Effects of Chronic Stress on Food Preference and Penile Morphology in Rats
Authors: Gregorio Bianca M. , Marchon Roger G. , Sampaio Francisco José B. , Costa Waldemar S. , Ferreira Filho José Aurelino D. , de Souza Diogo B. 
Published: May 2022

Hypothesis

Chronic stress is related to raised desires of comfort foods and these factors (stress and high energetic diets) may alter the penile morphology.

Aim

To evaluate the effects of chronic stress on the dietetic preference and to evaluate both factors (diet and stress) on the penile morphology of adult rats.

Methods

Thirty two adult Wistar rats were divided into four experimental groups: Control group (C), receiving standard rat chow, and under normal conditions; Control/Comfort Food group (CF), receiving standard chow and comfort food (Froot Loops®), and under normal conditions; Chronic Stress group (S), receiving standard chow, and submitted to stressful situations; Chronic Stress/Comfort Food (SCF), receiving standard chow and comfort food, and submitted to stressful situations. The experiments initiated when animals completed three months of age. All groups had ad libitum access to standard rat chow and water, and groups receiving comfort food also had access to Froot Loops®. The chronic stress was induced by restriction, animals were daily contained in polypropylene tubes for two hours, for eight weeks. Body mass and food intake were checked weekly and daily, respectively. After eight weeks all animals were killed, and the penis were removed and fixed. The penile middle shaft was processed for paraffin embedding and used for histomorphometric analysis. Penile area, corpus cavernosum (with and without tunica albuginea) was measured, and the surface densities (Sv) of cavernosal tissues were quantified. Data were analyzed by One‐Way Anova with post‐test of Bonferroni, considering p<0.05.

Results

Body mass were similar among the groups. However, food intake in S and SCF groups were lower than in C group (↓23% and ↓26%, P<0.0001, respectively). Concerning food preference, the CF and SCF groups presented high consumption (↑24% and ↑58%, P<0.0001) of the comfort food in comparison to standard diet, being the comfort food intake higher in the SCF group (↑19% P<0.0001). Regarding penile morphology, the penile area and corpus cavernosum area (with and without tunica albuginea) were lower in group S in comparison to CF group. The connective tissue Sv of group S was 13% and 9% higher than in groups C and CF, respectively. Also, group SCF had 10% higher connective tissue Sv in comparison to group C. Regarding the smooth muscle Sv, groups S and SCF had lower densities (reductions of 47% and 39%, respectively) in comparison to group C. This reduction (of 38%) was also showed when comparing SCF to CF groups. Differences on sinusoidal space Sv was only noted among groups S and C, with a reduction of 27% in stressed animals.

Conclusion

Chronic stress reduces food intake even when highly palatable foods are available. Stressed animals consume more comfort food than non‐stressed animals. Chronic stress induces morphological modifications in penile area and in corpus cavernosum structure with possible impact in erectile function. By the other hand, the consumption of comfort foods during stressful periods ameliorated (but not prevented) the penile morphological modifications induced by stress.