Animal models for benign prostatic hyperplasia

Comparative effects of finasteride and laser-irradiated silver nanoparticles on testicular function and histology in testosterone induced benign prostatic hyperplasia in rats

AIMS

The objective of this study was to compare the effects of finasteride, a medication used to treat benign prostatic hyperplasia (BPH), and laser irradiated silver nanoparticles (AgNPs), a potential candidate for BPH therapy (Sanchez-Salas, 2017; Marghani et al., 2022) [1,2], on the sex hormone profiles, sperm quality, steroidogenesis, testicular oxidative stress, and histomorphology changes in BPH rats.

MATERIALS AND METHODS

BPH was induced in male Sprague-Dawley (SD) rats via intramuscular (i.m.) injection of 5 mg/kg BW testosterone propionate (TP) for 14 days. Once the BPH model was induced, rats were divided into four groups (n = 6) as follows: the control group; the BPH group; the BPH/Fina group, which received 5 mg/kg BW finasteride by oral gavage daily for 14 days; and the BPH/AgNPs group, which received a daily intraperitoneal (i.p.) injection of 50 mg/kg BW AgNPs, followed by 5 min of exposure to a 532 nm NIR laser in the prostatic area for the constitutive 14 days.

KEY FINDINGS

On day 14, the BPH rats had a significant increase in prostate specific antigen (PSA), dihydrotestosterone, and prostate weights, while testicular weights and sperm quality were significantly lower than in the control rats. On day 28, laser irradiated AgNps treated BPH rats showed improved sex hormone balance, testicular weights, sperm quality, steroidogenesis, and an ameliorative effect on testicular histopathology compared to finasteride.

SIGNIFICANCE

Surprisingly, these findings suggest that laser irradiated AgNPs can be used as an alternative therapy to finasteride for the treatment of BPH without causing negative effects on the testes.

First-Principles Model to Evaluate Quantitatively the Long-Life Behavior of Cellulose Acetate Polymers

A deep understanding of the degradation of cellulose diacetate (CDA) polymer is crucial in finding the appropriate long-term stability solution. This work presents an investigation of the reaction mechanism of hydrolysis using electronic density functional theory calculations with the B3LYP/6-31++G** level of theory to determine the energetics of the degradation reactions. This information was coupled with the transition-state theory to establish the kinetics of degradation for both the acid-catalyzed and noncatalyzed degradation pathways. In this model, the dependence on water concentration of the polymer as a function of pH and the evaporation of acetic acid from the polymer is explicitly accounted for. For the latter, the dependence of the concentration of acetic acid inside the films with the partial pressure on the surrounding environment was measured by sorption isotherms, where Henry's law constant was measured as a function of temperature. The accuracy of this approach was validated through comparison with experimental results of CDA-accelerated aging experiments. This model provides a step forward for the estimation of CDA degradation dependence on environmental conditions. From a broader perspective, this method can be translated to establish degradation models to predict the aging of other types of polymeric materials from first-principles calculations.

Piperazine-Derived α1D/1A Antagonist 1- Benzyl-N- (3-(4- (2-Methoxyphenyl) Piperazine-1-yl) Propyl) -1H- Indole-2- Carboxamide Induces Apoptosis in Benign Prostatic Hyperplasia Independently of α1-Adrenoceptor Blocking

Previous studies have indicated that α_1D/1A antagonist naftopidil (NAF) suppresses prostate growth by decreasing cell proliferation without affecting apoptosis and prostate volume in benign prostatic hyperplasia (BPH). A NAF-derived α1D/1A antagonist 1- benzyl-N-(3-(4-(2-methoxyphenyl) piperazine-1-yl) propyl)-1H-indole-2- carboxamide (HJZ-12) has been reported from our laboratory, which exhibits high subtype-selectivity to both α_1D- and α_1A- AR (47.9- and 19.1- fold, respectively) with respect to a1B-AR in vitro. However, no further study was conducted. In the present study, a pharmacological evaluation of HJZ-12 in BPH was performed on an estrogen/androgen-induced rat BPH model and human BPH-1 cell line. In vivo, HJZ-12 exhibited better performance than NAF in preventing the progression of rat prostatic hyperplasia by not only decreasing prostate weight and proliferation (similar to NAF) but also, shrinking prostate volume and inducing prostate apoptosis (different from NAF). In vitro, HJZ-12 exhibited significant cell viability inhibition and apoptotic induction in BPH-1 cell line, without presenting cell anti-proliferation properties. Intriguingly, the role of HJZ-12 on cell viability and apoptosis was an α1-independent action. Furthermore, RNA-Seq analysis was applied to screen out six anti-apoptotic genes (Bcl-3, B-lymphoma Mo-MLV insertion region 1 [Bmi-1], ITGA2, FGFR3, RRS1, and SGK1). Amongst them, Bmi-1 was involved in the apoptotic induction of HJZ-12 in BPH-1. Overall, HJZ-12 played a remarkable role in preventing the progression of prostatic hyperplasia through α1-independent apoptotic induction, indicating that it will be a multi-target effective candidate for BPH treatment.

