Diets rich in saturated and polyunsaturated fatty acids induce morphological alterations in the rat ventral prostate

Abstract

Aim: To evaluate the influence of dietary lipid quality on the body mass, carbohydrate metabolism and morphology of the rat ventral prostate.

Materials and methods: Wistar rats were divided into four groups: SC (standard chow), HF-S (high-fat diet rich in saturated fatty acids), HF-P (high-fat diet rich in polyunsaturated fatty acids) and HF-SP (high-fat diet rich in saturated and polyunsaturated fatty acids). We analyzed body mass, fat mass deposits, plasma blood, insulin resistance and the ventral prostate structure.

Results: Groups that received high-fat diets were heavier and presented larger fat deposits than SC group. The HF-S and HF-SP groups had higher glucose, insulin and total cholesterol serum levels and insulin resistance compared with the SC. The acinar area, epithelium height and area density of the lumen were higher in the HF-SP than in the other groups. The epithelium area density and epithelial cell proliferation were greater in the HF-P and HF-SP than in the SC group. All of the groups that received high-fat diets had greater area density of the stroma, area density of smooth muscle cells and stromal cell proliferation compared with the SC group.

Conclusion: Diets rich in saturated and/or polyunsaturated fatty acids induced overweight. Independently of insulin resistance, polyunsaturated fatty acids increased prostate stromal and epithelial cell proliferation. Saturated fatty acids influenced only stromal cellular proliferation. These structural and morphometric alterations may be considered risk factors for the development of adverse remodeling process in the rat ventral prostate.

Figure 1. The acinar area changes caused by lard and canola oil on rat ventral prostate.

HF-SP (a high-fat diet rich in saturated and polyunsaturated fatty acid) (D) resulted in a greater acinar area than the other diets. (A) SC, standard chow diet; (B) HF-S, a high-fat diet rich in saturated fatty acid (lard) and (C) HF-P, a high-fat diet rich in polyunsaturated fatty acid (canola oil). The symbol [a] indicates a result that is different from the SC group, [b] indicates a result that is different from the HF-S group and [c] indicates a result that is different from the HF-P group (one-way ANOVA and Bonferroni’s post hoc test, p<0.05). H&E staining, 200x.

Figure 2. Epithelial height changes caused by lard and canola oil on rat ventral prostate.

HF-SP, a high-fat diet rich in saturated and polyunsaturated fatty acid) (D) resulted in higher epithelial cell height than the other diets. (A) SC, standard chow diet; (B) HF-S, a high-fat diet rich in saturated fatty acid (lard) and (C) HF-P, a high-fat diet rich in polyunsaturated fatty acid (canola oil). The symbol [a] indicates a result that is different from the SC group, [b] indicates a result that is different from the HF-S group and [c] indicates a result that is different from the HF-P group (one-way ANOVA and Bonferroni’s post hoc test, p<0.05). H&E staining, 600x.

Figure 3. Morphological changes caused by different high-fat diets.

(A) SC, standard chow diet produced no prostate alterations; (B) HF-S, a high-fat diet rich in saturated fatty acid (lard) caused an increase in the area density of the connective tissue and the smooth muscle cells; (C) HF-P, a high-fat diet rich in polyunsaturated fatty acid (canola oil) promoted an increase in the area density of the epithelium, the connective tissue and the smooth muscle cells; (D) HF-SP, a high-fat diet rich in saturated and polyunsaturated fatty acids induced an increase in the area density of the lumen, the epithelium, the connective tissue and the smooth muscle cells. The symbol [a] indicates a result that is different from the SC group, [b] indicates a result that is different from the HF-S group and [c] indicates a result that is different from the HF-P group (one-way ANOVA and Bonferroni’s post hoc test, p<0.05). H&E staining and immunostaining for Alpha Smooth Muscle Actin, 200x.

Figure 4. PCNA-positive cells in the epithelium and stroma of the rat ventral prostate.

(A) SC, standard chow diet, (B) HF-S, high-fat diet rich in saturated fatty acid (lard), (C) HF-P, high-fat diet rich in polyunsaturated fatty acid (canola oil) and (D) HF-SP, high-fat diet rich in saturated and polyunsaturated fatty acids. The symbol [a] indicates a result that is different from the SC group (one-way ANOVA and Bonferroni’s post hoc test, p<0.05). Immunostaining for Proliferating Cell Nuclear Antigen- PCNA, 600x.