ABC | Volume 113, Nº5, November 2019

Original Article Muniz et al. Metabolic disorders in a modified dyslipidemia model Arq Bras Cardiol. 2019; 113(5):896-902 Table 2 – Body and liver weight and biochemical parameters of Wistar rats after six weeks of treatment with standard and high-fat diets Parameter Diet STD HLD HL/HCD Body weight (g) Initial 249.05 ± 21.44 a 243.85 ± 15.09 a 242.35 ± 16.78 a Final 499.58 ± 65.32 a 564.08 ± 39.73 a 508.58 ± 47.68 a Gain 250.53 ± 48.40 b 320.23 ± 44.50 a 266.23 ± 38.21 a,b Liver Weight (g) 14.90 ± 2.33 b 15.92 ± 1.65 b 27.10 ± 5.94 a Relative weight (g/100g body weight) 2.98 ± 0.24 b 2.82 ± 0.14 b 5.28 ± 0.80 a Serum lipid profile (mg/dL) TC 59.83 ± 15.99 b 64.58 ± 14.13 b 87.75 ± 8.54 a LDL-c 4.23 ± 0.71 b 6.98 ± 2.09 b 23.63 ± 4.55 a HDL-c 30.74 ± 4.11 a 34.42 ± 7.77 a 26.74 ± 4.23 a non-HDL-c 29.09 ± 12.13 b 30.17 ± 10.84 b 61.01 ± 6.95 a VLDL-c 10.68 ± 1.58 b 16.77 ± 4.58 a,b 18.52 ± 7.51 a TG 53.42 ± 7.91 b 83.83 ± 22.90 a,b 92.58 ± 37.55 a Liver enzymes (U/L) ALT 48.72 ± 15.91 b 28.16 ± 6.00 b 210.30 ± 137.78 a AST 154.67 ± 22.42 b 117.00 ± 29.84 b 300.63 ± 60.26 a Data are expressed as mean ± standard deviation. a,bValues in the same row with different superscript letters are significantly different (Tukey test, p < 0.05). STD: standard diet; HLD: high-lard diet; HL/HCD: high-lard and high-cholesterol diet; Relative liver weight = (liver weight/body weight) x 100; TC: total cholesterol; LDL-c: low-density lipoprotein cholesterol; HDL-c: high-density lipoprotein cholesterol; VLDL-c: very low-density lipoprotein cholesterol; TG: triacylglycerol; non‑HDL-c: non-high-density lipoprotein cholesterol; ALT: alanine aminotransferase; AST: aspartate aminotransferase. of inflammatory infiltrates with a Leica Las V4 Software (Leica Imaging Systems Ltd., Cambridge, UK), a Leica DM2000 microscope (Leica Microsystems Wetzlar GmbH, Wetzlar, Switzerland), a Leica DC230 video camera (Leica Microsystems AG, Heerbrugg, Switzerland), and an online computer. Twenty fields of hepatic parenchyma of each animal were randomly selected and analyzed, at 100x and 400x magnification. Statistical analysis Data were expressed as mean ± standard deviation. The literature considers bodyweight and biochemical parameters obtained in animal models as parametric data. 8-12 Thus, we determined statistical significance using the one-way analysis of variance (ANOVA), followed by Tukey test for mean comparisons (p<0.05). STATISTICA software, version 7.0 (StatSoft, Inc., Tulsa, OK, USA) was used for statistical analyses. Results The lard used in the formulation of diets contained 39 g/100 g of saturated fat and 72 mg/100 g of cholesterol. In high-fat diets (HLD and HL/HCD), lard contributed with approximately 15 mg of cholesterol/100 g of diet, besides the cholesterol added to theHL/HCD. Forty-four percent (44%) of theHLD and HL/HCD energy derived from lipids, a value four times higher than that of STD (11%). The initial body weight of the animals did not differ among the groups, ensuring the homogeneity of group repetitions. Animals fed HLD showed higher body weight gain than those from the STD group. Liver weight and relative liver weight of animals fed HL/HCD were higher (p < 0.05) than those of other groups (Table 2). Animals fed HL/HCD showed higher TC, TG, LDL-c, VLDL-c, non-HDL-c, ALT, and AST serum levels than those from STD and HLD groups. Serum lipid profile and liver enzymes of animals fed HLD were not different from those of the STD group (Table 2). We found microscopic changes (Figure 1) in the liver of animals fed HL/HCD, as the hepatic tissue architecture was not preserved, with hepatocyte ballooning (characterized by swelling and/or vacuolation), alterations in sinusoidal blood capillaries, and passive hyperemia (capillaries and veins engorged with blood). In addition, rats fed HL/HCD presented moderate macrovesicular hepatic steatosis associated with a marked infiltration by lymphomononuclear cells. On the other hand, animals fed HLD had their hepatic tissue architecture preserved, containing hepatocytes with usual morphological aspect, and preserved vascular distribution, centrilobular vein, and portal triad. Furthermore, the HLD group showed mild microvesicular hepatic steatosis associated with lower infiltration by lymphomononuclear cells. The hepatic tissue architecture of the STD group was maintained with typical hepatocytes, preserved 898