Effects of immobilization stress on kidneys of Wistar male rats: a morphometrical and stereological analysis

Chronic unpredictable mild stress increases serum aldosterone without affecting corticosterone levels and induces hepatic steatosis and renal injury in young adult male rats

Stress is often associated with anxiety and depressive symptoms in adolescents. Stress is associated with components of metabolic syndrome and inflammation. The present study hypothesizes that aldosterone, more than corticosterone, promotes chronic stress-hepatic steatosis and fibrosis, as well as renal inflammation and fibrosis in young adult rats. Thirty-two young adult male Wistar rats of 51 days old were divided into four groups (n = 8 per group): Control (C), chronic unpredictable mild stress (CUMS), control plus vehicle (C plus veh), CUMS plus eplerenone, a selective aldosterone blocker (CUMS plus EP). On postnatal day 51, eplerenone was administered orally through a gastric tube two hours before the start of the stress test. The CUMS paradigm was administered once daily at different times, with no repetition of the stressor sequence for four weeks. Renal inflammation and fibrosis were measured, as well as liver glycogen, triacylglycerol, and fibrosis levels. The serum concentrations of corticosterone, aldosterone, sodium, and creatinine were measured in urine and serum. The CUMS group showed a high level of serum aldosterone without affecting the level of corticosterone, increased urinary sodium, tubular atrophy, glomerular sclerosis, the presence of inflammation, and fibrosis, without affecting creatinine, increased glycogen content, triacylglycerol, and moderate fibrosis in the liver, and treatment with eplerenone prevented the inflammation, fibrosis, glycogen, and triacylglycerol. Our results show that chronic stress-induced aldosterone promotes hepatic steatosis and renal injury more than corticosterone. The prevention by eplerenone supports our hypothesis.

Alterations of serum biochemical parameters and tyrosine phosphorylation in kidney and liver of chronic stress-induced rats

Abstract Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male Sprague–Dawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.

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.

Caffeine Administration Mitigates Chronic Stress-Induced Behavioral Deficits, Neurochemical Alterations, and Glial Disruptions in Rats

Prolonged exposure to stress has detrimental effects on health, and the consumption of caffeine, mostly contained in energy drinks, has become a widely adopted stress coping strategy. Currently, there is limited information regarding the effects of caffeine intake on chronic stress exposure. Thus, this study investigated the effects of caffeine administration on chronic stress-induced behavioral deficits, neurochemical alterations, and glial disruptions in experimental rats. Thirty male Wistar rats were randomly assigned to five groups (n = 6): non-stress control, stress control, and caffeine groups of doses 12.5, 25, and 50 mg/kg. The stress control and caffeine groups were subjected to an unpredictable chronic mild stress (UCMS) protocol daily for 14 days. The rats were evaluated for phenotypic and neurobehavioral assessments. Thereafter, the rat brains were processed for biochemical and immunohistochemical assays. Caffeine administration was found to ameliorate behavioral dysfunctions in rats exposed to UCMS. The UCMS-induced changes in brain levels of monoamines, cholinesterases, and some oxidative stress biomarkers were reversed by caffeine. Caffeine administration also produced mild protective effects against UCMS-induced changes in GFAP and Iba-1 expression in stress-specific brain regions. These results showed that low and moderate doses of caffeine reversed most of the stress-induced changes, suggesting its ameliorative potential against chronic stress-induced alterations.

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.

Fluoxetine partially alleviates inflammation in the kidney of socially stressed male C57 BL/6 mice

Stress-related illnesses are linked to the onset and progression of renal diseases and depressive disorders. To investigate stress-induced changes in the renal transcriptome associated with the development of depressive behaviors, we generated here a chronic social defeat stress (CSDS) model of C57 BL/6 male mice and then performed RNA sequencing of the kidneys to obtain an inflammation-related transcriptome. Administration of the antidepressant drug fluoxetine (10 mg·kg-1 ·day-1 ) during CSDS induction could partially alleviate renal inflammation and reverse CSDS-induced depression-like behaviors. Moreover, fluoxetine also modulated gene expression of stress-related hormone receptors, including prolactin and melanin-concentrating hormone. These results suggest that CSDS can induce gene expression changes associated with inflammation in the kidney of C57 BL/6 male mice, and this inflammation can be treated effectively by fluoxetine.

