Prophylactic Sargassum duplicatum inhibit joint damage in adjuvant arthritic rats exposed to cold stress through inhibition of NF-KB activation

Activation of NF-κB play important roles in inflammatory process of rheumatoid arthritis (RA). Cold stress cause increased body heat production by thermogenesis achieved by accelerating uncoupling oxidative phosphorylation. We aimed to investigate whether Sargassum duplicatum was able to reduce the extent of joint damage through inhibition of NF- κB activation in adjuvant arthritis an animal model of RA. Male adjuvant arthritic rats (age=10-12 wk; n=10/group) were exposed to cold stress (5°C for 15 min/day for 7 days) with/without Sargassum duplicatum extract (400 mg/kg BW/day po) given from 7 days prior to cold stress until the end of the experiment. The control group did not receive either cold exposure or Sargassum duplicatum. At the end of the experiment plasma malondialdehyde (MDA) level as biomarker of oxidative stress was measured using spectrophotometry method, joint NF-κB levelwas measured by counting NF-κB positive cells in imunohistochemistry and the severity of joint damage was measured by the histopathological scoring system. The results showed that cold stress significantly increased plasma MDA level (4.2666±0.1940 μM vs. 2.9297±0.1499 μM; p≤0.05; p≤0.005), increased joint NF-κB level (58.8±10.871 vs. 43.5±6.223; p≤0.001), and increased joint histopathological score (median: 4vs3; p≤0.001). Sargassum duplicatum extract administration in cold stress treated group significantly decreased plasma MDA level (2.2569±0.0792 μM vs. 4.2666±0.1940 μM; p≤0.001), joint NF- κB positive cells (24.3±4.832 vs. 58.8±10.871; p≤0.001) and joint histopathological score (median: 3vs4; p≤0.001). Conclusion: Prophylactic Sargassum duplicatum extract significantly reduced joint damage through inhibition of NF-κB expression and reduction of oxidative stress in adjuvant arthritic rats exposed to cold stress.