研究目的：自噬与非酒精性脂肪肝病的发生发展密切相关，而运动可以通过诱导肝细胞自噬活动来对肝脏健康产生积极影响。尽管有氧运动和高强度间歇训练在人类健康中的益处已被广泛研究，但它们对肥胖状态下的肝脏自噬相关蛋白表达的影响仍需进一步探讨。因此，本研究旨在对比分析这两种运动形式对大鼠肝细胞脂质代谢和自噬活动的影响，以期找出改善肥胖和肝脂质代谢的更有效运动干预手段，并从溶酶体生物发生和自噬体生物发生两个角度进一步探讨运动干预调控肝细胞自噬的可能机制。

研究方法：本研究选取42只3周龄的SPF级雄性SD大鼠作为实验对象，大鼠随机分为普通饮食组（n=10）和高脂饮食组（n=32），高脂饮食组大鼠随后接受为期12周的高脂饮食干预以诱导肥胖模型的建立，肥胖造模期间，普通饮食组大鼠生活方式保持不变。肥胖模型成功建立后，将肥胖模型大鼠进一步划分为三个实验组：单纯肥胖组、肥胖+有氧运动组以及肥胖+高强度间歇训练组，对其进行为期12周的运动干预实验。实验结束后，对所有大鼠进行处死并采集肝脏组织和血清等实验样本。肝脏组织脱水处理后进行HE染色观察。同时，利用全自动生化分析方法检测小鼠血清中的总胆固醇、甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇以及肝脏中的甘油三脂和总胆固醇的含量。通过RT-qPCR和Western Blot技术，分别检测LAMP1、LC3-B和P62三个自噬相关分子在基因和蛋白质水平上的表达量。

研究结果：

（1）运动干预对肥胖大鼠体重和内脏脂肪重量的影响。与SC组大鼠相比，HC组大鼠体重和内脏脂肪重量均显著升高（P<0.01,P<0.01）;与HC组大鼠相比，HH和HM两组大鼠体重和内脏脂肪重量显著降低（P<0.01,P<0.01）。

（2）运动干预对肥胖大鼠肝脏组织形态学的影响。肝脏大体外观：SC组大鼠肝脏呈现深红褐色，肝小叶表面光滑，质地柔软，有弹性；HC组大鼠肝脏呈现淡黄色，肝小叶变厚，表面粗糙，小叶边缘圆钝，包膜紧张，切面油腻；HM组和HH组肝脏呈深红褐色，外观形态与SC组并无差别。HE染色结果：SC组大鼠肝细胞排列正常，肝窦排列整齐，细胞核呈单核或双核位于细胞中央，胞质均匀丰富。HC组大鼠肝细胞体积增大，排列混乱，胞浆内肉眼可见大小不一的脂滴空泡，脂滴空包以大脂滴空泡为主，将肝细胞胞核挤压至细胞一边，肝窦变窄，排列混乱。HH组大鼠肝细胞部分肝窦变窄，但胞质均匀丰富，胞质中有少量体积较小的脂滴空泡，细胞核位于细胞中央。HM组大鼠肝细胞排列整齐，肝窦排列整齐，细胞核呈单核或双核位于细胞中央，胞质均匀丰富，仅极少数肝细胞胞浆内存在少量体积较小的脂滴空泡。

（3）运动干预对肥胖大鼠血糖、血脂和肝脏功能指标的影响。与SC组大鼠相比，HC组大鼠血脂指标包括TC、TG、LDL-C和肝功指标AST和ALT均显著升高（P<0.05，P<0.01, P<0.05, P<0.01, P<0.001），而HC组大鼠空腹血糖水平和HDL-C并未出现显著性的差异（P>0.05，P>0.05）。与HC组大鼠相比，HM组大鼠空腹血糖，TC、TG、LDL-C和肝功指标AST和ALT均出现显著降低（P<0.01，P<0.05, P<0.05, P<0.05, P<0.01）而HDL-C的水平无显著改变（P>0.05）；HH组大鼠空腹血糖，TG、LDL-C和肝功指标AST和ALT均出现显著降低（P<0.05，P<0.05, P<0.05, P<0.05）而对HDL-C和TC的水平无显著性影响（P>0.05，P>0.05）。

（4）运动干预对肥胖大鼠肝脏脂质代谢指标的影响。与SC组大鼠相比，HC组大鼠肝脏TC和TG的水平显著升高（P<0.01, P<0.01）；与HC组大鼠相比，HM组和HH组大鼠肝脏TC和TG水平显著降低（P<0.05，P<0.01）和（P<0.05，P<0.05）。

