Effects of chronic restraint stress in the prostate of prepubertal and adult rats

Purpose: To investigate the effects of chronic stress in the prostate of prepubertal and adult rats. Methods: Thirty-two male rats were assigned into four groups depending on the type of treatment (control or stressed) and the age at which stress was initiated (prepubertal or adult). Restraint stress stimuli were applied for six weeks. Stressed prepubertal and adult rats evaluated immediately after the last stress stimuli were named SP and SA groups, respectively. Age-matched rats were used as control groups (CP and CA). At the end of the experiment, the rats were euthanized, and prostate morphological parameters were evaluated and statistically compared. Results: Application of stress stimuli to the SP group resulted in reduced body weight, but no prostate morphological modification was noted. The SA group showed reduced testosterone level and prostatic epithelium surface density, in comparison to CA group. Further, the prostatic lumen surface density was increased in adult stressed animals, in comparison to adult controls. Conclusions: The stress stimuli promoted changes in hormonal and morphological parameters in the prostate of adult stressed rats. Prepubertal stressed animals did not presented modifications of prostate morphology.

Anatomic study of verumontanum during endoscopic surgeries in patients with benign prostatic hyperplasia

ABSTRACT Introduction and objective: To evaluate changes in verumontanum anatomy in patients with benign prostatic hyperplasia (BPH) who used 5-alpha reductase inhibitors (5-ARIs) and to propose an anatomical classification of the verumontanum. Materials and Methods: We studied 86 patients with BPH and 7 patients without the disease (age under 40 years-old who underwent kidney or ureteral lithotripsy). Of the patients with BPH, 34 (mean age=67.26) had 5-ARIs use and 52 (mean age=62.69) did not use the drug. During surgeries, photographs of the seminal colliculus were taken and later, with the aid of software (Image J), the length (longitudinal diameter) and width (transverse diameter) of the verumontanum were measured in all patients. During the procedure, we evaluated the different types of verumontanum. For statistical analysis, the R-Project software was used. Results: In the group of patients with BPH who were taking medication (group 1), the mean measures of length and width of the verumontanum were 4.69mm and 2.94mm respectively. In the group of patients with BPH who did not use the drug (group 2), the mean diameters were 4.54mm and 3.20mm respectively. In the control group (group 3), the average length and width were 5.63mm and 4.11mm respectively. There was an increase in longitudinal and transverse measurements of the control group with an increase in body mass index (BMI) (p=0.0001 and p=0.035 respectively). In addition, there was a reduction in transverse diameter in the group of BPH using 5-ARI with increased prostate volume (p=0.010). We found five different verumontanum types: "volcano" (51.61%), "lighthouse" (24.73%), "whale tail" (12.90%), "hood" (5.38%) and "castle door" (5.38%), which we propose as an anatomical classification. Conclusion: Veromontanum has smaller measurements in patients with BPH regardless of treatment. In the control group, there was an increase in verumontanum diameters with an increase in BMI. The volcano type of verumontanum was the most frequent regardless of groups and BMI.

Does treatment with dutasteride or finasteride has impact on renal morphology? Experimental study

ABSTRACT Purpose: To investigate whether renal modifications occur following treatment with dutasteride or finasteride. Methods: Twenty-four male rats were divided into three groups: control (that received distilled water), dutasteride (0.5 mg/kg/day), and finasteride (5 mg/kg/day) groups. All administrations were given by gavage for 40 consecutive days. After inducing euthanasia, blood was collected for urea and creatinine analyses, and both the kidneys were collected for stereological analyses of kidney morphology. Results: Serum urea and creatinine levels were increased in both the finasteride and the dutasteride groups compared with those in the control group. In addition, kidney weight, kidney volume, cortical volume, glomerular volumetric density, and mean glomerular volume were reduced in both treatment groups. Finally, the number of glomeruli per kidney was reduced by 26.8% in the finasteride group and by 51.6% in the dutasteride group compared with that in the control group. Conclusions: The 5-ARIs finasteride and dutasteride promoted morphological and functional damages in rat kidneys. In addition, rats in the dutasteride group showed more severe renal modifications than those in the finasteride group.

