Figure 3.

Effect of PA on acylcarnitines in SCs. The schematic diagram of fatty acid β-oxidation in SCs is shown on the left. Free carnitine in plasma enters cells through organic cation/carnitine transporter 2 (OCTN2). Long-chain fatty acids then enter the mitochondria with the help of carnitine and are transformed into acylcarnitines by carnitine palmitoyltransferase 1 (CPT1), which is located in the outer membrane of mitochondria. Acylcarnitines then pass through the inner mitochondrial membrane (IMM) through carnitine acyltransferase (CACT) to exchange free carnitine. Carnitine palmitoyltransferases 2 (CPT 2), which is located in the IMM, converts acylcarnitines into acyl-CoA and free L-carnitine for the next oxidation reaction. Medium- and short-chain fatty acids do not require carnitine to enter mitochondria for oxidation. Subsequently, acylcarnitines are oxidized in the form of acyl coenzyme A (acyl-CoA) by a series of enzymes to produce acyl-CoA with two less carbon atoms than the original and acetyl-CoA, which is finally oxidized by the TCA cycle to produce CO₂ and H₂O as well as to release energy. The changes in long-, medium- and short-chain acylcarnitines are shown in panels A–C, respectively. Data were expressed as mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001.