The Effects of Antioxidants and Pulsed Magnetic Fields on Slow and Fast Skeletal Muscle Atrophy Induced by Streptozotocin: A Preclinical Study.

Results: Our findings suggest that antioxidants and PMF may alleviate impaired protein synthesis and degradation pathways in skeletal muscle atrophy. PTS showed a positive effect on the anabolic pathway, while RSV and PMF demonstrated potential for ameliorating the catabolic pathway. Notably, the combination therapy of antioxidants and PMF exhibited a stronger ameliorative effect on skeletal muscle atrophy than either intervention alone. Conclusion: The present results highlight the benefits of employing a multimodal approach, involving both antioxidant and PMF therapy, for the management of muscle-wasting conditions. These treatments may have potential therapeutic implications for skeletal muscle atrophy.

Effect of 40 Hz Magnetic Field Application in Posttraumatic Muscular Atrophy Development on Muscle Mass and Contractions in Rats.

Muscle atrophy refers to the deterioration of muscle tissue due to a long-term decrease in muscle function. In the present study, we simulated rectus femoris muscle atrophy experimentally and investigated the effect of pulsed electromagnetic field (PEMF) application on the atrophy development through muscle mass, maximal contraction force, and contraction-relaxation time. A quadriceps tendon rupture with a total tenotomy was created on the rats' hind limbs, inhibiting knee extension for 6 weeks, and this restriction of the movement led to the development of disuse atrophy, while the control group underwent no surgery. The operated and control groups were divided into subgroups according to PEMF application (1.5 mT for 45 days) or no PEMF. All groups were sacrificed after 6 weeks and had their entire rectus femoris removed. To measure the contraction force, the muscles were placed in an organ bath connected to a transducer. As a result of the atrophy, muscle mass and strength were reduced in the operated group, while no muscle mass loss was observed in the operated PEMF group. Furthermore, measurements of single, incomplete and full tetanic contraction force and contraction time (CT) did not change significantly in the operated group that received the PEMF application. The PEMF application prevented atrophy resulting from 6 weeks of immobility, according to the contraction parameters. The effects of PEMF on contraction force and CT provide a basis for further studies in which PEMF is investigated as a noninvasive therapy for disuse atrophy development. © 2022 Bioelectromagnetics Society.

The healing effect of pulsed magnetic field on burn wounds.

A burn is one of the most difficult injuries people can face.The primary pathology is coagulation necrosis resulting from tissue damage.Many wound care products have been developed to be used in situations such as the poor general condition of the patient and lack of solid area to be grafted. However, the high costs of these products make their use complicated.In this study, the effect of PEMF on cutaneous wound healing in an animal burn model was evaluated and the dose and duration of the magnetic field should be discussed for this effect to occur. Animals were divided into five groups including eight each (n = 40) (Groups 1, 2, 3, 4, 5).Group 1 was the control group; received no treatment after second-degree burn wound. Group 2 received daily wound care with saline. Group 3 received daily wound care with pomade containing mupirocin. Group 4 received Pulsed Electromagnetic Field signal for 60 min (1.5 m T and 40 Hz for seven days and Group 5 also received PEMF signal for 60 min the same frequency and intensity for14 days. Microscopically, second-degree burn wounds were successfully detected in all rats. Histopathological examination results in no significant difference between groups in neutrophil infiltration. The difference between the groups in vascularization was statistically significant between Group II and Group V (p < 0.001) and between Group I and Group V (p = 0.005) Epithelialization was present in 75% of the rats in Group V, while no epithelialization was observed in any of the other groups. In conclusion, we observed a significant improvement in the stasis zone of the group receiving Pulsed Electromagnetic Field for two weeks.

Pterostilbene protects cochlea from ototoxicity in streptozotocin-induced diabetic rats by inhibiting apoptosis.