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.

Energy Homeostasis-Associated (Enho) mRNA Expression and Energy Homeostasis in the Acute Stress Versus Chronic Unpredictable Mild Stress Rat Models

The energy homeostasis-associated (Enho) gene, the transcript for the Adropin peptide, is usually linked to energy homeostasis, adiposity, glycemia, and insulin resistance. Studies on Enho expression in stressful conditions are lacking. This work aimed to investigate Enho mRNA expression and energy homeostasis in acute stress (AS) versus chronic unpredictable mild stress (CUMS) rat models. A total of thirty male Wistar rats (180-220 g) were fed a balanced diet with free access to water. Rats were divided into three equal groups (n = 10): (a) the normal control (NC) group; (b) the AS group, where one episode of stress for 2 h was applied; and (c) the CUMS group, in which rats were exposed to a variable program of mild stressors for 4 weeks. Energy homeostasis was analyzed by the PhenoMaster system for the automatic measuring of food intake (FI), respiratory O₂ volume (VO₂), CO₂ volume (VCO₂), respiratory quotient (RQ), and total energy expenditure (TEE). Finally, liver, whole brain, and adipose (WAT) tissue samples were collected, total RNA was prepared, and RT-PCR analysis of the Enho gene was performed. The CUMS group showed higher VO₂ consumption and VCO₂ production, and a higher RQ than the AS group. Furthermore, the TEE and FI were higher in the CUMS group compared to the AS group. Enho gene expression in the liver, brain, and WAT was significantly higher in the CUMS group than in the AS and NC groups. We can conclude that in the chew-fed AS rats, hypophagia was evident, with a shift in the RQ toward fat utilization, with no changes in body weight despite the increase in Enho mRNA expression in all studied tissues. In the CUMS group, the marked rise in Enho mRNA expression may have contributed to weight loss despite increased FI and TEE.

Effect of Psychosocial Distress on the Rate of Kidney Function Decline

BACKGROUNDS

Chronic kidney disease is a growing global health problem. Psychosocial stress has been found to induce changes in biological processes and behavioral patterns that increase risks of cardiovascular and metabolic diseases. However, the association between psychosocial stress and kidney function is not well understood.

OBJECTIVE

To evaluate the association between psychosocial stress and kidney function decline.

DESIGN

In this prospective cohort study, psychosocial distress was assessed using the psychosocial well-being index short-form (PWI-SF).

PARTICIPANTS

Data of a total of 7246 participants were retrieved from a community-based cohort (Korean Genome and Epidemiology Study).

MAIN MEASURES

The rate of estimated glomerular filtration rate (eGFR) decline was calculated for each individual. Rapid eGFR decline was defined as a decrease of ≥ 3 mL/min/1.73 m² per year. The presence of kidney disease was defined as eGFR < 60 mL/min/1.73 m² at baseline or proteinuria of higher than trace levels from two consecutive urine test results.

KEY RESULTS

A total of 7246 participants were analyzed. The mean eGFR was 92.1 ± 14.0 mL/min/1.73 m². Rapid eGFR decline was observed in 941 (13.0%) participants during a median follow-up of 11.7 years. When the participants were categorized into tertiles according to PWI-SF score, rapid eGFR decline was more prevalent in the group with the highest PWI-SF score (15.8%) than in the group with the lowest score (12.2%). Multivariate logistic regression analysis revealed that the risk of rapid eGFR decline was significantly increased in the tertile group with the highest PWI-SF score compared to the lowest group (odds ratio, 1.35; 95% confidence interval, 1.15-1.59). This association was maintained even after adjusting for confounding variables and excluding participants with kidney disease.

CONCLUSIONS

Higher levels of psychosocial distress were closely associated with an increased risk of rapid kidney function decline.

