Whole-body vibration mediates mechanical hypersensitivity through Aβ-fiber and C-fiber thermal sensation in a chronic pain model

Whole-body vibration (WBV), which is widely used as a type of exercise, involves the use of vibratory stimuli and it is used for rehabilitation and sports performance programmes. This study aimed to investigate the effect of WBV treatment in a chronic pain model after 10 WBV sessions. An animal model (chronic pain) was applied in 60 male Wistar rats (±180 g, 12 weeks old) and the animals were treated with low intensity exercise (treadmill), WBV (vibrating platform), and a combined treatment involving both. The controls on the platform were set to a frequency of 42 Hz with 2 mm peak-to-peak displacement, g ≈ 7, in a spiral mode. Before and after the vibration exposure, sensitivity was determined. Aβ-fibers-mediated mechanical sensitivity thresholds (touch-pressure) were measured using a pressure meter. C-fibers-mediated thermal perception thresholds (hot pain) were measured with a hot plate. After each session, WBV influenced the discharge of skin touch-pressure receptors, reducing mechanical sensitivity in the WBV groups (P < 0.05). Comparing the conditions "before vs. after", thermal perception thresholds (hot pain) started to decrease significantly after the third WBV session (P < 0.05). WBV decreases mechanical hyperalgesia after all sessions and thermal sensitivity after the third session with the use of WBV.

Effects of Maternal Physical Exercise on Global DNA Methylation and Hippocampal Plasticity of Rat Male Offspring

Intrauterine exposure to exercise is beneficial to cognition of the offspring. Although it is advisable to start practicing physical exercise during pregnancy, it is probable that practitioners or sedentary women keep their previous habits during gestation. This study was designed to evaluate the effects of maternal aerobic exercise initiated before and maintained during gestation, or performed in these isolated periods, on cognition and plasticity in the hippocampus of offspring. Groups of male pups were categorized by the exposure of their mothers to: treadmill off (sedentary, SS), pregestational exercise (ES), gestational exercise (SE) or combined protocols (EE). Between postnatal day 20 (P20) and P23 the offspring received one daily 5-bromo-2'-deoxiuridine (BrdU) injection and, from P47 to P51, were evaluated by the Morris water maze task. At P53, hippocampal global DNA methylation, survival of progenitor cells (BrdU), Brain-derived Neurotrophic Factor (BDNF) and reelin levels were measured. The offspring from ES, SE and EE mothers demonstrated improved spatial learning compared to SS, but hippocampal DNA methylation was significantly modified only in the offspring from ES mothers. The offspring from ES and SE mothers presented higher number of BrdU+ and reelin+ hippocampal cells than EE and SS. No differences were observed in the BDNF levels among the groups. The maternal pregestational and gestational isolated exercise protocols showed similar effects for offspring plasticity and spatial cognitive ability, while the combined protocol simply improved their spatial learning. Interestingly, only pregestational exercise was able to induce plasticity in the offspring hippocampus associated with modulation of global DNA methylation.

Paternal physical exercise modulates global DNA methylation status in the hippocampus of male rat offspring

It is widely known that maternal physical exercise is able to induce beneficial improvements in offspring cognition; however, the effects of paternal exercise have not been explored in detail. The present study was designed to evaluate the impact of paternal physical exercise on memory and learning, neuroplasticity and DNA methylation levels in the hippocampus of male offspring. Adult male Wistar rats were divided into two groups: sedentary or exercised fathers. The paternal preconception exercise protocol consisted of treadmill running, 20 minutes daily, 5 consecutive days per week for 22 days, while the mothers were not trained. After mating, paternal sperm was collected for global DNA methylation analysis. At postnatal day 53, the offspring were euthanized, and the hippocampus was dissected to measure cell survival by 5-bromo-2′-deoxiuridine and to determine the expression of synaptophysin, reelin, brain-derived neurotrophic factor and global DNA methylation levels. To measure spatial memory and learning changes in offspring, the Morris water maze paradigm was used. There was an improvement in spatial learning, as well as a significant decrease in hippocampal global DNA methylation levels in the offspring from exercised fathers compared with those from sedentary ones; however, no changes were observed in neuroplasticity biomarkers brain-derived neurotrophic factor, reelin and 5-bromo-2′-deoxiuridine. Finally, the global DNA methylation of paternal sperm was not significantly changed by physical exercise. These results suggest a link between paternal preconception physical activity and cognitive benefit, which may be associated with hippocampal epigenetic programming in male offspring. However, the biological mechanisms of this modulation remain unclear.

Synaptophysin and caspase-3 expression on lumbar segments of spinal cord after sensorimotor restriction during early postnatal period and treadmill training

The purpose of the current study was to investigate whether locomotor stimulation training could have beneficial effects on spinal cord plasticity consequent to sensorimotor restriction (SR). Male Wistar rats were exposed to SR from postnatal day 2 (P2) to P28. Control and experimental rats underwent locomotor stimulation training in a treadmill from P31 to P52. The intensity of the synaptophysin and caspase-3 immunoreaction was determined on ventral horn of spinal cord. The synaptophysin immunoreactivity was lower in the ventral horn of sensorimotor restricted rats compared to controls animals and was accompanied by an increased caspase-3 immunoreactivity. Those alterations were reversed at the end of the training period. Our results suggest that immobility affects the normal developmental process that spinal cord undergoes in early postnatal life influencing both pro-apoptotic and synapse markers. Also, we demonstrated that this phenomenon was reversed by 3 weeks of treadmill training.

The Effects of Two Different Exercise Programs on the Ultrastructural Features of the Sciatic Nerve and Soleus Muscle After Sciatic Crush

Peripheral nerve injuries constitute a significant medical problem and the recovery is critically dependent on post-injury treatment. In this study, following sciatic nerve crush, we investigated the effects of a 4-week endurance training program (ET) and balance and coordination training program (BCT) on the ultrastructural features of the sciatic nerve and soleus muscle. The animals were randomly divided into Sham, non-trained (NT), ET, and BCT groups each of which included three animals. Ultra-thin cross and longitudinal sections (70-85 nm) were digitized and analyzed comparatively. The electron micrographic analysis of the sciatic nerve showed similar organelles features in the injury groups (myelin debris and swelling mitochondria). Nonetheless, the ET group presented better ultrastructural features as demonstrated by the greater predominance of rounded fibers and more defined organization in the myelinated axon bundles. In the soleus muscle's analyses, the injured groups demonstrated similar organelles' features (nucleus contained highly heterochromatic nuclei and smaller mitochondria). However, ET and BCT groups showed apparently enlarged myofibril cross-sectional areas and less collagen around muscle fibers, although, the ET group displayed reduced intermyofibrillar spaces and more closely aligned myofilaments when compared with the BCT group. Based on electron micrographic analysis, our findings suggest the presence of ultrastructural differences between the Sham, NT, and the trained groups. Therefore, exercise type seems to be responsible for producing some different positive features in the trained groups, while ET seems to have a more pronounced influence on the ultrastructural features of the sciatic nerve and the soleus muscle after a crush injury. Anat Rec, 300:1654-1661, 2017. © 2017 Wiley Periodicals, Inc.