The role of the androgen receptor in prostate development and benign prostatic hyperplasia: A review

Benign prostatic hyperplasia (BPH) is a benign enlargement of the prostate in which incidence increases linearly with age, beginning at about 50 years old. BPH is a significant source of morbidity in aging men by causing lower urinary tract symptoms and acute urinary retention. Unfortunately, the etiology of BPH incidence and progression is not clear. This review highlights the role of the androgen receptor (AR) in prostate development and the evidence for its involvement in BPH. The AR is essential for normal prostate development, and individuals with defective AR signaling, such as after castration, do not experience prostate enlargement with age. Furthermore, decreasing dihydrotestosterone availability through therapeutic targeting with 5α-reductase inhibitors diminishes AR activity and results in reduced prostate size and symptoms in some BPH patients. While there is some evidence that AR expression is elevated in certain cellular compartments, how exactly AR is involved in BPH progression has yet to be elucidated. It is possible that AR signaling within stromal cells alters intercellular signaling and a "reawakening" of the embryonic mesenchyme, loss of epithelial AR leads to changes in paracrine signaling interactions, and/or chronic inflammation aids in stromal or epithelial proliferation evident in BPH. Unfortunately, a subset of patients fails to respond to current medical approaches, forcing surgical treatment even though age or associated co-morbidities make surgery less attractive. Fundamentally, new therapeutic approaches to treat BPH are not currently forthcoming, so a more complete molecular understanding of BPH etiology is necessary to identify new treatment options.

Protective effect of black mulberry (Morus nigra L.) fruit hydroalcoholic extract against testosterone-induced benign prostatic hyperplasia in rats

BACKGROUND

Finding new agents for prevention and/or treatment of benign prostatic hyperplasia (BPH) especially from natural sources is a demanding field.

OBJECTIVES

This study aimed to evaluate the effect of black mulberry (BM) (Morus nigra) fruit hydroalcoholic extract on the establishment of BPH in rats.

MATERIALS AND METHODS

Forty-nine adult male rats were randomly assigned into 7 equal groups: I: Sham control (SC), a sham surgery was performed. II: positive control (PC), rats were castrated and received testosterone propionate, at 10mg/kg/day S.C. for BPH induction. III: comparative control (CC), BPH was induced and the rats received finasteride at 5mg/kg/day P.O. IV-VII: (T1-T4): BPH was induced and the rats received BM extract at 25, 50, 100 and 200mg/kg/day P.O. for 4 consecutive weeks.

RESULTS

Finasteride and/or BM extract especially at the two higher dosages, significantly affected prostate weight, prostatic index, percent of inhibition, serum and prostatic levels of dihydrotestosterone (DHT), serum prostate-specific antigen (PSA), antioxidant parameters of prostatic tissue as well as histopathological and histomorphometric parameters (epithelial thickness and acinar area) of prostate.

CONCLUSIONS

BM extract has protective effects against experimentally-induced BPH in rats with regard to histopathological and biochemical parameters which may be related to its antioxidant as well as DHT reducing properties in prostatic tissue.

The α1-adrenoceptor-mediated human hyperplastic prostate cells proliferation is impaired by EGF receptor inhibition

Benign prostatic hyperplasia (BPH) is an aging-related and progressive disease linked to an up-regulation of α₁-adrenoceptors. The participation of EGF receptors (EGFR) in the GPCRs' signalosome has been described but so far data about the contribution of these receptors to prostatic stromal hyperplasia are scanty. We isolated and cultured vimentin-positive prostate stromal cells obtained from BPH patients. According to intracellular Ca²⁺ measurements, cell proliferation and Western blotting assays, these cultured hyperplastic stromal cells express functional α_1-adrenoceptors and EGFR, and proliferate in response to the α_1-adrenoceptor agonist phenylephrine. Interestingly, in these cells the inhibition of EGFR signaling with GM6001, CRM197, AG1478 or PD98059 was associated with full blockage of α₁-adrenoceptor-mediated cell proliferation, while cell treatment with each inhibitor alone did not alter basal cell growth. Moreover, the co-incubation of AG1478 (EGFR inhibitor) with α_1A/α_1D-adrenoceptor antagonists showed no additive inhibitory effect. These findings highlight a putative role of EGFR signaling to α₁-adrenoceptor-mediated human prostate hyperplasia, suggesting that the inhibition of this transactivation cascade could be useful to reduce BPH progression.

