Effects of chronic stress on bladder morphology of rats and impact of comfort food diet as an ameliorating agent.

OBJECTIVES: To investigate the effects of chronic stress on bladder morphology and the impact of food preference (standard or comfort foods) on the bladder of stressed rats. METHODS: In total, 32 Wistar male rats (3 months old) were divided into four groups: control (C), stressed (S), control + comfort food (C + CF), and stressed + comfort food (S + CF). Groups C and C + CF were maintained under normal conditions, while groups S and S + CF were subjected to chronic stress by the restraint method. Groups C and S received standard rat chow, while groups C + CF and S + CF received comfort food (Froot Loops®) and standard chow. The stress stimuli were induced daily for 2 h over 8 weeks. After 8 weeks, all animals were killed, and the bladders were removed and used for histomorphometric analysis. RESULTS: Body mass was similar among the groups. Stress did not promote differences regarding food intake, but animals receiving comfort food showed higher calories intake (in kcal/Kg) than animals receiving only standard chow. The C + CF and S + CF groups preferred comfort food over the standard chow; this preference was higher in the S + CF than in the C + CF group. The surface density of smooth muscle was reduced in stressed animals, while connective tissue and elastic system fiber content were increased in stressed groups. Further, epithelial height was increased in rats submitted to chronic stress. The surface density of elastic system fibers was decreased by the consumption of comfort food. CONCLUSIONS: Chronic stress induces morphological modifications on the bladder wall and epithelium. These modifications may be related to lower urinary tract symptoms. Additionally, chronic stress caused a higher preference for comfort food intake which did not ameliorate or aggravate the stress-induced bladder alterations.

Quercetin as a nephroprotector after warm ischemia: histomorphometric evaluation in a rodent model.

PURPOSE: To quantitatively evaluate the possible long-term protective effects of quercetin during renal warm ischemia. MATERIALS AND METHODS: Male rats were allocated into 4 groups: sham (S), sham quercetin (SQ), ischemia (I), and ischemia quercetin (IQ). Groups SQ and IQ received quercetin (50mg/kg) before and after surgery. Groups I and IQ had their left renal vessels clamped for 60 minutes. All animals were euthanized four weeks after the procedure, and serum urea and creatinine levels were measured. Renal weight and volume, cortex-non-cortex area ratio (C-NC), cortical volume (CV), glomerular volumetric density (Vv[glom]), volume-weighted glomerular volume (VWGV) and number of glomeruli per kidney (N[glom]) were evaluated by stereological methods. Results were considered statistically significant when p < 0.05. RESULTS: Serum urea levels in group I increased by 10.4% in relation to group S, but no differences were observed among the other groups. The C-NC of group I was lower than those of all other groups, and group IQ had similar results to sham groups. The Vv[glom] and N[glom] of group I were lower than those of group S (33.7% and 28.3%, respectively) and group IQ had no significant difference compared to the S group. CONCLUSIONS: Quercetin was effective as a nephroprotective agent in preventing the glomerular loss observed when the kidney was subjected to warm ischemia. This suggests that this flavonoid may be used preventively in kidney surgery, when warm ischemia is necessary, such as partial nephrectomy.

Anatomical background of ovine kidney for use as animal model: analysis of arterial segmentation, proportional volume of each segment and arterial injury after cranial pole partial nephrectomy.

OBJECTIVE: To study the arterial segments of ovine kidney, present a proportional volume analysis of each kidney arterial segment, and analyze arterial injuries caused by simulated partial nephrectomy of cranial pole. MATERIALS AND METHODS: Forty-eight ovine kidneys injected with polyester resin into the renal arteries and collecting system were used in this study. Eighteen kidneys were used to study the arterial segments and the proportional volume of each renal segment. Other 30 kidneys were submitted to superior pole resection at a distance of 1.0cm, 0.5cm, or exactly at the cranial hilar edge, just before the resin hardening. These endocasts were used to evaluate the arterial injuries caused by these different resection planes. RESULTS: Ovine renal artery divided into two (ventral and dorsal) or three segmental arteries. Dorsal segment presented higher proportional volume than ventral segment. For kidneys with three segments, the third segment was on the caudal region (caudo-ventral or caudo-dorsal segment) and presented the lowest proportional volume. None of the resected kidneys (at 1.0, 0.5 or at the cranial hilar edge) presented injury of arterial branches that irrigate non-resected region. CONCLUSION: The segmental distribution of renal artery, the proportional volume of each segment and arterial injuries after cranial pole resection in ovine kidneys are different from what is observed in human kidneys. Meanwhile, ovine kidneys show a primary segmental division on anterior and posterior, as in humans, but different from swine. These anatomical characteristics should be considered when using ovine as animal models for renal experimental and/or training procedures.