Histomorphometric comparison of the corpus cavernosum of rats submitted to euthanasia with ketamine and xylazine or isoflurane

ABSTRACT Purpose: To compare the penile histoarchitecture of rats euthanized with isoflurane or with ketamine and xylazine. Methods: Fourteen male rats were divided into two groups: ISO, with animals euthanized with isoflurane; and K+X, with animals euthanized with ketamine (150 mg/kg) associated with xylazine (15 mg/kg). Immediately after the death, the penises were dissected, fixed in a 4% buffered formalin solution, and processed for histomorphometric analysis. The surface densities (Sv) of the corpus cavernosum structures (connective tissue, smooth muscle, sinusoidal space, and elastic fibers) were evaluated using Image J software. The distribution of collagen types I and III was qualitatively assessed. Statistical analyses were performed using the Student's t test for data comparison, considering it statistically significant when p < 0.05. Results: Regarding the Sv of connective tissue, smooth muscle and sinusoidal space, there were no differences between animals in both groups. On the other hand, the animals euthanized with the association of ketamine and xylazine showed the Sv of elastic fibers 24.8% higher in relation to animals euthanized with isoflurane. Conclusions: The euthanasia method affected one of the morphological parameters of the rat penises. The choice of euthanasia method must be standardized to reduce bias and to obtain reliable and reproducible results.

Expression of stromal elements of prostatic adenocarcinoma in different gleason scores

Abstract Purpose: To quantify and compare the expression of stromal elements in prostate adenocarcinoma of different Gleason scores with non-tumor area (control). Methods: We obtained 132 specimens from samples of prostate peripheral and transition zone. We analyzed the following elements of the extracellular matrix: collagen fibers, elastic system, smooth muscle fibers and blood vessels. The tumor area and non-tumor area (control) of the TMA (tissue microarray) were photographed and analyzed using the ImageJ software. Results: The comparison between the tumor area and the non-tumor area showed significant differences between stromal prostate elements. There was an increase of collagen fibers in the tumor area, mainly in Gleason 7. Elastic system fibers showed similar result, also from the Gleason 7. Blood vessels showed a significant increase occurred in all analyzed groups. The muscle fibers exhibited a different behavior, with a decrease in relation to the tumor area. Conclusions: There is a significant difference between the extracellular matrix in prostate cancer compared to the non-tumor area (control) especially in Gleason 7. Important modifications of the prostatic stromal elements strongly correlate with different Gleason scores and can contribute to predict the pathological staging of prostate cancer.

Effect of a high-fat diet on the rat bladder wall and bioactive action of Brazil nut oil

ABSTRACT High-fat diet-induced obesity is associated with metabolic disorders. The Brazil nut has bioactive substances and has been used to control the damage caused by obesity in several organs. The work intended to show the damage caused by high-fat diet in the bladder wall and if the Brazil nut oil added to the diet could ameliorate or reverse this effect. Sixty-day-old rats were divided into two groups: C (control, n = 30) and HF (high-fat, n = 30) diets. At 90 days, 10 animals of each group were sacrificed. The others were divided into 4 groups: C and HF (animals that maintained their previous diet, n = 10 for each group) and C / Bno and HF / Bno (animals whose control or high-fat diet was supplemented by Brazil nut oil, n = 10 for each group). Sacrifice occurred at 120 days, and the bladders were removed and analyzed. Epithelial height was increased in the HF compared to the C group. In contrast, the C / Bno had a lower epithelial height compared to the others. The percentage of collagen between the detrusor muscle fibers was significantly greater in C / Bno, HF and HF / Bno than in control group. The HF had a larger muscle fiber diameter than the C group, while the C / Bno presented lower values than the HF and HF / Bno groups. HF diets induced bladder wall damage. These changes in the rat's bladder wall were partially reversed by the Bno.

The relationship between renal warm ischemia time and glomerular loss. An experimental study in a pig model

Abstract Purpose: To investigate the glomerular number after different warm ischemia times. Methods: Thirty two pigs were assigned into four groups. Three groups (G10, G20, and G30) were treated with 10, 20, and 30 minutes of left renal warm ischemia. The sham group underwent the same surgery without renal ischemia. The animals were euthanized after 3 weeks, and the kidneys were collected. Right kidneys were used as controls. The kidney weight, volume, cortical-medullar ratio, glomerular volumetric density, volume-weighted mean glomerular volume, and the total number of glomeruli per kidney were obtained. Serum creatinine levels were assessed pre and postoperatively. Results: Serum creatinine levels did not differ among the groups. All parameters were similar for the sham, G10, and G20 groups upon comparison of the right and left organs. The G30 group pigs' left kidneys had lower weight, volume, and cortical-medullar ratio and 24.6% less glomeruli compared to the right kidney. A negative correlation was found between warm ischemia time and glomerular number. Conclusions: About one quarter of glomeruli was lost after 30 minutes of renal warm ischemia. No glomeruli loss was detected before 20 minutes of warm ischemia. However, progressive glomerular loss was associated with increasing warm ischemia time.

