Extremely low frequency magnetic exposure attenuates oxidative stress and apoptotic cell death in injured spinal cord of rats

Secondary spinal cord injury (SCI) sets on immediately after trauma which results in vascular, morphological and biochemical changes at the site of lesion. Amongst these, the crucial events such as oxidative stress and apoptosis result in spreading the injury to adjacent tissues following the initial insult. Exposure to extremely low frequency magnetic field (ELFMF) is reported to modulate oxidative stress and cell death in vivo. Here, we investigated the influence of ELFMF on oxidative stress and cell death after SCI. Adult male Wistar rats were divided into Sham-SCI (Laminectomy only), Sham-SCI+MF (ELFMF exposure; 17.96 ?T intensity, 50 Hz frequency, 2 h duration/day to Sham-SCI rats), SCI (complete transection of T13 spinal cord) and SCI+MF (ELFMF exposure to SCI rats) groups. They were sacrificed on day 2 for antioxidant assay and day 1, 2 and 3 for cell death study. The oxidative stress was assessed by antioxidant enzyme activities and the cell death was assessed by TUNEL assay and Caspase-3 immnuohistochemistry. Data revealed significant reduction in the lipid peroxidation and number of cells undergone cell death besides improvement in antioxidant levels in the spinal cord of ELFMF exposed SCI rats. These novel findings demonstrate the potential of ELFMF to attenuate oxidative stress and cell death in the early stage of secondary injury process after SCI.

Rat bone marrow stromal cell transplantation ameliorates complete spinal cord injury induced sensorimotor dysfunctions and associated neurotransmitters

Traumatic spinal cord injury (SCI) leads to sensorimotor dysfunction with significant impact on the patient and their family’s quality of life, social, and economic status. There is no complete restorative treatment so far. Bone marrow stromal cells (BMSCs) have anti-inflammatory and neuroprotective effects and recently emerged as a therapeutic candidate for SCI repair. Here, we examined the role of rat BMSCs transplantation on thoracic (T11) complete SCI induced dysfunctions, namely hyperalgesia, allodynia, locomotion, spinal reflexes, and spinal neurotransmitters in rats. Pre-labelled BMSCs were injected on day 9 after SCI locally. We observed that BMSCs transplantation facilitate locomotor recovery (week 2-8) and attenuated hyperalgesia and allodynia to varying sensory stimuli (week 6-8) after SCI. In addition, spinal reflexes and neurotransmitters were affected significantly by complete SCI, which were partially restored by BMSCs transplantation. Histological analyses also revealed the presence of BMSCs at the injury site and appear to fill the lesion cavities, thereby significantly reducing the lesion volume. Our data shows the beneficial effects of BMSCs transplantation on complete SCI-induced sensorimotor functional deficits in rats.

Extremely Low Frequency Magnetic Field Exposure Attenuates Pain By Inactivation Of Descending Facilitatory System In Complete Spinal Cord Injured Rats

Background:To investigate the effect of chronic exposure to extremely low frequency magnetic field (ELF- MF) on pain modulation status of completely spinal cord injured (SCI) in rats. Methods: Male Wistar rats were divided into Sham (Laminectomy), SCI (complete transection of T13 spinal cord) and SCI+MF (ELF-MF: 17.96 μT, 50 Hz, 2h/day exposure to SCI rats) groups. Pain was studied by utilizing threshold of tail flick (TTF), forepaw lick latency (FPL) and its modulation by temporal summation (TS) and diffuse noxious inhibitory control (DNIC). These tests were performed before surgery (week 0), and after surgery (weeks 4 and 8). Locomotor function was assessed by BBB score at post-SCI weeks 1,3,5,7 and 8. At the end of week 8, spinal cords were collected for histological analysis. Results: Data revealed post-SCI significant decrease in TTF and FPL. The amplitude of TS response was increased, while TTF response was not disappeared after pressure pain application in DNIC paradigm. SCI rats also revealed a significant lower BBB score. However, MF exposure to SCI rats significantly restored the above parameters. Conclusion: Our observations suggested reduction in post-SCI hyperalgesia by inactivation of descending facilitatory system after MF exposure to SCI rats.

Prenatal music stimulation facilitates the postnatal functional development of the auditory as well as visual system in chicks (Gallus domesticus).

