Rotenone Exerts Similar Stimulatory Effects On H2o2 Production By Isolated Brain Mitochondria From Young-adult And Old Rats.

Chronic and systemic treatment of rodents with rotenone, a classical inhibitor of mitochondrial respiratory complex I, results in neurochemical, behavioral, and neuropathological features of Parkinson's disease. The aim of the present study was to evaluate whether brain mitochondria from old rats (24 months old) would be more susceptible to rotenone-induced inhibition of oxygen consumption and increased generation of H2O2 than mitochondria from young-adult rats (3-4 months old). Isolated brain mitochondria were incubated in the presence of different rotenone concentrations (5, 10, and 100nM), and oxygen consumption and H2O2 production were measured during respiratory states 3 (ADP-stimulated respiration) and 4 (resting respiration). Respiratory state 3 and citrate synthase activity were significantly lower in mitochondria from old rats. Mitochondria from young-adult and old rats showed similar sensitivity to rotenone-induced inhibition of oxygen consumption. Similarly, H2O2 production rates by both types of mitochondria were dose-dependently stimulated to the same extent by increasing concentrations of rotenone. We conclude that rotenone exerts similar effects on oxygen consumption and H2O2 production by isolated brain mitochondria from young-adult and old rats. Therefore, aging does not increase the mitochondrial H2O2 generation in response to complex I inhibition.

Mesenchymal Stem Cells Engrafted In A Fibrin Scaffold Stimulate Schwann Cell Reactivity And Axonal Regeneration Following Sciatic Nerve Tubulization.

The present study investigated the effectiveness of mesenchymal stem cells (MSCs) associated with a fibrin scaffold (FS) for the peripheral regenerative process after nerve tubulization. Adult female Lewis rats received a unilateral sciatic nerve transection followed by repair with a polycaprolactone (PCL)-based tubular prosthesis. Sixty days after injury, the regenerated nerves were studied by immunohistochemistry. Anti-p75NTR immunostaining was used to investigate the reactivity of the MSCs. Basal labeling, which was upregulated during the regenerative process, was detected in uninjured nerves and was significantly greater in the MSC-treated group. The presence of GFP-positive MSCs was detected in the nerves, indicating the long term survival of such cells. Moreover, there was co-localization between MSCs and BNDF immunoreactivity, showing a possible mechanism by which MSCs improve the reactivity of SCs. Myelinated axon counting and morphometric analyses showed that MSC engrafting led to a higher degree of fiber compaction combined with a trend of increased myelin sheath thickness, when compared with other groups. The functional result of MSC engrafting was that the animals showed higher motor function recovery at the seventh and eighth week after lesion. The findings herein show that MSC+FS therapy improves the nerve regeneration process by positively modulating the reactivity of SCs.

Improvement Of The Physical Performance Is Associated With Activation Of No/pgc-1α/mttfa Signaling Pathway And Increased Protein Expressions Of Electron Transport Chain In Gastrocnemius Muscle From Rats Supplemented With L-arginine.

To examine the influence of l-arginine supplementation in combination with physical training on mitochondrial biomarkers from gastrocnemius muscle and its relationship with physical performance. Male Wistar rats were divided into four groups: control sedentary (SD), sedentary supplemented with l-arginine (SDLA), trained (TR) and trained supplemented with l-arginine (TRLA). Supplementation of l-arginine was administered by gavage (62.5mg/ml/day/rat). Physical training consisted of 60min/day, 5days/week, 0% grade, speed of 1.2km/h. The study lasted 8weeks. Skeletal muscle mitochondrial enriched fraction as well as cytoplasmic fractions were obtained for Western blotting and biochemical analyses. Protein expressions of transcriptor coactivator (PGC-1α), transcriptor factors (mtTFA), ATP synthase subunit c, cytochrome oxidase (COXIV), constitutive nitric oxide synthases (eNOS and nNOS), Cu/Zn-superoxide dismutase (SOD) and manganese-SOD (Mn-SOD) were evaluated. We also assessed in plasma: lipid profile, glycemia and malondialdehyde (MDA) levels. The nitrite/nitrate (NOx(-)) levels were measured in both plasma and cytosol fraction of the gastrocnemius muscle. 8-week l-arginine supplementation associated with physical training was effective in promoting greater tolerance to exercise that was accompanied by up-regulation of the protein expressions of mtTFA, PGC-1α, ATP synthase subunit c, COXIV, Cu/Zn-SOD and Mn-SOD. The upstream pathway was associated with improvement of NO bioavailability, but not in NO production since no changes in nNOS or eNOS protein expressions were observed. This combination would be an alternative approach for preventing cardiometabolic diseases given that in overt diseases a profound impairment in the physical performance of the patients is observed.

