalence of LBP in the present study was 64.6% (95% CI = 60.7–68.5). The results revealed that there were statistically significant differences between men and women with respect to LBP and body mass index (BMI) (P < 0.001), marital status (P < 0.001), occupational status (P < 0.001), housing condition (P < 0.001), and smoking habits (P < 0.001). Back pain had a greater influence on the lifestyle habits of the women than men. Stepwise multiple regression analysis showed that only BMI (OR = 2.54, 95% CI = 2.30–281; P < 0.001), prolonged standing (OR = 6.22, 95% CI = 4.01–9.67; P < 0.0001), weakness in leg (OR = 2.11, 95% CI = 1.16–3.85; P = 0.0142), lifting heavy weights (OR = 6.34, 95% CI = 4.09–9.84; P = 0.019) regular exercise (OR = 12.47, 95% CI = 7.50–20.71; P < 0.001) and smoking habits (OR = 1.61, 95% CI = 1.08–2.38; P < 0.05) had a significant effect on the presence of LBP in these patients. Conclusions:  The study showed that the prevalence of back‐related disability was higher among women than men in the UAE. Also, low socio‐economic status and adverse lifestyle habits may constitute risk factors and predictors of LBP.

No abstract