A Scoping Review of Life-Course Psychosocial Stress and Kidney Function

Increased exposure to maternal psychosocial stress during gestation and adverse neonatal environments has been linked to alterations in developmental programming and health consequences in offspring. A programmed low nephron endowment, among other altered pathways of susceptibility, likely increases the vulnerability to develop chronic kidney disease in later life. Our aim in this scoping review was to identify gaps in the literature by focusing on understanding the association between life-course exposure to psychosocial stress, and the risk of reduced kidney function. A systematic search in four databases (PubMed, ProQuest, Wed of Science, and Scopus) was performed, yielding 609 articles. Following abstract and full-text review, we identified 19 articles meeting our inclusion criteria, reporting associations between different psychosocial stressors and an increase in the prevalence of kidney disease or decline in kidney function, mainly in adulthood. There are a lack of studies that specifically evaluated the association between gestational exposure to psychosocial stress and measures of kidney function or disease in early life, despite the overall evidence consistent with the independent effects of prenatal stress on other perinatal and postnatal outcomes. Further research will establish epidemiological studies with clear and more comparable psychosocial stressors to solve this critical research gap.

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

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.

The Cost of Adaptation to Information Loading in Mice with Various Genetic Profiles

It was found that male BALB/c and F1(C57BL/6×DBA/2) mice are able to recognize the structure of a complex food-gathering task, when modeling the information loading similar to intellectual work in humans. There were significant differences between linear and hybrid animals in the pattern of learning process formation and prevailing psychoemotional reactions that accompany information load. Factors of information loading (uncertainty of maze environment and solution of the food-gathering task) had a specific influence on the CNS and manifested in individual non-specific features. The presented experimental conditions (changes in the metabolic and functional state) revealed pronounced intergroup differences in the reaction of the functional zones of the adrenal cortex. In hybrid mice, information loading induced a significant decrease in testosterone level and thickness of the zona reticularis producing precursor hormones. This is probably due to disruption of interactions in the adrenal-thyroid system in hybrid mice, whereas in BALB/c mice, these interactions fully protect from suppression of testosterone production, the main anabolic hormone. The individual characteristics of the response to information loading can be formed as a result of unequal involvement of the psychophysiological, psychological, and autonomic systems responsible for adaptation to environmental factors.

Role of purinergic signaling pathways in the adaptogenic-like activity of methyl jasmonate in rats exposed to unpredictable chronic mild stress

Objectives Purinergic signaling pathway has been implicated in maladaptation of animals subjected to chronic stress. Previous studies have shown that methyl jasmonate (MJ) exhibited adaptogenic properties in mice exposed to unpredictable chronic mild stress (UCMS) via antioxidant and neuroprotective-related mechanisms. Methods This study evaluated the role of purinergic system in adaptogenic-like activity of MJ. Male Wistar rats were treated intraperitoneally with vehicle (10 mL/kg) or MJ (25, 50, or 100 mg/kg) 30 min prior exposure to UCMS. Thereafter, rats were assessed for swimming endurance in forced swim test (FST) and post-swimming motor coordination on beam walk test (BWT) apparatus. The rats' brains were processed for adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine deaminase, and arginase quantification. Hematological parameters, cholesterol, triglyceride, creatinine, and urea nitrogen were also determined. Results MJ prolonged swimming endurance time and reversed stress-induced post-swimming motor dysfunction. The altered hematological parameters induced by UCMS in rats were significantly (p<0.05) attenuated by MJ. MJ also reversed UCMS-induced alterations of total cholesterol, triglyceride, creatinine, and urea nitrogen levels. MJ averted UCMS-induced alterations in purinergic system by decreasing ATP and ADP hydrolysis, adenosine deaminase, and arginase activities in rats' brains. Conclusions Overall, these findings further suggest that MJ has adaptogenic-like activity in rats exposed to UCMS, which may be related to modulation of the purinergic signaling pathway.