Evaluation of the effects of chronic stress applied from the prepubertal to the adult stages or only during adulthood on penile morphology in rats.

The present study aimed to evaluate the effects of chronic stress from the prepubertal to the adult stages or during adulthood on penile morphology in rats. The animals were immobilized in a cylinder for 2 h daily for a total of six weeks to simulate stress. Ten rats were exposed to stress stimulus beginning from the prepubertal age, while nine rats were exposed to stress stimulus only during adulthood. Animals were killed at 24 h after the last stress session for short-term evaluation (SP-S and SA-S), while other age-matched rats were sacrificed at 6 weeks after the last stress session for long-term evaluation (SP-L and SA-L). Age-matched animals were used as controls (CP-S, CA-S, CP-L and CA-L). After treatment, serum testosterone levels and areas of cavernosum structures were evaluated. We observed no changes in serum testosterone levels after stress treatment. Results revealed that the area of the corpus cavernosum without the tunica albuginea in animals in the SA-S group was 16% lower than that in the CA-S group. The smooth muscle was 31% lower in the SP-L group than in the SP-S group and 42% lower in the SA-S group than in the CA-S group. The elastic fiber system was 48% lower in the SP-L group than in the CP-L group and 59% lower in the SA-S group than in the CA-S group. Chronic stress promoted morphological changes in the rat penis and was significantly more pronounced when the stress occurred throughout the adulthood. Chronically applied single stress stimulus caused greater damage to the penis when induced directly during adulthood than when introduced before puberty to adulthood and could be associated with erectile dysfunction.

Immediate and Late Effects of Stress on Kidneys of Prepubertal and Adult Rats.

BACKGROUND/AIMS: Stress had been related to physiological and morphological alterations in different organs, however kidney morphology and function after stress conditions are not well-known. To evaluate the effects of chronic stress on renal morphology in prepubertal and adult rats, and to investigate if the effects of induced stress remain stable or worsen following removal of the stress stimuli. METHODS: Forty prepubertal rats (4 weeks old) and thirty six adult rats (10 weeks old) were used. Each age group was divided a into control group and a stressed group. Stressed animals were restrained in rigid tubes 2 hours per day for 6 weeks. Animals were euthanized 24 hours after the last stress stimulus for immediate evaluation (50% of the groups), and 6 weeks after the last stress stimulus for late evaluation (50% of the groups). Kidney weight and volume, cortical-medullar ratio, glomerular volumetric density, volume-weighted glomerular volume, and number of glomeruli per kidney were evaluated using the Image J software. RESULTS: Prepubertal stressed animals showed reduced kidney weight and volume, and increased cortical-medullar ratio in comparison to its control group when evaluated immediately. Furthermore, stressed prepubertal and adult animals evaluated immediately had reduced glomerular volumetric density. Most importantly, all stressed groups exhibited reduced number of glomeruli per kidney. Other analyzed parameters did not difeer significantly the groups. CONCLUSION: Chronic stress induced before and after puberty led to irreversible glomerular loss, however, renal impairment was interrupted by removal of the stress stimuli.

Mannitol reduces nephron loss after warm renal ischemia in a porcine model.