An evaluation of aversive memory and hippocampal oxidative status in streptozotocin-induced diabetic rats treated with resveratrol

The present study evaluated the effects of streptozotocin (STZ)-induced diabetes on aversive memory, free radical content and enzymatic antioxidant activity in the hippocampus of adult Wistar rats submitted to oral treatment with resveratrol. Animals were divided into eight groups: non-diabetic rats treated with saline (ND SAL), non-diabetic rats treated with resveratrol at a dose 5mg/kg (ND RSV 5), non-diabetic rats treated with resveratrol at a dose 10mg/kg (ND RSV 10), non-diabetic rats treated with resveratrol at a dose 20mg/kg (ND RSV 20), diabetic rats treated with saline (D SAL), diabetic rats treated with resveratrol at a dose 5mg/kg (D RSV 5), diabetic rats treated with resveratrol at a dose 10mg/kg (D RSV 10) and diabetic rats treated with resveratrol at a dose 20mg/kg (D RSV 20). The animals received oral gavage for 35days. The contextual fear conditioning task was performed to evaluate aversive-based learning and memory. The oxidative status was evaluated in the hippocampus, by measuring the free radical content - using a 2',7'-dichlorofluorescein diacetate probe - and enzymatic antioxidant activities, such as superoxide dismutase and glutathione peroxidase. Our main behavioral results demonstrated that rats from the D RSV 10 and D RSV 20 groups showed an increase in freezing behavior when compared, respectively, to the ND RSV 10 (p<0.01) and ND RSV 20 (p<0.05). Oxidative stress parameters remained unchanged in the hippocampus of all the experimental groups. In contrast to previous experimental findings, our study was unable to detect either cognitive impairments or oxidative stress in the hippocampus of the diabetic rats. We suggest additional long-term investigations be conducted into the temporal pattern of STZ-induced diabetic disruption in memory and hippocampal oxidative status, as well as the effects of resveratrol on these parameters, in a time and dose-dependent manner.

Resveratrol prevents akinesia and restores neuronal tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta of diabetic rats

This study evaluated the effects of resveratrol on locomotor behaviors, neuronal and glial densities, and tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta of rats with streptozotocin-induced diabetes. Animals were divided into four groups: non-diabetic rats treated with saline (SAL), non-diabetic rats treated with resveratrol (RSV), diabetic rats treated with saline (DM) and diabetic rats treated with resveratrol (DM+RSV). The animals received oral gavage with resveratrol (20 mg/kg) for 35 days. The open field test and the bar test were performed to evaluate bradykinesia and akinesia, respectively. The Nissl-stained neuronal and glial densities and the dopaminergic neuronal density were estimated using planar morphometry. Tyrosine hydroxylase immunoreactivity was evaluated using regional and cellular optical densitometry. In relation to the locomotor behaviors, it was observed that the DM group developed akinesia, which was attenuated by resveratrol in the DM+RSV group, while the DM and DM+RSV groups showed bradykinesia. Our main morpho-physiological results demonstrated: a decrease in the cellular tyrosine hydroxylase immunoreactivity in the DM group, which was attenuated by resveratrol in the DM+RSV group; a higher neuronal density in the RSV group, when compared to the DM and DM+RSV groups; an increase in the glial density in the DM group, which was also reversed by resveratrol in the DM+RSV group. Resveratrol treatment prevents akinesia development and restores neuronal tyrosine hydroxylase immunoreactivity and glial density in the substantia nigra pars compacta of diabetic rats, suggesting that this polyphenol could be a potential therapeutic option against diabetes-induced nigrostriatal dysfunctions.

Physical training improves non-spatial memory, locomotor skills and the blood brain barrier in diabetic rats

Type 1 diabetes mellitus (T1DM) progressively affects cognitive domains, increases blood-brain barrier (BBB) permeability and promotes neurovascular impairment in specific brain areas. Physical exercise, on the other hand, has beneficial effects on brain functions, improving learning and memory. This study investigated the effects of treadmill training on cognitive and motor behavior, and on the expression of proteins related to BBB integrity, such as claudin-5 and aquaporin-4 (AQP4) in the hippocampus and striatum in diabetic rats. For this study, 60 Wistar rats were divided into four groups (n=15 per group): non-trained control (NTC), trained control (TC), non-trained diabetic (NTD), trained diabetic (TD). After diabetic induction of 30 days by streptozotocin injection, the exercise groups were submitted to 5 weeks of running training. After that, all groups were assessed in a novel object-recognition task (NOR) and the rotarod test. Additionally, claudin-5 and AQP4 levels were measured using biochemical assays. The results showed that exercise enhanced NOR task performance and rotarod ability in the TC and TD animals. Diabetes produced a decrease in claudin-5 expression in the hippocampus and striatum and reduced AQP4 in the hippocampus. Exercise preserved the claudin-5 content in the striatum of TD rats, but not in the hippocampus. The reduction of AQP4 levels produced by diabetes was not reversed by exercise. We conclude that exercise improves short-term memory retention, enhances motor performance in diabetic rats and affects important structural components of the striatal BBB. The results obtained could enhance the knowledge regarding the neurochemical benefits of exercise in diabetes.