Glomerular loss after arteriovenous and arterial clamping for renal warm ischemia in a swine model

ABSTRACT PURPOSE: To evaluate the glomerular loss after arteriovenous or arterial warm ischemia in a swine model. METHODS: Twenty four pigs were divided into Group Sham (submitted to all surgical steps except the renal ischemia), Group AV (submitted to 30 minutes of warm ischemia by arteriovenous clamping of left kidney vessels), and Group A (submitted to 30 minutes of ischemia by arterial clamping). Right kidneys were used as controls. Weigh, volume, cortical volume, glomerular volumetric density (Vv[Glom]), volume-weighted glomerular volume (VWGV), and the total number of glomeruli were measured for each organ. RESULTS: Group AV showed a 24.5% reduction in its left kidney Vv[Glom] and a 25.4% reduction in the VWGV, when compared to the right kidney. Reductions were also observed when compared to kidneys of sham group. There was a reduction of 19.2% in the total number of glomeruli in AV kidneys. No difference was observed in any parameters analyzed on the left kidneys from group A. CONCLUSIONS: Renal warm ischemia of 30 minutes by arterial clamping did not caused significant glomerular damage, but arteriovenous clamping caused significant glomerular loss in a swine model. Clamping only the renal artery should be considered to minimize renal injury after partial nephrectomies.

Nutritional supplementation with arginine protects radiation-induced effects. An experimental study

ABSTRACT PURPOSE: To investigate the protective effect of L-arginine on the prostate (nonneoplasic) of rats with radiation-induced injury. METHODS: Twenty-nine Wistar rats, male adult, allocated into three groups: Control group (C) was not exposed to irradiation (n=10); Radiated group (R) had undergone pelvic irradiation (n=10); Supplemented and radiated group (R+S) had undergone pelvic irradiation plus L-arginine supplementation (n=9). The animals were observed for signs of toxicity. After euthanization, the prostate was dissected under magnification and stained by hematoxylin and eosin to study acinar structures and stained with Picrosirius red for collagen analysis. RESULTS: After radiation exposure, all animals presented diarrhea, but supplementation with L-arginine reduced this effect. The weight gain in the R+S group was significantly higher than in the C and R groups. In the R+S group the collagen density and the prostate acinar area was similar to the R and C groups. Epithelial height was significantly reduced in group R compared with group C (p<0.0001). When comparing the group R+S with R, a statistical difference was observed to be present (p<0.0001). CONCLUSIONS: Pelvic radiation promotes systemic effects and some structural modifications in the ventral prostate of rats. These modifications can be prevented by oral supplementation with L-arginine.

Deleterious effects of prepubertal corticosterone treatment on rat prostate

PURPOSE:To investigate the structural and functional changes induced by corticosterone (CORT) in the ventral prostrate (VP) of rats in order to study chronic stress effects in the prepubertal phase.METHODS:Wistar rats received daily saline or CORT injections during the pubertal period from the 5th to 25th day of postnatal life. The animals were distributed into four groups: 1 - Control (n=5); 2 - Control 99mTc-P (n=5); 3 - Treated with CORT (n=14); 4 - Treated with CORT and 99mTc-P (n=10). All rats were sacrificed at two months of age. Technical tissue uptakes of 99mTc-P were used to evaluate the functional and stereological methods for morphological analysis.RESULTS:Acini distribution in the group treated with CORT differed significantly (p 0.0001) from the control. The control group's epithelial average height (10.01±0.24 microns) was statistically significant (p 0.0001) from rats treated with CORT (19.27±0.73microns). The collagen distribution was lower in the treated group (2.79%) when compared to control (3.97%). The radioactivity percentage in the groups marked with 99mTc-P (%Ati/g) did not demonstrate a statistically significant difference (p=0.285897).CONCLUSION:Chronic administration of corticosterone in prepubertal rats causes changes in their acinar structure and their ventral prostate stroma, indicating possible deleterious effects of this hormone.