BACKGROUND: Mannitol has been employed to ameliorate renal warm ischemia damage during partial nephrectomy, however, there is limited scientific evidence to support the use of mannitol during partial nephrectomy. The objective of the present study was to investigate the glomerular number after renal warm ischemia, with and without the use of mannitol in a Pig Model. METHODS: Twenty-four male pigs were assigned into three groups. Eight animals were allocated to the sham group that was subjected to laparoscopic dissection of the left renal hilum, without renal ischemia. Eight animals were allocated to the ischemia group that had the left renal hilum clamped for 30 min through laparoscopic access. Eight animals received mannitol (250 mg/kg) before the occlusion of renal hilum for 30 min. The kidneys were collected after the euthanasia of the pigs 21 days post surgery. The right kidney was utilized as a self-control for each animal. Serum creatinine, urea levels, the weight and volume of the kidneys were measured. Glomerular volumetric density, volume-weighted glomerular volume, and cortical volume were quantified through stereological methods and employed to determine the number of nephrons per kidney. Student's t test and ANOVA were used for statistical analysis. RESULTS: In the ischemia group, the left kidney recorded a reduction of 24.6% (290, 000 glomeruli) in the number of glomeruli in comparison to the right kidney. Kidneys subjected to ischemia also displayed decreased weight and volume in comparison to the sham and mannitol groups. No difference was observed between the left and right kidneys from the sham and mannitol groups. Further, no distinction in serum creatinine and urea among the groups was observed. CONCLUSION: The use of mannitol significantly reduces nephron loss during warm ischemia in pigs.

Does a Ureteral Obstruction Affect the Contralateral Kidney Morphology? A Stereological Analysis in a Rodent Model.

OBJECTIVE: To investigate, in a rodent model, the influence of an obstructed kidney/ureter on the contralateral organ morphology. METHODS: Thirty-six rats were randomly assigned into the following groups: untreated ureteral obstruction group (UO-U, n = 10), submitted to a ligature of the ureter at day 0; UO group (at day 0) followed by nephrectomy after 24 h (UO-N, n = 8); nephrectomy group (N, n = 9), submitted to nephrectomy at day 0; and sham group (S, n = 9), submitted to simulated surgery at day 0. All these procedures were performed on the left kidney/ureter. All animals were euthanized 30 days after surgery, and the right kidneys were collected for stereological analysis. Data were compared using a one-way analysis of variance with Bonferroni's post test, considering p < 0.05 as significant. RESULTS: The kidney volume, weight, and cortical volume were augmented in groups UO-N and N, compared to group S. Kidneys from the UO-U group showed only a moderate augmentation in kidney weight, with a reduction in the cortical-medullar ratio, compared to the kidneys in group S. No differences in the glomerular volumetric density, volume-weighted glomerular volume, and number of glomeruli were observed among the right kidneys of the studied groups. CONCLUSION: An obstructed kidney/ureter is more prejudicial to the contralateral kidney morphology than an absent kidney.

Glomerular Morphology and Renal Function after Warm Ischemia by Main Artery or Selective Clamping in a Porcine Model.

OBJECTIVE: The study aimed to evaluate the ischemic and non-ischemic areas after selective arterial occlusion by using stereological analysis of glomeruli, and to compare them with main arterial clamping and sham-operated animals. MATERIALS AND METHODS: Twenty-four male pigs were used in the study. The animals were divided into 3 groups with 8 animals in each as follows: group sham, submitted to laparoscopic dissection of the renal pedicle but not submitted to ischemia; group arterial (A), submitted to left renal artery clamping; and group selective (S), submitted to left renal artery caudal branch occlusion. Groups A and S underwent 30 min of warm ischemia. Left and right kidneys were collected after 21 days and renal fragments were processed for stereological evaluation. Glomerular volume density (Vv[glom]), mean glomerular volume (MGV), and glomerular density were measured. Serum creatinine and urea were assessed preoperatively, 10 days after surgery, and before euthanasia. RESULTS: There was no significant difference among groups with regard to renal function. Renal weight and volume were similar among groups. Also, no difference was observed between the groups with regard to Vv[glom], MGV, and glomerular density, both when compared to its right control or when left kidneys were compared. CONCLUSIONS: Selective arterial clamping technique was neither superior nor inferior to main artery clamping.

The sheep as a model for healing studies after partial nephrectomy.

