The number and periodicity of seizures induce cardiac remodeling and changes in micro-RNA expression in rats submitted to electric amygdala kindling model of epilepsy

Generalized tonic-clonic seizures (GTCS) are the main risk factor for sudden unexpected death in epilepsy (SUDEP). Also, among the several mechanisms underlying SUDEP there is the cardiac dysfunction. So, we aimed to evaluate the impact of the number of seizures on heart function and morphology in rats with epilepsy. Rats were randomized into three groups: Sham (without epilepsy), 5 S, and 10 S groups, referred as rats with epilepsy with a total of 5 or 10 GTCS, respectively. Epilepsy was induced by electrical amygdala kindling. The ventricular function was analyzed by the Langendorff technique and challenged by ischemia/reperfusion protocol. Cardiac fibrosis and hypertrophy were analyzed by histology. We also analyzed cardiac metalloproteinases (MMP2 and MMP9), ERK 1/2 and phosphorylated ERK1/2 (P-ERK) by western blot; microRNA-21 and -320 by RT-PCR; and oxidative stress (TBARS, catalase activity and nitrite) by biochemical analysis. Only the 5S group presented decreased values of ventricular function at before ischemia/reperfusion (baseline): intraventricular systolic pressure, developed intraventricular pressure, positive and negative dP/dt. During ischemia/reperfusion protocol, the variation of the ventricular function did not differ among groups. Both 5S and 10S groups had increased cardiomyocyte hypertrophy and fibrosis compared to Sham, but in the 5S group, these alterations were higher than in the 10S group. The 5S group increased in microRNA-21 and decreased in microRNA-320 expression compared to Sham and the 10S group. The 10S group increased in MMP9 and decreased in P-ERK/ERK expression, and increased in nitrite content compared to both Sham and the 5S group. Therefore, seizures impair cardiac function and morphology, probably through microRNA modulation. The continuation of seizures seems to exert a preconditioning-like stimulus that fails to compensate the cardiac tissue alteration.

Assessment of vitamin D and inflammatory markers profile in cardiac tissue on Parkinson disease animal model

BACKGROUND

Cardiovascular dysfunctions are common non-motor symptoms in patients with Parkinson's disease (PD) that can result in reduced quality of life and even death. Research in animal models designed to characterize the pathological association between PD and cardiovascular abnormalities is still in its infancy. This study assessed the early impact of the nigrostriatal dopaminergic damage on cardiological features in the unilateral 6-OHDA rat model of PD.

METHODS

Male Wistar rats received unilateral intrastriatal injections of 6-OHDA and sham rats were injected with saline. Animals were studied 15 days later. Immunohistochemistry was used for visualization of tyrosine hydroxylase (TH)-positive neurons in the nigrostriatal system. Electrocardiogram recordings of heart rate were performed in conscious rats. Heart levels of vitamin D, inflammatory cytokines and C-reactive protein were assessed through electrochemiluminescence immunoassay, quantitative reverse transcription PCR and turbidimetric method, respectively.

RESULTS

We found a post-injury reduction of TH-immunoreactivity of approximately 45% in the substantia nigra pars compacta and 20% in the striatum. Heart rate reduction was found in 6-OHDA-lesioned rats as compared with sham counterparts. Reduced levels of vitamin D and increased levels of inflammatory factors (C-reactive protein, IL-6, TNF-α and TGF-β) were detected in the heart tissue of PD rats in comparison with sham.

CONCLUSION

Our findings suggest a link between cardiac tissue changes and cardiac functional changes early after the central dopaminergic damage induced by 6-OHDA. Knowledge of the cardiac abnormalities in the 6-OHDA model is critical in identifying future therapeutic targets and disease-modifying approaches for PD non-motor features.