The role of prostaglandin and E series prostaglandin receptor type 4 receptors in the development of bladder overactivity in a rat model of chemically induced prostatic inflammation

OBJECTIVES

To evaluate, using a rat model of non-bacterial prostatic inflammation, the prostaglandin production and expression profiles of E-series prostaglandin (EP) receptor subtypes, which are reportedly implicated in the development of overactive bladder, in the bladder mucosa, and to investigate the effect of EP receptor type 4 (EP4) blockade on bladder overactivity after prostatic inflammation.

METHODS

Male Sprague-Dawley rats were used. Prostatic inflammation was induced by formalin injection (5%; 50 μL per lobe) into the bilateral ventral lobes of the prostate. At 10 days after induction of prostatic inflammation or vehicle injection, bladder tissues from the deeply anaesthetized rats were harvested and separated into mucosal and detrusor layers. Then, prostaglandin E2 (PGE2) concentrations and protein levels of PGE2 receptors (EP1-4) in the bladder mucosa and detrusor were measured by ELISA and Western blotting, respectively. In separate groups of control and formalin-treated rats, awake cystometry was performed to evaluate the changes in bladder activity after prostatic inflammation. In addition, the effect of intravesical administration of a selective EP4 antagonist (ONO-AE3-208; 30 μm) on bladder activity was evaluated in control rats and rats with prostatic inflammation.

RESULTS

PGE2 concentration and protein levels of EP4, but not other EP receptor subtypes, in the bladder mucosa and detrusor layers were significantly increased in formalin-injected rats vs vehicle-injected control rats. In cystometry, rats with prostatic inflammation exhibited a significant decrease in intercontraction intervals (ICIs) compared with control rats. Intravesical application of ONO-AE3-208 (30 μm), but not vehicle application, significantly increased ICIs in rats with prostatic inflammation, whereas ONO-AE3-208 at this concentration did not significantly affect any cystometric values in control rats.

CONCLUSIONS

Because intravesical administration of an EP4 antagonist effectively improved bladder overactivity after prostatic inflammation, EP4 activation, along with increased PGE2 production in the bladder mucosa, seems to be an important contributing factor to bladder overactivity induced by prostatic inflammation. Thus, blockade of EP4 in the bladder could be a therapeutic approach to male lower urinary tract symptoms attributable to benign prostatic hyperplasia with prostatic inflammation.

A single low dose of cadmium exposure induces benign prostate hyperplasia like condition in rat: A novel benign prostate hyperplasia rodent model

Abnormal prostate growth is the most prevalent pathological sign in aged human males, as reflected by high incidence of benign prostate hyperplasia (BPH) and prostate cancer. In spite of the high prevalence, the etiology and pathophysiology of BPH is unclear due to the lack of any established rodent model for study. It has been demonstrated that the cadmium (Cd) mimics the activity of androgen or estrogen by interacting with the steroid hormone receptors in the prostate and elicits BPH, but the specific receptor which binds to Cd is still unknown. Our lab studies with BPH patients highlighted a strong co-relation between smokings with increased Cd content. Changes in the maximum urinary flow rate (Qmax) and prostatic acid phosphatase (PAP) level further supports that Cd can induce BPH like condition. Therefore, the present study was aimed to induce BPH like condition in rats by Cd administration. The dose of cadmium was standardized in an age- and time-dependent manner, which was further examined by prostate weight, histology, and PAP levels that elucidated the pathogenesis of BPH. Further to understand the molecular basis, steroid hormone receptor antagonist experiment was performed. Gene expression and immunohistochemistry data suggest that Cd induces hyperplasia like condition by activating the androgen receptor and estrogen receptor-α and suppresses the action of estrogen receptor-β. The experimental model used here is a cost effective, less time consuming and potentially valuable tool for investigating the respective functions of epithelial and stromal hormone receptors. The applicability of this model would be helpful in understanding the pathogenesis of BPH and its progression.

Tamsulosin modulates, but does not abolish the spontaneous activity in the guinea pig prostate gland

AIMS

To examine the effects of the α1A -adrenoceptor antagonist, tamsulosin, on spontaneous contractile and electrical activity in the guinea-pig prostate gland.