Enriched environment induces beneficial effects on memory deficits and microglial activation in the hippocampus of type 1 diabetic rats

Type 1 diabetes mellitus (T1DM) has been associated with long-term complications in the central nervous system, causing brain cellular dysfunctions and cognitive deficits. On the other hand, enriched environment (EE) induces experience-dependent plasticity, especially in the hippocampus, improving the performance of animals in learning and memory tasks. Thus, our objective was to investigate the influence of the EE on memory deficits, locomotion, corticosterone levels, synaptophysin (SYP) protein immunoreactivity, cell survival and microglial activation in the dentate gyrus (DG) of T1DM rat hippocampus. Male Wistar rats (21-day-old) were exposed to EE or maintained in standard housing (controls, C) for 3 months. At adulthood, the C and EE animals were randomly divided and diabetes was induced in half of them. All the animals received 4 doses of BrdU, 24 h apart. Hippocampus-dependent spatial memory, general locomotion and serum corticosterone levels were evaluated at the end of the experiment. The animals were transcardially perfused 30 days post-BrdU administration. Our results showed that EE was able to prevent/delay the development of memory deficits caused by diabetes in rats, however it did not revert the motor impairment observed in the diabetic group. SYP immunoreactivity was increased in the enriched healthy group. The EE decreased the serum corticosterone levels in diabetic adult rats and attenuated the injurious microglial activation, though without altering the decrease of the survival cell. Thus, EE was shown to help to ameliorate cognitive comorbidities associated with T1DM, possibly by reducing hyperactivity in the hypothalamic-pituitary-adrenal axis and microglial activation in diabetic animals.

Inflammatory response and oxidative stress in developing rat brain and its consequences on motor behavior following maternal administration of LPS and perinatal anoxia

Cerebral palsy (CP) is a disorder of locomotion, posture and movement that can be caused by prenatal, perinatal or postnatal insults during brain development. An increased incidence of CP has been correlated to perinatal asphyxia and maternal infections during gestation. The effects of maternal exposure to low doses of bacterial endotoxin (lipopolysaccharide, LPS) associated or not with perinatal anoxia (PA) in oxidative and inflammatory parameters were examined in cerebral cortices of newborns pups. Concentrations of TNF-α, IL-1, IL-4, SOD, CAT and DCF were measured by the ELISA method. Other newborn rats were assessed for neonatal developmental milestones from day 1 to 21. Motor behavior was also tested at P29 using open-field and Rotarod. PA alone only increased IL-1 expression in cerebral cortex with no changes in oxidative measures. PA also induced a slight impact on development and motor performance. LPS alone was not able to delay motor development but resulted in changes in motor activity and coordination with increased levels of IL-1 and TNF-α expression associated with a high production of free radicals and elevated SOD activity. When LPS and PA were combined, changes on inflammatory and oxidative stress parameters were greater. In addition, greater motor development and coordination impairments were observed. Prenatal exposure of pups to LPS appeared to sensitize the developing brain to effects of a subsequent anoxia insult resulting in an increased expression of pro-inflammatory cytokines and increased free radical levels in the cerebral cortex. These outcomes suggest that oxidative and inflammatory parameters in the cerebral cortex are implicated in motor deficits following maternal infection and perinatal anoxia by acting in a synergistic manner during a critical period of development of the nervous system.

Plantar pressure distribution patterns of individuals with prediabetes in comparison with healthy individuals and individuals with diabetes

BACKGROUND

Since elevated mechanical stress along with loss of plantar protective sensation are considered relevant factors in skin breakdown resulting in diabetic foot ulcerations, the assessment of plantar pressure is important for the prevention of diabetic foot complications. Prediabetes subjects are at risk of chronic hyperglycemia complications, among them neuropathy, but information about plantar loading in this population is not available. We aimed to compare baropodometric parameters of individuals with prediabetes versus healthy persons and persons with diabetes mellitus (DM).

METHODS

Baropodometric data from 73 subjects (15 with prediabetes (pre-DM), 28 with type 2 DM, 30 healthy) aged between 29 and 69 years of both genders were registered through a pressure platform with self-selected gait speed and first-step protocol. Peak plantar pressure, stance time, percentage of contact time, percentage of contact area and pressure-time integral were assessed in five plantar foot regions: heel, midfoot, metatarsals, hallux, and toes 2 to 5. Groups were compared by one-way analysis of variance with Scheffé post hoc (α = 0.05).

RESULTS

Age, body mass index, gender, and arch height index did not differ between groups. Pre-DM and DM subjects presented increased peak pressure and pressure-time integral in metatarsals (p = .010; p > .001), as well as increased percentage of contact time in midfoot (p = .006) and metatarsals (p = .004) regions when compared with healthy subjects. Stance time was significantly higher (p = .017) in DM subjects.

CONCLUSIONS

Pre-DM subjects seem to exhibit an altered plantar pressure distribution pattern similar to that often found in DM subjects.

Repeatability of infrared plantar thermography in diabetes patients: a pilot study

OBJECTIVE

Infrared (IR) thermography has been used as a complementary diagnostic method in several pathologies, including distal diabetic neuropathy, by tests that induce thermoregulatory responses, but nothing is known about the repeatability of these tests. This study aimed to assess the repeatability of the rewarming index in subjects with type 2 diabetes mellitus (T2DM) and nondiabetic control subjects.

METHODS

Using an IR camera, plantar IR images were collected at baseline (pre-) and 10 min after (post-) cold stress testing on two different days with 7 days interval. Plantar absolute average temperatures pre- and post-cold stress testing, the difference between them (ΔT), and the rewarming index were obtained and compared between days. Repeatability of the rewarming index after the cold stress test was assessed by Bland-Altman plot limits of agreement.

RESULTS

Ten T2DM subjects and ten nondiabetic subjects had both feet analyzed. Mean age did not differ between groups (p = .080). Absolute average temperatures of plantar region pre- (p = .033) and post-cold stress test (p = .019) differed between days in nondiabetic subjects, whereas they did not differ in T2DM subjects (pretest, p = .329; post-test, p = .540). ΔT and rewarming index did not differ between days for both groups, and the rewarming index presented a 100% agreement of day-to-day measurements from T2DM subjects and 95% with nondiabetic subjects.

CONCLUSIONS

The rewarming index after cold stress testing presented good repeatability between two days a week in both groups. Despite T2DM subjects presenting no differences on absolute temperature values between days, ΔT or rewarming index after cold stress testing remain recommended beside absolute temperature values for clinical use.