Deleterious effects of prepubertal corticosterone treatment on rat prostate

PURPOSE: To investigate the structural and functional changes induced by corticosterone (CORT) in the ventral prostrate (VP) of rats in order to study chronic stress effects in the prepubertal phase. METHODS: Wistar rats received daily saline or CORT injections during the pubertal period from the 5th to 25th day of postnatal life. The animals were distributed into four groups: 1 - Control (n=5); 2 - Control 99mTc-P (n=5); 3 - Treated with CORT (n=14); 4 - Treated with CORT and 99mTc-P (n=10). All rats were sacrificed at two months of age. Technical tissue uptakes of 99mTc-P were used to evaluate the functional and stereological methods for morphological analysis. RESULTS: Acini distribution in the group treated with CORT differed significantly (p<0.0001) from the control. The control group's epithelial average height (10.01±0.24 microns) was statistically significant (p<0.0001) from rats treated with CORT (19.27±0.73microns). The collagen distribution was lower in the treated group (2.79%) when compared to control (3.97%). The radioactivity percentage in the groups marked with 99mTc-P (%Ati/g) did not demonstrate a statistically significant difference (p=0.285897). CONCLUSION: Chronic administration of corticosterone in prepubertal rats causes changes in their acinar structure and their ventral prostate stroma, indicating possible deleterious effects of this hormone. .

Structural study of endopelvic fascia in prostates of different weights. Anatomic study applied to radical prostatectomy

PURPOSE: To evaluate the structure of the endopelvic fascia in prostates of different weights. METHODS: We studied 10 patients with BPH (prostates>90g); 10 patients with prostate adenocarcinoma (PAC) (prostates<60g) and five young male cadavers (control group). During the surgery a small sample of endopelvic fascia was obtained. We analyzed elastic fibers, collagen and smooth muscle. The stereological analysis was done with the Image Pro and Image J programs. Means were statistically compared using the one-way ANOVA with the Bonferroni test and a p<0.05 was considered statistically significant. RESULTS: The mean of the prostate weight was 122 g in BPH patients, 53.1g in PAC patients and 18.6g in control group. Quantitative analysis documented that there are no differences (p=0.19) in Vv of elastic fibers and in Vv of type III collagen (p=0.88) between the three groups. There was a significant difference (p=0<0.0001) in the quantification of SMC in patients with prostates >90g (mean=9.61%) when compared to patients with prostates <60g (mean=17.92%) and with the control group (mean=33.35%). CONCLUSION: There are differences in endopelvic fascia structure in prostates>90g, which can be an additional factor for pre-operatory evaluation of radical prostatectomy. .

Scientific leaders for the future: primary and secondary education / Preparando lideranças científicas para o futuro: ensino médio e fundamental

Objective: To present a high school insertion pilot project in post graduate programs (PPG) and discuss the mechanisms for the formation of leaders in science. Methods: This study presents a review and pilot project. Bibliographic search occurred in sites of CAPES, MEC, SciELO and library of virtual books from January/ 2014 to February/2015. The pilot is in PPG-Medicine III Translational Surgery/UNIFESP and Pathophysiology and Surgical Sciences / UERJ. The junior undergraduate students (ICj) came from public school and develop scientific activities: scientific meetings, graduation and inclusion in research projects. The evaluation will occur at the end of one year, with the results essays, reports and participation in scientific events. Results: In Brazil, one of the main challenges of education is the high average years of study. The PNPG (2011-2020) shows the insertion of basic education in all PPG. In the Pathophysiology and Surgical Sciences/UERJ there are currently 11 high school students who have followed the scientific meetings and are being prepared for the inclusion in research projects. There was 30% of absence, owing to the high school hours. This result and the experience allow creating future alternatives to enhance the integration project. Conclusion: The leadership in science is formed from a complex relationship between basic education and investment in research. PPG-Medicine III courses follow the vanguard with initiatives focused on scientific and technological development. Thus, projects involving basic education students represent promoter model and environment leaders.

