Surgical Procedures Required for Measurement Reduce Nerve Conduction Velocity: An In Vivo and In Vitro Comparative Study.

Background: Although in vitro methods have disadvantages, they are still commonly used to measure nerve conduction velocity (NCV) in experimental studies. Therefore, this study was designed to demonstrate the effect of the surgical procedures required for in vitro methods on nerve fibers and the effect of in vivo and in vitro methods on the results of electrophysiological measurements.Methods: Rats were assigned to the in vivo (control-1, injury-1, and diabetic-1) and in vitro (control-2, injury-2, and diabetic-2) groups. The NCV and compound action potential amplitudes were measured, and the nerve fibers were histologically examined.Results: Damaged axons and myelin sheaths were observed in the control-2 group. The electrophysiological values of the in vitro groups were lower than those of the in vivo groups. Furthermore, these values were lower for the diabetic and injury groups than for the control groups.Conclusions: This study showed that the surgical procedures required for the in vitro method reduced the measured values. Owing to the previous and current disadvantages of the in vitro method, the in vivo method was more sensitive for the NCV measurement. Moreover, measurements can be performed using the current in vivo method for small nerve fibers.

The Impact of Type II Diabetes on Tongue Dysplasia and p16-Related Aging Process: An Experimental Study.

OBJECTIVE: To evaluate the effect of streptozotocin-induced experimental diabetes mellitus on p16, p53, Ki67, and Bcl2 expressions and histopathological changes in the tongue of the rats. MATERIAL AND METHODS: Twenty-two adult female Sprague-Dawley rats were used. The rats were randomly divided into 2 groups (n = 14) as control (C) (n = 8) and diabetic (DM) (n = 6). The rats in the DM group were given streptozotocin as a single intraperitoneal dose for induction of diabetes. Histopathological and immunohistochemical evaluations of formalin-fixed and paraffin-embedded tissue sections of the tongue were used. RESULTS: Significant differences were observed between the DM group and the control group in terms of epithelial thickness, length of filiform papillae, and width of filiform papillae (p = 0.005, p = 0.001, and p = 0.006, respectively). There was no significant difference between the groups in terms of mononuclear inflammatory cell infiltration, capillary proliferation, and dysplasia (p = 0.204, p = 0.244, and p = 0.204, respectively). As a result of immunohistochemical studies, no significant difference was found between the groups in terms of p53, Ki67, and Bcl-2 expressions (p = 0.588, p = 0.662, and p = 0.686, respectively). A significant difference was found between the groups when p16 expression was evaluated (p = 0.006). CONCLUSIONS: In our study, streptozotocin-induced experimental diabetes mellitus induced p16 expression but did not show any difference in p53, Bcl-2, and Ki67 levels. It should be considered in the studies that the pathological changes at the early stages of the relationship between DM and oral cancer may be related to p16 expression; however, it may also be linked with p16-related aging process.

Ozone Partially Decreases Axonal and Myelin Damage in an Experimental Sciatic Nerve Injury Model.

AIM: To investigate the effects of ozone in experimental acute sciatic nerve injury. MATERIAL AND METHODS: Twenty-eight male rats were divided into four groups (n = 7): control (C), ozone (O), injury (SNI), and treatment with ozone after injury (SNI + Ozone). Sciatic nerve injury was generated by compressing the right sciatic nerve for 90 s using a Yasargil aneurysm clip in groups SNI and SNI + Ozone. A 70 µg/ml concentration of ozone was given four times (once a day at 1st, 24th, 48th, and 72th h) at a dose of 0.5 mg/kg to groups O and SNI + Ozone after injury by an intraperitoneal injection. Nerve conduction velocities of all rats were measured by in vivo electrophysiological tests at the end of the day 4. Then, plasma malondialdehyde, total oxidant and antioxidant status were measured and also axonal and myelin changes in sciatic nerves of histopathological examination were performed. The data were analyzed by Kolmogorov Smirnov test, Mann-Whitney U-test, and Chi square test. p <.05 was considered statistically significant. RESULTS: The proximal and distal latency difference were higher and nerve conduction velocity were lower in SNI group than C and O groups, and the myelin structure was found to be broken in group SNI compared to groups C and O. However, the amplitude of the compound action potential, the nerve conduction velocity were significantly higher in group SNI + Ozone than in group SNI. Moreover, myelin injury was significantly lower in group SNI + Ozone compared to group SNI. Total oxidant status in group SNI was significantly higher than in groups C, O, and SNI + Ozone. But, total antioxidant status in group SNI was significantly lower than in groups C, O, and SNI + Ozone. CONCLUSION: This study showed that the administration of ozone at a dose of 0.5 mg/kg after peripheral nerve injury in rats reduces myelin and axonal injury.

Effect of systemic application of bone marrow-derived mesenchymal stem cells on healing of peripheral nerve injury in an experimental sciatic nerve injury model.

