Cochlear pathology in preeclamptic rats: protective effects of vitamin D and magnesium sulfate.

Background/aim: This study investigated the possible degeneration in cochlear morphology induced by preeclampsia (PE) and the therapeutic/preventive effect of vitamin D (Vit D) and magnesium sulfate (MgSO4) used separately and together on feto-maternal outcomes. Materials and methods: We created PE in rats using a reduced uterine perfusion pressure (RUPP) animal model and recorded blood pressure (BP), embryonic survival (ES), and embryonic weight (EW) and evaluated cochlear morphology by electron microscopy. Results: The PE group had elevated BP, a decreased number and weight of live pups, and significant degeneration in the cochlea compared to the sham group. In the PEV group, we observed significant beneficial effects of Vit D supplementation at 14.5 and 19.5 dpc in terms of BP (p < 0.05), EW (p < 0.001), and cochlear degeneration compared to the PE group. In the PEM group, BP (p < 0.05) and cochlear degeneration nearly reached the level found in the sham group. However, although the EW was statistically different in the PE group, it did not reach sham group levels. We also observed that BP returned to sham level (p < 0.01) and noticed significant increases in the EW (p < 0.0001) and ES (p = 0.017) in the PEMV group compared to the PE group. According to the scanning electron microscope results, combined administration of VitD and MgSO4 is more effective than separate administration in improving cochlear degeneration induced by PE. Conclusion: The administration of Vit D and MgSO4 during pregnancy has beneficial effects on PE pathology and may play a significant role in preventing PE-related complications, including cochlear degeneration.

Histological analysis of the effects of thymoquinone on testicular damage in pentylenetetrazole-induced temporal lobe epilepsy model.

In this study, it was aimed to investigate possible ameliorating effects of thymoquinone on testicular damage in an epilepsy model. Adult male Wistar rats were divided into 4 groups. The animals in sham-operated groups were given saline or thymoquinone (s.c.); and the animals in pentylenetetrazole (PTZ) group were applied PTZ. The animals in PTZ+thymoquinone group were given thymoquinone (i.p) for 6 days after applying PTZ. Hematoxylin-eosin, periodic acid-Schiff and TUNEL staining and PCNA, StAR, inhibin ß-B immunohistochemistry and ZO-1 immunofluorescence methods were applied. Staining intensity and cell numbers were determined. Degeneration of seminiferous tubules was observed in PTZ group. Most of the tubules showed normal morphology in the PTZ+thymoquinone group. Apoptotic cell index was found to be increased and proliferative index decreased in PTZ group. Thymoquinone administration decreased apoptotic index and increased proliferation index. In PTZ group, ZO-1, StAR and inhibin ß-B immunohistochemical staining intensity was observed to be decreased and after thymoquinone application, ZO-1 was increased. StAR and inhibin ß-B-positive cell numbers were decreased in PTZ group and increased in the PTZ +thymoquinone group. In this study, it was observed that PTZ-induced epileptic seizures caused testicular damage in the rat and thymoquinone ameliorated these effects.

Association of Conductive Hearing Loss with the Structural Changes in the Organ of Corti.

OBJECTIVE: The aim of the study was to evaluate the association of conductive hearing loss (CHL) with the structural changes in the organ of Corti. METHODS: Twenty ears of 10 healthy adult Wistar albino rats were included in the study. The right ears (n = 10) of the animals served as controls (group 1), and no surgical intervention was performed in these ears. A tympanic membrane perforation without annulus removal was performed under operative microscope on the left ears (n = 5) in 5 of 10 animals (group 2). A tympanic membrane perforation with annulus removal was performed under operative microscope on the left ears (n = 5) of the remaining 5 animals (group 3). Auditory brainstem response testing was performed in the animals before the interventions. After 3 months, the animals were sacrificed, their temporal bones were removed, and inner ears were investigated using scanning electron microscopy (SEM). The organ of Corti was evaluated from the cochlear base to apex in the modiolar axis, and the parameters were scored semiquantitatively. RESULTS: In group 1, the pre- and post-intervention hearing thresholds were similar (p > 0.05). In group 2, a hearing decrease of at least 5 dB was encountered in all test frequencies (p > 0.05). In group 3, at the frequency range of 2-32 kHz, there was a significant hearing loss after 3 months (p < 0.01). After 3 months, the hearing thresholds in group 2 and 3 were higher than group 1 (p < 0.01). The hearing threshold in group 3 was higher than group 2 (p < 0.01). On SEM evaluation, the general cell morphology and stereocilia of the outer hair cells were preserved in all segments of the cochlea in group 1 with a mean SEM score of 0.2. There was segmental degeneration in the general cell morphology and outer hair cells in group 2 with a mean SEM score of 2.2. There was widespread degeneration in the general cell morphology and outer hair cells in group 3 with a mean SEM score of 3.2. The SEM scores of group 2 and 3 were significantly higher than group 1 (p < 0.05). The SEM scores of group 3 were significantly higher than group 2 (p < 0.05). CONCLUSION: CHL may be associated with an inner ear damage. The severity of damage appears to be associated with severity and duration of CHL. Early correction of CHL is advocated in order to reverse or prevent progression of the inner ear damage, which will enhance the success rates of hearing restoration surgeries. Subjective differences and compliance of the hearing aid users may be due to the impact of CHL on inner ear structures.

