Drogas imunossupressoras afetam os núcleos hipotalâmicos envolvidos na ingestão alimentar ? estudo experimental / Do the immunosuppressive drugs affect the hypothalamic nuclei involved in the regulation of food intake? an experimental study

RESUMO - RACIONAL: Drogas imunossupressoras são indispensáveis para pacientes pós-transplante, diminuindo, significativamente, os riscos de rejeição inerentes a este tipo de procedimento. No entanto, seus efeitos colaterais sobre os núcleos hipotalâmicos envolvidos na regulação da ingestão de alimentos e o efeito no excessivo ganho de peso e suas comorbidades associadas são desconhecidos. OBJETIVO: Analisar a ocorrência de alterações morfológicas dos núcleos paraventricular, área hipotalâmica lateral, dorsomedial, ventromedial e arqueado em ratos Wistar submetidos ao tratamento imunossupressor com Tacrolimus (TAC) ou Micofenolato Mofetil (MMF). MÉTODOS: Foram utilizados Ratos Wistar machos adultos distribuídos, randomicamente, em quatro grupos de acordo com o tratamento oral utilizado por 14 semanas: Controle; Sham (Placebo); Tacrolimus (TAC 1mg/kg peso) e Micofenolato Mofetil (MMF 30mg/kg peso). Ao final do tratamento, os animais foram eutanasiados e seus encéfalos fixados para o processamento histológico. Posteriormente, as lâminas foram fotodocumentadas para o desenvolvimento da análise estereológica dos corpos celulares dos neurônios dos núcleos hipotalâmicos, tendo como parâmetros a densidade neuronal e no número de neurônios. RESULTADOS: Todos os grupos estudados mostraram curva de ganho de peso ponderal durante todo o período de experimento. Não houve diferença significativa na densidade neuronal e no número de neurônios hipotalâmicos dos núcleos hipotalâmicos entre os grupos estudados. Não foram detectadas alterações morfológicas dos corpos celulares dos neurônios hipotalâmicos capazes de serem imputadas ao uso dos imunossupressores envolvidos no estudo. CONCLUSÃO: O tratamento dos animais experimentais com os imunossupressores não evidenciou alterações no número e densidade dos corpos celulares dos neurônios dos núcleos hipotalâmicos estudados.

ABSTRACT - BACKGROUND: Immunosuppressive drugs are essential for reducing the rejection risk in post-transplant patients, which is commonly associated with this procedure. However, side effects of those drugs on the hypothalamic nuclei involved in the food intake regulation, excessive weight gain, and also associated comorbidities are still unknown. PURPOSE: The purpose of this study was to analyze possible changes in the neuronal morphology and cell density in the paraventricular nuclei, lateral hypothalamic area, dorsomedial nuclei, and ventromedial and arcuate nuclei in Wistar rats submitted to immunosuppressive treatment with tacrolimus (TAC) or mycophenolate mofetil (MMF). METHODS: Adult male Wistar rats were randomly assigned to the following groups according to the oral treatment administered for 14 weeks: control, sham (placebo), TAC (1 mg/kg of weight), and MMF (30 mg/kg of weight). After treatment, the animals were sacrificed and their brains fixed for later histological staining. Subsequently, the slides were photodocumented for stereological analysis of the hypothalamic nuclei. RESULTS: All experimental groups showed a weight gain throughout the study. There was no significant difference in neuronal density/number of cells in the hypothalamic nuclei between groups. Morphological changes were not detected in the hypothalamic neurons. CONCLUSION: Treatments with immunosuppressants could not modify the morphological and cell density aspects of the hypothalamic nuclei during this supplementation period.

Stereological study and analysis of oxidative stress during renal aging in rats

Purpose To evaluate renal histological changes by stereology and morphometry and analyze the main markers of oxidative stress in rats undergoing natural aging. Methods Seventy two Wistar rats were divided into six groups of 12 rats each, which were euthanized at 3, 6, 9, 12, 18, and 24 months of age. Right kidney was stereologically and morphometrically analyzed to calculate the volumetric density (Vv[glom]), numerical density (Nv[glom]) and glomerular volume (Vol[glom]). Left kidney was used to determine the levels of nonprotein thiols, lipid peroxidation, and protein carbonylation, as well as the activities of superoxide-dismutase and catalase enzymes. Results Both Vv[glom] and Nv[glom] values showed gradual decreases between groups. Activity of superoxide-dismutase was elevated at 24 months of age, and the levels of nonprotein thiols were higher in older animals. Greater catalase activity and protein carbonylation were observed in animals between 6 and 12 months of age but lessened in older rats. Lipid peroxidation decreased in the older groups. Conclusions Morphometric and stereological analyses revealed a gradual decrease in the volume and density of renal glomeruli during aging, as well as kidney atrophy. These findings related to oxidative stress clarify many changes occurring in kidney tissues during senescence in rats.