Role of purinergic signaling pathways in the adaptogenic-like activity of methyl jasmonate in rats exposed to unpredictable chronic mild stress

Objectives Purinergic signaling pathway has been implicated in maladaptation of animals subjected to chronic stress. Previous studies have shown that methyl jasmonate (MJ) exhibited adaptogenic properties in mice exposed to unpredictable chronic mild stress (UCMS) via antioxidant and neuroprotective-related mechanisms. Methods This study evaluated the role of purinergic system in adaptogenic-like activity of MJ. Male Wistar rats were treated intraperitoneally with vehicle (10 mL/kg) or MJ (25, 50, or 100 mg/kg) 30 min prior exposure to UCMS. Thereafter, rats were assessed for swimming endurance in forced swim test (FST) and post-swimming motor coordination on beam walk test (BWT) apparatus. The rats' brains were processed for adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine deaminase, and arginase quantification. Hematological parameters, cholesterol, triglyceride, creatinine, and urea nitrogen were also determined. Results MJ prolonged swimming endurance time and reversed stress-induced post-swimming motor dysfunction. The altered hematological parameters induced by UCMS in rats were significantly (p<0.05) attenuated by MJ. MJ also reversed UCMS-induced alterations of total cholesterol, triglyceride, creatinine, and urea nitrogen levels. MJ averted UCMS-induced alterations in purinergic system by decreasing ATP and ADP hydrolysis, adenosine deaminase, and arginase activities in rats' brains. Conclusions Overall, these findings further suggest that MJ has adaptogenic-like activity in rats exposed to UCMS, which may be related to modulation of the purinergic signaling pathway.

Immediate and late effects of chronic stress in the testes of prepubertal and adult rats

The objective of this study was to investigate the effects of chronic stress on the testes of prepubertal and adult rats and to evaluate whether any alterations could be reversed when stress induction is ended. Seventy-six male rats were assigned to eight groups depending on the type of treatment (control or stressed), the age at which stress was initiated (prepubertal or adult), and the time of evaluation (immediate or late). Stress stimuli were applied for 6 weeks. Stressed prepubertal and adult rats evaluated immediately after the last stress stimulus were included in SP-I and SA-I groups, respectively. The late prepubertal (SP-L) and adult (SA-L) groups of stressed rats were evaluated 6 weeks after the last stress stimulus. Age-matched rats were used as controls (CP-I, CA-I, CP-L, and CA-L groups). Application of stress stimuli to rats in the SP-I group resulted in body weight and seminiferous tubule diameter reduction. The rats in the SA-I group also showed several functional (testosterone level and sperm parameter) and morphological (testicular weight and seminiferous tubule diameter) reductions. The rats in the SP-L group showed increased body weight and intertubular compartment volumetric and absolute densities and reduced tubular compartment volumetric density. The rats in the SA-L group presented only reduced sperm viability. Stress stimuli promoted changes in the rats in all the study groups. The testes of the adult rats were the most affected by chronic stress. However, the stressed adult rats recovered well from the testicular alterations.

Effect of Mesenchimal Stem Cells on Apoptosis Indices in Renal Parenchyma during Experimental Stress

Background. Kidneys are extremely sensitive to various environmental factors. Stress disturbs prooxidant-antioxidant balance, causes hyperproduction of reactive oxygen species, changes activity of the nitroxidergic system components, regulating apoptosis. The use of mesenchymal stem cells can normalize functioning of damaged organs in the pathological process.

Aim: to assess the effectiveness of mesenchymal stem cells in a single 24-hour immobilization according to the dynamics of apoptosis indices in renal tissue – nitric oxide (NO) and fragmented DNA.

Materials and methods. The study included male nonlinear white rats aged 3 to 4 months and weighing 225 ± 25 grams. Experimental stress was modeled by the immobilization of animals in the fixation chambers within 24 hours. The efficacy of cell therapy was determined by the change in the concentration of the tested substances at 1, 3, 7, 14, 21 and 30 days of the experiment.