Cellular components of the human medial amygdaloid nucleus

The medial nucleus (Me) is a superficial component of the amygdaloid complex. Here we assessed the density and morphology of the neurons and glial cells, the glial fibrillary acidic protein (GFAP) immunoreactivity, and the ultrastructure of the synaptic sites in the human Me. The optical fractionator method was applied. The Me presented an estimated mean neuronal density of 1.53 × 10⁵ neurons/mm³ (greater in the left hemisphere), more glia (72% of all cells) than neurons, and a nonneuronal:neuronal ratio of 2.7. Golgi-impregnated neurons had round or ovoid, fusiform, angular, and polygonal cell bodies (10-30 μm in diameter). The length of the dendrites varied, and pleomorphic spines were found in sparsely spiny or densely spiny cells (1.5-5.2 spines/dendritic μm). The axons in the Me neuropil were fine or coarsely beaded, and fibers showed simple or notably complex collateral terminations. The protoplasmic astrocytes were either isolated or formed small clusters and showed GFAP-immunoreactive cell bodies and multiple branches. Furthermore, we identified both asymmetrical (with various small, clear, round, electron-lucent vesicles and, occasionally, large, dense-core vesicles) and symmetrical (with small, flattened vesicles) axodendritic contacts, also including multisynaptic spines. The astrocytes surround and may compose tripartite or tetrapartite synapses, the latter including the extracellular matrix between the pre- and the postsynaptic elements. Interestingly, the terminal axons exhibited a glomerular-like structure with various asymmetrical contacts. These new morphological data on the cellular population and synaptic complexity of the human Me can contribute to our knowledge of its role in health and pathological conditions.

Prenatal stress produces social behavior deficits and alters the number of oxytocin and vasopressin neurons in adult rats

The present study investigated the long-lasting effects of prenatal repeated restraint stress on social behavior and anxiety, as well as its repercussions on oxytocin (OT) and vasopressin (VP)-positive neurons of the paraventricular (PVN) and supraoptic (SON) nuclei from stressed pups in adulthood. Female Wistar rats were exposed to restraint stress in the last 7 days of pregnancy. At birth, pups were cross-fostered and assigned to the following groups: prenatally non-stressed offspring raised by prenatally non-stressed mothers (NS:NS), prenatally non-stressed offspring raised by prenatally stressed mothers (S:NS), prenatally stressed offspring raised by prenatally non-stressed mothers (NS:S), prenatally stressed offspring raised by prenatally stressed mothers (S:S). As adults, male prenatally stressed offspring raised both by stressed mothers (S:S group) and non-stressed ones (NS:S group) showed impaired social memory and interaction. In addition, when both adverse conditions coexisted (S:S group), increased anxiety-like behavior and aggressiveness was observed in association with a decrease in the number of OT-positive magnocellular neurons, VP-positive magnocellular and parvocellular neurons of the PVN. The NS:S group exhibited a reduction in the amount of VP-positive magnocellular neurons compared to the S:NS. Thus, the social behavior deficits observed in the S:S and NS:S groups may be only partially associated with these alterations to the peptidergic systems. No changes were shown in the OT and VP cellular composition of the SON nucleus. Nevertheless, it is clear that a special attention should be given to the gestational period, since stressful events during this time may be related to the emergence of behavioral impairments in adulthood.

Plantar thermography is useful in the early diagnosis of diabetic neuropathy

OBJECTIVES

This study evaluated plantar thermography sensitivity and specificity in diagnosing diabetic polyneuropathy using cardiac tests (heart rate variability) as a reference standard because autonomic small fibers are affected first by this disease.

METHODS

Seventy-nine individuals between the ages of 19 and 79 years old (28 males) were evaluated and divided into three groups: control (n = 37), pre-diabetics (n = 13) and type 2 diabetics (n = 29). The plantar images were recorded at baseline and then minutes after a provocative maneuver (Cold Stress Test) using an infrared camera that is appropriate for clinical use. Two thermographic variables were studied: the thermal recovery index and the interdigital anisothermal technique. Heart rate variability was measured in a seven-test battery that included three spectral indexes (in the frequency domain) and four Ewing tests (the Valsalva maneuver, the orthostatic test, a deep breathing test, and the orthostatic hypotension test). Other classically recommended tests were applied, including electromyography (EMG), Michigan inventory, and a clinical interview that included a neurological physical examination.

RESULTS

Among the diabetic patients, the interdigital anisothermal technique alone performed better than the thermal recovery index alone, with a better sensitivity (81.3%) and specificity (46.2%). For the pre-diabetic patients, the three tests performed equally well. None of the control subjects displayed abnormal interdigital anisothermal readouts or thermal recovery indices, which precluded the sensitivity estimation in this sample of subjects. However, the specificity (70.6%) was higher in this group.

CONCLUSION

In this study, plantar thermography, which predominately considers the small and autonomic fibers that are commonly associated with a sub-clinical condition, proved useful in diagnosing diabetic neuropathy early. The interdigital anisothermal test, when used alone, performed best.

Human cutaneous sensors on the sole of the foot: altered sensitivity and recovery time after whole body vibration

The goal of this study was to investigate the effect of whole body vibration (WBV) on human tactile sensitivity, both the immediate effects and the recovery time in the case of altered sensitivity. Twenty adults (25.3±2.6 years, 10 males) participated in a 10-min WBV session, at a frequency of 42 Hz with 2 mm amplitude in a spiral mode. Sensitivity was measured before and four times after WBV exposure. Pressure sensation was determined using Von Frey monofilaments. Vibration perception thresholds for 30 and 200 Hz were measured using a custom built neurothesiometer. The sensation was measured in 5 anatomical regions of the right foot. Sensitivity of measured cutaneous perception was significantly reduced. Fast-adapting mechanoreceptors for 200 Hz and 30 Hz showed 5.2 and 3.8 times lower sensation values immediately after WBV, respectively. Pressure sensation was 2 times lower in comparison to the baseline condition. In general, tactile sensitivity recovery time was between 2 and 3 h. WBV influences the discharge of fast-adapting skin mechanoreceptors. By determining the recovery time, it might be possible to estimate how long the effects of WBV on tactile sensitivity last.

Implications of olfactory lamina propria transplantation on hyperreflexia and myelinated fiber regeneration in rats with complete spinal cord transection

Transplantation with olfactory ensheathing cells (OECs) has been adopted after several models of spinal cord injury (SCI) with the purpose of creating a favorable environment for the re-growth of injured axons. However, a consensus on the efficacy of this cellular transplantation has yet to be reached. In order to explore alternative parameters that could demonstrate the possible restorative properties of such grafts, the present study investigated the effects of olfactory lamina propria (OLP) transplantation on hyperreflexia and myelinated fiber regeneration in adult rats with complete spinal cord transection. The efficacy of OLP (graft containing OECs) and respiratory lamina propria (RLP, graft without OECs) was tested at different post-injury times (acutely, 2- and 4-week delayed), to establish the optimum period for transplantation. In the therapeutic windows used, OLP and RLP grafts produced no considerable improvements in withdrawal reflex responses or on the low-frequency dependent depression of H-reflex. Both lamina propria grafts produced comparable results for the myelinated fiber density and for the estimated total number of myelinated fibers at the lesion site, indicating that the delayed transplantation approach does not seem to limit the regenerative effects. However, animals transplanted with OLP 2 or 4 weeks after injury exhibit smaller myelin sheath thickness and myelinated fiber area and diameter at the lesion site compared to their respective RLP groups. Despite the ongoing clinical use of OECs, it is important to emphasize the need for more experimental studies to clarify the exact nature of the repair capacity of these grafts in the treatment of SCI.