Diabetes mellitus (DM) causes ototoxicity by inducing oxidative stress, microangiopathy, and apoptosis in the cochlear sensory hair cells. The natural anti-oxidant pterostilbene (PTS) (trans-3,5-dimethoxy-4-hydroxystylbene) has been reported to relieve oxidative stress and apoptosis in DM, but its role in diabetic-induced ototoxicity is unclear. This study aimed to investigate the effects of dose-dependent PTS on the cochlear cells of streptozotocin (STZ)-induced diabetic rats. The study included 30 albino male Wistar rats that were randomized into five groups: non-diabetic control (Control), diabetic control (DM), and diabetic rats treated with intraperitoneal PTS at 10, 20, or 40 mg/kg/day during the four-week experimental period (DM + PTS10, DM + PTS20, and DM + PTS40). Distortion product otoacoustic emission (DPOAE) tests were performed at the beginning and end of the study. At the end of the experimental period, apoptosis in the rat cochlea was investigated using caspase-8, cytochrome-c, and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin end labeling (TUNEL). Quantitative real-time polymerase chain reaction was used to assess the mRNA expression levels of the following genes: CASP-3, BCL-associated X protein (BAX), and BCL-2. Body weight, blood glucose, serum insulin, and malondialdehyde (MDA) levels in the rat groups were evaluated. The mean DPOAE amplitude in the DM group was significantly lower than the means of the other groups (0.9-8 kHz; P < 0.001 for all). A dose-dependent increase of the mean DPOAE amplitudes was observed with PTS treatment (P < 0.05 for all). The Caspase-8 and Cytochrome-c protein expressions and the number of TUNEL-positive cells in the hair cells of the Corti organs of the DM rat group were significantly higher than those of the PTS treatment and control groups (DM > DM + PTS10 > DM + PTS20 > DM + PTS40 > Control; P < 0.05 for all). PTS treatment also reduced cell apoptosis in a dose-dependent manner by increasing the mRNA expression of the anti-apoptosis BCL2 gene and by decreasing the mRNA expressions of both the pro-apoptosis BAX gene and its effector CASP-3 and the ratio of BAX/BCL-2 in a dose-dependent manner (P < 0.05 compared to DM for all). PTS treatment significantly improved the metabolic parameters of the diabetic rats, such as body weight, blood glucose, serum insulin, and MDA levels, consistent with our other findings (P < 0.05 compared to DM for all). PTS decreased the cochlear damage caused by diabetes, as confirmed by DPOAE, biochemical, histopathological, immunohistochemical, and molecular findings. This study reports the first in vivo findings to suggest that PTS may be a protective therapeutic agent against diabetes-induced ototoxicity.

The effects of daylight exposure on melatonin levels, Kiss1 expression, and melanoma formation in mice.

AIM: To determine how daylight exposure in mice affects melatonin protein expression in blood and Kiss1 gene expression in the hypothalamus. The second aim was to assess the relationship between skin cancer formation, daylight exposure, melatonin blood level, and kisspeptin gene expression level. METHODS: New-born mice (n=96) were assigned into the blind group or daylight group. The blind group was raised in the dark and the daylight group was raised under 12 hours light/12 hours dark cycle for 17 weeks. At the end of the 11th week, melanoma cell line was inoculated to mice, and tumor growth was observed for 6 weeks. At the end of the experiment, melatonin level was measured from blood serum and Kiss1 expression from the hypothalamus. RESULTS: The blind group had significantly higher melatonin and lower Kiss1 expression levels than the daylight group. Tumor volume was inversely proportional to melatonin levels and directly proportional to Kiss1 expression levels. Tumor growth speed was lower in the blind than in the daylight group. CONCLUSION: Melatonin and Kiss1 were shown to be nvolved in tumor suppression. They were affected by daylight and were mutually affected by each other.

The effects of extremely low-frequency pulsed electromagnetic fields on analgesia in the nitric oxide pathway.