（5）运动干预对大鼠肝细胞自噬相关基因表达的影响。与SC组相比，HC组大鼠肝细胞PLIN2基因的表达显著增加（P<0.01），但P62,LAMP1和LC3的表达未产生显著性改变（P>0.05，P>0.05，P>0.05）；与HC组大鼠相比，HM组大鼠肝细胞LC3的表达显著增加（P<0.05）并显著降低PLIN2的表达（P<0.05），对P62和LAMP1的表达无显著影响（P>0.05,P>0.05）；HH组大鼠PLIN2的表达显著降低（P<0.05），LAMP1,P62和LC3的表达未产生显著改变（P>0.05, P>0.05, P>0.05）。

（6）运动干预对肥胖大鼠肝脏自噬相关蛋白的影响。与SC组相比，HC组大鼠肝细胞LC3-Ⅱ蛋白的表达显著降低（P<0.05），P62的水平显著增加（P<0.001），对LAMP1的表达未产生显著性影响（P>0.05）。与HC组大鼠相比，HM组大鼠肝细胞LC3-Ⅱ蛋白的表达显著升高（P<0.05），P62的水平显著降低（P<0.001），对LAMP1的表达未产生显著性影响（P>0.05）；HH组大鼠肝细胞P62蛋白的水平显著降低（P<0.01）但LAMP1和LC3-Ⅱ蛋白未产生显著性改变（P>0.05，P>0.05）。

研究结论：中等强度持续有氧运动和高强度间歇训练都能够有效控制体重并减少肝脏脂质沉积，改善肝脏功能，这些有益改变可能和增强的肝细胞自噬活动有关，运动增强的自噬活动可能与自噬体的生物发生增强有关。中等强度持续有氧运动与高强度间歇训练相比，在控制体重方面一样有效，但中等强度持续有氧运动在降低肥胖造成的肝脏脂质沉积方面效果更为优越，这可能和更强的自噬活动的发生有关。

Research Objectives: Autophagy is closely related to the occurrence and development of non-alcoholic fatty liver disease (NAFLD), and exercise may positively impact liver health by inducing autophagy. Although the benefits of aerobic exercise and high-intensity interval training (HIIT) on human health have been widely studied, their effects on autophagy-related protein expression in the liver under obese conditions require further investigation. Therefore, this study aims to compare the effects of these two exercise forms on lipid metabolism and autophagy activity in rat liver cells. The goal is to identify more effective exercise interventions to improve obesity and liver lipid metabolism and to explore the potential mechanisms of exercise intervention in regulating liver cell autophagy from the perspectives of lysosome biogenesis and autophagosome biogenesis.

Research Methods: This study selected 42 three-week-old male SPF SD rats as experimental subjects, randomly dividing them into a normal diet group (n=10) and a high-fat diet group (n=32). The high-fat diet group underwent a 12-week high-fat diet intervention to establish an obesity model, while the normal diet group maintained their regular lifestyle. After successfully establishing the obesity model, the obese rats were further divided into three experimental groups: simple obesity group, obesity + aerobic exercise group, and obesity + HIIT group, undergoing a 12-week exercise intervention. After the experiment, all rats were sacrificed, and liver tissues and serum samples were collected. Liver tissues were dehydrated and subjected to HE staining for observation. Automated biochemical analysis was used to measure total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol in the serum, and triglycerides and total cholesterol in the liver. The expression levels of three autophagy-related molecules, LAMP1, LC3-B, and P62, were detected at the gene and protein levels using RT-qPCR and Western Blot techniques.

Research Results:

(1). The Effects of Exercise Intervention on Body Weight and Visceral Fat Weight in Obese Rats:

Compared to the Sedentary Control (SC) group, the High-Calorie (HC) group showed significant increases in body weight and visceral fat weight (P<0.01, P<0.01). Compared to the HC group, both the High-Intensity Interval Training (HH) and Moderate-Intensity Continuous Training (HM) groups showed significant decreases in body weight and visceral fat weight (P < 0.01, P< 0.01).