Regular moderate exercise alleviates gastric oxidative damage in rats via the contribution of oxytocin receptors.

KEY POINTS: A moderate level of exercise has beneficial effects for the prevention of gastric ulcers. Although regular aerobic exercise was shown to elevate serum oxytocin levels and exogenously administered oxytocin exerts an anti-ulcer activity, the role of endogenous oxytocin in the gastroprotective effects of exercise has not yet been elucidated. We showed that increased anxiety and oxidative gastric damage induced by gastric ulcers were reversed in pre-exercised rats, while reduced hypothalamic oxytocin expression and decreased myenteric oxytocin receptor expression due to gastric ulcers were abolished by exercise. We also reported that the blockade of oxytocin receptors exaggerated gastric damage in exercised rats with ulcers. Our data establish that endogenous oxytocin is the key mediator in the beneficial effects of regular physical activity in alleviating gastric injury. ABSTRACT: Exercise increases serum oxytocin levels and exogenous oxytocin exerts an anti-ulcer activity; but the role of oxytocin in the protective effects of exercise against gastric ulcers has not yet been evaluated. This study was designed to investigate the impact of regular swimming exercise on oxidative gastric injury, and the role of oxytocin receptor activity in the anxiolytic and anti-inflammatory actions of exercise. Adult Wistar albino rats of both sexes performed swimming exercise (30 min/day, 5 days) or stayed sedentary. At the end of the 6-week exercise/sedentary protocol, rats were injected intraperitoneally with atosiban (0.1 mg/kg/day) or saline for 4 days. On the 5th day, under anaesthesia, acetic acid (ulcer) or saline (sham) was applied onto the gastric serosa and the treatments were continued. On the 9th day, anxiety levels were determined; gastric blood flow was measured, and blood, gastric and brain tissues were obtained. Induction of ulcers in sedentary rats increased anxiety and serum corticosterone levels; but reduced gastric blood flow and resulted in apoptosis and oxidative gastric damage with increased cytokine expressions. However, when ulcers were induced in pre-exercised rats, behavioural and biochemical alterations due to gastric damage were reversed. The inhibition of oxytocin receptors by atosiban exaggerated pro-inflammatory cytokine expressions and gastric lipid peroxidation in the stomachs of exercised rats with ulcers. When rats had regularly exercised prior to ulcer induction, reductions in the immunolabelling of hypothalamic oxytocin and myenteric oxytocin receptors were abolished, suggesting that exercise-induced alleviation of gastric injury may involve the reversal of down-regulated oxytocinergic activity.

Ultrastructural GABA immunogold labeling in the substantia nigra pars reticulata of kindled genetic absence epilepsy rats.

