The photoperiod and heat stress effects on histometrical structure of rat prostate gland

Background: there is not enough information about the effects of heat stress and photoperiod on different lobes structure. objectives: the present study aims at determining the histological changes and the rate of changes in each lobes of rat prostate, affected by photoperiod changes and heat stress. methods: to this end, 15 adult male wistar rats were divided to three groups: 1. the control group in which the rats were kept in 12l: 12d and 25°c temperature condition, 2. the heat stress group in which the rats were kept in 12l: 12d and 42+1 °c temperature condition for 4 to 5 hours per day, and 3. the photoperiod group in which the rats were kept in 16l: 8d and 25°c temperature condition. after 30 days, samples were taken from different lobes and sections with 5 to 6µ thickness were made and stained by h&e and pas. results: the microscopic results showed that histomorphometrical structure and histochemical reactions of the different lobs of normal prostate of the rats are different. the proportion of parenchyma to stroma decreased by heat stress; however, it increased by photoperiod. the maximum changes were seen in ventral lobe. the epithelial thickness, lumen diameter, and number of secretory units also increased by photoperiod (16l:8d), but it decreased by heat stress. the number of secretory cells were increased by heat stress because the cell size decreased; however, they decreased by long photoperiod regime. the number of folded secretory units increased by photoperiod, while heat stress has an adverse effect (p < 0.001). the serum testosterone increased by long photoperiod and decreased by heat stress (p < 0.01). conclusions: this study shows that long photoperiod has important effects on increasing the rat prostate parenchyma and its activity.