Effect of a high-calorie diet on pro- to anti-inflammatory macrophage ratio through fat accumulation in rat lung tissue

Abstract

Effect of a high-calorie diet on pro- to anti-inflammatory macrophage ratio through fat accumulation in rat lung tissue Indah Puji Lestari, Iin Noor Chozin, Teguh Rahayu Sartono, Laksmi Sasiarini, Hendy Setyo Yudhanto Medical Journal of Indonesia Basic Medical Research ABSTRACT BACKGROUND A high-calorie diet increases the risk of obesity. Accumulation of fat causes inflammation, as seen by the increased ratio of pro- to anti-inflammatory macrophages in a high-calorie diet. The pro-inflammatory shift in macrophage polarization may result in hypoxia, fibrosis, emphysema, and asthma. This study aimed to determine the effect of a high-calorie diet on pro- to anti-inflammatory macrophage ratio through fat accumulation. METHODS This experimental study used in vivo test in 16 male Sprague-Dawley rats aged 10–12 weeks. The rats were divided into high-calorie and normal diet groups for 16 weeks. Obesity in rats was defined as having a body mass index (BMI) of >0.68 g/cm2 . Examination of lung fat accumulation was done through oil red O staining, while pro- to anti-inflammatory macrophage ratio was tested through CD11c and CD206 expressions by immunohistochemical method. RESULTS The high-calorie diet group had higher BMI (0.72 [0.02] versus 0.62 [0.03]; p<0.001), lung fat accumulation (32.73 [10.55] versus 0.37 [0.38]; p<0.001), and pro- to anti-inflammatory macrophage ratio (0.83 [0.02] versus 0.24 [0.006]; p<0.001). The higher the fat accumulation, the higher the pro- to anti-inflammatory macrophage ratio (r = 0.933; p<0.001). CONCLUSIONS The ratio of pro- to anti-inflammatory was higher in the high-calorie diet group, indicating polarization of macrophages toward pro-inflammatory macrophages. KEYWORDS high-calorie, lung, macrophages