BACKGROUND: The pig has been considered the best model for renal surgery. However, recent research has demonstrated that the kidney of pigs heals differently from that of humans. The objective of this study was to evaluate sheep as an alternative animal model for studying collecting system healing after laparoscopic partial nephrectomy. MATERIALS AND METHODS: The caudal pole of the left kidney was removed from eight female adult domestic sheep using laparoscopic partial nephrectomy. Monopolar energy was used for hemostasis only in the parenchyma, avoiding coagulation near the collecting system, which was left opened. After 14 d, all animals were euthanized, and their left kidney was removed. Serum levels of urea and creatinine were assessed preoperatively and postoperatively (on days 2, 6, 10, and 14), and peritoneal fluid samples were collected during necropsy for urea and creatinine evaluation. An ex vivo retrograde pyelogram was performed, and a retrograde injection of methylene blue ink was administered to evaluate urinary leakage. Samples from the operated pole were analyzed using histologic methods. RESULTS: During necropsy, an urinoma surrounding the operated kidney was observed in one animal. Peritoneal fluid levels of urea and creatinine were elevated. Retrograde pyelograms exhibited contrast-medium extravasation through the operated pole in all kidneys. The opened collecting system was also confirmed by methylene blue ink injection. The operated pole was covered by collagenous tissue and adhered to adjacent organs. CONCLUSIONS: Sheep should be considered as an adequate experimental model for research on collecting system healing after partial nephrectomy.

Effect of antioxidants on outcome of testicular torsion in rats of different ages.

PURPOSE: We assessed reproductive and testicular function in adult rats after testicular torsion created before, during and after puberty, and with vs without resveratrol or arginine treatment. MATERIALS AND METHODS: Age matched rats were divided into groups, including simulated surgery without testicular torsion, 720-degree testicular torsion for 4 hours, testicular torsion with resveratrol treatment and testicular torsion with arginine treatment. To study reproductive function at age 12 weeks each rat mated with 3 females. The males were sacrificed at age 14 weeks. Spermatozoids were collected from the epididymal tail and evaluated for concentration, motility and viability. Testicular samples were collected for morphological analysis. RESULTS: Reproductive function was not altered by testicular torsion but antioxidants improved potency. Compared to sham operated and contralateral samples all spermatozoid parameters from testicular torsion samples were inferior. Resveratrol and arginine did not improve spermatozoid quality or quantity in torsed testes but contralateral samples were improved by each drug. The seminiferous epithelium of rats submitted to testicular torsion during puberty was least affected. Each antioxidant partially to totally prevented the morphological alterations found in rats with untreated testicular torsion. Rats submitted to testicular torsion before puberty that were treated with antioxidants showed the fewest changes. CONCLUSIONS: Testicular morphology was altered less in rats when torsion occurred earlier in life, that is during puberty. Treatment with antioxidants improved contralateral spermatozoid production and some fertility parameters. Each antioxidant also prevented testicular morphology alterations after testicular torsion. Prepubertal rats benefited most from antioxidant treatment.

Three-dimensional models of physeal fractures in the femur for the teaching of veterinary medicine.

PURPOSE: To develop and assess three-dimensional models of physeal fractures in dog femurs (3D MPFDF) using radiographic imaging. METHODS: The study was conducted in three phases: development of 3D MPFDF; radiographic examination of the 3D MPFDF; and comparative analysis of the anatomical and radiographic features of the 3D MPFDF. RESULTS: The base model and the 3D MPFDF achieved high fidelity in replicating the bone structures, accurately maintaining the morphological characteristics and dimensions such as length, width, and thickness, closely resembling natural bone. The radiographs of the 3D MPFDF displayed distinct radiopaque and radiolucent areas, enabling clear visualization of the various anatomical structures of the femur. However, in these radiographs, it was challenging to distinguish between the cortical and medullary regions due to the use of 99% internal padding in the printing process. Despite this limitation, the radiographs successfully demonstrated the representation of the Salter-Harris classification. CONCLUSIONS: This paper presents a pioneering project focused on technological advancement aimed at developing a method for the rapid and cost-effective production of three-printed models and radiographs of physeal fractures in dogs.

Does prolonged pneumoperitoneum affect the kidney? Oxidative stress, stereological and electron microscopy study in a rat model.

PURPOSE: Pneumoperitoneum (Pp) at 12 to 15 mmHg in rats is associated with kidney damage. However, Pp at 8 mmHg is now known to best correlate to working pressures used in humans. Thus the aim of this work was to study the kidney of rats submitted to prolonged Pp at 8 mmHg. MATERIALS AND METHODS: Rats were divided into a Sham group (n = 14), submitted to anesthesia, and a Pp group (n = 14), submitted to Pp at 8 mmHg, followed by deflation. In both groups, 7 animals were immediately killed and their kidneys were used for oxidative stress analyses. The remaining 7 rats in each group were evaluated after 6 weeks for the number of glomeruli and podocyte morphology. RESULTS: For all analyzed parameters Sham and Pp groups presented no statistical difference. CONCLUSION: When submitted to adequate Pp pressures (8 mmHg), no kidney damage occurs in rats.

