Resting heart rate variability and plasma noradrenaline level as a measurement of autonomic nervous system activity in mature, aging rats

Introduction and objective. Aging is a process that also affects the autonomic nervous system (ANS) making it less adaptable to environmental and intrinsic stimuli and affecting its ability to maintain body homeostasis. The aim of this study was to estimate the resting ANS function using heart rate variability (HRV) method and by noradrenaline measurement in aging, 2–12-months-old rats. Materials and method. Resting 15-minute-long ECG recordings were performed in anaesthetized rats with a subsequent spectral HRV analysis. Basic non-normalized HRV components in the range of very low (VLF), low (LF) and high (HF) frequency, along with the total HRV spectrum power (TP) were estimated. Moreover, normalized LF (nLF) and normalized HF (nHF) were calculated. Blood samples were also collected to assay plasma noradrenaline (NA) level. Results. In the overall assessment, plasma noradrenaline level as well as both TP and all non-normalized HRV components demonstrated a tendency for reduction when compared the first (2nd) and last (12th) months. In the case of nLF and nHF, a trend of nLF predominance in the 2nd and 3rd month was revealed while an inverse relation was observed from the 6th month on, with nHF superiority. Overall, males reached comparable or slightly higher NA and non-normalized HRV values compared to females, although most differences were not statistically significant. A parallel decline of LF (starting from the 10th month) and HF (from the 6th month) was demonstrated in both male and female animals. Female rats had a little more stable nLF and nHF course in the study time. Conclusions. Rat ANS aging is associated with global HRV decrease with parallel plasma NA decline, although without selective impairment of individual (sympathetic/parasympathetic) ANS components

Urine uromodulin estimation in partial bladder outlet obstruction and cyclophosphamide-induced haemorrhagic cystitis models in rats

Introduction: Uromodulin (UMOD) is a glycoprotein excreted by the thick ascending limb of the Henle’s loop and distal convoluted tubule cells, playing various, yet still unclear roles. An abnormal urinary UMOD excretion is observed in many pathophysiological conditions. The aim of our study was to assess urine UMOD excretion in experimental partial bladder outlet obstruction (PBOO), reflecting BPH in humans, and in cyclophosphamide-induced haemorrhagic cystitis (CP-HC).Materials and methods: PBOO and CP-HC rats and two appropriate control groups were studied. The PBOO model was surgically induced by partial proximal urethral obstruction and CP-HC by four i.p. cyclophosphamide administrations (every two days). 24-hour urine collections were performed in both PBOO (on 3rd, 7th, 12th and 15th day after surgery) and CP-HC rats (on 1st, 3rd, 5th and 7th day). UMOD was determined with the ELISA method. Both 24-hour urinary UMOD excretion and urinary UMOD concentrations were determined.Results: In the overall assessment, PBOO rats were characterized by decreased mean urinary UMOD concentration. However, as the urine volume, except for transient drop on 3rd day following PBOO operation, was steadily increasing, the daily urinary uromodulin excretion did not differ from the control one. Contrary to PBOO, CP-HC rats demonstrated mean urinary concentration similar to that of the control rats, while their 24hr UMOD excretion in urine was almost doubled due to urine volume increase (from 1.6 up to almost 3 fold). The highest UMOD urinary output was observed after the 3rd and 4th doses of cyclophosphamide.Discussion: A reduced urinary UMOD excretion in early PBOO phase may be considered as a marker of distal tubular cells damage due to incomplete bladder emptying and increased pressure retrograding to distal tubules. This effect disappears with structural, adaptive histological changes of the bladder wall leading to an improved voiding. In CP-HC animals, the elevated urinary UMOD level may be associated with complex inflammatory response due to the cytotoxic CP action. UMOD assessment in this model may reflect renal and urological toxicity as UMOD excretion rises with the cumulative cyclophosphamide dose

Low-frequency electromagnetic field influences human oral mucosa keratinocyte viability in response to lipopolysaccharide or minocycline treatment in cell culture conditions