Genetic Absence Epilepsy Rats from Strasbourg (GAERS) is a well-known animal model of absence epilepsy and they are resistant to electrical kindling stimulations. The present study aimed to examine possible differences in gamma-aminobutyric acid (GABA) levels and synapse counts in the substantia nigra pars reticulata anterior (SNRa) and posterior (SNRp) regions between GAERS and Wistar rats receiving kindling stimulations. Animals in the kindling group either received six stimulations in the amygdala and had grade 2 seizures or they were kindled, having grade five seizures. Rats were decapitated one hour after the last stimulation. SNR regions were obtained after vibratome sectioning of the brain tissue. GABA immunoreactivity was detected by immunogold method and synapses were counted. Sections were observed by transmission electron microscope and analyzed by Image J program. GABA density in the SNRa region of fully kindled GAERS and Wistar groups increased significantly compared to that of their corresponding grade 2 groups. The number of synapses increased significantly in kindled and grade 2 GAERS groups, compared to kindled and grade 2 Wistar groups, respectively, in the SNRa region. GABA density in the SNRp region of kindled GAERS group increased significantly compared to that of GAERS grade 2 group. In the SNRp region, both kindled and grade 2 GAERS groups were found to have increased number of synapses compared to that of GAERS control group. We concluded that both SNRa and SNRp regions may be important in modulating resistance of GAERS to kindling stimulations.

Ultrastructural investigation of synaptic alterations in the rat hippocampus after irradiation and hyperthermia.

This study aimed to investigate ultrastructural synaptic alterations in rat hippocampus after in utero exposure to irradiation (IR) and postnatal exposure to hyperthermia (HT). There were four groups in each of the time points (3rd and 6th months). IR group: Pregnant rats were exposed to radiation on the 17th gestational day. HT group: Hyperthermia was applied to the rat pups on the 10th day after their birth. IR+HT group: Both IR and HT were applied at the same time periods. Control group: No IR or HT was applied. Rat pups were sacrificed after 3 and 6 months. Thin sections from the dentate gyrus (DG) and the CA3 of hippocampus were evaluated for synapse numbers by electron microscopy. Synapses were counted, and statistical analysis was performed. Abnormalities in myelin sheath, mossy terminals and neuropil were observed in the CA3 and DG of all groups. The synapses in the CA3 region were significantly increased in the IR-3rd month, IR-6th month, and IR+HT-3rd month groups vs control group. Synapses were significantly increased in the DG of HT-3rd month group. A trend for an increase in synapse numbers was seen in the CA3 and DG. Increased number of synapses in the rat hippocampus may be due to mossy fiber sprouting, possibly caused by in utero irradiation and/or postnatal hyperthermia.

Neuroprotective Effect of Erythropoietin on Phenylhydrazine-Induced Hemolytic Hyperbilirubinemia in Neonatal Rats.

Neonatal unconjugated hyperbilirubinemia might cause severe bilirubin neurotoxicity in especially hemolytic conditions. The study aimed to elucidate the potential neuroprotective effects of erythropoietin (EPO) in hemolysis-induced hyperbilirubinemia. In newborn rats, hyperbilirubinemia secondary to hemolysis was induced by injecting with phenylhydrazine hydrochloride (PHZ) and rats were injected with either vehicle or EPO. At 54th hour of the PHZ injection, rats were decapitated. Serum levels of TNF-α, IL-1ß, IL-10, brain-derived neurotrophic factor (BDNF) and S100-B and brain malondialdehyde, glutathione levels and myeloperoxidase activities were measured. TUNEL staining and NF-κB expression were evaluated. As compared to control pups, in vehicle-treated PHZ group, TNF-α and IL-1ß levels, malondialdehyde level and myeloperoxidase activity were increased with concomitant decreases in IL-10 and glutathione. All EPO regimens reversed PHZ-induced alterations in IL-10, TNF-α, malondialdehyde and glutathione levels. Three-day-treatment abolished increases in myeloperoxidase activity and IL-1ß levels, while BDNF and S100-B were elevated. Increased TUNEL (+) cells and NF-κB expressions in the brain of PHZ group were reduced in the 3-day-treated group. EPO exerted anti-inflammatory effects on PHZ-induced neural damage in newborn rats, while the neuroprotection was more obvious when the treatments were repeated successively. The results suggest that EPO treatment may have a therapeutic potential in supporting neuroplasticity in the hyperbilirubinemic neonates.

The neuroprotective and anti-apoptotic effects of melatonin on hemolytic hyperbilirubinemia-induced oxidative brain damage.