Rhythmic sound or music is known to improve cognition in animals and humans. We wanted to evaluate the effects of prenatal repetitive music stimulation on the remodelling of the auditory cortex and visual Wulst in chicks. Fertilized eggs (0 day) of white leghorn chicken (Gallus domesticus) during incubation were exposed either to music or no sound from embryonic day 10 until hatching. Auditory and visual perceptual learning and synaptic plasticity, as evident by synaptophysin and PSD-95 expression, were done at posthatch days (PH) 1, 2 and 3. The number of responders was significantly higher in the music stimulated group as compared to controls at PH1 in both auditory and visual preference tests. The stimulated chicks took significantly lesser time to enter and spent more time in the maternal area in both preference tests. A significantly higher expression of synaptophysin and PSD-95 was observed in the stimulated group in comparison to control at PH1-3 both in the auditory cortex and visual Wulst. A significant inter-hemispheric and gender-based difference in expression was also found in all groups. These results suggest facilitation of postnatal perceptual behaviour and synaptic plasticity in both auditory and visual systems following prenatal stimulation with complex rhythmic music.

Effect of magnetic field on food and water intake and body weight of spinal cord injured rats.

Chronic (2h/d × 8 weeks) exposure to magnetic field (MF; 50 Hz, 17.9 T) in complete spinal cord (T13) transected rats restored food intake (FI), water intake (WI) and body weight (BW) which were decreased in the spinal cord injured rats. The results suggest a significant beneficial effect of chronic exposure to magnetic field of paraplegic rats.

Gender specificity of sucrose induced analgesia in human adults.

Sweet, palatable substances such as sucrose are reported to calm infants undergoing routine investigative procedures. The analgesic effect persists in pre pubertal children and adults with a hint of gender dependent variation in the analgesic response. The present study was therefore designed to explore gender specificity of sucrose induced analgesia in adult volunteers utilizing the nociceptive flexion reflex, an objective tool for pain assessment. Nociceptive flexion reflex was recorded, both before and after (up to 15 min) ingestion of 100 ml of 25% sucrose solution in 6 male and 6 female volunteers. In the male volunteers the maximum amplitude of the response was 20.8 +/- 7.7 microV before sucrose ingestion and 22.6 +/- 9.1 microV, 6.6 +/- 0.7 microV, 6.2 +/- 1.1 microV, 7.5 +/- 0.9 microV at 0, 5, 10 and 15 minutes post sucrose ingestion respectively. In female volunteers, the maximum amplitude of the response was 33.7 +/- 17.7 microV before sucrose ingestion and 43.6 +/- 17.2 microV, 7.1 +/- 1.2 microV, 25.9 +/- 16.1 microV, 50.6 +/- 16.3 microV at the same time intervals post sucrose ingestion. The maximum amplitude values were significantly lower in the males at 10 and 15 minutes after sucrose ingestion (P < 0.05). This is the first objective report of gender specificity in sucrose induced analgesia in adult humans. The gender dependent variation in sucrose induced analgesia is prolonged in male (15 min) and short lived in female (5 min) volunteers. This knowledge may have important implications in pain management.

Amygdalar neuronal responses to peripheral nociceptive stimuli in rats.

Amygdala plays a very important role in the mediation of pain. In the present study the behaviour of the amygdalar neurons in response to various peripheral noxious stimuli was observed. Noxious mechanical, thermal, electrical, chemical and the non-noxious stimuli (touch) were applied individually to the animal and then the neuronal responses to these stimuli were recorded. Our results showed that the majority of amygdalar units recorded from medial, lateral and basolateral nuclei, responded to different peripheral noxious (thermal, electrical, chemical mechanical) and non-noxious stimuli by excitation. However few neurons decreased their activity on stimulation. Some of these neurons also exhibited after discharge following application of higher intensity of noxious stimuli.

Antinociceptive effect of sucrose ingestion in the human.

Sucrose ingestion has been shown to alleviate pain and distress in rats, human infants as well as adults. Sucrose induced analgesia is related to the reward value associated with its sweet taste. The sweet taste of sucrose is a stimulus for the activation of endogenous opioid pool. The opioids in turn modulate pain perception. It has been demonstrated in a number of animal and human studies that sucrose ingestion increases the hypothalamic/CSF opioid levels. This gains support from the results obtained from naloxone challenge test, a neuro-endocrine method for assessment of endogenous opioid tone. Moreover, the analgesic effects of sucrose can be reversed by administration of opioid antagonists such as naloxone. On the other hand, long-term sucrose ingestion leads to hyperalgesia in rats and it has been hypothesized to result from a complex interaction of sucrose with the endogenous opioid system leading to a deficiency of opioids. In the present article mechanisms underlying sucrose induced analgesia including the interaction of the palatability and reward value of food with the neural substrates and its neuro-chemical basis have been reviewed in the light of both animal and human studies. In addition, clinical application of the knowledge about sucrose and its modulatory effect on the endogenous opioid system has been suggested.