Prostate apoptosis after doxazosin treatment in the spontaneous hypertensive rat model

Effects of the dutasteride and sildenafil association in the penis of a benign prostatic hyperplasia animal model

OBJECTIVE

The aim of this study was to investigate whether concomitant treatment of dutasteride and sildenafil could prevent structural changes in the penis of a BPH rodent model.

METHODS

Thirty-two adult male rats were divided into the following groups: Ctrl, untreated control rats; BPH, untreated spontaneously hypertensive rats (SHRs); BPH + D, SHRs treated with dutasteride; and BPH + DS, SHRs treated with dutasteride and sildenafil. All treatments were performed during 40 days, following which the penises were collected for histomorphometrical analysis. The results were compared via one-way ANOVA with Bonferroni's post-test, considering p values <.05 as significant.

RESULTS

The smooth muscle density decreased by 28.6% and 21.4% in BPH + D and BPH + DS, respectively, when compared to the BPH group. The sinusoid space density reduced by 32.2% in BPH, when compared to the Ctrl group; this density was also reduced by 22.6% in BPH + D, when compared to the BPH group. The density of the elastic fibers increased 51.6% and 65.6% in BPH + D and BPH + DS, when compared to the BPH group.

CONCLUSION

Treatment with dutasteride promoted morphological changes in the corpus cavernous of this BPH model. Concomitant treatment with sildenafil did not prevent the morphological changes caused by dutasteride; on the contrary, it also promoted a further increase in elastic fibers.

Sustained density of neuroendocrine cells with aging precedes development of prostatic hyperplasia in spontaneously hypertensive rats

BACKGROUND

Neuroendocrine (NE) cells may have an impact on the development and initial growth of benign prostatic hyperplasia (BPH) according to previous human studies.

METHODS

To explore the relationship of NE cells and BPH development, we compared the density of NE cells and also prostatic weight in spontaneously hypertensive rats (SHR), which develop by aging, and Wistar-Kyoto rats (WKY) as control. The total weights of the epithelium and stroma in the ventral lobes of 8-, 12, 16-, 28- and 56-week-old SHR and WKY were calculated using Image J software. NE cells in the ventral prostatic ducts (VPd) were quantified using immunohistochemical staining for serotonin.

RESULTS

Although there was no significant difference in the estimated total weight of the epithelium and stroma in the ventral lobes adjusted by body weight (ES weight) between the two groups at 8, 12 and 16 weeks of age, ES weight was significantly greater in the SHR group than in the WKT group at 28 and 56 weeks. The density of NE cells in the VPd decreased with aging in the WKY group, whereas it was sustained until 16 weeks and then decreased with aging in the SHR group. The difference in the density between the two groups was most marked at 16 weeks of age.

CONCLUSION

In the natural history of BPH, NE cells may play an important role in the initial development of BPH because sustained density of NE cells in the VPd precedes the development of prostatic hyperplasia.

The corpus cavernosum after treatment with dutasteride or finasteride: A histomorphometric study in a benign prostatic hyperplasia rodent model

Erectile dysfunction is a common side effect of finasteride and dutasteride treatments. The objective of this study was to investigate the structural changes in the penis using a benign prostatic hyperplasia (BPH) rodent model treated with dutasteride or finasteride. Sixty male rats were divided into the following groups: C, untreated control rats; C + D, control rats receiving dutasteride; C + F, control rats receiving finasteride; H, untreated spontaneously hypertensive rats (SHRs); H + D, SHRs treated with dutasteride; and H + F, SHRs treated with finasteride. Treatments were performed for 40 days, and penises were collected immediately thereafter. The organs were analyzed using histomorphometric methods to determine the cross-sectional penile area, as well as the surface density (Sv) of smooth muscle fibers, connective tissue, elastic system fibers, and sinusoidal spaces of the corpus cavernosum. The results were compared using a one-way ANOVA with Bonferroni's posttest. Groups C + D and C + F had a significantly smaller penile cross-sectional area, but more elastic system fiber Sv compared to Group C. Group C + D showed less smooth muscle Sv, and Group H showed more connective tissue but a smaller sinusoidal space Sv in the corpus cavernosum compared to Group C. Groups H + D and H + F had less smooth muscle Sv than Group H. Group H + D also had more connective tissue and elastic system fiber Sv than Group H. Both dutasteride and finasteride promoted penile modifications in the control rat penis, although this affect was greater in Group H animals. In this rodent model, dutasteride was the drug that most affected the corpus cavernosum.

Influence and pathophysiological mechanisms of simvastatin on prostatic hyperplasia in spontaneously hypertensive rats

OBJECTIVE

To explore the effects and mechanisms of simvastatin on prostate hyperplasia in spontaneously hypertensive rats (SHRs).