Melatonin exerts protection in several inflammatory and neurodegenerative disorders. To investigate the neuroprotective effects of melatonin in an experimental hemolysis-induced hyperbilirubinemia, newborn Sprague-Dawley rats (25-40 g, n = 72) were injected with phenylhydrazine hydrochloride (PHZ; 75 mg/kg) and the injections were repeated at the 24th hour. Rats were treated with saline or melatonin (10 mg/kg) 30 min before the first and second PHZ injections and 24 h after the 2nd PHZ injections. Control rats (n = 24) were injected with saline, but not PHZ. At sixth hours after the last injections of saline or melatonin, all rats were decapitated. Tumor necrosis factor (TNF)-α, IL-1ß, IL-10 and brain-derived neurotrophic factor (BDNF) and S100B levels in the plasma were measured. Brain tissue malondialdehyde (MDA), glutathione (GSH) levels and myeloperoxidase (MPO) activities were measured, and brain tissues were evaluated for apoptosis by TUNEL method. In the saline-treated PHZ group, hemoglobin, hematocrit levels were reduced, and total/direct bilirubin levels were elevated when compared to control group. Increased plasma TNF-α, IL-1ß levels, along with decreased BDNF, S100B and IL-10 values were observed in the saline-treated PHZ group, while these changes were all reversed in the melatonin-treated group. Increased MDA levels and MPO activities in the brain tissues of saline-treated hyperbilirubinemic rats, concomitant with depleted brain GSH stores, were also reversed in the melatonin-treated hyperbilirubinemic rats. Increased TUNEL(+) cells in the hippocampus of saline-treated PHZ group were reduced by melatonin treatment. Melatonin exerts neuroprotective and anti-apoptotic effects on the oxidative neuronal damage of the newborn rats with hemolysis and hyperbilirubinemia.

Nesfatin-1 alleviates gastric damage via direct antioxidant mechanisms.

BACKGROUND: Indomethacin is a nonsteroidal anti-inflammatory drug, which is known to produce serious side effects, causing ulcerative lesions. Nesfatin-1, a newly identified anorexigenic peptide, was recently shown to have neuroprotective effects. The aim of the study was to investigate the anti-inflammatory effects of nesfatin-1 on indomethacin-induced gastric ulcer. MATERIALS AND METHODS: After a 24-h starvation period, ulcer was induced in Sprague-Dawley rats by subcutaneous administration of indomethacin (25 mg/kg), whereas control group received vehicle. Fifteen minutes after ulcer induction, rats were treated with either saline or nesfatin-1 (0.1, 0.3, or 1 µg/kg, intraperitoneally). At the fourth hour, all rats were decapitated and their trunk blood was collected for tumor necrosis factor (TNF)-α and interleukin (IL)-6 measurements. Stomach samples were examined microscopically and analyzed for myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), luminol-, and lucigenin-enhanced chemiluminescence (CL) levels. RESULTS: Ulcer induction increased serum TNF-α; and IL-6 levels, gastric CL and MDA levels and MPO activity but decreased gastric GSH content (P < 0.05-0.001). On the other hand, 0.1 µg/kg dose of nesfatin-1 reduced microscopic and macroscopic damage scores, decreased MPO activity and MDA levels, CL and IL-6 levels, whereas gastric GSH was replenished (P < 0.01). However, indomethacin-induced increase in TNF-α level was abolished at only 1 µg/kg dose of nesfatin-1 (P < 0.01). CONCLUSIONS: Nesfatin-1 alleviated indomethacin-induced gastric injury, suggesting that the anti-inflammatory and gastroprotective effects of nesfatin-1 on oxidative gastric damage could be implemented by supporting the balance in oxidant and antioxidant systems while inhibiting the generation of pro-inflammatory mediators.

Effect of perinatal and postnatal thiamine deficiency on auditory pathway of the Wistar-Albino rats.

OBJECTIVE: In this study, we created an animal model to demonstrate the effects of thiamine on the hearing pathways of new-borns during pregnancy and lactation by inducing a dietary thiamine deficiency in the mother. METHODS: The study included 16 female Wistar albino rats. The animals were separated into four groups and provided the appropriate amounts of dietary thiamine according to their groups during pre-pregnancy, pregnancy, and lactation periods. Three pups from each mother were included in the study, and 12 pups were selected from each group. On the fortieth day after birth, the auditory pathways of 48 pups in the 4 groups were examined electro physiologically and ultra-structurally. RESULTS: In Group N-N, morphology of hair cells stereocilia degeneration was not obtained in all turns of cochlea. In Group N-T, Inner Hair Cells (IHCs) and Outher Hair Cells (OHCs) stereocilia didn't show degeneration in all turns of cochlea but had rupture inrows of HCs stereocilia. In group T-N IHCs stereocilia less degeneration was observed in all turns of cochlea. OHC stereocilia partial loss was observed only in basal turn of cochlea. In Group T-T IHCs stereocilia was observed less degeneration and rupture in all turns of cochlea. CONCLUSION: Thiamine is vital for the development of cochlear hair cells during both prenatal and postnatal periods. Even partial deficiency of thiamine causes significant degeneration to the auditory pathway. LEVEL OF EVIDENCE: The level of evidence of this article is 5. This article is an experimental animal and laboratory study.

