EMODIN PROTECTS PRIMARY HEPATOCYTES FROM PRO-OXIDATIVE EFFECTS AND AKT PATHWAYS DISREGULATION INDUCED BY A HIGH-FAT/LOW CARBOHYDRAT DIET .

Background and aim: High fat diet in animal models may predispose to several metabolic disturbances including fatty infiltration in the liver alone (simple steatosis) or associated with necro-inflammation and fibrosis (steatohepatitis). Excessive fatty acids in diet may also induce an alteration of liver cell homeostasis due to an increase of oxidative stress. In the last years, several studies have emphasized the hepato-protective effect of some natural antioxidants. Thus, here we investigated the effects of Emodin, an antraquinone derivative with antioxidant and anti-cancer abilities, on the homeostasis of hepatocytes derived from rats fed high-fat and low carbohydrate diet. Methods: We used Sprague-Dawley rats fed ad libitum with a standard diet (SD) or with a high fat/low carbohydrate (HFD-LC) diet. After 1 month, Emodin was added to the drinking water of a part of HFD-LC rats. The experiment was termed after additional two months, when animals were sacrificed to perform liver hystology, and to isolate primary hepatocytes by a perfusive method. Results: Our results demonstrated that HFD-LC rats did not become obese, whereas Emodin caused a weight gain (20-30%). As revealed the staining with Ematoxilin-Eosin, control group and HFD-LC treated with Emodin mantained their normal liver hystology, while HFD-LC rats showed a mild steatosis predominantly macrovacuolar. Interestingly, also cytomorphology of primary hepatocytes from HFD-LC rats were greatly different from control hepatocytes. Moreover HFD-LC rat cells presented lower vitality, greater oxidative stress and impaired Akt pathway. Emodin not only preserved hepatocyte morphology but also cell viability, the rate of cell proliferation, the oxidation of lipids and levels of glutathione. In addition, Emodin seems to interfere with Akt pathway; in fact, as shown by western blot analysis, it restores the phosphorylation levels of PTEN (phosphatase and tensin homolog). Conclusions: Despite the low grade of liver steatosis, high-fat/low carbohydrate diet significantly modifies hepatocyte homeostasis, altering oxidative stress response and Akt signalling. Moreover, the addition of Emodin to diet protects hepatocytes fron these intracellular changes comforting on the possibility to use this natural antioxidant as treatment of liver steatosis, and encouraging further studies.