Fish Oil Supplementation Reduces Heart Levels of Interleukin-6 in Rats with Chronic Inflammation due to Epilepsy

Sudden unexpected death in epilepsy (SUDEP) is a major cause of premature death related to epilepsy. The causes of SUDEP remain unknown, but cardiac arrhythmias and asphyxia have been suggested as a major mechanism of this event. Inflammation has been implicated in the pathogenesis of both epilepsy and ventricular arrhythmia, with interleukin-6 (IL-6) being recognized as a crucial orchestrator of inflammatory states. Our group previously reported that levels of IL-6 were increased in the hearts of epileptic rats. In this scenario, anti-inflammatory actions are among the beneficial effects of fish oil dietary supplementation. This investigation revealed that elevated levels of IL-6 in the heart were markedly reduced in epileptic rats that were treated in the long-term with fish oil, suggesting protective anti-inflammatory actions against dangerously high levels of IL-6. Based on these findings, our results suggest beneficial effects of long-term intake of fish oil in reducing the inflammation associated with chronic epilepsy.

Restriction of rapid eye movement sleep during adolescence increases energy gain and metabolic efficiency in young adult rats

NEW FINDINGS

What is the central question of this study? Sleep curtailment in infancy and adolescence may lead to long-term risk for obesity, but the mechanisms involved have not yet been determined. This study examined the immediate and long-term metabolic effects produced by sleep restriction in young rats. What is the main finding and its importance? Prolonged sleep restriction reduced weight gain (body fat stores) in young animals. After prolonged recovery, sleep-restricted rats tended to save more energy and to store more fat, possibly owing to increased gross food efficiency. This could be the first step to understand this association. Sleep curtailment is associated with obesity and metabolic changes in adults and children. The aim of the present study was to evaluate the immediate and long-term metabolic alterations produced by sleep restriction in pubertal male rats. Male Wistar rats (28 days old) were allocated to a control (CTL) group or a sleep-restricted (SR) group. This was accomplished by the single platform technique for 18 h per day for 21 days. These groups were subdivided into the following four time points for assessment: sleep restriction and 1, 2 and 4 months of recovery. Body weight and food intake were monitored throughout the experiment. At the end of each time period, blood was collected for metabolic profiling, and the carcasses were processed for measurement of body composition and energy balance. During the period of sleep restriction, SR animals consumed less food in the home cages. This group also displayed lower body weight, body fat, triglycerides and glucose levels than CTL rats. At the end of the first month of recovery, despite eating as much as CTL rats, SR animals showed greater energy and body weight gain, increased gross food efficiency and decreased energy expenditure. At the end of the second and fourth months of recovery, the groups were no longer different, except for energy gain and gross food efficiency, which remained higher in SR animals. In conclusion, sleep restriction affected weight gain of young animals, owing to reduction of fat stores. Two months were sufficient to recover this deficit and to reveal that SR rats tended to save more energy and to store more fat.

Maternal obesity and late effects on offspring metabolism

Objective : The aim of this study was to evaluate the late effects of maternal obesity induced by lesion of the ventromedial hypothalamus on offspring metabolism.Materials and methods : Thirty days after the bilateral lesion of the ventromedial hypothalamus, female rats were mated and divided into 2 groups of pregnant animals: Control (C) – false lesion (sham) and Obese (OB) – lesion. Three months after that, with the groups of mothers, offspring were divided into control and obese animals that received a normocaloric diet (C-N and OB-N), and control and obese animals that received a hypercaloric diet (C-H and OB-H). At 120 days of age, the animals were euthanized and their carcasses, feces and food were submitted to calorimetric analysis to determine energy balance and body composition.Results : During the growth period, offspring from obese mothers showed higher values of body weight and food intake than controls. Obese animals showed higher body weight gain and gross food efficiency than control animals in adulthood. The hypercaloric diet led to increased metabolizable energy intake, percentage of absorbed energy and energy expenditure in both groups. Body composition was only affected by the association of hypercaloric diet and maternal obesity that led to increased body fat.Conclusions : Maternal obesity has led to the development of later overweight in offspring, suggesting fetal programming. According to the trend presented, it is believed that the prolonged intake of hypercaloric diets in adult animals may, as an additional effect, induce worsening of the overweight induced by maternal obesity. Arq Bras Endocrinol Metab. 2014;58(3):301-7