Anti-Inflammatory Effect of Dendrobium huoshanense Polysaccharides on Carrageenan-Induced Air Pouch Synovitis in Mice

Abstract Objective: The purpose was to observe the anti-inflammatory effects of Dendrobium huoshanense polysaccharides (DHPs) on carrageenan-induced sterile air pouch synovitis. Materials and Methods: A total of 30 Institute of Cancer Research (ICR) mice were randomly and equally assigned to the control, carrageenan-induced air pouch synovitis model (model), and carrageenan-induced air pouch synovitis model + DHP (200 mg/kg of body weight) (model + DHP) groups. Mice in the model + DHP group were intragastrically administered 200 mg/kg BW of DHP solution daily for 10 days. Mice in the control and model groups were intragastrically administered the same amount of distilled water. Two hours after intragastric administration on day 10, 1 mL of a 1% carrageenan solution in a sterile 0.9% saline solution was injected into the air pouch of mice in the model and model + DHP groups. Six hours later, the mice were sacrificed and 4 mL of ice-cold sterile 0.9% saline solution was injected into the air pouch to fully wash its inner wall. The lavage fluid was collected to observe the color and turbidity of the lavage fluid, as well as the appearance of the backside of the air pouch. The exudate volume, total number of leukocytes, protein content, levels of malondialdehyde (MDA), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α), and total superoxide dismutase (T-SOD) activity of the lavage fluid were analyzed. Results: The results showed that pretreatment with DHPs reduced the carrageenan-induced exudate volume ( P < 0.01), total leukocytes ( P < 0.05), and protein content ( P < 0.01) in the air pouch lavage fluid. Furthermore, mice in the model + DHP group had significantly higher ( P < 0.01) T-SOD activity and lower MDA content ( P < 0.05), IL-1β ( P < 0.05), and TNF-α ( P < 0.01) levels in the air pouch lavage fluid compared with the model group. Conclusion: It is concluded that DHPs partially alleviated carrageenan-induced sterile inflammation, and its mechanism may be related to reducing exudation and scavenging oxygen-free radicals, inhibiting lipid peroxidation, and reducing the level of the proinflammatory factors, such as IL-1β and TNF-α.