The aim of the current study was to investigate the influence of low-frequency electromagnetic field (LF-EMF) exposure on viability parameters of oral mucosa keratinocytes cultured in in vitro conditions. The effect of LF-EMF stimulation on cell viability was also specified in the simultaneous presence of lipopolysaccharide (LPS) infectious agent or minocycline (Mino) anti-inflammatory agent. Viability parameters such as early-, late apoptosis and necrosis of keratinocytes were analysed by the flow cytometry method (FCM).The exposure of human oral keratinocyte cell cultures to LF-EMF acting alone or combined with LPS/minocycline agents caused changes in the percentage of cells that undergo programmed or incidental cell death. The overall obtained results are compiled in a graphical form presented in Fig. 1

Repeated transcranial direct current stimulation induces behavioral, metabolic and neurochemical effects in rats on high-calorie diet

Due to its high prevalence, obesity is considered an epidemic, which stimulated research on non-invasive methods to reduce excess body fat. Transcranial direct current stimulation (tDCS) is a non-invasive technique used to modulate the activity of cerebral cortex, which has already found increasing interest in medicine as a promising methodology. The aim of this study was to analyze the impact of tDCS on feeding behavior, metabolic abnormalities and neurotransmitters in certain brain areas involved in appetite control of obese rats. The male Wistar rats were divided into five subgroups depending on consumed diet effect (lean, obese) and tDCS type (anodal, cathodal, sham, and no stimulation). Two 10-min daily sessions of tDCS for 8 consecutive days of the study were applied. Rats subjected to active tDCS (anodal right or cathodal left of the prefrontal cortex) had reduced appetite and showed lesser body weight gain than the animals subjected to sham procedure or those receiving no stimulation at all. Furthermore, tDCS contributed to reduction of epididymal fat pads and to a decrease in blood concentration of leptin. Neurochemical examination revealed that tDCS modulated serotonin pathways of the reward-related brain areas and contributed to a significant decrease in the density of D2 but not D1 dopamine receptors in the dorsal striatum, recorded 5 h after the last stimulation. No significant effect of tDCS on dopamine and it's metabolites in examined brain regions was observed. It seems that the hypothalamus was not affected by tDCS application as no changes in measured neurotransmitters were detected at any examined time point. However, these results do not exclude the possibility of the delayed response of the monoamines in the examined brain areas to tDCS application. Altogether, these findings imply that repeated tDCS of the prefrontal cortex may change feeding behavior of obese rats. Either right anodal or left cathodal tDCS were sufficient to decrease food intake, to reduce body adiposity and to normalize other metabolic anomalies. These beneficial effects can be at least partially explained by changes in serotoninergic and in lesser extent dopaminergic system activity within some brain areas belonging to reward system

Experimental model for acute kidney injury caused by uropathogenic Escherichia coli

Introduction: Acute kidney injury (AKI) is the rapid deterioration of renal function, diagnosed on the basis of an increase in serum creatinine and abnormal urinary parameters. AKI is associated with increased risk of mortality or chronic kidney disease (CKD).The aim of the study was to develop an experimental model for AKI resulting from Escherichia coli-induced pyelonephritis. E. coli was isolated from a patient with clinical symptoms of urinary tract infection (UTI).Material/Methods: The study included three groups of female Wistar rats (groups 1, 2 and 3), in which pyelonephritis was induced by transurethral inoculation with highly virulent E. coli (105, 107 and 109 cfu/ml, respectively). Urine and blood samples for analysis were obtained prior to the inoculation (day 0), as well as 7, 14 and 21 days thereafter.Results: Aside from a microbiological examination of urine samples, daily urine output, serum creatinine (CreaS), creatinine clearance (CrCl), interleukin 6 (IL-6), fractional excretion of sodium (FENa) and fractional excretion of urea (FEUrea) were determined. A histopathological examination of kidney and urinary bladder specimens was conducted as well. While UTI-related pyelonephritis developed irrespective of E. coli inoculum size, AKI was observed only following transurethral administration of E. coli at the intermediate and high dose, i.e. 107 and 109 cfu/ml, respectively (group 2 and 3). Discussion: An increase in CreaS and abnormal diuresis were accompanied by changes in parameters specific for various forms of AKI, i.e. FENa and FEUrea. Based on these changes, administration of E. coli at 107 cfu/ml was demonstrated to induce renal AKI, whereas inoculation with 109 cfu/ml seemed to cause not only ascending pyelonephritis, but perhaps also bacteremia and urosepsis (prerenal component of AKI)