Obesity is currently a worldwide phenomenon. The consumption of calorie-rich foods is responsible for most obesity cases, but not all humans exposed to high-calorie diets develop obesity. According to recent studies, exposure to fat-rich diets may be the actual cause of obesity. Dietary long-chain fatty acids affect brain function and are linked to food intake and motivation-related behaviors. Recently, many studies have shown that different types of fatty acids play different roles in animals. In our study, the effects of stearic acid (a saturated fatty acid) and oleic acid (a monounsaturated fatty acid) in diets on hedonic feeding behaviors were investigated, and changes of feeding-related protein levels in the brain were detected to explore the possible mechanism underlying the effects of these fatty acids. As a result, mice fed a diet containing stearic acid, compared to a diet containing oleic acid, exhibited increased food intake, hedonic eating, and an operant response to sucrose and locomotor activity. Furthermore, stearic acid corresponded to a higher level of leptin in serum than oleic acid. In addition, the stearic acid treated group had lower protein levels of p-JAK2 and p-STAT3 in the VTA and a higher dopamine concentration in the NAc than the oleic acid-treated group. Meanwhile, the protein level of TH in the NAc was higher and the protein level of the DA transporter in the VTA was lower in the stearic acid-fed group than in the oleic acid-fed group. In conclusion, these findings indicated that a diet containing stearic acid can increase hedonic feeding behavior and affect mesolimbic dopamine system signals in mice. Moreover, the lowering of serum leptin and leptin signaling in the VTA may contribute to this effect.

肥胖目前是一种世界性现象。大多数肥胖病例都是食用高热量食物造成的，但并非所有接触高热量饮食的人都会患上肥胖症。根据最近的研究，摄入富含脂肪的饮食可能是肥胖的真正原因。膳食中的长链脂肪酸会影响大脑功能，并与食物摄入和动机相关行为有关。近年来，许多研究表明，不同类型的脂肪酸在动物体内发挥着不同的作用。在我们的研究中，研究了饮食中的硬脂酸（一种饱和脂肪酸）和油酸（一种单不饱和脂肪酸）对享乐摄食行为的影响，并检测了大脑中与摄食相关的蛋白质水平的变化，以探讨其可能的作用。这些脂肪酸作用的潜在机制。结果，与含有油酸的饮食相比，喂养含有硬脂酸的饮食的小鼠表现出食物摄入量增加、享乐饮食以及对蔗糖和运动活动的操作反应。此外，硬脂酸对应的血清瘦素水平高于油酸。此外，与油酸处理组相比，硬脂酸处理组的 VTA 中 p-JAK2 和 p-STAT3 蛋白水平较低，NAc 中多巴胺浓度较高。同时，与油酸喂养组相比，硬脂酸喂养组的NAc中TH的蛋白水平较高，VTA中DA转运​​蛋白的蛋白水平较低。总之，这些发现表明，含有硬脂酸的饮食可以增加小鼠的享乐进食行为并影响中脑边缘多巴胺系统信号。此外，血清瘦素和 VTA 中瘦素信号传导的降低可能有助于这种效果。