Perivascular Adipose Tissue And Vascular Responses In Healthy Trained Rats.

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37-year-old Female With Intraventricular Mass.

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Vagotomy Ameliorates Islet Morphofunction And Body Metabolic Homeostasis In Msg-obese Rats.

The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca2+ mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca2+ mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats.

Intravesical Bacillus Calmette-guérin Efficiently Reduces P70s6k1 But Not 4e-bp1 Phosphorylation In Nonmuscle Invasive Bladder Cancer.

We characterized the functional consequences of intravesical bacillus Calmette-Guérin on the molecular mechanism of the AKT/mTOR signaling pathway in nonmuscle invasive bladder cancer. To our knowledge this has not been reported previously. At age 7 weeks female Fischer 344 rats received 1.5 mg/kg MNU intravesically every other week for 6 weeks. They were randomized at 10 per group to MNU (0.2 ml vehicle), bacillus Calmette-Guérin (10(6) cfu Connaught strain), rapamycin (15 μg/ml) and bacillus Calmette-Guérin plus simultaneous rapamycin, each intravesically for 6 weeks. At week 15 the bladders were collected for histopathology, immunohistochemistry and immunoblot to determine p-AKT, Rictor, Raptor, p-4E-BP1, p-p70S6K1, p-AMPK-α, p-mTOR and p-p53. Papillary carcinoma (pTa) and high grade intraepithelial neoplasia (pTis) predominated in the MNU group while normal urothelium, papillary and flat hyperplasia were more common in treated groups. Nonmuscle invasive bladder cancer treated with bacillus Calmette-Guérin showed suppression of p70S6K1 but not 4E-BP1 phosphorylation. This suggests that 4E-BP1 is regulated differently than p70S6K1, escaping the bacillus Calmette-Guérin action that occurs in a mTOR independent manner. The association of bacillus Calmette-Guérin with rapamycin but not rapamycin monotherapy affected p70S6K1 and 4E-BP1 phosphorylation with no features of in situ carcinoma (pTis). The activation status of p70S6K1 and 4E-BP1 might be used to stratify patients who could benefit from targeting such molecular elements with multitarget/multidrug intravesical therapy. In the future 4E-BP1 might be a worthwhile new target for bacillus Calmette-Guérin refractory nonmuscle invasive bladder cancer.

Jnk And Ikkβ Phosphorylation Is Reduced By Glucocorticoids In Adipose Tissue From Insulin-resistant Rats.

