The level of 1C diets fed prior to cell isolation affects lipid metabolism in primary liver cells isolated from Atlantic salmon (Salmo salar)

Liver cells were isolated from 6 fish fed a diet containing 12.1 g methionine/kg, 11.02 mg vitamin B6/kg, 0.20 mg vitamin B12/kg and 7.80 mg folate/kg (named high-1C diet). These cells were compared to liver cells isolated from 6 fish fed a diet containing 6.7 g methionine/kg, 7.01 g vitamin B6/kg, 0.15 mg vitamin B12/kg and 2.60 mg folate/kg (named low-1C diet). Isolated cells were plated on 6-well plates in Leibovitz medium and treated with 10 mM metformin, 10 mM metformin for 24 hr followed by 0.4 mM oleic acid (OA) for 24 hr or only 0.4 mM OA for 24 hr. The cells were compared to untreated controls added only the medium. All cells were harvested 48 hr after being plated. Cells isolated from Atlantic salmon fed low-1C diets showed higher gene expression of MGAT-2 (p < .0001), CPT-1 (p = .028), FAS (p = .0006), LXR (p = .020), ACC (p = .032) and MnSOD (p < .0001). The low- or high-1C diets fed prior to cell isolation had no effect on gene expression of ApoB100, PPARa, CD36, SREBP-2 or Bcl-2. Metformin treatment increased the expression of the anti-apoptotic protein Bcl-2 (p = .0001) indicating an anti-apoptotic effect. Metformin generally increased the expression of genes associated with lipid oxidation and transport, but decreased the expression of genes associated with cholesterol metabolism confirming our earlier results using this model.