Swimming training induces liver adaptations to oxidative stress and insulin sensitivity in rats submitted to high-fat diet

Figures & data

Table 1. Composition and energy content of diets.

Ingredients (g/kg)	Control AIN-93	High-fat diet
Corn starch	620.70	–
Sucrose	100.00	–
Fructose	–	33.0
Casein	140.00	180.50
Condensed milk	–	316.00
Soybean oil	40.00	–
Lard	–	370.00
Fiber (cellulose)	50.00	50.00
Wheat bran	–	–
Mineral mix (AIN-93G-MX)*	–	35.00
Mineral mix (AIN-93M-MX)*	35.00	–
Vitamin mix (AIN-93G-VX)*	10.00	10.00
dl-Methionine	1.80	3.00
Choline chloride	2.50	2.50
Macronutrients (% by weight)
Carbohydrate	72.07	20.68
Fat	4.00	39.53
Protein	14.00	20.26
Macronutrients (% kcal)
Carbohydrate	75.82	15.92
Fat	9.46	68.48
Protein	14.72	15.60
kcal/g	3.80	5.19
kJ/g	15.91	21.73

Composition of diets (g/kg) consumed by rats that started the experiment at 4 weeks of age and for 13 weeks.

*See Reeves et al. [47].

Table 2. Rat Genome Database (RGD) accession numbers and primer sequences of genes selected for qRT-PCR.

Gene	Accession number (RGDID)	Primer sequence (5′–3′)
Rn18s	5687330	F GTAAGTGCGGGTCATAAG R CCATCCAATCGGTAGTAGC
Insr	2917	F CCTTGGATCGTTCCTCTCAC R GGTCCGTTTGATGCTCAGAG
Irs-1	2922	F TGAGAGCGGTGGTGGTAAGC R GGGCTGCTGGTGTTGGAATC
Irs-2	69316	F GCAGGACTTTCCCAGTGAACG R GCCACACCACATTCGCATG
AKT-2	2082	F GGAGGTCATGGAGCATCGGTTC R GTTTGAAGGGTGGCAGGAGC
Slc2a4	2711	F GGTGCCTTGGGAACACTCAAC R TGCAGGAGAGCAGGGAGTACTG
Pparγ	3371	F CGTGAAGCCCATCGAGGACATC R TCTGGAGCACCTTGGCGAACAG

Primers used (Forward and Reverse).

Table 3. Biometric, biochemical and cardiovascular parameters of rats fed a control diet (CT) or a high-fat diet (FAT), and submitted to physical training (PT) or kept sedentary (SED).

	CT diet		FAT diet
	SED	PT	SED	PT
Total cholesterol (mmol/l)	1.8 ± 0.03	1.7 ± 0.08	2.1 ± 0.03*	1.8 ± 0.07
ALT (U/l)	54.2 ± 1.2	62.4 ± 3.1	68.2 ± 3.4*	70.0 ± 3.5*
AST (U/l)	8.1 ± 2.2	14.9 ± 4.3	5.3 ± 1.8	11.1 ± 3.1
Albumin (µmol/l)	4.1 ± 0.1	4.1 ± 0.06	4.1 ± 0.08	4.06 ± 0.09
Glycemia (mmol/l)	6.2 ± 0.2	6.5 ± 0.3	7.2 ± 0.1*	6.6 ± 0.2
Insulin (ng/ml)	1.3 ± 0.2	1.5 ± 0.3	2.4 ± 0.1*	1.4 ± 0.2
Lactate (mmol/l)	9.41 ± 1.2	10.2 ± 2.4	16.9 ± 0.9*	8.03 ± 0.2^#
MAP (mmHg)	109 ± 5.8	125 ± 5.2	147 ± 5.7*	107 ± 11.7^#
HR (beats/min)	369 ± 7.8	338 ± 27.5	435 ± 7.2*	384 ± 4.6^#
Liver (g/100 g body mass)	3.3 ± 0.08	3.2 ± 0.04	3.0 ± 0.05	3.0 ± 0.04
Retroperitoneal fat (g/100 g body mass)	1.66 ± 0.1	1.49 ± 0.1	3.42 ± 0.1*	2.5 ± 0.09^#
Body mass (g)	287 ± 3.6	263 ± 6.1	336 ± 9.6*	289.6 ± 9^#
N	5–6	5–6	5–6	5–6

