Rat corpus cavernosum differs from that of humans by lesser amounts of smooth muscle cells, greater amounts of collagen and the presence of fibrillar collagen and smooth muscle cell subendothelial layers. Therefore, these differences should be considered when using the rat penis for studies on erection.

Objective To analyse the histological components of the transition zone in both normal human prostate and benign prostatic hyperplasia (BPH), and to determine the volumetric density (

OBJECTIVETo report a quantitative and qualitative histological analysis of spongiosum tissue in patients with bulbar urethral strictures. MATERIALS AND METHODSUrethral specimens from 15 patients who had end-to-end anastomotic urethroplasty were evaluated; the control group comprised five bulbar urethras from cadavers. The collagen content, elastic fibres, smooth muscle and vessels were analysed using stereological methods. RESULTSThere was complete loss of the relationship between smooth muscle, extracellular matrix and sinusoids in the peri-luminal area (PLA), with collagen replacement. The extension of the fibrotic area was greater in those with a traumatic than in those with an atraumatic stricture. The content of smooth muscle and collagen in the peripheral spongiosum (PS) area was similar for the stricture and control groups, and results were comparable for traumatic and atraumatic groups and those with suprapubic cystostomy diversion or not before surgery. There was a remarkably lower vascular density in the traumatic than in the atraumatic group. There was an increase in type III collagen in the PLA and in type I collagen in the PS; collagen type III in the PLA was greater in the group with no suprapubic cystostomy diversion before surgery. There were fewer elastic fibres in both stricture areas (PLA and PS) than in the control group. CONCLUSIONSUrethral stricture formation is characterized by marked changes in extracellular matrix features, with consequent changes in organ function.

This paper verifies the morphological changes induced by immobilization stress on the kidney of rats by using stereological methods. Fifteen 4-week-old Wistar male rats were randomly assigned to control (n = 7) and stressed (n = 8) groups. Stress stimuli were performed over 5 weeks by immobilization of the rats for 2 h daily in a rigid opaque plastic cylinder that restrained their movements. Increases in the adrenal mass index (p < 0.05) and decreases in serum testosterone levels (p < 0.05) demonstrated the efficacy of the stressor stimuli. Stressed rats presented diminished body weight gain when compared to controls (p < 0.05). The mean values of kidney weight, kidney volume, kidney volume index and glomerular volume density were significantly lower in the stressed group (p < 0.05); nevertheless, no significant difference was found in the cortical/medullar ratio or in the volume-weighted mean glomerular volume. The number of glomeruli per kidney was 45% lower in the stressed group (p < 0.0001), but no change in serum creatinine levels was found. However, the morphological alterations may have serious implications predisposing individuals to renal disease and hypertension in adult life.

Intravaginal torsion is the most frequent type, and torsion due to long mesorchium is associated with cryptorchism. The most frequently found anatomical relation between testis and epididymis in the study group was Type I.

In patients with ED there was a statistically significant reduction in the percentage of elastic fibres, but no statistically significant difference in collagen and smooth muscle fibres, and no appreciable differences in collagen distribution between the groups.

The corpus cavernosum (CC) extracellular matrix is essential for normal penile erection and is implicated in erectile dysfunction. Although investigations of these issues have used the rabbit CC, organization of its components is not well known to date. We characterized and quantified the volumetric density (Vv) of the elastic system fibers in the corpus spongiosum (CS), CC and tunica albuginea (TA) of the rabbit penis. Adult New Zealand rabbits (n ¼ 10) were used. The penile midshaft fragments were fixed with 4% phosphate-buffered formalin solution and/or Bouin's liquid for 24-48 h, and processed using standard histological techniques. The sections were stained with Weigert's Fucsin-Resorcin with previous oxidation. The elastic system fibers Vv (%) was determined in 25 random fields of each fragment, using the M-42 test grid. The histochemical methods detected elastic system fibers in CS, CC and TA of all animals. The Vv of elastic fibers average was 25.0372.0% for CC, 32.2371.41% for CS and 22.3873.61% for TA. Results for CC and CS were not significantly different. The great amount of elastic fibers distribution beneath the endothelium suggest that these fibers may have an important role in the erection process in rabbits. The present data should therefore provide important information for devising experiments and interpreting results when using the rabbit penis as a model for penile dysfunctions, especially when making comparisons with humans.

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