AIM: To investigate the effects of systemic application of bone marrow-derived mesenchymal stem cells in a compression model of peripheral nerve injury. MATERIAL AND METHODS: 24 male Wistar albino rats were randomly divided into 3 equal groups (n=8):Control (C),injury (I),and stem cell and injury (SI).The sciatic nerve of rats in the I and SI groups was subjected to clip compression for 5 minutes.Moreover,approximately 5x105 bone marrow-derived mesenchymal stem cells were given via tail vein of the rats in the SI group immediately after clip compression. The nerve conduction velocities and amplitudes of the rats were measured 30 days later.Then,the sciatic nerves were removed, and myelin damage grading and axon counting were performed.The data were analyzed by One-Way ANOVA and Tukey\'s post-hoc test.P values less than 0.05 were considered to be statistically significant. RESULTS: While the proximal,distal and mean latency values were higher in the I and SI groups than in the control group,the same measurements were lower in the SI group than in the I group.While the nerve conduction velocity,the compound action potential and the number of axons were lower in the I and SI groups than in the control group,the same measurements were higher in the SI group than in the I group.Moreover,myelin damage was found to be lower in the SI group than in the I group. CONCLUSION: It has been shown that systemic application of bone marrow-derived mesenchymal stem cells in a compression model of peripheral nerve injury has a positive impact on both myelin sheath and axon survival.

The effects of ozone therapy on caspase pathways, TNF-α, and HIF-1α in diabetic nephropathy.

BACKGROUND: Accelerated apoptosis plays a vital role in the development of diabetic vascular complications. Ozone may attenuate diabetic nephropathy by means of decreased apoptosis-related genes. The aim of our study was to investigate the effect of ozone therapy on streptozotocin-induced diabetic nephropathy in rats. Also the histopathological changes in diabetic kidney tissue with ozone treatment were evaluated. METHODS: The rats were randomly divided into six groups (n = 7): control (C), ozone (O), diabetic (D), ozone-treated diabetic (DO), insulin-treated diabetic (DI), and ozone- and insulin-treated diabetic (DOI). D, DI, and DOI groups were induced by a single intraperitoneal injection of streptozotocin. Ozone was given to the O, DO, and DOI groups. Group DI and DOI received subcutaneous (SC) insulin (3 IU). All animals received daily treatment for 6 weeks. RESULTS: Expressions of caspase-1-3-9, HIF-1α, and TNF-α genes were significantly higher in D group compared to C group (p < 0.05 for all). Ozone treatment resulted in significant decrease in the expressions of these genes in diabetic kidney tissue compared to both C and D group (p < 0.05 for all). Caspase-1-3-9, HIF-1α, and TNF-α gene expressions were found to be lower in DOI group compared to C group (p < 0.05 for all). Also adding ozone treatment to insulin therapy resulted in more significantly decrease in the expressions of these genes in diabetic tissue compared to only insulin-treated diabetic group (p < 0.05 for all). Regarding histological changes, ozone treatment resulted in decrease in the renal corpuscular inflammation and normal kidney morphology was observed. Both insulin and ozone therapies apparently improved kidney histological findings with less degenerated tubules and less inflammation of renal corpuscle compared to D, DO, and DI groups. CONCLUSION: Ozone therapy decreases the expressions of apoptotic genes in diabetic kidney tissue and improves the histopathological changes.

Nephrotoxic effects of varenicline as the most effective drug used for smoking cessation: a preliminary experimental study.

PURPOSE: Varenicline is a new most effective drug for smoking cessation. Its effect on kidney functions remains unclear. This study purposed to investigate whether varenicline causes nephrotoxicity in rats. METHODS: Fifteen rats were randomly assigned to three groups: control, 0.0125 mg kg(-1) varenicline and 0.025 mg kg(-1) varenicline (single dose for 3 days, i.p.). Before and after experimental period, serum neutrophil gelatinase-associated lipocalin, creatinine and urea levels were measured. Total oxidant and antioxidant status were measured in kidney homogenates. Histological examination was performed in kidney. RESULTS: The nephrotoxic effects of varenicline were detected by histopathological and biochemical examinations in the varenicline treatment groups. No change was observed in the control group. CONCLUSIONS: These findings firstly indicate that a 3-day varenicline treatment causes nephrotoxic effects in rats.

Single dose varenicline may trigger epileptic activity.

Varenicline is a new drug for smoking cessation, and its effect on epilepsy is not clear. The aim of this study was to investigate whether different doses of varenicline cause epileptic activity. Forty rats were randomly assigned to the following eight groups: control, saline, and 0.025, 0.04, 0.1, 0.5, 1, and 2 mg kg(-1) varenicline (single dose, i.p.). EEGs were recorded before the varenicline injection and during the following 240 min. While epileptic discharges were observed on the EEGs of the rats in all of the varenicline-treated groups, motor findings of epileptic seizure were not observed in some rats in these groups except the 1 and 2 mg kg(-1) groups. These findings indicate that different single doses of varenicline cause epileptic activity in rats.

Selenium partially prevents cisplatin-induced neurotoxicity: a preliminary study.

