Bilayer scaffold from PLGA/fibrin electrospun membrane and fibrin hydrogel layer supports wound healingin vivo.

Hybrid scaffolds from natural and synthetic polymers have been widely used due to the complementary nature of their physical and biological properties. The aim of the present study, therefore, has been to analyzein vivoa bilayer scaffold of poly(lactide-co-glycolide)/fibrin electrospun membrane and fibrin hydrogel layer on a rat skin model. Fibroblasts were cultivated in the fibrin hydrogel layer and keratinocytes on the electrospun membrane to generate a skin substitute. The scaffolds without and with cells were tested in a full-thickness wound model in Wistar Kyoto rats. The histological results demonstrated that the scaffolds induced granulation tissue growth, collagen deposition and epithelial tissue remodeling. The wound-healing markers showed no difference in scaffolds when compared with the positive control. Activities of antioxidant enzymes were decreased concerning the positive and negative control. The findings suggest that the scaffolds contributed to the granulation tissue formation and the early collagen deposition, maintaining an anti-inflammatory microenvironment.

Short-term effects of therapeutic hypothermia following hypoxia-ischemia in neonatal male and female rats.

Nowadays, the only treatment for human babies suffering from hypoxia-ischemia (HI) is therapeutic hypothermia (TH). However, a better understanding of the specific effects of TH in males and females is important to improve its clinical application. The present study evaluated the short-term effects of TH on the brain injury and behavioral outcomes in male and female neonatal rats submitted to neonatal HI. Seven-day-old Wistar rats underwent a surgery for unilateral occlusion of the right common carotid artery and were exposed to a hypoxic atmosphere (8% oxygen) for 75 min. Then, the animals in the TH group were submitted to TH (scalp temperature of 32°C) for 5 h. In the behavioral tests, no remarkable differences triggered by HI or TH were observed relative to SHAM animals. Only females of the HI group presented lower latency to complete the righting reflex test. TH reduced the volume of brain injury in males, but not in females. The animals of the HI group showed a reduction in the number of neurons in the CA1 and dentate gyrus (DG) regions of the hippocampus and TH partially prevented neuronal death. In the CA1 region of the hippocampus, animals from the HI group showed more degenerating cells relative to the SHAM, which was reversed by TH. In the DG, animals from the HI group showed an increase in the number of degenerating neurons, which was partially reversed by TH only in males. Our data show that HI leads to a brain injury, which was attenuated by TH in a sex-dependent way and clarify the importance of the assessment of males and females in order to outline specific strategies for the treatment of each sex in newborns suffering from HI.

Endurance and resistance exercise training programs elicit specific effects on sciatic nerve regeneration after experimental traumatic lesion in rats.

OBJECTIVE: To evaluate the effects of endurance, resistance, and a combination of both types of exercise training on hindlimb motor function recovery and nerve regeneration after experimental sciatic nerve lesion in rats. METHODS: Sciatic nerve crush was performed on adult male rats, and after 2 weeks of the nerve lesion, the animals were submitted to endurance, resistance, and a combination of endurance-resistance training programs for 5 weeks. Over the training period, functional recovery was monitored weekly using the Sciatic Functional Index (SFI) and histological and morphometric nerve analyses were used to assess the nerve regeneration at the end of the trainings. RESULTS: The SFI values of the endurance-trained group reached the control values from the first posttraining week and were significantly better than both the resistance-trained group at the first, second, and third posttraining weeks and the concurrent training group at the first posttraining week. At the distal portion of the regenerating sciatic nerve, the endurance-trained group showed a greater degree of the myelinated fiber maturation than the sedentary, resistance-trained, and concurrent training groups. Furthermore, the endurance-trained group showed a smaller percentage area of endoneurial connective tissue and a greater percentage area of myelinated fibers than the sedentary group. CONCLUSION: These data provide evidence that endurance training improves sciatic nerve regeneration after an experimental traumatic injury and that resistance training or the combination of 2 strategies may delay functional recovery and do not alter sciatic nerve fiber regeneration.

Ovarian tissue vitrification: the use of a novel metal closed system for clinical grade cryopreservation.