Peripheral insulin resistance (IR) is one of the main side effects caused by glucocorticoid (GC)-based therapies, and the molecular mechanisms of GC-induced IR are not yet fully elucidated. Thus, we aimed to investigate the effects of dexamethasone treatment on the main components of insulin and inflammatory signaling in the adipose tissue of rats. Male Wistar rats received daily injections of dexamethasone (1mg/kg body weight (b.w.), intraperitoneally (i.p.)) for 5 days (DEX), whereas control rats received saline (CTL). The metabolic status was investigated, and the epididymal fat fragments were collected for lipolysis and western blot analyses. The DEX rats became hyperglycemic, hyperinsulinemic, insulin resistant and glucose intolerant, compared with the CTL rats (P<0.05). The basal glycerol release in the fat fragments was 1.5-fold higher in the DEX rats (P<0.05). The phosphorylation of protein kinase B (PKB) at ser(473) decreased by 44%, whereas, the phosphorylation of insulin receptor substrate (IRS)-1 at ser(307) increased by 93% in the adipose tissue of the DEX rats after an oral bolus of glucose (P<0.05). The basal phosphorylation of c-jun-N-terminal kinase (JNK) and inhibitor of nuclear factor kappa-B (IKKβ) proteins was reduced by 46% and 58%, respectively, in the adipose tissue of the DEX rats (P<0.05). This was paralleled with a significant reduction (47%) in the glucocorticoid receptor (GR) protein content in the adipose tissue of the DEX rats (P<0.05). The insulin-resistant status of rats induced by dexamethasone administration have PKB and IRS-1 activity attenuated in epididymal fat without increases in the phosphorylation of the proinflammatory signals JNK and IKKβ.

The Effects Of High Doses Of Nandrolone Decanoate And Exercise On Prostate Microvasculature Of Adult And Older Rats.

The present study aimed to investigate the effects of the interaction between the abusive use of nandrolone decanoate (ND) and physical activity on the prostate structure of adult and older rats. We evaluated whether the use of ND, associated or not with physical exercise during the post-pubertal stage, interferes with the morphophysiology of the prostate. Fifty-six male Sprague-Dawley rats were divided into eight groups. The animals were treated for eight weeks and divided into sedentary and trained groups, with or without ND use. Four groups were sacrificed 48 h after the end of the eight week experiment (adult groups), and four other groups were sacrificed at 300 days of age (older groups). The prostate was collected and processed for stereological and histopathological analysis and for the expression of AQP1 and VEGF by the Western blotting technique. Both ND and physical activity altered the ventral prostate structure of the rats; the AQP1 and VEGF expression increased in young animals subjected to physical exercise. Thus, it was concluded that the use of ND, associated or not with exercise during the post-pubertal stage, interferes with the morphophysiology of the prostate.

Effect Of Pain Chronification And Chronic Pain On An Endogenous Pain Modulation Circuit In Rats.

We tested the hypothesis that chronic pain development (pain chronification) and ongoing chronic pain (chronic pain) reduce the activity and induce plastic changes in an endogenous analgesia circuit, the ascending nociceptive control. An important mechanism mediating this form of endogenous analgesia, referred to as capsaicin-induced analgesia, is its dependence on nucleus accumbens μ-opioid receptor mechanisms. Therefore, we also investigated whether pain chronification and chronic pain alter the requirement for nucleus accumbens μ-opioid receptor mechanisms in capsaicin-induced analgesia. We used an animal model of pain chronification in which daily subcutaneous prostaglandin E2 (PGE2) injections into the rat's hind paw for 14 days, referred to as the induction period of persistent hyperalgesia, induce a long-lasting state of nociceptor sensitization referred to as the maintenance period of persistent hyperalgesia, that lasts for at least 30 days following the cessation of the PGE2 treatment. The nociceptor hypersensitivity was measured by the shortening of the time interval for the animal to respond to a mechanical stimulation of the hind paw. We found a significant reduction in the duration of capsaicin-induced analgesia during the induction and maintenance period of persistent mechanical hyperalgesia. Intra-accumbens injection of the μ-opioid receptor selective antagonist Cys(2),Tyr(3),Orn(5),Pen(7)amide (CTOP) 10 min before the subcutaneous injection of capsaicin into the rat's fore paw blocked capsaicin-induced analgesia. Taken together, these findings indicate that pain chronification and chronic pain reduce the duration of capsaicin-induced analgesia, without affecting its dependence on nucleus accumbens μ-opioid receptor mechanisms. The attenuation of endogenous analgesia during pain chronification and chronic pain suggests that endogenous pain circuits play an important role in the development and maintenance of chronic pain.