Loop nerve graft prefabrication for peripheral nerve defect reconstruction.

BACKGROUND: Delayed autologous nerve graft reconstruction is inevitable in devastating injuries. Delayed or prolonged repair time has deleterious effects on nerve grafts. We aimed improving and accelerating nerve graft reconstruction process in a rat long nerve defect model with loop nerve graft prefabrication particularly to utilize for injuries with tissue loss. METHODS: Twenty-four Sprague-Dawley rats were allocated into three groups. 1.5 cm long peroneal nerve segment was excised, reversed in orientation, and used as autologous nerve graft. In conventional interpositional nerve graft group (Group 1), nerve defects were repaired in single-stage. In loop nerve graft prefabrication group (Group 2), grafts were sutured end-to-end (ETE) to the proximal peroneal nerve stumps. Distal ends of the grafts were sutured end-to-side to the peroneal nerve stumps 5 mm proximal to the ETE repair sites in first stage. In second stage, distal ends of the prefabricated grafts were transposed and sutured to distal nerve stumps. In staged conventional interpositional nerve graft group (Group 3), grafts were sutured ETE to proximal peroneal nerve stumps in first stage. Distal ends of the grafts and nerve stumps were tacked to the surrounding muscles until the final repair in second stage. Follow-up period was 4 weeks for each stage in Groups 2 and 3, and 8 weeks for Group 1. Peroneal function index (PFI), electrophysiology, and histological assessments were conducted after 8 weeks. P<0.05 was considered significant for statistical analysis. RESULTS: PFI results of Group 1 (-22.75±5.76) and 2 (-22.08±6) did not show statistical difference (p>0.05). Group 3 (-33.64±6.4) had a statistical difference compared to other groups (p<0.05). Electrophysiology results of Group 1 (16.19±2.15 mV/1.16±0.21 ms) and 2 (15.95±2.82 mV/1.17±0.16 ms) did not present statistical difference (p>0.05), whereas both groups had a statistical difference compared to Group 3 (10.44±1.96 mV/1.51±0.15 ms) (p<0.05). Axon counts of Group 1 (2227±260.4) and 3 (2194±201.1) did not have statistical difference (p>0.05), whereas both groups had significantly poor axon counts compared to Group 2 (2531±91.18) (p<0.05). CONCLUSION: Loop nerve graft prefabrication improved axonal regeneration without delay. Loop prefabrication can accelerate prolonged regeneration time for the injuries indicating a delayed nerve reconstruction. Higher axon counts derived with loop nerve prefabrication may even foster its investigation in immediate long nerve defect reconstructions in further studies.

Synaptic organization of the rat thalamus: a quantitative study.

First-order thalamic nuclei receive driving afferents from ascending pathways and transmit processed information to the cortex. Higher-order thalamic nuclei receive driver messages from layer 5 of cortex and transmit information from one cortical area to the other. The different types of axon terminals RL (round vesicles, large terminals), RS (round vesicles, small terminals) and F (flattened vesicles) and their synaptic junctions have been here compared in three first-order (ventrobasal, lateral geniculate and anteroventral) and three higher-order (posterior, lateral posterior and mediodorsal) thalamic nuclei of the rat. In the present study, the higher-order relays differ from first-order relays as in the cat, in having fewer driver terminals (RL) and synapses than do the first-order relays. However, the F terminals showed opposite ratios in the first versus higher-order thalamic nuclei. The majority of the terminals in all thalamic nuclei studied were RS terminals. The area measurements of the three types of terminals and synaptic lengths showed no significant differences between first and higher-order nuclei. The driver inputs represent the minority and the modulatory inputs represent the majority of the terminals and synapses in all thalamic nuclei. In conclusion, there is a relative paucity of driver inputs, whereas modulatory inputs establish more numerous synapses to achieve finer modulation.