(2). The Effects of Exercise Intervention on Hepatic Tissue Morphology in Obese Rats:

Macroscopic appearance of the liver: The liver of SC rats appeared dark reddish-brown, with smooth liver lobules, soft texture, and elasticity. The liver of HC rats appeared light yellow, with thickened liver lobules, rough surface, rounded edges of lobules, tense capsule, and greasy cut surface. The livers of HM and HH rats appeared dark reddish-brown, with no significant difference in appearance compared to the SC group. Results of HE staining: The hepatocytes of SC rats were arranged normally, with orderly hepatic sinusoids and nuclei located centrally. The cytoplasm was uniformly rich. The hepatocytes of HC rats had increased volume, disorganized arrangement, visible macroscopic lipid droplets of varying sizes in the cytoplasm, and compressed nuclei. The hepatic sinusoids became narrow and disorganized. The hepatocytes of HH rats had partially narrowed hepatic sinusoids, but the cytoplasm was uniformly rich, with a few small-sized lipid droplets. The nuclei were located centrally. The hepatocytes of HM rats were arranged orderly, with orderly hepatic sinusoids, nuclei located centrally, uniformly rich cytoplasm, and only a few hepatocytes with small-sized lipid droplets in the cytoplasm.

(3). The Effects of Exercise Intervention on Blood Glucose, Blood Lipids, and Liver Function Indicators in Obese Rats: Compared to the SC group, the HC group showed significant increases in blood lipid indicators including TC, TG, LDL-C, and liver function indicators AST and ALT (P < 0.05, P < 0.01, P< 0.05, P < 0.01, P<0.001), while there were no significant differences in fasting blood glucose levels and HDL-C (P>0.05, P>0.05). Compared to the HC group, the HM group showed significant decreases in fasting blood glucose levels, TC, TG, LDL-C, and liver function indicators AST and ALT (P<0.01, P<0.05, P<0.05, P< 0.05, P < 0.01), while HDL-C levels remained unchanged (P>0.05). The HH group showed significant decreases in fasting blood glucose levels, TG, LDL-C, and liver function indicators AST and ALT (P<0.05, P< 0.05, P<0.05, P<0.05), while there were no significant changes in HDL-C and TC levels (P>0.05, P>0.05).

(4). The Effects of Exercise Intervention on Hepatic Lipid Metabolism Indicators in Obese Rats:

Compared to the SC group, the HC group showed significant increases in hepatic TC and TG levels (P<0.01, P<0.01). Compared to the HC group, both the HM and HH groups showed significant decreases in hepatic TC and TG levels (P< 0.05, P<0.01).

(5). The Effects of Exercise Intervention on the Expression of Autophagy-Related Genes in Hepatocytes of Obese Rats: Compared to the SC group, the expression of the PLIN2 gene in hepatocytes of the HC group significantly increased (P<0.01), but the expression of P62, LAMP1, and LC3 did not change significantly (P >0.05, P >0.05, P >0.05). Compared to the HC group, the expression of LC3 in hepatocytes of the HM group significantly increased (P<0.05), and the expression of PLIN2 significantly decreased (P<0.05), while there was no significant effect on the expression of P62 and LAMP1 (P>0.05, P>0.05). The expression of PLIN2 in hepatocytes of the HH group significantly decreased (P<0.05), while the expression of LAMP1 and LC3 did not change significantly (P> 0.05, P>0.05).

(6). The Effects of Exercise Intervention on Hepatic Autophagy-Related Proteins in Obese Rats:

Compared to the SC group, the expression of LC3-II protein in hepatocytes of the HC group significantly decreased (P<0.05), while the level of P62 significantly increased (P<0.001), and there was no significant effect on the expression of LAMP1 (P>0.05). Compared to the HC group, the expression of LC3-II protein in hepatocytes of the HM group significantly increased (P < 0.05), while the level of P62 significantly decreased (P<0.001), and there was no significant effect on the expression of LAMP1 (P>0.05). The level of P62 protein in hepatocytes of the HH group significantly decreased (P<0.01), but there were no significant changes in the expression of LAMP1 and LC3-II protein (P > 0.05, P >0.05).

Research Conclusion: Moderate-intensity continuous aerobic exercise and high-intensity interval training can effectively control body weight, reduce hepatic lipid deposition, and improve liver function. These beneficial changes may be related to enhanced hepatic cell autophagy activity, and the enhanced autophagy activity induced by exercise may be related to the enhancement of autophagosome biogenesis. Moderate-intensity continuous aerobic exercise is as effective as high-intensity interval training in controlling body weight but is superior in reducing hepatic lipid deposition caused by obesity, which may be related to the occurrence of stronger autophagy activity.