Fischer rats fed a high-fat diet (30% fat, FAT) or a control diet (AIN-93, CT) for 13 weeks and submitted to physical training (PT) or maintained sedentary (SED) during the last 6 weeks of diet. ALT, alanine aminotransferase; AST, aspartate aminotransferase.

*P < 0.05 compared to CT-SED group.

^#P < 0.05 compared to FAT- SED group (two-way ANOVA followed by Bonferroni post-test).

Figure 1. (A) Activity of enzyme superoxide dismutase (SOD, U/mg protein; n = 5–6), (B) activity of the enzyme catalase (CAT, U/mg protein, n = 9–13), (C) reduced glutathione (GSH, nmol/ml, n = 5–11), (D) oxidized glutathione (GSSG, nmol/ml, n = 7–12) and (E) GSH/GSSG ratio (n = 5–9) in liver of rats fed a high-fat diet (30% fat, FAT) or a control diet (AIN-93, CT) for 13 weeks and submitted to physical training (PT), or maintained sedentary (SED) during the last 6 weeks of the diet. *P < 0.05 compared to CT-SED group. ^#P < 0.05 compared to FAT-SED group (two-way ANOVA followed by Bonferroni post-test).

Figure 2. (A) Concentrations of malondialdehyde (MDA, U/mg of protein; n = 5–10) by concentrations of thiobarbituric acid-reactive substances (TBARS) method and (B) carbonyl proteins (nmol/mg of protein, n = 6) in the liver of rats fed a high-fat diet (30% fat, FAT) or a control diet (AIN-93, CT) for 13 weeks and submitted to physical training (PT) or maintained sedentary (SED) during the last 6 weeks of the diet. *P < 0.05 compared to CT-SED group. ^#P < 0.05 compared to FAT-SED group (two-way ANOVA followed by Bonferroni post-test).

Figure 3. Evaluation of gene expression (U.A.) of insulin signaling pathway mediators (n = 3–4) and peroxisome proliferator-activated receptor gamma (PPARγ, n = 4) in the liver of rats fed a high-fat diet (30% fat, FAT) or a control diet (AIN-93, CT) for 13 weeks and submitted to physical training (PT) or maintained sedentary (SED) during the last 6 weeks of the diet. (A) Insulin receptor (IR), (B) Insulin receptor substrate 1 (IRS-1), (C) Insulin receptor substrate 2 (IRS-2) (D) serine/threonine kinase 2 (AKT-2), (E) glucose transporter type 4 (GLUT4), (F) peroxisome proliferator-activated receptor gamma (PPARγ). *P < 0.05 compared to CT-SED group. ^#P < 0.05 compared to FAT-SED group (two-way ANOVA followed by Bonferroni post-test).

Figure 4. Photomicrographs of liver stained with hematoxylin and eosin (HE). Arrow indicates microvesicular steatosis, and arrowhead indicates macrovesicular steatosis. (A) Rat fed with a control (CT) diet and maintained sedentary (SED). (B) Rat submitted to a control (CT) diet and physical training (PT). (C) Rat submitted to a high-fat (FAT) diet and maintained sedentary (SED). (D) Rat submitted to a high-fat (FAT) diet and physical training (PT). Magnification 440×. Bar = 50 μ. Qualitative evaluation of macrovesicular steatosis (E) and microvesicular steatosis (F) in liver tissue, using a grade from absent to mild, moderate or intense.

Reeves PG, Nielsen FH, Fahey GC. AIN-93 purified diets for laboratory rodents: final report of the American Institute of Nutrition ad hoc writing committee on the reformulation of the AIN-76A rodent diet. J Nutr. 1993;123(11):1939–1951.

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