Effects of metformin and simvastatin on mitophagy in the hepatocytes of mice fed with a high fat diet

Tip 2 dijabetes predstavlja veliki zdravstveni problem za ljudsko društvo. Ovoj bolesti često prethodi kliničko stanje koje se naziva metabolički sindrom. C57BL/6J miševi na režimu ishrane sa visokim sadržajem masti (HFD) su dugo korišćen životinjski model za tip 2 dijabetes i metabolički sindrom. Nova saznanja o patogenezi insulinske rezistencije, koja je karakteristična za tip 2 dijabetes i metabolički sindrom, ukazala su na veliki značaj poremećaja u mitohondrijama. Ćelije regulišu sadržaj i oblik mitohondrija mitohondrijalnom biogenezom, fisijom i fuzijom mitohondrija i uklanjanjem oštećenih mitohondrija mitofagijom, koja predstavlja jedan od oblika selektivne autofagije. Autofagija je ćelijski katabolički proces pomoću koga ćelije uklanjaju oštećene i/ili nepotrebne delove citoplazme, među njima i organele, uz pomoć lizozomalnih enzima. Mitofagija ima pretežno zaštitnu ulogu jer se ovim procesom mogu ukloniti oštećene i/ili nefunkcionalne mitohondrije koje bi mogle dovesti do povećane produkcije kiseoničkih slobodnih radikala i oštećenja ćelije. Metformin i statini su često korišćeni lekovi u dijabetesu tipa 2 i metaboličkom sindromu i za oba ova leka se zna da ispoljavaju direktan uticaj na mitohondrije. Jetra je organ u kome se odigrava najveći deo metabolizma, a obilje mitohondrija je čini očiglednim izborom za proučavanje ovih organela i efekata lekova na njihovo uklanjanje procesom mitofagije. Cilj: Cilj ovog istraživanja bio je da se ispita uticaj ishrane sa visokim sadržajem masti na ultrastrukturne karakteristike subcelularnih struktura, mitofagiju i ekspresiju regulatora autofagije u jetri, aorti i ishijadičnom nervu C57BL/6J miševa, kao i da se ispita uticaj metformina i simvastatina na ultrastrukturne karakteristike subcelularnih struktura, mitofagiju i ekspresiju regulatora autofagije u jetri, aorti i ishijadičnom nervu C57BL/6J miševa na režimu ishrane sa visokim sadržajem masti. Materijal i metode: Miševi soja C57BL/6J muškog pola bili su podeljeni u četiri grupe: grupa miševa na režimu ishrane HFD-om, metforminom tretirana grupa na režimu ishrane HFD-om, simvastatinom tretirana grupa na režimu ishrane HFD-om i kontrolna grupa miševa iste starosti...Type 2 diabetes represents a major health burden to the society and it is often preceded by a clinical condition referred to as metabolic syndrome. High fat diet (HFD) fed C57BL/6J mice are a long-used animal model for both the metabolic syndrome and type 2 diabetes. Novel insights into the pathogenesis of insulin resistance, a feature of both of the aforementioned conditions, placed increased significance on mitochondrial disturbances. Cells regulate mitochondrial content and shape by mitochondrial biogenesis, fission and fusion of mitochondria, and removal of damaged mitochondria by mitophagy, which represents one of the several selective forms of autophagy. Autophagy is a cellular catabolic process by which cells remove damaged and/or unnecessary parts of the cytoplasm, including organelles, with the participation of lysosomal enzymes. Mitophagy is generally considered to be cytoprotective, because damaged and/or dysfunctional mitochondria give rise to an excessive reactive oxygen species production, which may have deleterious consequences to the cells. Metformin and statins are frequently used drugs in type 2 diabetes and metabolic syndrome, and both drugs are known to exert direct effects on mitochondria. Liver is an organ where major part of metabolism takes place, and abundance of mitochondria makes it an obvious choice to study these organelles and the effects these drugs might have on the removal of mitochondria by mitophagy. Aim: The aim of this study was to assess the effects of HFD feeding on the ultrastructural characteristics of subcellular structures, mitophagy and autophagy regulators expression in C57BL/6J mice liver, aorta and sciatic nerve and the effects of metformin and simvastatin on the aforementioned cellular elements and processes. Material and methods: Male C57BL/6J mice were assigned to four groups: HFD fed, metformin treated HFD fed, simvastatin treated HFD fed and age matched control group. After the animals were sacrificed by cervical dislocation, samples of liver, aorta and sciatic nerve were collected for morphological and biochemical analysis..