α7 nicotinic receptor agonist and positive allosteric modulators differently improved schizophrenia-like cognitive deficits in male rats.

The majority of schizophrenia patients have cognitive deficits as a separate symptom cluster independent of positive or negative symptoms. Current medicines, unfortunately, cannot provide clear benefits for cognitive symptoms in patients. Recent findings showed decreased α7 nicotinic acetylcholine receptor (nAChR) expressions in subjects with schizophrenia. α7 nAChR full/partial agonists and positive allosteric modulators (PAMs) may be valuable drug candidates to treat cognitive deficits of disease. This study comparatively investigated the effect of α7 nAChR agonist (A-582941), type I PAM (CCMI), type II PAM (PNU-120596), and the antipsychotic drug (clozapine) on behavioral, molecular, and immunohistochemical parameters in a subchronic MK-801 model of schizophrenia in male rats. Novel object recognition (NOR) and Morris water maze (MWM) tests were performed to evaluate recognition and spatial memories, respectively. Gene and protein expressions of parvalbumin, glutamic acid decarboxylase-67 (GAD67), and α7 nAChR were examined in the rats' hippocampal tissue. The subchronic MK-801 administration produced cognitive deficits in the NOR and MWM tests. It also decreased the protein and gene expressions of parvalbumin, GAD67, and α7 nAChR in the hippocampus. Clozapine, A-582941, and PNU-120596 but not CCMI increased the parvalbumin and α7 nAChR expressions and provided benefits in recognition memory. Interestingly, clozapine and CCMI restored the MK-801 induced deficits on GAD1 expression and spatial memory while A-582941 and PNU-120596 were ineffective. These results indicated that α7 nAChR agonist, type I and type II PAMs may provide benefits in different types of cognitive deficits rather than a complete treatment in schizophrenia.

Electromagnetic Waves from Mobile Phones may Affect Rat Brain During Development.

AIM: To investigate the effects of electromagnetic waves (EMWs) from mobile phones (MPs) on rat brains of rats by morphological and biochemical analysis. MATERIAL AND METHODS: EMW was applied for two hours/day until birth in stand-by fetal and EMW fetal groups and postnatal 60 < sup > th < /sup > day in stand-by and EMW groups. The control group was not exposed to MP. On postnatal 60 < sup > th < /sup > day, brain malondialdehyde (MDA) and glutathione (GSH) levels were measured, and western blot analysis was performed to determine glial fibrillary acidic protein (GFAP) content. Hematoxylin and eosin staining and GFAP immunohistochemistry were applied. Trigeminal nerves were examined using the transmission electron microscope. RESULTS: In comparison to controls, rats exposed to MP in stand-by or talk modes had significantly increased neuronal damage in the cortex and hippocampus. Increased MDA levels in the EMW group and decreased GSH levels in the stand-by, EMW fetal and EMW groups were found compared with controls. Increased GFAP content in the EMW group and increased GFAP staining in the EMW fetal and EMW groups compared to controls were observed. EMW group had a significantly decreased number of myelinated axons than control animals. CONCLUSION: The results of this study suggests that 1800 MHz EMWs (SAR=1.79 W/kg) exposure in the prenatal and early postnatal life may lead to trigeminal nerve damage in addition to oxidative stress-induced neuronal degeneration and astroglial activation in the rat brain. Effects seem to be mode related, being more detrimental in groups exposed to MP during talk mode.

Neurogenesis is Enhanced in Young Rats with Genetic Absence Epilepsy: An Immuno-electron Microscopic Study.