Stereological analysis of elastic fibers of the corpus cavernosum of rats during the aging process

Abstract Purpose To evaluate changes in the quantity of elastic fibers in the corpora cavernosa of rats during the natural aging process, and to assess the degree of this change by determining volumetric density (Vv) at different ages via stereological analysis. Methods Forty-eight rats, raised under similar conditions, were subjected to the natural aging process and divided into four groups (G1 to G4), according to age at the time of penectomy (6, 9, 12, and 24 months, respectively). Histological sections of the middle segment of the penis were stained with Weigert's resorcin-fuchsin, and the volumetric density (Vv) of elastic fibers of the corpora cavernosa were determined via stereological analysis. Results There were no statistically significant differences in Vv among groups G1, G2, and G3. These three groups were therefore considered as a single group. The mean Vv of this group showed a statistically significant reduction compared to that of G4 (0.16 vs. 0.11, p<0.05). Conclusion Natural aging in rats was responsible for a reduction in volumetric density of elastic fibers of the corpora cavernosa (approximately 30% decrease in Vv) during senescence.

Quantitative analysis of the renal aging in rats. Stereological study

ABSTRACT PURPOSE: To evaluate the renal function and the renal histological alterations through the stereology and morphometrics in rats submitted to the natural process of aging. METHODS: Seventy two Wistar rats, divided in six groups. Each group was sacrificed in a different age: 3, 6, 9, 12, 18 and 24 months. It was performed right nephrectomy, stereological and morphometric analysis of the renal tissue (renal volume and weight, density of volume (Vv[glom]) and numerical density (Nv[glom]) of the renal glomeruli and average glomerular volume (Vol[glom])) and also it was evaluated the renal function for the dosage of serum creatinine and urea. RESULTS: There was significant decrease of the renal function in the oldest rats. The renal volume presented gradual increase during the development of the rats with the biggest values registered in the group of animals at 12 months of age and significant progressive decrease in older animals. Vv[glom] presented statistically significant gradual reduction between the groups and the Nv[glom] also decreased significantly. CONCLUSIONS: The renal function proved to be inferior in senile rats when compared to the young rats. The morphometric and stereological analysis evidenced renal atrophy, gradual reduction of the volume density and numerical density of the renal glomeruli associated to the aging process.

Analysis of the histology of the scar bladder and biochemical parameters of rats with a solitary kidney undergoing immunosuppression with tacrolimus

PURPOSE: To evaluate bladder histology in healing and biochemical analysis of rats with single kidney in ischemia/reperfusion, treated with tacrolimus. METHODS: Fifty rats randomized into five groups. Three rats died in surgery, 47 rats divided in groups: Control (non-operated, n=10), Sham (operated without drugs, n=8), T1 (operated + tacrolimus 1mg/kg, n=10), T2 (operated + tacrolimus 0.1 mg/kg, n=10), T3 (operated + tacrolimus 10mg/kg, n=9). The surgery was: laparotomy, right nephrectomy, left kidney ischemia/reperfusion, cystotomy followed by bladder suture. After that, rats were submited to gavage daily (Control and Sham with saline solution. T1, T2, T3 with tacrolimus in doses already mentioned). On the 14th day, after death induction, cystectomy was performed and bladder was histologicaly analysed. The serum urea, creatinine and tacrolimus were analysed too. RESULTS: There was difference in serum tacrolimus in T3 compared to the other groups (p<0.05). There was higher doses of creatinine in T3 group and higher urea in groups with tacrolimus. There were significant differences among all histologic variables comparing groups with and without tacrolimus (p<0.05). CONCLUSION: Tacrolimus associated with ischemia/reperfusion is nephrotoxic, suppresses inflammation and seems to delay the healing bladder. .