Results. There was a sharp increase in the total amount of nitrates / nitrites and the level of DNA fragmentation in the homogenates of the renal parenchyma after the action of an acute stressor, which may indicate the induction of apoptosis. It was proved that in animals, receiving mesenchymal stem cells as a treatment, the restoration of the studied parameters in the kidney tissue was significantly accelerated in comparison with the controls values.

Conclusion. Mesenchymal stem cells protect cells from self-destruction and activate reparation, which makes them promising for further study.

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.

Morphometric changes and AQP2 expression in kidneys of young male rats exposed to chronic stress and a high-sucrose diet

OBJECTIVE

Consumption of a cafeteria-like diet and chronic stress have a negative impact on kidney function and morphology in adult rats. However, the interaction between chronic restraint stress and high-sucrose diet on renal morphology in young rats is unknown. A high-sucrose diet does not modify serum glucose levels but reduces serum corticosterone levels in stressed young rats, in this way it is confusing a possible potentiate or protector effect of this diet on kidney damage induced by stress.

METHODS

Wistar male rats at 4 weeks of age were randomly assigned into 4 groups: control (C), stressed (St), high-sucrose diet (S30), and chronic restraint stress plus a 30% sucrose diet (St + S30). Rats were fed with a standard chow and tap water (C group) or 30% sucrose diluted in water (S30 group). Chronic restraint stress consisted of 1-h daily placement into a plastic cylinder, 5 days per week, and for 4 weeks.

RESULTS

Stressed rats exhibited a low number of corpuscles, glomeruli, high number of mesangial cells, major deposition of mesangial matrix and aquaporin-2 protein (AQP-2) expression, and low creatinine levels. Meanwhile, high-sucrose diet ameliorated AQP-2 expression and avoided the reduction of creatinine levels induced by chronic stress. The combination of stress and high-sucrose diet maintained similar effects on the kidney as stress alone, although it induced a greater reduction in the area of proximal tubules.

CONCLUSIONS

Our results show that both chronic stress and a high-sucrose diet induce histological changes, but chronic stress may generate an accelerated glomerular hypertrophy associated with functional changes before puberty.

Increase serum cortisol in young guinea pig offspring in response to maternal iron deficiency

Iron deficiency (ID) has been reported as a risk factor in the pathology of attention-deficit/hyperactivity disorder, although the mechanisms seem unclear. Previous results from our research group showed that guinea pig offspring born from ID dams were significantly more active in the Open Field Test than the controls. This behavior could potentially be associated to stress. We therefore hypothesized that maternal iron deficiency (MID) elevates the offspring serum cortisol, a biomarker of stress, during childhood and possibly at mature age. Twenty-four female guinea pigs were fed an iron-sufficient (IS) diet (114 mg/kg) or ID diet (11.7 mg/kg) during the gestation and lactation. Pups in both groups were weaned at postnatal day (PNd) 9 and given an IS diet. Hematocrit and serum cortisol levels were measured in dams at every trimester of gestation and in pups at PNd24 and 84. We found no impact of MID on dam's cortisol values. However, our findings indicate that MID increased cortisol secretion in the offspring during childhood, cortisol values being significantly elevated in ID than IS pups at PNd24 (P < .05). During adulthood (PNd84), both groups showed comparable cortisol levels. The elevated cortisol secretion observed in the offspring born from ID mothers during childhood may indicate increased stress reactivity which may have contributed to the higher level of activity when tested in a novel open environment. These findings suggest that MID can potentially act as internal stressor affecting the early development conceivably leading to increased stress levels in the children.

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.

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

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.

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

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.

