PSVII-23 - Effect of trans 10, cis 12 conjugated linoleic acid to dedifferentiated mature bovine adipocytes

Abstract: Stromal vascular fraction (SVF) derived preadipocytes has commonly been used as a model to study beef marbling biology. Trans 10, cis 12 conjugated linoleic acid (t10, c12 CLA) has been shown to inhibit adipogenesis and lipogenesis in SVF derived adipocytes. However, CLA effects in other primary bovine adipocyte models have not been studied. For the present study, we hypothesized that adding CLA would inhibit lipogenesis and adipogenesis in dedifferentiated mature adipocytes (DFAT). DFAT cells were sourced from the brisket of a 15-month old steer, and cultured with differentiation media (DMEM with 10% FBS, 0.25 uM dexamethasone, 0.5 mM 3-isobutyl-methylxanthine (IBMX), 2uM troglitazone, 10ug/ml bovine insulin, 20nM glucose, 2x antibiotics/antimycotics, and test FAs) for 6 days followed by maturation media (DMEM with 10% FBS, 2uM troglitazone, 10ug/ml bovine insulin, 20nM glucose, 2x antibiotics/antimycotics, and test FAs) for 6 days. Treatments included 100uM of t10, c12 CLA, linoleic acid (c9, c12-18:2), and oleic acid (c9-18:1), while control cells received no exogenous FAs. Cells were stained by Oil Red O on day 12, and were collected on day 6 for gene expression analysis for adipogenic markers using qPCR. Relative lipid droplet accumulation was quantified by using Oil Red O staining. Assessment of lipid droplets by Oil Red O staining showed that there is no significant difference of lipid accumulation among t10,c12 CLA, c9, c12 18:2, and c9-18:1 in FA-treated DFAT cells (P < 0.05). Gene expression results showed that peroxisome proliferator-activated receptor-γ(PPAR-γ) expression in DFAT cells differentiated with FA treatments were not significantly different from the control in DFAT cells (P > 0.05) while showed significantly lower expression of stearoyl-CoA 9-desaturase 1 (SCD1) with t10, c12 18:2 than linoleic acid(P < 0.05). To further investigate the response of DFAT cells to t10, c12 18:2 in terms of SCD-1 expression and activity, DFAT cells were treated with 100uM t10, c12 CLA conjugated with bovine serum albumin (BSA) and collected for western blot and fatty acid analysis. Western blot indicated that DFAT cells treated with t10, c12 CLA showed lower SCD-1 expression than BSA vehicle control. Fatty acid analysis by gas chromatography (GC) suggested that DFAT cells treated with t10, c12 CLA has decreased SCD-1 activity index (C16:1: C16:0, C18:1: C18:0) (P < 0.05). In conclusion, bovine DFAT cells exhibit similar response to t10, c12 CLA to bovine stromal vascular fraction from the literature in terms of SCD-1 expression and activity, while PPAR-γ expression is not affected by t10, c12 CLA.