Effects of physical exercise in biochemical parameters and dorsolateral prostate lesions: data from a rat model of prostate cancer

Abstract

Prostate cancer (PCa) is among the most prevalent cancers worldwide. Physical exercise is widely recognized due to its beneficial effects. This study aimed to evaluate the effects of physical exercise on biochemical parameters and in dorsolateral prostate lesions in a rat model of PCa. Ninety-five male Wistar Unilever rats were randomly divided into eight groups sacrificed at 35 (groups I) or 61 weeks of age (groups II): control sedentary groups (Cont+Sed I (n=10); Cont+Sed II (n=10)); induced sedentary group (PCa+Sed I (n=10); PCa+Sed II (n=15)); control exercised groups (Cont+EX I (n=10); Cont+EX II (n=10)) and induced exercised groups (PCa+EX I (n=10); PCa+EX II (n=20)). All procedures were approved (DGAV, no. 021326). Animals from exercised groups started the exercise program in a treadmill at 8 weeks of age, for 28 weeks or 53 weeks. The animals were trained 5 days/week, 60 min per day. Prostate lesions were induced at 12 weeks of age, with sequential administration of flutamide, testosterone propionate and N-methyl-N-nitrosourea, and subcutaneous implants of crystalline testosterone. Animals were sacrificed at 35 or 61 weeks of age. Peripheral blood of all animals was collected by intracardiac puncture. A complete necropsy was performed. The dorsolateral prostate tissues sections were processed for histological analysis. Data were analysed using SPSS 25. p<0.05 were considered statistically significant. Serum levels of albumin and cholesterol were higher in group PCa+Sed I when compared with group PCa+Sed II (p<0.05). Testosterone levels were higher in exercised groups when compared with sedentary ones, in both control and PCa groups I and II (p<0.05). No differences were observed in the remaining parameters (p>0.05). Dorsolateral prostate lesions were classified as dysplasia, prostatic intraepithelial neoplasia (PIN) and microinvasive carcinoma. The number of prostate lesions was higher in animals from groups II than in those from groups I, mainly in PCa+Sed II animals when compared with PCa+Sed I (p<0.05). Conversely, the PIN frequency was higher in group PCa+EX II than in group PCa+Ex I (p<0.05). Although the differences were not statistically significant, the animals from group PCa+Ex II showed a slight decrease in the frequency of lesions than the PCa+Sed II group (p>0.05). Overall, the animals sacrificed at 61 weeks of age developed more dorsolateral prostate lesions than animals sacrificed at 35 weeks of age, which may be related to a longer testosterone exposure.