ABSTRACT

Administration of exogenous melatonin has been established as a powerful hepatoprotective strategy in over 120 experimental in vivo studies, using various animal species, applying over 40 different models of stress [1-125] (Table 12.1). The data presented here are certainly incomplete: there are more studies investigating hepatoprotective effects of melatonin, not included in this overview. For this chapter, only a selection of the most important in vivo studies with acute onset models of stress or toxicities were chosen (Pubmed™ literature research from 1966 until today; inclusion criteria: melatonin and liver; hand-by-hand search for in vivo studies with a hepatoprotective aim of melatonin therapy). Other studies, especially the ones on chronic diseases (cirrhosis, pancreatitis, and diabetes), tumor or cancer development/metastases, aging, dietary changes, exercise-induced stress, remote organ injuries, and studies coadministering melatonin with other substances were excluded, even though they may be showing similar and very convincing results. The available literature from this research indicates that melatonin may protect from hepatic injury after different types of shock, ischemia/reperfusion, trauma, cholestasis, radiation, application of over 30 types of toxic agents, and damages inicted by different microorganisms, in rats, mice, chicks, and hamsters [1-125]. Many models were investigated by more than one researcher, and all studies-independent of the type of hepatic injury-show similar results with respect to melatonin’s effects on hepatic oxidative stress, interleukin signaling, hepatocellular integrity, and survival.