There is growing interest in the effects of extremely low-frequency electromagnetic fields on mechanisms in biological organisms. This study's goal is to determine the role of the Nitiric Oxide (NO) pathway for thermal pain by intentionally interfering with it using a pulsed electromagnetic field generated by an extremely low-frequency alternating current (ELF-PEMF) in combination with BAY41-2272 (sGC activator), NOS inhibitor l-NAME, and NO donor l-arginine. This study included 72 adult male Wistar albino rats (mean weight of 230 ±â€¯12 g). The rats were kept at room temperature (22 ±â€¯2 °C) in a 12-h light/dark cycle and in a room with sound insulation. PEMF (50 Hz, 5 mT) were applied four times a day for 30 min and at 15-min intervals for 15 days. Analgesic effects were assessed with tail-flick and hot-plate tests. Before the tests, NO donor l-arginine (300 mg/kg), sGC activator BAY41-2272 (10 mg/kg), and NOS inhibitor l-name (40 mg/kg) were injected intraperitoneally into rats in six randomly-selected groups. The maximum analgesic effect of a 5 mT electromagnetic field was on day 7. PEMF significantly increased the analgesia effect when the functioning of the NO pathway was ensured with l-arginine, which is a NO donor, and BAY41-2271, which is the intracellular receptor and sGC activator. However, there was no difference between rats treated with PEMF and the NOS inhibitor l-NAME as compared to rats only treated with PEMF. In conclusion, PEMF generate analgesia by activating the NO pain pathway.

The effect of resveratrol on the histologic characteristics of the cochlea in diabetic rats.

OBJECTIVES/HYPOTHESIS: The aim of this study was to investigate changes in the cochlea and the potential dose-dependent effects of resveratrol (RSV) against diabetes mellitus (DM) ototoxicity. STUDY DESIGN: Animal model. METHODS: Twenty-four male Wistar albino rats were divided into four groups. Baseline distortion product otoacoustic emission (DPOAE) measurements were evaluated. Group I was the control group, group II was made diabetic with single-dose streptozotocin, and groups III and IV were rendered diabetic as group II and administered 10 and 20 mg RSV, respectively, intraperitoneally for 4 weeks. All animals were sacrificed after repeated DPOAE measurement. Apoptosis was investigated using caspase-3, Bax (Bcl-associated X protein), and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) staining. RESULTS: The DPOAE values in the diabetic group were found to be significantly lower compared with the other groups at 5,714 Hz and 8,000 Hz (P < .05). No significant difference in otoacoustic emission was detected in the comparison of the RSV doses (P > .05). The histopathologic investigation using caspase-3, Bax, and TUNEL staining showed that the mean rank of the diabetic group was significantly higher compared with the RSV10, RSV20, and control groups (DM > RSV10 > RSV20 > control) (P < .05). CONCLUSIONS: These results imply that RSV administration offered statistically significant protection for the cochleas of rats against diabetes. This protective effect improved histologically with higher doses. LEVEL OF EVIDENCE: NA Laryngoscope, 129:E1-E6, 2019.

Therapeutic Potential of Pterostilbene and Resveratrol on Biomechanic, Biochemical, and Histological Parameters in Streptozotocin-Induced Diabetic Rats.

AIMS: The aim of this study was to investigate the effects of pterostilbene (PTS) (trans-3,5-dimethoxy-4'-hydroxystilbene) and resveratrol (RSV) (trans-3,5,4' trihydroxystilbene) applied at different doses for the treatment of streptozotocin- (STZ-) induced diabetic rats. MATERIALS AND METHODS: At the end of the 5-week experimental period, the right gastrocnemius muscles of the rats were examined biomechanically, while the left ones were examined histologically. In addition, blood glucose, serum insulin, and malondialdehyde (MDA) levels were analyzed in blood samples taken from the rats. RESULTS: The skeletal muscle isometric contraction forces, which showed a decrease with diabetes, were observed to increase with antioxidant applications. Blood glucose, serum insulin, and MDA levels in diabetic rats approached normal levels after applying PTS. When the electron microscopic images of the rat skeletal muscle were examined, those in the combination treatment group were observed to show a better enhancement in the skeletal muscle morphological structure compared to the other diabetic and treatment groups. CONCLUSION: According to the findings, we suggest that these antioxidant treatments might have good therapeutic nutraceutical potential for some muscle diseases that coexist with diabetes. These treatments should be comprehensively investigated in the future.

The impact of magnesium on isometric twitch parameters and resting membrane potential of the skeletal muscle in diabetic rats.