METHODS

The effects of tamsulosin (0.1 and 0.3 nM) were investigated in adult and ageing male guinea pig prostate glands using conventional tension recording and electrophysiological intracellular microelectrode recording techniques.

RESULTS

Tamsulosin reduced spontaneous activity, and had different age-dependent effects on adult and ageing guinea pigs at different concentrations. 0.1 nM tamsulosin caused a significantly greater reduction of spontaneous contractile and electrical activity in ageing guinea pigs in comparison to adult guinea pigs. In contrast, 0.3 nM tamsulosin had a significantly greater reduction of spontaneous contractile and electrical activity in adult guinea pigs in comparison to ageing guinea pigs.

CONCLUSIONS

This study demonstrates that tamsulosin can modulate spontaneous myogenic stromal contractility and the underlying spontaneous electrical activity; tamsulosin does not block spontaneous activity. This reduction in spontaneous activity suggests that downstream cellular mechanisms underlying smooth muscle tone are being targeted, and these may represent novel therapeutic targets to better treat benign prostatic hyperplasia.

Pharmacological characterization of N1-(2-methoxyphenyl)-N4-hexylpiperazine as a multi-target antagonist of α1A/α1D-adrenoceptors and 5-HT1A receptors that blocks prostate contraction and cell growth

Benign prostatic hyperplasia (BPH) is a progressive disease related to the imbalance of cell growth and apoptosis, and it plays a key role in the development of lower urinary tract symptoms (LUTS). The main pharmacological treatment is based on α1A-adrenoceptor blockers, but in several cases monotherapy has failed. Recent studies of prostate pathophysiology have noted the role of α1D-adrenoceptors and 5-HT1A receptors in prostate cell proliferation in addition to the usual role of α1A-adrenoceptors in prostate contraction. N-phenylpiperazine is a scaffold structure that may confer drug affinity for these three receptors. Therefore, the present work aimed to investigate the pharmacological characteristics of N1-(2-methoxyphenyl)-N4-hexylpiperazine (LDT66). Using isometric contraction assays with rat prostate and aorta, LDT66 reduced phenylephrine-induced contractions and showed K B values of 3.4 and 2.2 nM for α1A- and α1D-adrenoceptors, respectively. According to the functional binding assays data, LDT66 showed a high affinity (nanomolar range) for the 5-HT1A receptors, behaving as an antagonist. LDT66 also showed a low affinity (micromolar range) for receptors unrelated to BPH such as α1B-adrenoceptors, α2A-adrenoceptors, muscarinic and 5-HT2A receptors, which is a desirable profile in order to prevent putative side effects. Accordingly, LDT66 (100 μg/kg) showed a marginal hypotensive effect. Using the DU-145 prostate cells, control experiments characterized the α1D-adrenoceptor- and 5-HT1A receptor-mediated cell growth by phenylephrine and 5-HT, respectively. LDT66 (50 nM) prevented both effects similarly. In conclusion, LDT66 is a high-affinity multi-target antagonist of relevant receptors for BPH, and it may be a new starting point for multi-target drug development to treat BPH and LUTS.

Contractile signaling pathways in mouse prostate smooth muscle

BACKGROUND

Prostate smooth muscle plays an important role in the physiological ejection of prostatic fluid and also in the pathogenesis of benign prostate hyperplasia. Although mouse is the best genetically engineered animal model to identify potential molecular targets for human diseases, only fragmentary information is available for basic mechanism of mouse prostate contraction.

METHODS

Small smooth muscle tubular rings were excised from four mouse prostate lobes to measure their isometric contractions. High K(+) , noradrenaline (NA), or acetylcholine (ACh) was applied with and without various antagonists and/or inhibitors to examine the contractile signaling pathways.

RESULTS

Maximum amplitude of agonist-induced contractions varied greatly with different lobes but not with different locations or orientations within each lobe. Both NA and ACh produced large contractions in ventral and dorsal rings, whereas only small contractions were elicited in lateral and anterior rings. Combination of alpha-1 and muscarinic antagonists suppressed K(+) depolarization-induced contraction potently in ventral rings, but slightly in anterior rings. Blocking of either Ca(2+) -release or Ca(2+) -influx reduced agonist-induced contraction of ventral rings, however, a considerable amount of contractility remained even with both blockers. Inhibitors of ROCK and PKC partially inhibited NA-induced contractions, whereas a combination of Ca(2+) -blockers and Ca(2+) -sensitization inhibitors strongly suppressed the contraction.