Objetivo: Apresentar um projeto piloto de inserção do ensino médio em programas de pós-graduação (PPG) e discutir os mecanismos para a formação de líderes em ciência. Métodos: Realizou-se um estudo de revisão e apresentação de piloto. A busca bibliográfica ocorreu nos sites da CAPES, MEC, Scielo e biblioteca de livros virtuais, de janeiro/2014 a fevereiro/2015. O piloto ocorre nos PPG-Medicina III em Cirurgia Translacional/UNIFESP e Fisiopatologia e Ciências Cirúrgicas/UERJ. Os alunos de iniciação científica júnior (ICj) são oriundos de escola pública e desenvolvem atividades científicas: participação em reuniões científicas, graduação e inserção nos projetos de pesquisa. A avaliação ocorrerá ao final de um ano, com redações dos resultados, relatórios e participações em eventos científicos. Resultados: No Brasil, um dos principais desafios da educação é a alta média de anos de estudo. O PNPG (2011-2020) apresenta a inserção da educação básica em todos os PPG. Na Fisiopatologia e Ciências Cirúrgicas/UERJ há atualmente 11 alunos do ensino médio, que já acompanharam as reuniões científicas e preparam-se para a inserção em projetos de pesquisa. Houve 30% de desistência, devido à alta carga horária escolar. Esse resultado e a experiência vivenciada permite criar alternativas futuras para aprimorar o projeto de inserção. Conclusão: A liderança em ciências é formada a partir de uma complexa relação entre educação básica e investimentos na pesquisa. Cursos de PPG-Medicina III seguem na vanguarda com iniciativas focadas no desenvolvimento científico e tecnológico. Assim, projetos envolvendo alunos da educação básica representam modelo e ambiente promotor de líderes.

Structural changes of dilated pelvic ureters in adults

PURPOSE: To perform a quantitative assessment of different types of pelvic ureter tissues with chronic dilation in adults, using stereological methods. METHODS: We analyzed fragments of dilated pelvic ureters obtained from 6 patients aged between 35 and 67 years (mean, 46 years) who underwent ureteral reimplantation surgery for different reasons. The obstruction duration ranged from 27 to 180 days (mean, 93 days). The control group included fragments of normal pelvic ureters obtained during nephrectomy in 7 kidney transplant donors (age: range, 25-51 years; mean, 36 years). The volumetric density of collagen in the ureter, elastic fibers, and smooth muscle fibers was assessed. RESULTS: The volumetric density (Vv) of collagen showed no significant difference between the two groups (control: 45.3 ± 6.1; dilated: 40.8 ± 6.9; P = 0.23). A statistically significant increase in Vv of elastic fibers was observed in the dilated ureters (control: 18.4 ± 1.2; dilated: 24.6 ± 5.4; P = 0.03). A statistically significant increase in the Vv of smooth muscle fibers was observed in the dilated ureter (control: 42.0 ± 6.0; dilated: 56.2 ± 6.1; P = 0.001). CONCLUSION: The chronically dilated pelvic ureters had significantly more elastin and smooth muscle contents than the controls. .

Lard and/or canola oil-rich diets induce penile morphological alterations in a rat model

PURPOSE: To investigate the effect of dietary lipid quantity and/or quality on penis morphology in adult rats. METHODS: Thirty-eight male Wistar rats were divided into 4 groups: normal lipid diet (NL), high-fat diet rich in saturated fatty acids (HF-S), high-fat diet rich in polyunsaturated fatty acids (HF-P), and high-fat diet rich in saturated and polyunsaturated fatty acids (HF-SP). Blood samples were collected and the penises were removed for histomorphometrical and immunohistochemical analysis. RESULTS: All high-fat diets promoted an increase in the body mass (p<0.0001). The HF-S and HF-SP groups presented hyperglycemia (p=0.0060), hyperinsulinemia (p=0.0030), and hypercholesterolemia (p=0.0020). Concerning the penis, the high-fat diets led to an increase in the collagen fibers (p<0.0001) and smooth muscle cell density area (p=0.0027), and a decline in the sinusoidal space density area (p<0.0001) and corpus cavernosum cell proliferation (p=0.0003). CONCLUSION: Diets rich in saturated and/or polyunsaturated fatty acids promoted overweight and induced penile changes in rodent models, which may lead to the development of erectile dysfunction. .

Age-dependent expression of Pten and Smad4 genes in the urogenital system of Wistar rats

PURPOSE: To analyze Pten and Smad4 gene expression in the urogenital system of Wistar rats in differents ages. METHODS: Pten and Smad4 mRNA expression was assessed in the bladder, ventral prostate, testis, ovaries, and uterus by real-time PCR. Statistical analysis using the ANOVA (p<0.05). RESULTS: Pten levels showed a progressive age-dependent increase in the bladder (male and female) and prostate and were elevated in the ovaries of the middle-aged. In the uterus, no statistically significant differences were observed; in the testis, increased and decreased levels were seen in young adult and middle-aged rats, respectively. Smad4 expression was downregulated in the ovaries of the pubertal group but increased in the middle age group. In the uterus, Smad4 expression in the oldest group was higher than the others groups. In the testis, Smad4 expression steadily declined with age; in the prostate, it was higher in middle-aged rats than in younger rats. A similar trend was observed in the bladder of male and female middle-aged rats, compared with the pubertal group. CONCLUSION: The changes in phosphatase tensin homologue and Smad4 mRNA expression in Wistar rats appear to be associated with hormonal modifications in puberty and may be related to early follicular and testicular development. .