Sinusoidal constriction and vascular hypertrophy in the diabetes-induced rabbit penis.

OBJECTIVE: To assess the morphological changes of penile vascular structures and the corpus cavernosum area in alloxan-induced diabetic rabbits. MATERIALS AND METHODS: Twenty male rabbits (2 months old) were divided into two groups with 10 rabbits each, the control group (CG) and the diabetic group (DG). The animals from DG received an intravenous injection of alloxan (100mg/kg) to induce the diabetes. Ten weeks after the induction of diabetes, all animals were euthanized. Two fragments of the penile shaft were harvested and samples were processed and paraffin embedded. Sections (5 µm) were cut and stained for histological and immunohistochemical markers. RESULTS: Nuclear protrusion toward the lumen, and cytoplasmic vacuolization were observed in the tunica intima of the dorsal artery of the penis in DG. The thicknesses of the tunica media increased significantly in DG (p = 0.0350). It was also observed a significant increase in the area of the tunica media (p = 0.0179). There was no significant change in smooth muscle cell density in the tunica media of the dorsal artery of the penis (p = 0.0855). The collagen fiber pattern of the tunica adventitia of the dorsal artery of the penis was different between the control and diabetic groups. There was a significant decrease in the area occupied by the cavernous sinuses in DG (p = 0.0013). CONCLUSION: Alloxan-induced diabetes mellitus in rabbits promotes important changes in penile vascular structures, thereby decreasing blood supply and affecting penile hemodynamics, leading to erectile dysfunction.

Use of homologous platelet gel to manage refractory diabetic lower extremity ulcers: additional experience at a tertiary hospital.

BACKGROUND: DLEUs are a major cause of morbidity. Appropriate treatment is essential, and newer methods to achieve ulcer healing have been described, including application of PG. OBJECTIVE: This study evaluated the effectiveness and safety of homologous PG in patients with chronic noninfected DLEU refractory to standard treatment as well as possible correlations between patient comorbidities and response to treatment. MATERIALS AND METHODS: Data from patients with chronic refractory DLEU managed with homologous PG between January 2014 and October 2022 were evaluated (comorbidities, wound characteristics, number and time of treatment, outcome). Outcome was classified as complete response (complete ulcer healing with reepithelialization), partial response (≥50% reduction in area and/or improvement of pain), or absence of response. The chi-square test was used to compare groups, with alpha level set at less than .05. RESULTS: A total of 81 patients (63 male, 18 female; median age, 65 years; median HbA1c, 7.6%; median ulcer area, 2.9 cm2) were proposed for PG application. A total of 62 patients had 3 or more comorbidities. Outcome was evaluated in 69 patients, with response observed in 49% (complete, 32%; partial, 17%). Worse outcomes occurred in patients with polyneuropathy (chi-square statistic: 4.183; P = .041). CONCLUSION: Homologous PG is a safe and possibly effective therapeutic alternative for DLEU that is unresponsive to standard therapies.

Effects of comfort food diet on the penile morphology of stressed rats.

Purpose: To investigate the effects of chronic stress, associated or not with comfort food, on the morphology of the penis. Materials & methods: Thirty-two adult Wistar rats were divided into four experimental groups: Control group (C), receiving standard rat chow, and under normal conditions; Stressed group (S), receiving standard chow, and submitted to stressful situations; Control + comfort food group (C + CF), receiving standard chow and comfort food, and under normal conditions; and Stressed + comfort food group (S + CF), receiving standard chow and comfort food, and submitted to stressful situations. At 10 weeks of age, food supply and stress were initiated. All groups had ad libitum access to standard chow and water, and groups receiving comfort food also had access to Froot Loops®. Chronic stress was induced by restriction, animals were contained daily in polypropylene tubes for 2 h, for eight weeks. After eight weeks all animals were killed; penises were removed for histomorphometric analysis. Results: Body mass was similar among the groups. Food intake in S + CF group was lower than in other groups. Concerning food preference, groups C + CF and S + CF preferred comfort food over the standard chow, with this preference being higher in S + CF than in C + CF. The area of the corpora cavernosa without tunica albuginea was lower in group S + CF than in group C. Most interestingly, the surface density of connective tissue in the corpora cavernosa was higher in groups S and S + CF compared to group C. In contrast, smooth muscle surface density was markedly lower in S + CF compared to groups C and C + CF, while group S also had reduced smooth muscle in comparison to group C. Conclusion: Chronic stress caused a morphological alteration on penile histomorphometry. Also, stress increased the preference for comfort foods which caused more deleterious effects in some parameters.