Exercise alleviates hypoalgesia and increases the level of calcitonin gene-related peptide in the dorsal horn of the spinal cord of diabetic rats

OBJECTIVE

The aim of this study was to evaluate the effects of treadmill training on nociceptive sensitivity and immunoreactivity to calcitonin gene-related peptide in the dorsal horn of the spinal cord of diabetic rats.

METHODS

Male Wistar rats were divided into three groups: control, diabetic and trained diabetic. Treadmill training was performed for 8 weeks. The blood glucose concentrations and body weight were evaluated 48 h after diabetes induction and every 30 days thereafter. The nociceptive sensitivity was evaluated using the tail-flick apparatus. The animals were then transcardially perfused, and the spinal cords were post-fixed, cryoprotected and sectioned in a cryostat. Immunohistochemistry for calcitonin gene-related peptide analysis was performed on the dorsal horn of the spinal cord.

RESULTS

The nociceptive sensitivity analysis revealed that, compared with the control and trained diabetic animals, the latency to tail deflection on the apparatus was longer for the diabetic animals. Optical densitometry demonstrated decreased calcitonin gene-related peptide immunoreactivity in the dorsal horn of the spinal cord in diabetic animals, which was reversed by treadmill training.

CONCLUSION

We concluded that treadmill training can alleviate nociceptive hypoalgesia and reverse decreased calcitonin gene-related peptide immunoreactivity in the dorsal horn of the spinal cord of diabetic animals without pharmacological treatment.

Effect of skilled and unskilled training on nerve regeneration and functional recovery

The most disabling aspect of human peripheral nerve injuries, the majority of which affect the upper limbs, is the loss of skilled hand movements. Activity-induced morphological and electrophysiological remodeling of the neuromuscular junction has been shown to influence nerve repair and functional recovery. In the current study, we determined the effects of two different treatments on the functional and morphological recovery after median and ulnar nerve injury. Adult Wistar male rats weighing 280 to 330 g at the time of surgery (N = 8-10 animals/group) were submitted to nerve crush and 1 week later began a 3-week course of motor rehabilitation involving either "skilled" (reaching for small food pellets) or "unskilled" (walking on a motorized treadmill) training. During this period, functional recovery was monitored weekly using staircase and cylinder tests. Histological and morphometric nerve analyses were used to assess nerve regeneration at the end of treatment. The functional evaluation demonstrated benefits of both tasks, but found no difference between them (P > 0.05). The unskilled training, however, induced a greater degree of nerve regeneration as evidenced by histological measurement (P < 0.05). These data provide evidence that both of the forelimb training tasks used in this study can accelerate functional recovery following brachial plexus injury.

Transplantation of mononuclear cells from human umbilical cord blood promotes functional recovery after traumatic spinal cord injury in Wistar rats

Cell transplantation is a promising experimental treatment for spinal cord injury. The aim of the present study was to evaluate the efficacy of mononuclear cells from human umbilical cord blood in promoting functional recovery when transplanted after a contusion spinal cord injury. Female Wistar rats (12 weeks old) were submitted to spinal injury with a MASCIS impactor and divided into 4 groups: control, surgical control, spinal cord injury, and one cell-treated lesion group. Mononuclear cells from umbilical cord blood of human male neonates were transplanted in two experiments: a) 1 h after surgery, into the injury site at a concentration of 5 x 10⁶ cells diluted in 10 µL 0.9% NaCl (N = 8-10 per group); b) into the cisterna magna, 9 days after lesion at a concentration of 5 x 10⁶ cells diluted in 150 µL 0.9% NaCl (N = 12-14 per group). The transplanted animals were immunosuppressed with cyclosporin-A (10 mg/kg per day). The BBB scale was used to evaluate motor behavior and the injury site was analyzed with immunofluorescent markers to label human transplanted cells, oligodendrocytes, neurons, and astrocytes. Spinal cord injury rats had 25% loss of cord tissue and cell treatment did not affect lesion extension. Transplanted cells survived in the injured area for 6 weeks after the procedure and both transplanted groups showed better motor recovery than the untreated ones (P < 0.05). The transplantation of mononuclear cells from human umbilical cord blood promoted functional recovery with no evidence of cell differentiation.

Effects of physical exercise on spatial memory and astroglial alterations in the hippocampus of diabetic rats

Type 1 diabetes mellitus (T1DM) is associated with neurocognitive dysfunction and astrogliosis. Physical exercise prevents cognitive impairments and induces important brain modifications. The aim of our study was to investigate the effect of treadmill exercise on spatial memory and astrocytic function in the hippocampus of a T1DM model. Fifty-seven Wistar rats were divided into four groups: trained control (TC) (n = 15), non-trained control (NTC) (n = 13), trained diabetic (TD) (n = 14) and non-trained diabetic (NTD) (n = 15). One month after streptozotocin-induced diabetes, exercise groups were submitted to 5 weeks of physical training, and then, all groups were assessed in the novel object-placement recognition task. Locomotor activity was analyzed in the open field apparatus using Any-maze software. The expression of glial fibrillary acidic protein (GFAP) and S100B in hippocampus and cerebrospinal fluid were measured using ELISA assay, and hippocampal GFAP immunoreactivity was evaluated by means of immunohistochemistry and optical densitometry. The results showed that physical exercise prevents and/or reverts spatial memory impairments observed in NTD animals (P < 0.01). Decreased locomotor activity was observed in both the NTD and TD groups when compared with controls (P < 0.05). ELISA and immunohistochemistry analyzes showed there was a reduction in GFAP levels in the hippocampus of NTD animals, which was not found in TD group. ELISA also showed an increase in S100B levels in the cerebrospinal fluid from the NTD group (P < 0.01) and no such increase was found in the TD group. Our findings indicate that physical exercise prevents and/or reverts the cognitive deficits and astroglial alterations induced by T1DM.