The prostate after administration of anabolic androgenic steroids: a morphometrical study in rats

Purpose Many adverse effects have been associated with abuse of anabolic-androgenic steroids (AAS), including disorders of the urogenital tract. The objective of this study is to analyze the morphological modifications in the prostate ventral lobe of pubertal and adult rats chronically treated with AAS, using morphometric methods. Materials and Methods: We studied 39 male Wistar rats weighing between 400 g and 550 g. The rats were divided into four groups: (a) control rats, with 105 days of age (C105) (n = 7); (b) control rats with 65 days of age (C65) (n = 9), injected only with the vehicle (peanut oil); (c) treated rats, with 105 days of age (T105) (n = 10) and (d) treated rats with 65 days of age (T65) (n = 13). The treated rats were injected with nandrolone decanoate at a dose of 10 mg.Kg-1 body weight. The steroid hormone and the vehicle were administered by intramuscular injection once a week for eight weeks. The rats were killed at 161 days of age (C105 and T105) and 121 days of age (C65 and T65) and the ventral prostate lobe was dissected and processed for histology. The height of the acinar epithelium, the surface densities of the lumen, epithelium and stroma were observed with X400 magnification using an Olympus light microscope coupled to a Sony CCD video camera, and the images transferred to a Sony monitor KX14-CP1. The selected histological areas were then quantified using the M42 test-grid system on the digitized fields. The data were analyzed with the Graphpad software. To compare the quantitative data in both groups (controls and treated) and the outcomes, Student's t-test was used (p < 0.05 was considered significant). Results: The weight (p < 0.001) and volume (p = 0.004) of the prostate ventral lobe showed differences between C65 and T65 groups and between C105 and T105 groups. The epithelium height showed no difference between groups C65 and T65 (p = 0.8509), but the T105 group showed an increase of 32% compared ...

Pneumoperitoneum induces morphological alterations in the rat testicle

PURPOSE:To investigate the seminiferous tubule histological morphology after an 8 mmHg pneumoperitoneum in the rat model. METHODS: Fourteen rats were divided into two groups: a Sham group submitted to anesthesia and a pneumoperitoneum (Pp) group submitted to abdominal insufflation at 8 mmHg during three hours, followed by desuflation. All rats were killed after six weeks, testicles were collected and evaluated for the tubule diameter, germinative epithelium height and Johnsen´s score. Means were compared by using the Student's-t-test. RESULTS:The seminiferous tubule diameter was diminished by 11.3% in the group submitted to pneumoperitoneum (p<0.05). No significant difference was found among the groups when analyzing the epithelium height and Johnsen´s score. CONCLUSION:In the rat model, the seminiferous tubules present structural alterations when subjected to pneumoperitoneum of 8 mmHg during three hours.

Age-related changes in the concentration of elastic fibers in different regions of the rabbit penis

PURPOSE: To investigate whether elastic fiber content in the corpus cavernosum (CC), corpus spongiosum (CS) and tunica albuginea (TA) of the rabbit penis undergoes modifications with age. METHODS: Rabbits were sacrificed, in groups of ten animals each, at 30, 120, 240, and 730 days of age. Histological sections were obtained from the penile middle shaft and were stained with Weigert's resorsin fuchsin. The content of elastic fibers was determined using stereological methods, and was expressed as volume fraction. RESULTS: At 730 days of age, elastic fiber content was increased by 54% (p<0.004), 78% (p<0.004), and 87% (p<0.004) in the TA, CC, and CS, respectively, compared with animals aged 30 days. After 30 days of age, the concentration gradually and significantly increased until 240 days of age. In 730-day old animals, the concentration, compared with the previous age group, was unchanged in the CC and decreased by 20% (p<0.004) in the TA. CONCLUSIONS: Elastic fiber contents in the rabbit penis correlate with properties of penile tissues. Although after one month of age there is a gradual increase in these concentrations, in two-year old animals this trend is interrupted, which suggests that this could be an early alteration due to senescence.