OBJECTIVE: To investigate whether a metal chamber is an appropriate system for vitrification of ovarian tissue under clinical grade. METHODS: Experimental study, control versus treatment. Bovine ovarian cortices cut in 1x1x1 mm fragments were vitrified using ethylene glycol and dimethyl sulfoxide inside steel cryovials, whose bases were in touch with Liquid Nitrogen (LN2). Screw caps closed the cryovials before plunging into LN2. Primordial (n=356) and primary (n=327) follicles and the stroma were analyzed after histological preparation using light microscopy. RESULTS: High rate of primordial (93%) and primary (80%) follicles presented normal morphology in the rewarmed fragments. There was not a significant difference between controls and primordial follicles morphology (P=0.1519). Significant difference was observed for the primary follicles (P=0.0097). Important to point out that stromal cells and collagen fibers presented a remarkable integrity, without major alterations in the cryopreserved tissues. CONCLUSIONS: The steel cryovial seems to be a safe means of vitrification under clinical grade conditions, with very fast cooling rates and no direct contact of the biological material with the liquid nitrogen (LN2). Ovarian reserve represented by primordial and primary follicles and stroma are very well preserved in this vitrification system.

Hepatoprotective and Antioxidant Potential of Organic and Conventional Grape Juices in Rats Fed a High-Fat Diet.

The objective of this study was to investigate the antioxidant and hepatoprotective effect of the chronic use of conventional (CGJ) or organic (OGJ) grape juice from the Bordeaux variety grape on oxidative stress and cytoarchitecture in the liver of rats supplemented with a high-fat diet (HFD) for three months. The results demonstrated that HFD induced an increase in thiobarbituric acid-reactive substances (TBARS), catalase (CAT) activity and 2',7'-dihydrodichlorofluorescein (DCFH) oxidation and a decrease in sulfhydryl content and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. HFD also induced hepatocellular degeneration and steatosis. These alterations were prevented by CGJ and OGJ, where OGJ was more effective. Therefore, it was concluded that HFD induced oxidative stress and liver damage and that the chronic use of grape juice was able to prevent these alterations.

Evaluation of chronic omega-3 fatty acids supplementation on behavioral and neurochemical alterations in 6-hydroxydopamine-lesion model of Parkinson's disease.

Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) have been widely associated to beneficial effects over different neuropathologies, but only a few studies associate them to Parkinson's disease (PD). Rats were submitted to chronic supplementation (21-90 days of life) with fish oil, rich in omega-3 PUFAs, and were uni- or bilaterally lesioned with 4microg of the neurotoxin 6-hydroxydopamine (6-OHDA) in the medial forebrain bundle. Although lipid incorporation was evidenced in neuronal membranes, it was not sufficient to compensate motor deficits induced by 6-OHDA. In contrast, omega-3 PUFAs were capable of reducing rotational behavior induced by apomorphine, suggesting neuroprotection over dyskinesia. The beneficial effects of omega-3 PUFAs were also evident in the maintenance of thiobarbituric acid reactive substances index from animals lesioned with 6-OHDA similar to levels from SHAM and intact animals. Although omega-3 PUFAs did not modify the tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta and in the ventral tegmental area, nor the depletion of dopamine (DA) and its metabolites in the striatum, DA turnover was increased after omega-3 PUFAs chronic supplementation. Therefore, it is proposed that omega-3 PUFAs action characterizes the adaptation of remaining neurons activity, altering striatal DA turnover without modifying the estimated neuronal population.

Sex differences in NADPH-diaphorase activity in the rat posterodorsal medial amygdala.

The rat posterodorsal medial amygdala (MePD) is a sexually dimorphic area implicated in the control of reproduction. Interestingly, nitric oxide (NO) synthetizing neurons are widely distributed in brain regions involved with the modulation of sexual behavior. Here we studied the NADPH-diaphorase (NADPH-d) activity and the number of positive cells in the MePD of adult males and adult females either across the estrous cycle (diestrus, proestrus, estrus, and metaestrus) or following ovariectomy and substitutive therapy (consisting of oil, estradiol alone, the combination of estradiol and progesterone, or progesterone alone). The NADPH-d histochemical technique was followed by a semi-quantitative analysis using optical densitometry. Males showed a higher MePD regional optical density and neuronal optical density than females across the estrous cycle, with the exception of the diestrus phase (P<0.01). No differences were found in these parameters during the ovarian cycle (P>0.05). There were no statistically significant differences among males and cycling females in the number of NADPH-d positive cells (P>0.05). Additionally, no statistically significant difference was found in the regional optical density, in the neuronal optical density, or in the number of NADPH-d positive neurons when comparing the data from ovariectomized females that received vehicle or the three different hormonal replacement therapies (P=0.07, P=0.18, and P=0.95, respectively). Results suggest that NADPH-d activity in the rat MePD is different between sexes but in females it is not affected by changing levels of circulating gonadal hormones in physiological or supraphysiological conditions.