Olfactory and respiratory lamina propria transplantation after spinal cord transection in rats: effects on functional recovery and axonal regeneration

Spinal cord injury (SCI) has very poor clinical prospects, resulting in irreversible loss of function below the injury site. Although applied in clinical trials, olfactory ensheathing cells transplantation (OEC) derived from lamina propria (OLP) is still a controversial repair strategy. The present study explored the efficacy of OLP or respiratory lamina propria (RLP) transplantation and the optimum period after SCI for application of this potential therapy. Adult male rats were submitted to spinal cord transection and underwent acute, 2-week or 4-week post-injury transplantation with pieces of OLP (containing OECs) or RLP (without OECs). After grafting, animals with OLP and RLP showed discrete and similar hindlimb motor improvement, with comparable spinal cord tissue sparing and sprouting in the lesion area. Acute transplantation of OLP and RLP seems to foster limited supraspinal axonal regeneration as shown by the presence of neurons stained by retrograde tracing in the brainstem nuclei. A larger number of 5-HT positive fibers were found in the cranial stump of the OLP and RLP groups compared to the lesion and caudal regions. Calcitonin gene-related peptide fibers were present in considerable numbers at the SCI site in both types of transplantation. Our results failed to verify differences between acute, 2-week and 4-week delayed transplantation of OLP and RLP, suggesting that the limited functional and axon reparative effects observed could not be exclusively related to OECs. A greater understanding of the effects of these tissue grafts is necessary to strengthen the rationale for application of this treatment in humans.

Treadmill training induces plasticity in spinal motoneurons and sciatic nerve after sensorimotor restriction during early postnatal period: new insights into the clinical approach for children with cerebral palsy

The aim of the present study was to investigate whether locomotor stimulation training could have beneficial effects on the morphometric alterations of spinal cord and sciatic nerve consequent to sensorimotor restriction (SR). Male Wistar rats were exposed to SR from postnatal day 2 (P2) to P28. Control and experimental rats underwent locomotor stimulation training in a treadmill for three weeks (from P31 to P52). The cross-sectional area (CSA) of spinal motoneurons innervating hind limb muscles was determined. Both fiber and axonal CSA of myelinated fibers were also assessed. The growth-related increase in CSA of motoneurons in the SR group was less than controls. After SR, the mean motoneuron soma size was reduced with an increase in the proportion of motoneurons with a soma size of between 0 and 800 μm(2). The changes in soma size of motoneurons were accompanied by a reduction in the mean fiber and axon CSA of sciatic nerve. The soma size of motoneurons was reestablished at the end of the training period reaching controls level. Our results suggest that SR during early postnatal life retards the growth-related increase in the cell body size of motoneurons in spinal cord and the development of sciatic nerve. Additionally, three weeks of locomotor stimulation using a treadmill seems to have a beneficial effect on motoneurons' soma size.

The effects of treadmill training on young and mature rats after traumatic peripheral nerve lesion

The purpose of this study was to investigate the possible effects of a treadmill training program on regeneration in young (3-month-old) and mature (13-month-old) rats with sciatic nerve crush using functional, electrophysiological, and morphometric analyses. When compared to both the young and mature untrained injury groups, those groups that underwent a treadmill training showed improved sensorimotor function evaluated by narrow beam test (p<0.04 and p<0.001, respectively), while muscle action potential amplitude was only greater in the young group (p<0.02). The treadmill training program was able to reduce myelinated fiber density in the young group (p<0.001), which appeared to increase after nerve injury (poly-innervation), but decreased with training, which means that the innervation became more functional. The data indicate that treadmill training is able to promote functional, electrophysiological and morphological recovery in young animals. However, in mature animals, improvement was only seen in terms of functional recovery.

Balance and coordination training after sciatic nerve injury

INTRODUCTION

Numerous therapeutic interventions have been tested to enhance functional recovery after peripheral nerve injuries.

METHODS

After sciatic nerve crush in rats we tested balance and coordination and motor control training in sensorimotor tests and analyzed nerve and muscle histology.

RESULTS

The balance and coordination training group and the sham group had better results than the sedentary and motor control groups in sensorimotor tests. The sham and balance and coordination groups had a significantly larger muscle area than the other groups, and the balance and coordination group showed significantly better values than the sedentary and motor control groups for average myelin sheath thickness and g-ratio of the distal portion of the nerve.

CONCLUSIONS

The findings indicate that balance and coordination training improves sciatic nerve regeneration, suggesting that it is possible to revert and/or prevent soleus muscle atrophy and improve performance on sensorimotor tests.

Treadmill step training-induced adaptive muscular plasticity in a chronic paraplegia model

The purpose of this study was to provide evidence that treadmill step training is capable of attenuating muscle atrophy and may regulate brain derived neurotrophic factor (BDNF) in soleus muscle after complete spinal cord transection (SCT) at T8-T9 in rats. Five days after SCT, spinal animals started a 9-week step-training program on a treadmill with partial body weight support and manual step help. The muscular trophism was studied by analyzing muscle weight and myofiber cross-sectional area of the soleus, while Western blot analysis was used to detect BDNF expression in the same muscle. Step training, initiated immediately after SCT in rats, may partially impede/revert muscular atrophy in chronic paralyzed soleus muscle. Moreover, treadmill step training promoted upregulation of the BDNF in soleus muscle, which was positively correlated with muscle weight and myofiber cross-sectional size. These findings have important implications for the comprehension of the neurobiological substrate that promotes exercise-induced effects on paralyzed skeletal muscle and suggests treadmill training is a viable therapeutic approach in spinal cord injuries.

The Amazonian herbal Marapuama attenuates cognitive impairment and neuroglial degeneration in a mouse Alzheimer model

Alzheimer's disease (AD) is expected to affect more than 22 million people worldwide by 2025, causing devastating suffering and enormous costs to families and society. AD is a multifactorial disease, with a complex pathological mosaic. In rodents, AD-like dementia can be induced by cerebral microinjection of Aβ peptide, leading to amyloid deposits, amnesia and various features of neurodegeneration. Marapuama (Ptychopetalum olacoides) is regarded as a "brain tonic" in the Amazon region and shows a nootropic profile in rodents.

AIM OF THE STUDY

Because a specific extract (POEE) of Marapuama was shown to possess promnesic and anti-amnesic properties, the aim of this study was to verify if POEE is also effective against Aβ(1-42)-induced cognitive deficit in mice. Additionally, Aβ deposits (Congo red), GFAP immunoreactivity (immunohistochemistry), and neurodegenerative changes in the hippocampal pyramidal layer (Nissl) were examined as measures of Aβ(1-42)-induced neurodegeneration.

