COMPARATIVE ANTIINFAMMATORY EFFECT OF EPA AND DHA DERIVATIVES ON OEC EXPOSED TO LPS.

Neurodegenerative diseases are characterized by neuroinflammation, a symptom with growing interest directed towards the development of active drugs for the reduction or elimination of its negative effects. It is largely reported on the anti-inflammatory and their potential neuroprotective activity in some neural cells of Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), belonging to the class of ?-3 polyunsaturated fatty acids. Most of the observed biological activities of these fatty acids are maintained, and in some case enhanced, in the corresponding amide derivatives or oxygenated metabolites. While free acids EPA and DHA are commercially available, the corresponding amides were prepared by aminolysis of the ethyl esters of EPA and DHA with ethanolamine in the presence of immobilized lipase from Candida antarctica (Novozym 435) and molecular sieves in tert-butyl methyl ether. Our study aims to elucidate the protective effect of both EPA and DHA, as well as the corresponding N-ethanolamides EPA-EA and DHA-EA, on Olfactory Ensheathing Cells (OECs) exposed to lipopolysaccharide (LPS)-induced neuroinflammation for 24 h. OECs are glial cells located in the olfactory system, which is the first to show a deficit in neurodegenerative diseases. To verify the anti-inflammatory effect of these compounds on OEC cultures and on cell morphological features, the expression of some cytoskeletal proteins, such as Vimentin and Glial Fibrillary Acid Protein (GFAP), was evaluated by immunocytochemical procedures. In addition, MTT test was carried out to establish the non-toxic concentrations and the optimal time of exposure. Mitotoxicity and cytotoxicity levels in stressed were detected by using the HCS Mitochondrial Health Kit, while apoptosis was determined by staining with the TUNEL Alexa Fluor Imaging assay. Our results show a decrease of GFAP and Vimentin expression in OECs treated with EPA or DHA acids or EPA-EA or DHA-EA and stressed with LPS when compared with OECs exposed to LPS alone. While a protective role on cell morphology is predominantly observed for EPA and DHA, the amides EPA-EA and DHA-EA mainly show anti-inflammatory effects, superior to those of free acids. These results highlight that all the tested compounds have anti-inflammatory activity on LPS-exposed OECs and may provide an innovative tool to contrast neuroinflammation, which plays a key role in several neurodegenerative diseases.