NADPH-diaphorase activity in the nociceptive pathways of land snail Megalobulimus abbreviatus: the involvement of pedal ganglia.

NADPH-diaphorase (NADPH-d) is a histochemical marker for nitric oxide synthase (NOS), widely used to identify nitric oxide (NO) producing cells in the nervous system of both vertebrates and invertebrates. Using NADPH-d histochemistry and semi-quantitative optical densitometry, we characterized the NO-producing neurons in the pedal ganglia of young and adult Megalobulimus abbreviatus, subjected to aversive thermal stimulus. The animals were killed at different times (3, 6, 12 and 24 h) following stimulus. The enzymatic activity was detected in different cellular subsets and neuronal processes. In all the studied pedal ganglia subregions, the optical density of positive neurons (P < 0.05) and neuropilar area 1 (P < 0.01) was significantly different in treated animals when compared to controls. The increase in nitrergic activity induced by nociceptive stimulus suggests the involvement of NO in the nociceptive circuit of M. abbreviatus, which is well maintained throughout evolution, and could be helpful in drawing cellular homologies with other gastropods.

Evaluation of estrogen neuroprotective effect on nigrostriatal dopaminergic neurons following 6-hydroxydopamine injection into the substantia nigra pars compacta or the medial forebrain bundle.

Studies involving estrogen treatment of ovariectomized rats or mice have attributed to this hormone a neuroprotective effect on the substantia nigra pars compacta (SNpc) neurons. We investigated the effect of estradiol replacement in ovariectomized rats on the survival of dopaminergic mesencephalic cell and the integrity of their projections to the striatum after microinjections of 1 microg of 6-hydroxydopamine (6-OHDA) into the right SNpc or medial forebrain bundle (MFB). Estradiol replacement did not prevent the reduction either in the striatal concentrations of DA and metabolites or in the number of nigrostriatal dopaminergic neurons following lesion with 1 microg of 6-OHDA into the SNpc. Nevertheless, estradiol treatment reduced the decrease in striatal DA following injection of 1 microg of 6-OHDA into the MFB. Results suggest therefore that estrogen protect nigrostriatal dopaminergic neurons against a 6-OHDA injury to the MFB but not the SNpc. This may be due to the distinct degree of lesions promoted in these different rat models of Parkinson's disease.

Capsaicin-induced avoidance behavior in the terrestrial Gastropoda Megalobulimus abbreviatus: evidence for TRPV-1 signaling and opioid modulation in response to chemical noxious stimuli.

The aim of this study was to measure the nociceptive response (avoidance latency) of the land snail Megalobulimus abbreviatus (N=8 in each group) after topical capsaicin exposure (0.1% and 0.5% in 20% ethanol) and to compare it to a well-studied stressful (50 degrees C) thermal stimulus model. We also tested if ruthenium red, and capsazepine, respectively nonselective and selective TRPV1 receptor antagonists, could modify both capsaicin- and thermal-evoked responses. Finally, animals were pretreated with morphine, naloxone or morphine plus naloxone prior to capsaicin stimuli. Latencies were measured when the animal lifted its head-foot complex 1 cm from the substrate. Data were compared using ANOVA and LSD post hoc, and the Student T Test (p<0.05). Capsaicin elicited dose-dependent withdrawal behavior. The capsaicin vehicle (20% ethanol) also evoked a less intense but significant avoidance reaction. Capsazepine and ruthenium red attenuated both capsaicin and heat withdrawal responses, when compared to vehicles. Morphine increased, and naloxone, either alone or in combination with morphine, reduced capsaicin-evoked latencies when compared to morphine or saline. These results indicate that the TRPV1 receptor plays a role in the nociceptive circuits of M. abbreviatus.