CONCLUSIONS

The ejection of prostatic fluid is differentially regulated in each prostate lobe. In ventral prostate smooth muscle, Ca(2+) -release, Ca(2+) -influx, and ROCK- and PKC-mediated Ca(2+) -sensitizations are all involved in NA-induced contractions. This finding is a useful step toward the understanding of the phenotypic changes in the smooth muscle of BPH prostate.

A Hoxb13-driven reverse tetracycline transactivator system for conditional gene expression in the prostate

BACKGROUND

Genetically engineered mouse models play important roles in analyses of prostate development and pathobiology. While constitutive genetic gain- and loss-of-function models have contributed significantly to our understanding of molecular events driving these processes, the availability of a tightly regulated inducible expression system could extend the utility of transgenic approaches. Here, we describe the development of a Tet-regulatory system that employs Hoxb13 transcriptional control elements to direct reverse tetracycline transactivator (rtTA) expression in the prostate.

METHODS

Using recombineering technology, the rtTA gene was placed under Hoxb13 cis-regulatory transcriptional control in the context of a 218-kb bacterial artificial chromosome. F(1) offspring carrying the Hoxb13-rtTA transgene were bred to a Tetracycline operator-Histone 2B-Green Fluorescent Protein (TetO-H2BGFP) responder line. Detailed reporter gene expression analyses, including doxycycline (Dox) induction and withdrawal kinetics, were performed in Hoxb13-rtTA|TetO-H2BGFP double transgenic adult mice and embryos.

RESULTS

Dox-dependent GFP expression was observed exclusively in the prostate and distal colon epithelia of double transgenic mice. Reporter gene mRNA was detected in the prostate within 6 hr of Dox exposure, and was extinguished within 24 hr after Dox withdrawal. Furthermore, Dox-induced reporter gene expression persisted after castration.

CONCLUSIONS

The Hoxb13-rtTA transgenic system provides a powerful tool for conditional Tet operator-driven transgene expression in the normal prostate and during disease progression. Used in conjunction with other prostate pathology models, these mice will enable precise, temporally controlled analyses of gene function and can provide opportunities for detailed analyses of molecular events underlying prostate diseases.

Combining growth hormone-releasing hormone antagonist with luteinizing hormone-releasing hormone antagonist greatly augments benign prostatic hyperplasia shrinkage

PURPOSE

Benign prostatic hyperplasia often affects aging men. Antagonists of the neuropeptide growth hormone-releasing hormone reduced prostate weight in an androgen induced benign prostatic hyperplasia model in rats. Luteinizing hormone-releasing hormone antagonists also produce marked, protracted improvement in lower urinary tract symptoms, reduced prostate volume and an increased urinary peak flow rate in men with benign prostatic hyperplasia. We investigated the influence of a combination of antagonists of growth hormone-releasing hormone and luteinizing hormone-releasing hormone on animal models of benign prostatic hyperplasia.

MATERIALS AND METHODS

We evaluated the effects of the growth hormone-releasing hormone antagonist JMR-132, given at a dose of 40 μg daily, the luteinizing hormone-releasing hormone antagonist cetrorelix, given at a dose of 0.625 mg/kg, and their combination on testosterone induced benign prostatic hyperplasia in adult male Wistar rats in vivo. Prostate tissue was examined biochemically and histologically. Serum levels of growth hormone, luteinizing hormone, insulin-like growth factor-1, dihydrotestosterone and prostate specific antigen were determined.

RESULTS

Marked shrinkage of the rat prostate (30.3%) occurred in response to the combination of growth hormone-releasing hormone and luteinizing hormone-releasing hormone antagonists (p<0.01). The combination strongly decreased prostatic prostate specific antigen, 6-transmembrane epithelial antigen of the prostate, interleukin-1β, nuclear factor-κβ and cyclooxygenase-2, and decreased serum prostate specific antigen.

CONCLUSIONS

A combination of growth hormone-releasing hormone antagonist with luteinizing hormone-releasing hormone antagonist potentiated a reduction in prostate weight in an experimental benign prostatic hyperplasia model. Results suggest that this shrinkage in prostate volume was induced by the direct inhibitory effects of growth hormone-releasing hormone and luteinizing hormone-releasing hormone antagonists exerted through their respective prostatic receptors. These findings suggest that growth hormone-releasing hormone antagonists and/or their combination with luteinizing hormone-releasing hormone antagonists should be considered for further development as therapy for benign prostatic hyperplasia.