Pine nut oil supplementation alleviates the obesogenic effects in high-fat diet induced obese rats: A comparative study between epididymal and retroperitoneal adipose tissue

Abstract

Pine nut oil (PNO) is a rich source of polyunsaturated fatty acids. It is obtained from species such as Pinus siberica, Pinus gerardinia, Pinus koraiensis, and so on. A few studies have shown its protective effect against obesity by regulating lipid metabolism and suppressing appetite. However, its effect on the release of adipokines and obesity-associated signaling pathways is yet to be investigated. We hypothesized that PNO might exert its antiobesogenic effects by modulating adiponectin/leptin-mediated cell signaling pathways. Therefore, the present study was designed to investigate the mechanism of action of 10% PNO substitution on the high-fat diet–induced obesity in male Wistar rats. PNO incorporation in the diet significantly decreased the body weight, body mass index, Lee index, liver weight, blood glucose levels, and adipose tissue size. It also reduced the levels of proinflammatory cytokines (interleukin-6 and tumor necrosis factor-α) and triglycerides and increased levels of high-density lipoprotein cholesterol in serum significantly. It was observed that incorporation of PNO led to a significant increase in ADIPOR1/R2 expression in visceral epididymal adipose tissue (vEAT). It also lowered serum leptin (P < .05) and increased adiponectin levels. Furthermore, PNO supplementation increased P-AMPK/AMPK and P-AKT/AKT ratio and decreased the expression of FOXO-1 in both visceral epididymal and retroperitoneal adipose tissue (vEAT and vRPAT). Therefore, the present study showed that incorporation of PNO in the diet might prevent obesity and improve the metabolic inflammatory state in obesity by controlling the release of adipokines and proinflammatory cytokines. Comparative analysis between vEAT and vRPAT also revealed that vEAT is metabolically more active in combating obesity than vRPAT.