MATERIALS AND METHODS

CF1 mice were subjected to the experimental Alzheimer model with the Aβ(1-42) i.c.v. administration. The effects of POEE 800 mg/kg were evaluated over 14 consecutive days of treatment.

RESULTS

The data show that 14 days of oral treatment with POEE (800 mg/kg) was effective in preventing Aβ-induced cognitive impairment, without altering the levels of BDNF and with parallel reductions in Aβ deposits and astrogliosis. CA1 hippocampus loss induced by Aβ(1-42) was also diminished in POEE-treated mice.

CONCLUSION

This study offers evidence of functional and neuroprotective effects of two weeks treatment with a Ptychopetalum olacoides extract against Aβ peptide-induced neurotoxicity in mice. Given the multifactorial nature of neurodegeneration, the considerable potential for an AChE inhibitor displaying associated neuroprotective properties such as here reported warrants further clinic evaluation.

Treadmill training improves motor skills and increases tyrosine hydroxylase immunoreactivity in the substantia nigra pars compacta in diabetic rats

The aim of this study was to evaluate the effects of treadmill training on motor skills and immunoreactivity to tyrosine hydroxylase in the substantia nigra pars compacta and ventral tegmental area from diabetic rats induced by streptozotocin. Male Wistar rats were divided into three groups: control, diabetic and trained diabetic. Treadmill training was performed for 8weeks. Blood glucose concentrations and body weight were evaluated 48h after diabetes induction and every 30days thereafter. Motor skills were evaluated on the rotarod and open field tests. Then, animals were transcardially perfused and the brains were post-fixed, cryoprotected and sectioned in a cryostat. Immunohistochemistry for tyrosine hydroxylase analyses was done in the ventral tegmental area and in the substantia nigra. Motor skills showed that diabetic animals had a decrease in the latency to fall and enhanced number of falls in the rotarod test compared to control and trained diabetic animals. In the open field, diabetic animals had a decrease in the number of crossed squares, rearings and spent a less time moving compared to control and trained diabetic animals. In diabetic animals, optical densitometry of immunohistochemistry showed that tyrosine hydroxylase reaction decreased in the ventral tegmental area and in the neurons and process in the substantia nigra. In the later region, that decrease was reversed by treadmill training. In conclusion, we demonstrated that treadmill training can reverse the loss of the motor skills, which was correlated to tyrosine hydroxylase immunoreactivity in the substantia nigra of diabetic animals without pharmacological treatment.

Thermographic evaluation of hind paw skin temperature and functional recovery of locomotion after sciatic nerve crush in rats

INTRODUCTION

Peripheral nerves are often damaged by direct mechanical injury, diseases, and tumors. The peripheral nerve injuries that result from these conditions can lead to a partial or complete loss of motor, sensory, and autonomic functions, which in turn are related to changes in skin temperature, in the involved segments of the body. The aim of this study was to evaluate the changes in hind paw skin temperature after sciatic nerve crush in rats in an attempt to determine whether changes in skin temperature correlate with the functional recovery of locomotion.

METHODS

Wistar rats were divided into three groups: control (n = 7), sham (n = 25), and crush (n = 25). All groups were subjected to thermographic, functional, and histological assessments.

RESULTS

ΔT in the crush group was different from the control and sham groups at the 1st, 3rd and 7rd postoperative days (p<0.05). The functional recovery from the crush group returned to normal values between the 3rd and 4th week post-injury, and morphological analysis of the nerve revealed incomplete regeneration at the 4th week after injury.

DISCUSSION

This study is the first demonstration that sciatic nerve crush in rats induces an increase in hind paw skin temperature and that skin temperature changes do not correlate closely with functional recovery.

Acetylcholinesterase inhibition in cognition-relevant brain areas of mice treated with a nootropic Amazonian herbal (Marapuama)

The goal of acetylcholinesterase inhibitors (AChEIs) used to treat Alzheimer's patients is an improvement in cholinergic transmission. While currently available AChEIs have limited success, a huge impediment to the development of newer ones is access to the relevant brain areas. Promnesic, anti-amnesic and AChEI properties were identified in a standardized ethanol extract from Ptychopetalum olacoides (POEE), a medicinal plant favored by the elderly in Amazon communities. The purpose of this study was to provide conclusive evidence that orally given POEE induces AChE inhibition in brain areas relevant to cognition. Histochemistry experiments confirmed that the anticholinesterase compound(s) present in POEE are orally bioavailable, inducing meaningful AChE inhibition in the hippocampus CA1 (∼33%) and CA3 (∼20%), and striatum (∼17%). Ellman's colorimetric analysis revealed that G1 and G4 AChE isoforms activities were markedly inhibited (66 and 72%, respectively) in hippocampus and frontal cortex (50 and 63%, respectively), while G4 appeared to be selectively inhibited (72%) in the striatum. Western blotting showed that POEE did not induce significant changes in the AChE immunocontent suggesting that its synthesis is not extensively modified. This study provides definitive proof of meaningful anticholinesterase activity compatible with the observed promnesic and anti-amnesic effects of POEE in mice, reaffirming the potential of this extract for treating neurodegenerative conditions where a hypofunctioning cholinergic neurotransmission is prominent. Adequate assessment of the safety and efficacy of this extract and/or its isolated active compound(s) are warranted.

Distribution of NADPH-diaphorase activity in the central nervous system of the young and adult land snail Megalobulimus abbreviatus

Nitric oxide (NO) is a gas produced through the action of nitric oxide synthase that acts as a neurotransmitter in the central nervous system (CNS) of adult gastropod mollusks. There are no known reports of the presence of NOS-containing neurons and glial cells in young and adult Megalobulimus abbreviatus. Therefore, NADPH-d histochemistry was employed to map the nitrergic distribution in the CNS of young and adult snails in an attempt to identify any transient enzymatic activity in the developing CNS. Reaction was observed in neurons and fibers in all CNS ganglia of both age groups, but in the pedal and cerebral ganglia, positive neurons were more intense than in other ganglia, forming clusters symmetrically located in both paired ganglia. However, neuronal NADPH-d activity in the mesocerebrum and pleural ganglia decreased from young to adult animals. In both age groups, positive glial cells were located beneath the ganglionic capsule, forming a network and surrounding the neuronal somata. The trophospongium of large and giant neurons was only visualized in young animals. Our results indicate the presence of a nitrergic signaling system in young and adult M. abbreviatus, and the probable involvement of glial cells in NO production.