To present the relationship between oral magnesium supplementation, blood glucose, and changes in isometric twitch parameters, resting membrane potential (RMP), in the gastrocnemius muscle in diabetic rats. Sixty rats were used in this study. The rats were divided into four groups: control (drinking tap water, Group I, n = 15), control with treated with magnesium sulfate (10 g/L) (Group II, n = 15), diabetic (Group III, n = 15), and diabetic with treated with magnesium sulfate (10 g/L) (Group IV, n = 15). In Group II and IV, the level of plasma magnesium was increased comparing to those of the control group (p < 0.05). Isometric twitch tensions were decreased significantly in the Group III, but Group IV isometric twitch tensions were increased significantly. Group IV RMP values were close to the Group I. Hyperglycemia decreases gastrocnemius muscle isometric twitch tension and increases RMP in diabetic rats. Magnesium treatment can prevent these diabetic complications.

Repetitive 50 Hz pulsed electromagnetic field ameliorates the diabetes-induced impairments in the relaxation response of rat thoracic aorta rings.

PURPOSE: To evaluate the characteristic features of mechanical responses and the membrane potential changes induced by repetitive pulsed electromagnetic field (PEMF, 50 Hz, 5 mT) in thoracic aorta rings obtained from streptozotocin-induced diabetic and healthy control rats to determine if PEMF could ameliorate problems associated with diabetes. METHODS: Sixty male Wistar rats weighing 250-290 g were randomly divided into two experimental groups, each containing 30 animals. Streptozotocin was given via tail vein to produce diabetes mellitus (DM) in the first group rats. The second group rats were treated only with % 0.9 saline and considered as non-DM group. Both groups were also divided into two subgroups as DM + PEMF, DM + sham, PEMF and sham, each containing 15 animals. Although the DM + PEMF and PEMF groups were treated, the DM + sham and sham groups were not treated with PEMF. The PEMF treatment occurred four times daily for 30 min at 15-min intervals repeated daily for 30 days. Thoracic aorta rings from both DM and non-DM rats exposed to PEMF were evaluated for contraction and relaxation responses and membrane potential changes in the presence or absence of chemical agents that were selected to test various modes of action. RESULTS: Relaxation response of thoracic aorta rings was significantly reduced in DM than non-DM group. PEMF treatment significantly increased the relaxation response of the diabetic rings to acetylcholine, and reduced the concentration response to phenylephrine. Resting membrane potential was significantly higher in DM than in non-DM group. Inhibitors of nitric oxide (NO), both nitro-L-arginine (L-NO-ARG) and L-NO-ARG + indometacin combination, produced a significant transient hyperpolarisation in all groups. Inhibitors of potassium channel activity, charybdotoxin or apamine, produced a membrane depolarisation. However, PEMF did not induce any significant effect on the membrane potential in DM group. CONCLUSIONS: Diabetes reduced the relaxation response of thoracic aorta rings. It also affected the membrane potentials of the rings. Treatment with PEMF ameliorated the diabetes-induced impairments in the relaxation response of these rings.

Effect of corneal thickness on intraocular pressure measurements with the Pascal dynamic contour, Canon TX-10 non-contact and Goldmann applanation tonometers in healthy subjects.

PURPOSE: To investigate the effects of central corneal thickness (CCT) on intraocular pressure (IOP) measurements of the Pascal dynamic contour tonometry (DCT), Canon TX-10 non-contact tonometry (NCT) and Goldmann applanation tonometry measurements (GAT) in healthy subjects. METHODS: IOP values of 135 eyes with normal corneas of 135 healthy volunteers were determined by DCT, NCT and by GAT. The CCT was measured using an ultrasonic pachymeter after all IOP determinations had been made. RESULTS: When DCT measurements were compared (IOP = 17.52 +/- 2.0 mmHg) with NCT measurements (IOP = 16.54 +/- 2.77 mmHg) and GAT measurements (IOP = 15.07 +/- 2.35 mmHg), DCT measurements were significantly higher than NCT and GAT (p < 0.001). There was a significant correlation between CCT with both NCT (r = 0.260, p = 0.003) and GAT measurements (r = 0.257, p = 0.005). There was a weak correlation that was not statistically significant between CCT and DCT (r = 0.160, p = 0.079). CONCLUSION: The IOP measurements with DCT seem to be less dependent on CCT. NCT appears to be more affected by variation in CCT than GAT.