Experimental infection with the Toxoplasma gondii ME-49 strain in the Brazilian BR-1 mini pig is a suitable animal model for human toxoplasmosis

Toxoplasma gondii causes toxoplasmosis, a worldwide disease. Experimentation with pigs is necessary for the development of new therapeutic approaches to human diseases. BR-1 mini pigs were intramuscularly infected with T. gondii with tachyzoites (RH strain) or orally infected with cysts (ME-49 strain). Haematology and serum biochemistry were analysed and buffy coat cells were inoculated in mice to determine tachyzoite circulation. No alterations were observed in erythrocyte and platelet values; however, band neutrophils increased seven days after infection with ME-49. Serology of the mice inoculated with pig blood leucocytes revealed circulating ME-49 or RH strain tachyzoites in the pigs' peripheral blood at two and seven or nine days post-infection. The tachyzoites were also directly observed in blood smears from the infected pigs outside and inside leucocytes for longer periods. Alanine-aminotransferase was high at days 21 and 32 in the RH infected pigs. After 90 days, the pigs were euthanised and their tissue samples were processed and inoculated into mice. The mice serology revealed the presence of parasites in the hearts, ileums and mesenteric lymph nodes of the pigs. Additionally, cysts in the mice were only observed after pig heart tissue inoculation. The infected pigs presented similar human outcomes with relatively low pathogenicity and the BR-1 mini pig model infected with ME-49 is suitable to monitor experimental toxoplasmosis.

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.

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.

Different from renal artery only clamping, artery and vein clamping causes a significant reduction in number of rat glomeruli during warm ischemia

PURPOSE

To evaluate glomerular injury in the rat model during renal warm ischemia (WI), comparing artery and vein (AV) clamping with artery only (AO) clamping.

MATERIALS AND METHODS

Twenty-four adult male rats underwent 60 minutes of renal WI in the left kidney. The animals were divided into three groups: AV clamping, AO clamping, and Sham surgery. After 30 days, the animals were euthanized, and both kidneys were processed for paraffin embedding and stained with hematoxylin and eosin. Glomerular volume density (Vv[glom]), mean glomerular volume (MGV), and number of glomeruli per mm(3) (Nv[glom]) were evaluated in the renal cortex.

RESULTS

The Vv[glom] was reduced in the left kidney (ischemic) when compared with the right kidney in both AV and AO groups by 11.1% and 35.4%, respectively; however, the difference was significant only in the AV group. The Nv[glom] was reduced in the left kidney when compared with the right kidney in both AV and AO groups by 11.6% and 31.4%, respectively; nevertheless, the difference was significant only in the AV group. The MGV of left and right kidneys was the same in both Sham and AO groups and was diminished by 6.7% in the AV group-not significant.

CONCLUSION

AV clamping causes a significant decrease in the number of glomeruli in the rat model, while AO clamping reduces the glomerular number, but not significantly. To minimize renal injury, AO clamping may be preferred over AV clamping when WI is necessary in patients with previously compromised renal function.

Laparoscopic partial nephrectomy under warm ischemia reduces the glomerular density in a pig model

PURPOSE

To investigate the number of nephrons, using unbiased stereological method, after warm ischemia for laparoscopic partial nephrectomy in a pig model.

METHODS

Fourteen pigs underwent left laparoscopic partial nephrectomy, and four animals were used as controls (not operated). Renal vessels were clamped, and 25% of kidney length was resected. The animals were euthanized after 2 weeks, and the kidneys were collected. Thus, we analyzed 14 left kidneys submitted to warm ischemia, 14 right kidneys from the same animals but not submitted to ischemia and eight kidneys from control animals. Renal fragments were processed using routine histological methods. The total operative time and the time of warm ischemia were recorded. Glomerular mean volume and glomerular density were quantified by stereological methods. Creatinine serum levels were assessed preoperatively and before euthanasia.

RESULTS

Surgical time was 71 ± 17 minutes, and ischemia time was 16 ± 5 minutes. The mean glomerular volume in the left kidneys was higher when compared with controls and to right kidneys (p<0.05). In addition, the glomerular density was reduced in the left kidneys (p<0.05) when compared with controls and right kidneys. Nevertheless, creatinine serum levels after 2 weeks of surgery were not different from the preoperative levels. No difference was found for stereological measurements between controls and right kidneys.

CONCLUSION

Stereological determination of glomerular density can be used as an accurate and objective method for studies regarding renal damage from ischemia. Warm ischemia during laparoscopic partial nephrectomy in pigs determined a significant reduction of glomerular density in the ipsilateral remaining parenchyma.