Cisplatin is an anticancer drug and it has neurotoxic effects. On the other hand, the neuroprotective effect of selenium was observed in previous studies. However, the effect of selenium on cisplatin-induced neurotoxicity has not been studied yet. Therefore, we aimed to investigate whether selenium prevent cisplatin-induced neurotoxicity. Twenty-one male Wistar albino rats were divided into three groups: control (C), cisplatin (CS), cisplatin and selenium (CSE, n=7 in each group). Cisplatin (12 mg/kg/day, i.p.) was administered for 3 days to CS and CSE groups. Also, CSE group received via oral gavage 3 mg/kg/day (twice-a-day as 1.5 mg/kg) selenium 5 days before of cisplatin injection and continued for 11 consecutive days. The same volumes of saline were intraperitoneally and orally administered to C group at same time. At the end of experimental protocol, electrophysiological and histopathological examinations were performed. The nerve conduction velocity, amplitude of compound action potential and number of axon of CS group were significantly lower than the C group. However, the same parameters of CSE group were significantly higher than the CS group. Although, cisplatin has a peripheral neurotoxic effect in rats, this effect was partially prevented by selenium treatment. Thus, it appears that co-administration of selenium and cisplatin may be a useful approach to decrease severity of peripheral neurotoxicity.

The Effects of Electromagnetic Fields Generated from 1800 MHz Cell Phones on Erythrocyte Rheological Parameters and Zinc Level in Rats.

OBJECTIVE: The aim of this study was to investigate the effects of the electromagnetic field generated from the 1800 MHz radiofrequency radiation (EF) on erythrocyte rheological parameters and erythrocyte zinc levels. MATERIAL AND METHODS: Twenty-four male Wistar Albino rats were randomly grouped as follows: 1) two control groups and 2) study groups: i) Group A: EF exposed group (2.5 h/day for 30 days, the phone on stand-by), and ii) Group B: EF exposed group (2.5 min/day for 30 days, the phone ringing in silent mode). At the end of the experimental period erythrocyte rheological parameters such as erythrocyte deformability and aggregation were determined by an ectacytometer. Erythrocyte zinc level, which affects hemorheological parameters, was also measured by atomic absorption spectrophotometer. RESULTS: Erythrocyte deformability was decreased in both study groups but the decrease in group A was not statistically significant. Exposure to EF did not have any significant effect on erythrocyte aggregation. On the other hand, erythrocyte zinc level was significantly reduced in both study groups. CONCLUSION: Exposure to EF may have decreased tissue oxygenation due to reduced erythrocyte deformability. Decrease in erythrocyte zinc level may have caused the impairment in erythrocyte deformability.

The effects of human umbilical cord blood transplantation in rats with experimentally induced spinal cord injury.

OBJECT: Even though there have been many efforts to recover neuronal dysfunction following spinal cord injuries, there are limitations to the treatment of these injuries. The purpose of this laboratory investigation was to determine the clinical and neurophysiological effects of human umbilical cord blood (HUCB) transplantation in a rat hemisection model of spinal cord injury. METHODS: In this study, experimental hemisection of the thoracic spinal cord was performed in rats. The rats were divided into 4 groups (6 rats in each group). One group of rats (Group 1) underwent thoracic laminectomy only. Rats in Group 2 underwent laminectomy and right hemisection of the thoracic spinal cord. Rats in Group 3 underwent right hemisection and implantation of freshly obtained HUCB on Day 0 postinjury. Rats in Group 4 underwent hemisection and implantation of freshly obtained HUCB on Day 4 postinjury. Clinical evaluations of rat motor function included the following: neurological examination, Rotarod performance, and inclined plane tests. Rats also underwent reflex evaluation. RESULTS: The neurological examinations revealed that the frequency of plegic rats was 70.8% at the beginning of the study across all 4 groups; this value decreased to 20.8% by the end of the study. The percentage of rats with a normal examination increased from 25% to 50%. The results of Rotarod performance and 8-week inclined plane performance tests showed statistical significance (p < 0.05) in an overall group comparison across all time points. At the end of the 8 weeks, a statistically significant difference was found in the inclined plane test results between rats in Groups 1 and 2. There were no statistically significant differences between Groups 1, 3, and 4 (p < 0.05). When the reflex responses of the hemisectioned sides were compared, statistically significant differences were detected between groups (p < 0.05). All groups were significantly different with regard to the right-side reflex response score (p < 0.05). Spinal cord preparations of rats in all groups were examined for histopathological changes. CONCLUSIONS: Human umbilical cord blood is stem cell rich and easily available, and it carries less risk of inducing a graft-versus-host reaction in the recipient. Human umbilical cord blood serum is also noted to contain stem cell­promoting factors, which is why cell isolation was not used in this study. Freshly obtained cord blood was also used because storage of cord blood has been reported to have some negative effects on stem cells. Transplantation of freshly obtained HUCB into the hemisectioned spinal cord experimental model demonstrated clinical and neurophysiological improvement.