Effect of Tunisian Olive Leaf Extract on oxidative stress and lung fibrosis in rats

Aims and Objectives: Oxidative stress is one of the most important etiopathogenic axes in pulmonary fibrosis. In this study, we aimed to investigate the effect of Tunisian Olive Leaf Extract (TOLE) rich in bioactive compounds more particularly polyphenols on oxidative stress and therefore on lung fibrosis induced by Bleomycin (BLM) in rats. Methods: Animals were randomly divided into 4 groups of 8 rats each. G1: Control group, G2: BLM group, G3: TOLE group, G4: BLM + TOLE group. BLM was administered by a single intra tracheal injection (4 mg/Kg) to G2 and G4. TOLE was administered intraperitoneally at a dose of (10 mg / kg/day) for 3 weeks to G3 and G4. The later received TOLE 3 days after BLM injection. At the end of the protocol, all rats were sacrificed and lungs were extracted. Antioxidant effects of TOLE in lung tissues were studied using standard spectrophotometric methods and fibrosis was assessed by histological analysis conforming to Ashcroft score. Results: Before starting the therapeutic protocol, analysis of TOLE by HPLC and LC-MS methods revealed an important amount of phenolic bioactive compounds such as oleuropein and hydroxytyrosol. At the end of protocol, we noticed that TOLE treatment normalized MDA and antioxidant enzyme levels (SOD and CAT) and decreased significantly fibrosis score in G4 compared to G2. Conclusion: These data are promising and should be complemented by further studies evaluating the dose response effect of TOLE on fibrotic process in BLM induced lung fibrosis.