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

Consumption of sucrose in maternal and postnatal stages leads to kidney affectation in adult male rats

High sugar-sweetened beverage intake has been related to human kidney disease and metabolic alterations. We determine the impact of high sucrose intake from pregnancy until early postnatal days and post-weaning on kidneys from adult male offspring rats. Wistar female rats were mated and assigned into two groups: one control drinking tap water (CM) and another drinking 5 % sucrose diluted in water (SM). Two offspring per mother were randomly allocated into two experimental groups at weaning. One had free access to simple water (CO) and the other to 5 % sucrose (SO) for 14 weeks. After treatment, levels of relative aquaporin-2 (AQP2), glomerulosclerosis index (GI), collecting tube area, perirenal fat, blood creatinine, and blood ureic nitrogen concentration (BUN) were determined. Two-way ANOVA followed by Bonferroni post-hoc test was used, considering P ≤ 0.05 as a significant statistical difference. Sucrose consumption during gestation/lactation and interaction increased AQP2 expression in the renal cortex and BUN concentration. In contrast, gestation/lactation consumption increased collecting tube area, post-weaning consumption favored perirenal fat, and finally, gestation/lactation, post-weaning, and the interaction caused glomerulosclerosis. Our results suggest that the consumption of sucrose water during gestation/lactation or post-weaning or combination triggers pathological changes in the kidneys of adult rats.

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.

Dietary intervention in adult rats exposed to a high-sugar diet early in life permanently impairs sperm quality

Childhood obesity predicts the presence of adult obesity. Obesity is associated with poor sperm quality. We hypothesized that exposure to a high-sugar diet (HSD) in early life would cause permanent histomorphology damage to the testes, resulting in reduced sperm quality in adult life. Wistar rats (aged 21days) were divided into four groups (n=6). In the first experiment, the rats received tap water (control) and a 30% sucrose diet for two months (S30). In the second experiment, the control and 30% sucrose diets were fed for two months, followed by replacement with tap water for two months (IS30). Eating and drinking were monitored. Animals were then euthanized, visceral and gonadal fat tissue and testes were collected, and epididymal spermatozoa were excised. Testicular samples were used for morphological description by H&E staining and for quantifying triacylglycerol content, caspase activity, and oxidative stress. Serum testosterone concentration was evaluated. Spermatozoa were used to assess sperm quality. Our results show that sperm quality was impaired by consuming HSD and could not be restored by dietary intervention. HSD feeding induced hyperplasia of visceral adipose tissue, increased testicular weight, and serum testosterone levels. The dietary intervention increased visceral adipose tissue, serum, and testicular triacylglycerol levels and normalized serum testosterone levels. Overall, the HSD diet caused permanent changes in seminiferous tubule cross-sectional area, caspase activity, oxidative stress, and sperm quality. Therefore, a high-sugar diet in early life causes permanent damage to sperm quality in adulthood.

Protective Effects of Kefir Against Unpredictable Chronic Stress Alterations in Mice Central Nervous System, Heart, and Kidney

Kefir is a probiotic mixture with anxiolytic and antioxidant properties. Chronic stress can lead to anxiety disorders and increase oxidative damage in organs such as the heart and kidney. In this study, we examined whether kefir ameliorates the anxiety-like behavior of mice submitted to chronic unpredictable stress (CUS) by modulating brain-derived neurotrophic factor (BDNF) and corticosterone levels and whether kefir modifies the oxidative parameters in the heart and kidney of mice. Male Swiss mice received kefir (0.3 mL/100 g/day) or milk for 30 days (gavage). On the 10th day, the mice were submitted to CUS. Behavioral analysis was performed using the elevated plus maze and forced swimming tests. BDNF levels were analyzed in brain tissues. Heart and kidney superoxide dismutase (SOD), catalase, glutathione (GSH), thiobarbituric acid reactive substances (TBARS), 3-nitrotyrosine, metalloproteinase-2 (MMP-2), and plasma corticosterone were evaluated. Kefir reverted the CUS-induced decrease in the time spent in the open arms, the increase in grooming frequency, and decrease in the head dipping frequency, but not the reduced immobility time. CUS decreased the cerebellum BDNF levels and increased corticosterone levels, which were restored by Kefir. Neither catalase and SOD activities nor GSH, TBARS, 3-nitrotyrosine, and MMP-2 were modified by CUS in the heart. In the kidney, CUS increased 3-nitrotyrosine and MMP-2. Kefir increased the antioxidant defense in the heart and kidney of control and CUS mice. These results suggest that kefir ameliorated CUS-induced anxiety-like behavior by modulating brain BDNF and corticosterone levels. Kefir also increased the antioxidant defense of mice heart and kidney.

Histomorphological testicular changes and decrease in the sperm count in pubertal rats induced by a high-sugar diet

BACKGROUND

During childhood and adolescence, excessive food consumption stimulates adipose tissue expansion promoting overweight in humans, and mice. A high-sucrose diet is related to obesity and metabolic syndrome. Infertility is commonly related to these pathologies. We aim to evaluate possible histomorphological testicular changes induced by a high-sucrose diet on sperm count during the post-weaning period.

METHODS

Wistar male rats aged 21 days, weaned, were randomly assigned into two groups: control (fed and hydrated normally) and sugar group (fed normally but hydrated with a solution containing 30% of diluted sucrose during 30 days). At the pubertal age of 51 days, animals were killed and blood samples were taken to measure testosterone and leptin. Testicles were collected and gonadal adipose tissue and semen samples from the epididymis were excised. Testicle samples were used for morphological description using H&E staining, as well as to quantify the triacylglycerol content and the lactate dehydrogenase (LDH) expression. Semen samples were used to assess motility, viability, and sperm count.

RESULTS

The sugar group presented an increase in the testicular weight, but a reduction in the cross-sectional area of seminiferous tubules. Moreover, disorganization of Sertoli cells and spermatogonia, an increase in the LDH expression within the entire seminiferous tubule, and a reduced sperm count and spermatozoid motility were found. These alterations were accompanied by high serum levels of testosterone and leptin.

CONCLUSIONS

Our results indicate strong damage of testis by sugar consumption during early life that may lead to the onset of infertility in adulthood.

High-sucrose diet potentiates hyperaldosteronism and renal injury induced by stress in young adult rats

Analyze the effect of stress and high-sucrose diet on serum aldosterone levels and the morphometric characteristics of the kidney in young adult rats. Wistar male rats aged 21 days old weaned were randomly assigned into four 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 ad libitum (C group) or 30% sucrose diluted in water (S30 group) during eight weeks. The St and St + S30 groups were subject to restraint stress (1-hour daily in a plastic cylinder, 5 days per week), four weeks before euthanasia. At 81 days old, all animals were killed and blood samples and kidneys were collected. Stressed rats had an increase in the serum aldosterone and renal triacylglycerol, a decrease in the area of the renal corpuscle, glomeruli, proximal tubules, and aquaporin 2 expressions with loss of glomeruli. For its part, the high-sucrose diet decreased the area of the renal corpuscle, glomeruli, and aquaporin 2 expressions in the cortex. The combination of stress and high- sucrose diet maintained similar effects on the kidney as the stress alone, although it induced an increase in the creatinine levels and renal glycogen. Our results showed that chronic stress induces hyperaldosteronism and kidney injury. The intake of a high-sucrose diet may potentiate the renal injury promoted by stress.