Kadsura heteroclita stem suppresses the onset and progression of adjuvant-induced arthritis in rats

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune diseased state, characterized by hyperplasia of the synovial membrane, degradation of cartilage, and bone erosion of diarthrodial joints. Kadsura heteroclita (Roxb) Craib (Schizandraceae), a traditional Tujia ethnomedicine called Xue Tong in China, has been long used for the prevention and treatment of rheumatic and arthritic diseases, especially in the southern China. This study aimed to evaluate anti-arthritic effects of the ethanol extract of Kadsura heteroclita stems (KHS) on complete Freund's adjuvant (CFA)-induced arthritis (AIA) in rats, as well as to explore the underlying mechanisms of anti-arthritis.

METHODS

AIA was established in male Sprague-Dawley (SD) rats as described previously, and animals were daily treated by gavage with KHS ethanol extract (200, 400, or 800 mg/kg) or vehicle (0.3% CMCNa) throughout the 30-day experiment. The incidence and severity of arthritis were evaluated using clinical parameters. At the end of experiments, tissue swelling and bone destruction of the hind paws were assessed by computed tomography (CT) and histopathological analyses. Serum levels of tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-17A and IL-17F were measured by ELISA, and protein expression of matrix metalloproteinases-1 (MMP-1), MMP-3 and tissue inhibitor of MMP-1 (TIMP-1) were detected by Western blot.

RESULTS

Treatment with KHS dose-dependently inhibited paw swelling and reduced arthritis scores of AIA rats. CT images displayed that KHS remarkably protected AIA rats from tissue swelling and bone erosion of joints. Histopathological analyses revealed that KHS markedly reduced inflammatory cell infiltration, synovial proliferation, and the formation of pannus in the ankle joints of AIA rats. KHS was found to significantly suppress the production of TNF-α, IL-1 β, IL-6, IL-17A and IL-17F, inhibited the protein expression of MMP-1 and MMP-3, and elevated the protein expressions of TIMP-1.

CONCLUSION

KHS demonstrates potential anti-arthritic effects via inhibiting pivotal mediators of inflammation and cartilage destruction. This study strongly supports identification and isolation of active fractions of KHS which would be a potential candidate for further investigation as a new anti-arthritic botanical drug.

Gene expression profiles reveal molecular mechanisms involved in the progression and resolution of bleomycin-induced lung fibrosis

Lung fibrosis is the final result of a large number of disorders and is usually considered an irreversible process. However, some evidence suggests that fibrosis could eventually be reversible. In this study we aimed to document the time-related reversibility of bleomycin-induced lung fibrosis and to examine the gene expression profile associated with its initial progression and subsequent resolution. C57BL/6 mice were instilled with a single dose of bleomycin and euthanized at 1, 4, 8, 12, and 16 wk. Control animals received an equal volume of saline. Lung fibrosis was examined by morphology and hydroxyproline content and the transcriptional signature by gene microarray analysis. Our results showed that bleomycin-injured mice developed prominent inflammation at 1 wk, followed by fibrosis that peaked at 2 mo. Then fibrosis resolved until lungs displayed almost normal architecture at 4 mo. Genomewide transcriptional profiling revealed 533 significantly changed genes. Self-organizing maps analysis of these genes identified four clusters based on the temporal pattern of gene expression. Clusters 1 and 2 contained genes upregulated during the inflammatory and fibrotic response and were enriched for extracellular matrix-related genes including several collagens, matrix metalloproteinases, and TIMP-1. Cluster 3 identified upregulated genes during the fibrotic response, and cluster 4 contained genes decreased during inflammation and fibrosis that increased during resolution. Most enriched pathways included genes involved in cell cycle and in regulation of transcription. Our findings corroborate the reversibility of bleomycin-induced lung fibrosis and reveal transcriptional signatures that characterize the progression and resolution.