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.

Radiation from a D-dimensional collision of shock waves: a remarkably simple fit formula.

Recently we estimated the energy radiated in the head-on collision of two equal D-dimensional Aichelburg-Sexl shock waves, for even D, by solving perturbatively, to first order, the Einstein equations in the future of the collision. Here, we report on the solution for the odd D case. After finding the wave forms, we extract the estimated radiated energy for D=5, 7, 9, and 11 and unveil a remarkably simple pattern, given the complexity of the framework: (for all D) the estimated fraction of radiated energy matches the analytic expression 1/2-1/D, within the numerical error (less than 0.1%). Both this fit and the apparent horizon bound converge to 1/2 as D→∞.

The bovine kidney as an experimental model: Simulated partial nephrectomy of the cranial pole and proportional analysis of the arterial segments.

Previous studies have shown that the pig kidney is not a good model for some procedures. This study aimed to describe the relationship between the collecting system and the intrarenal arteries, the arterial segments, and to evaluate the bovine kidney as an experimental model for partial nephrectomy of the cranial pole. Polyester resin endocasts of the kidney collecting system together with the intrarenal arteries were prepared. Thirty-two kidneys were used to evaluate the relationship between the collecting system and the intrarenal arteries, while 25 kidneys were transversally sectioned at different points to simulate partial nephrectomy of the cranial pole. Polyester resin of different colors was injected into each segmental artery of the 24 kidneys to evaluate the arterial segments proportionally. The renal artery was divided into cranial and caudal primary branches in 75% of the cases. The cranioventral branch curved on the cranial pole and ran toward the ventral mid-zone in 56.3% of the cases, resembling the retropelvic artery of the human kidney. The kidney was divided into two (25%) or three (75%) arterial segments. The caudal arterial segment had the highest proportional volume (62%). The cranioventral branch was damaged in 28.6% of the kidneys sectioned 1 cm inside the hilum. The arterial branching pattern, the arterial segmentation, and the impairment of the arterial supply after the simulated partial nephrectomy of the cranial pole are quite different from those found in humans. Thus, all differences should be taken into account when using the bovine kidney as a model.

Estudos anteriores demonstraram que o rim do porco não é um bom modelo para alguns procedimentos. O objetivo deste estudo foi descrever a relação entre o sistema coletor e as artérias intrarrenais, os segmentos arteriais, e avaliar o rim bovino como modelo experimental para a nefrectomia parcial do polo cranial. Foram confeccionados moldes de resina de poliéster do sistema coletor renal associado às artérias intrarrenais. Para a avaliação da relação entre o sistema coletor e as artérias intrarrenais foram utilizados trinta e dois rins, enquanto outros trinta e cinco rins foram cortados transversalmente em diferentes regiões para simular a nefrectomia parcial do polo cranial. Resina de poliéster de diferentes cores foi injetada em cada segmento arterial de 24 rins para avaliar proporcionalmente os segmentos arteriais. A artéria renal se dividiu em ramos primários cranial e caudal em 75% dos casos. O ramo cranioventral contornou o polo cranial e seguiu para a região média ventral em 56,3% dos casos, lembrando a artéria retropiélica do rim humano. O rim estava dividido em dois (25%) ou três (75%) segmentos arteriais. O segmento arterial caudal apresentou o maior volume proporcional (62%). O ramo cranioventral foi lesionado em 28,6% dos rins seccionados 1 cm internamente ao hilo. O padrão da ramificação arterial, os segmentos arteriais, e o dano ao suprimento arterial após a nefrectomia simulada parcial do polo cranial são bem diferentes daqueles encontrados em humanos. Então, todas as diferenças devem ser levadas em consideração quando se usa o rim bovino como modelo.

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

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.