RESUMO
Inflammation and oxidative stress are interrelated processes, during which many pathological processes lead to the reactive oxygen species (ROS) and the cytokines release. The aim of this experimental study was to analyse the effects of chlorogenic acid, in oral daily administration, against the oxidative stress and oedema development in experimental carrageenan-induced rat paw inflammation. The oxidative stress parameters were investigated after a paw inflammation was produced in rats that previoulsy received, for 14 days, either chlorogenic acid (100 mg/day or 150 mg/day) or indomethacin (1 mg/kg/day). The paw oedema was measured through plethysmometry made at 2, 6 and 24 hours after carrageenan injection. The oxidative stress was investigated through spectrophotometry. Blood samples, paw skin and kidneys were collected to investigate malondialdehyde (MDA), glutathione (GSH) and oxidized glutathione (GSSG). The protein expression of oxidative stress-related pathways was analysed in skin and kidneys through Western blot. The present study showed that indomethacin and both doses of chlorogenic acid, after 14 days of oral administration, exerted antioedematous effects during the inflammation development after carrageenan local injection. Compared to the group that received only carrageenan injection, significant decreases of the inflamed paw volume were shown in the treated groups (P < 0.001), in all inflammation phases. The lipid peroxidation was significantly decreased by both doses of chlorogenic acid in inflamed skin (P < 0.0001) and kidney (P < 0.0001). In serum, it was significantly inhibited by indomethacin (P < 0.01) and by 100 mg/day of chlorogenic acid (P < 0.05). The antioxidant protection, evaluated through the ratio GSH/GSSG, was significantly increased by chlorogenic acid in inflamed skin (P < 0.0001) and kidney (100 mg/day, P < 0.01; 150 mg/day, P < 0.0001). In serum, only indomethacin administration produced significant increases of the antioxidant protection (P < 0.05). Western blot analysis showed significant decreases of COX-2 in inflamed skin and kidney in the groups of rats that received indomethacin or 100 mg/day of chlorogenic acid. The effects of chlorogenic acid on NF-κB and pNF-κB were dose-dependent.