METHODS

Thirty-six male SHRs were randomly divided into three groups: the 10 and the 20 mg/kg/d simvastatin group and the control group. After 6 weeks the ultra-microscopic prostate structures were observed. The serum levels of interleukin-6 (IL-6), insulin-like growth factor (IGF-1) and angiotensin II (Ang-II) were measured by enzyme-linked immunosorbent assays. The endothelium-derived nitric oxide synthase (eNOS) expression was evaluated with immunohistochemistry.

RESULTS

Compared to the control group, the 20 mg/kg/d simvastatin group presented with lower absolute (p = 0.005) and relative prostate weight (p = 0.009). The basal cells and columnar cells presented with edema, condensed heterochromatin in interstitial fibroblast nuclei, widened nucleus gaps, and decreased mitochondria and endoplasmic reticulum in the 10 mg/kg/d simvastatin group, these changes were more pronounced in the 20 mg/kg/d simvastatin group. The IL-6 levels in the 10 and 20 mg/kg/d simvastatin groups were lower than those of the controls (p = 0.005 and p = 0.008). The IGF-1 levels of the 20 mg/kg/d simvastatin group were reduced compared to the control group (p = 0.016).

CONCLUSIONS

Simvastatin can delay and inhibit prostatic hyperplasia and progression in SHR. These actions may be mediated through the suppression of inflammatory and growth factors.

Terazosin treatment induces caspase-3 expression in the rat ventral prostate

BACKGROUND

Quinazoline-based alpha1-adrenergic receptor antagonists may not act solely on smooth muscle contractility. We evaluated the in vivo effect of terazosin on the expression of caspase-3 in the rat ventral prostate.

METHODS

Fifteen Wistar rats were treated with terazosin (1.2 mg/kg body weight, given orally every second day) for 120 days. Another 15 control animals received the same amount of distilled water. The expression of caspase-3 was assessed immunohistochemically in formalin-fixed, paraffin-embedded tissue sections.

RESULTS

Terazosin treatment did not affect prostate weight and histomorphology. In controls caspase-3 was expressed weakly and sporadically. In contrast, strong and weak expression was evident in 67% and 33% of the terazosin-treated specimens, respectively.

CONCLUSIONS

These findings implicate the induction of caspase-3 expression by terazosin as a potential molecular mechanism of its apoptotic action on prostate cells.

Angiotension II receptor 1 blocker modifies the expression of apoptosis-related proteins and transforming growth factor-beta1 in prostate tissue of spontaneously hypertensive rats

OBJECTIVE

To assess whether angiotensin II (Ang II), important in hypertension and highly expressed in benign prostatic hyperplasia (BPH), is involved in prostate growth, by analysing changes in the histological composition, tissue apoptotic status and level of transforming growth factor-beta1 (TGFbeta1) induced by an Ang II type 1 receptor blocker, losartan, in the prostates of spontaneously hypertensive (SH) rats.

MATERIALS AND METHODS

We assessed four groups of six rats each: normotensive Wistar-Kyoto counterparts of SH rats; untreated SH rats; SH rats given low-dose losartan (10 mg/kg/day for 10 weeks); and SH given high-dose losartan (30 mg/kg/day for 10 weeks). We evaluated the histological composition and expression of TGFbeta1 and apoptosis-related proteins, i.e. Bax and the 116-kDa poly (adenosine diphosphate-ribose) polymerase (PARP), by Western blotting in the rat prostate ventral lobes.

RESULTS

Compared with Wistar-Kyoto rats, untreated SH rats had a significantly increased epithelium component in the prostate (P < 0.01), but with losartan treatment, SH rats showed less of the epithelium component than untreated rats (P < 0.01 for both low- and high-dose losartan). Western-blot analysis showed a significantly increased level of Bax in high-dose losartan-treated rats (P < 0.01). The expression of 116 kDa PARP was also decreased in these rats (P < 0.01), which suggests increased caspase-3 activity. In addition, TGFbeta1 levels were significantly elevated in high-dose losartan-treated rats (P < 0.01).

CONCLUSION

These results show that losartan can induce apoptosis of prostate epithelium and increase the TGFbeta1 expression in SH rats, suggesting that Ang II stimulation might be involved in the pathogenesis of BPH, which might correlate with the regulation of TGFbeta1 expression.

Quinazoline α1-Blockers: Are there any News about their Efficacy in Inhibiting Prostate Tumor Growth?

α1-adrenoceptor agonists have recently been recognized as growth factors for several cell types, including both stromal smooth muscle- and epithelial cells of the prostate gland, by triggering off a cascade of intracellular signal transduction pathway that controls cell proliferation. On the contrary, quinazoline α1 -blockers (doxazosin, terazosin, prazosin) inhibit cell kinetics and induce, above all, anoikis and apoptotic death of both stromal smooth muscle- and epithelial cells, through α1 -adrenoceptor-indipendent mechanisms, thus preventing or delaying prostate tumor growth.