Treadmill training increases the size of A cells from the L5 dorsal root ganglia in diabetic rats

The aim of this study was to evaluate the effects of physical training on the L5 dorsal root ganglion (DRG) cells in streptozotocin diabetic rats. Male adult rats were divided into 3 groups: (control, diabetic and trained diabetic). Treadmill training was performed for 10 weeks (5 days/week, twice a day). Blood glucose concentrations and body weight were evaluated 48h after diabetes induction and every 30 days thereafter. Then, animals were killed and the right L5 DRG removed. Histological and morphometric analysis consisted of evaluating nuclear and cellular volumes and areas in A and B cells at light and ultrastructural levels. Blood glucose concentrations were higher in both diabetic groups vs controls at all periods. Body weights were lower in all diabetics vs controls at all periods after diabetes induction, with a significant time vs group interaction. In A cells, the cellular and nuclear volumes were lower than control animals only in the diabetic group; control and trained diabetic animals did not differ; in B cells the cellular and nuclear volumes were lower in diabetic and trained diabetic rats. The cellular areas of A cells were smaller in diabetic rats than in control and trained diabetic rats, while the cellular areas of B cells were smaller in the diabetic and trained groups. In conclusion, treadmill training was able to increase the size of A cells from the DRG in diabetic rats and improved the morphological features of these cells.

Ultrastructural analysis of the dorsal body gland of the terrestrial snail Megalobulimus abbreviatus (Becquaert, 1948)

The ultrastructure of the reproductive gland, dorsal body (DB), of Megalobulimus abbreviatus was analysed. Electron microscope immunohistochemistry was used to detect FMRFamide-like peptides in the nerve endings within this gland. Nerve backfilling was used in an attempt to identify the neurons involved in this innervation. In M. abbreviatus, the DB has a uniform appearance throughout their supraesophageal and subesophageal portions. Dorsal body cells have several features in common with steroid-secreting gland cells, such as the presence of many lipid droplets, numerous mitochondria with tubular cristae and a developed smooth endoplasmic reticulum cisternae. Throughout the DB in M. abbreviatus numerous axonal endings were seen to be in contact with the DB cells exhibiting a synaptic-like structure. The axon terminals contained numerous electron-dense and scanty electron-lucid vesicles. In addition, the DB nerve endings exhibited FMRFamide immunoreactive vesicles. Injection of neural tracer into the DB yielded retrograde labelling of neurons in the metacerebrum lobe of the cerebral ganglia and in the parietal ganglia of the subesophageal ganglia complex. The possibility that some of these retrograde-labelled neurons might be FMRFamide-like neurons that may represent a neural control to the DB in M. abbreviatus is discussed.

Different effects of anoxia and hind-limb immobilization on sensorimotor development and cell numbers in the somatosensory cortex in rats

Cerebral palsy (CP) is a group of movement and posture disorders attributed to insults in the developing brain. In rats, CP-like motor deficits can be induced by early hind-limb sensorimotor restriction (SR; from postnatal days P2 to P28), associated or otherwise with perinatal anoxia (PA; on P0 and P1). In this study, we address the question of whether PA, early SR or a combination of both produces alterations to sensorimotor development. Developmental milestones (surface righting, cliff aversion, stability on an inclined surface, proprioceptive placing, auditory startle, eye opening) were assessed daily from P3 to P14. Motor skills (horizontal ladder and beam walking) were evaluated weekly (from P31 to P52). In addition, on P52, the thickness of the somatosensory (S1) and cerebellar cortices, and corpus callosum were measured, and the neuronal and glial cell numbers in S1 were counted. SR (with or without PA) significantly delayed the stability on an inclined surface and hastened the appearance of the placing reflex and impaired motor skills. No significant differences were found in the thickness measurements between the groups. Quantitative histology of S1 showed that PA, either alone or associated with SR, increased the number of glial cells, while SR alone reduced neuronal cell numbers. Finally, the combination of PA and SR increased the size of neuronal somata. We conclude that SR impairs the achievement of developmental milestones and motor skills. Moreover, both SR and PA induce histological alterations in the S1 cortex, which may contribute to sensorimotor deficits.

Beneficial effects of treadmill training in experimental diabetic nerve regeneration

OBJECTIVES

We investigated the effects of treadmill training (10 weeks) on hindlimb motor function and nerve morphometric parameters in diabetic rats submitted to sciatic nerve crush.

MATERIALS AND METHOD

Wistar rats (n = 64) were divided into the following groups: non-diabetic; trained non-diabetic; non-diabetic with sciatic nerve crush; trained non-diabetic with sciatic nerve crush; diabetic; trained diabetic; diabetic with sciatic nerve crush or trained diabetic with sciatic nerve crush. Diabetes was induced by streptozotocin injection (50 mg/kg, iv). Hindlimb motor function was evaluated weekly by assessing sciatic functional indices, and the proximal and distal portions of the sciatic nerve were used for morphometric analysis.

RESULTS

At 13 weeks post-injury, the distal nerve portion of all injured groups and the proximal nerve portion of the diabetic with sciatic nerve crush group presented altered morphometric parameters such as decreased myelinated fiber diameter (~7.4 + 0.3μm vs ~4.8 + 0.2μm), axonal diameter (~5 + 0.2μm vs ~3.5 + 0.1μm) and myelin sheath thickness (~1.2 + 0.07μm vs ~0.65 + 0.07μm) and an increase in the percentage of area occupied by endoneurium (~28 + 3% vs ~60 + 3%). In addition, in the non-diabetic with sciatic nerve crush group the proximal nerve portion showed a decreased myelinated fiber diameter (7.4+0.3μm vs 5.8 + 0.3μm) and myelin sheath thickness (1.29 + 0.08μm vs 0.92 + 0.08μm). The non-diabetic with sciatic nerve crush, trained non-diabetic with sciatic nerve crush, diabetic with sciatic nerve crush and trained diabetic with sciatic nerve crush groups showed normal sciatic functional index from the 4th,4th,9th and 7th week post-injury, respectively. Morphometric alterations in the proximal nerve portion of the diabetic with sciatic nerve crush and non-diabetic with sciatic nerve crush groups were either prevented or reverted to values similar to the non-diabetic group by treadmill training.

CONCLUSION

Diabetic condition promoted delay in sciatic nerve regeneration. Treadmill training is able to accelerate hindlimb motor function recovery in diabetic injured rats and prevent or revert morphometric alterations in proximal nerve portions in non-diabetic and diabetic injured rats.