| Background and Objective:The prostate gland in both man and rat is richly innervated with adrenergic and cholinergic nerve fibers. It receives both sympathetic and parasympathetic neural input. Sympathetic input is supplied by the hypogastric nerve, while parasympathetic input is furnished by the pelvic nerve. Adrenergic fibers functionally innervate the stroma, and cholinergic ones innervate the epithelium. The potential involvement of the sympathetic nervous system in the pathogenesis of benign prostatic hyperplasia has recently attracted scientific interest. Experimental denervation of the prostate induces atrophic changes of the acini as well as a decrease in their secretory activity. Moreover,α-adrenergic antagonists have been used for the treatment of BPH for many years.Stress can effect the function of almost all organ systems, most likely due to production and release of several humoral factors. The sympathetic nervous system and hypothalamic-pituitary-adrenal axis have been known to reactive to psychological factors such as stress. Growing data suggests that stress conditions could be associated with the development or aggravation of prostatic disease including prostatis and benign prostatic hyperplasia. The present study aims to investigate the influence of chronic stress and blockade of sympathetic nerve on rat prostate.Materials and Methods:Male Wistar rats (90 days of age) purchased from Animal Center of Shandong University were used. We used the model of Vaalasti A et al. of chemical sympathectomy with 6-hydroxydopamine (6-OHDA) on the ventral prostate of the rat and restraint water-immersion stress (WIRS) on rats. The rats were divided into four groups of eight rats each as follows. A: an untreated control group. B: In this group rats were under WIRS 1h/d for 2 weeks. C: On the day 1 and 8, 6-OHDA was administered with a dose of 50mg/kg i.v. D: WIRS daily plus 6-OHDA on day 1 and 8 as above. The experiment was terminated at 14 days. Blood flow of ventral prostate, plasma catecholamine and cortisol were measured. The weight and secretions of dissected prostate lobes were measured and histology was performed by hematoxylin and eosin stain. Immunohistochemical staining of nerve growth factor (NGF) was also investigated.Results:After 14 days' stress, the blood flow of ventral prostate decreased and plasma cortisol increased. The level of catecholamine in rat blood had no significant change after chronic stress or denervation of peripheral sympathetic nerve. Chronic stress resulted in loses of tissue weight and secretions of the ventral lobes of the rat prostatic complex, while tissue weight of ventral prostate was also reduced in 6-OHDA treated rats. In the WIRS group, the apparent proliferation of epithelium of ventral lobes were observed and dorsolateral ones were almost unaffected. On the other hand, the hyperplasia changes were not seen after the chemical sympathectomy had been done during stress.NGF immunoreactive protein localized to the columnar secretory epithelium lines of prostate tissue. Stress increased NGF expression in ventral lobes. Denervation led to significant decreation of NGF level in ventral and lateral lobes. Stress after denervation increased expression of NGF.Conclusions:Chronic stress may induce epithelial proliferation of ventral prostate in rats, the overactivity of sympathetic nervous system is involved in the pathogenesis of prostatic disease. NGF has a mitogenic effect on prostate. It is involved in the hyperplasia and atrophy in prostate of male rat in response to chronic stress and denervation. |
PDF Full Text Request