AIM: To investigate neurogenesis in both adult and 3-week-old genetic absence epilepsy rats from Strasbourg (GAERS) to determine if newly formed neurons within the dentate gyrus (DG) form synaptic contacts with GABAergic (gamma aminobutyric acid) and glutamatergic nerve terminals and compared to the control (non-GAERS) Wistar rats. MATERIAL AND METHODS: Brain tissue was processed for electron microscopic assessment. Thin sections from the hippocampal DG were double-labelled for anti-GABA or anti-VGLUT1 (vesicular glutamate transporter 1) and anti-doublecortin (DCX) antibodies using immunogold methodology and examined with the transmission electron microscope for morphological changes and to quantify the density of gold labeling. RESULTS: DCX immunoreactivity was demonstrated within axon terminals, dendrites and somata in all groups. DCX and GABA or VGLUT1 were found to be co-localized in the axon terminals in all groups. We observed that DCX-immunoreactive (-ir) profiles formed synaptic contacts with GABAergic and glutamatergic terminals. The percentage of DCX labeling in dendrites, compared to axons, and the percentage of DCX-ir terminal profiles forming asymmetrical synapses, compared to those forming symmetrical synapses, were increased in all groups compared to the control group. DCX immunoreactivity in the 21-day-old GAERS group was found to be increased compared to the Wistar group. CONCLUSION: We conclude that newly born neurons are incorporated into the local hippocampal network in both the GAERS and the control Wistar rats. The results suggest that the neurogenesis taking place in the hippocampus may also be involved in the mechanism underlying absence seizures in GAERS.

Effect of Tacrolimus on Peripheral Nerve Regeneration in Allograft Transplantation: A Light and Electron Microscopic Study.

OBJECTIVES: Peripheral nerve injuries are common in Europe; however, the treatment techniques may lead to disabilities. This study aimed to evaluate the effect of tacrolimus use on the capacity of the epineural sheath graft to improve its regeneration quality in rat sciatic nerves as a treatment option for nerve injuries. MATERIALS AND METHODS: In the experimental process, 30 male Sprague Dawley were used as recipients and 10 Wistar rats were used as donors. Under anesthesia, all rats were operated on to resect the sciatic nerve. The nerve tissue of Wistar rats was used as allograft. In the autograft group, the resected nerve was reversed and sutured, resulting in an epineural sheath graft. For the allograft groups, rats were randomly divided into 2 groups as the tacrolimus-treated group and the nontreated group after allograft transplant. Tacrolimus was administered intramuscularly at 0.1 mg/kg daily for 12 weeks. After the treatment period, rats were killed and evaluated histomorphologically with light and electron microscopy. RESULTS: Histological examination showed no remarkable differences between different regions of the sciatic nerves (distal, middle, and proximal). The axonal density was decreased in the allograft groups compared with the autograft group (P < .001). Results showed that the number of mast cells was increased in the allograft group without tacrolimus treatment (P < .05). Similarly, there was a mild increase in mast cell count in the tacrolimus-treated allograft group. CONCLUSIONS: Our results showed that tacrolimus use in rats with implanted epineural nerve sheath supported recovery in terms of morphological and physiological regeneration of the nerve.

Repeated Atmospheric Pressure Alteration Effect on the Cochlea in Rats: Experimental Animal Study.

OBJECTIVE: This study aimed to evaluate the effects of repeated pressure alterations on cochlear structures in rats in an attempt to understand indirectly the inner ear status of flight crew who are repeatedly exposed to pressure alterations.METHODS: There were 12 adult Wistar albino rats equally divided into 2 groups: Group 1 (controls) and Group 2 (study group). The animals in Group 2 were exposed to repeated pressure changes in a pressure cabin which is regulated by manometers. The animals in Group 1 were placed in the cabin without being exposed to pressure changes. Auditory brainstem response (ABR) testing was performed in all animals at the beginning and at the end of the study. After 12 wk the animals were sacrificed and their cochleas were investigated using scanning electron microscopy (SEM).RESULTS: In the study group, hearing decreases at 2 kHz, 4 kHz, 6 dB at 8 kHz, and 32 kHz were encountered at the end of 3 mo. On SEM evaluation of the control group, the outer hair cells (OHC) and stereocilia were normal throughout the cochlea. In the study group, there were irregularities in lateral surface connections and separations, collapse, and adhesions in the basal segment of the cochlea and partial loss of stereocilia throughout the cochlea.CONCLUSION: Repeated alterations in the atmospheric pressure can lead to damage in the inner ear with subtle or evident hearing loss. Frequent flyers like air workers may be at risk of inner ear damage, which may be considered an occupational health problem.Eroglu S, Dizdar HT, Cevizci R, Cengiz AB, Ogreden S, Bulut E, Ilgezdi S, Dilci A, Ustun S, Sirvanci S, Kaya OT, Bayazit D, Caki BO, Oktay MF, Bayazit Y. Repeated atmospheric pressure alteration effect on the cochlea in rats: experimental animal study. Aerosp Med Hum Perform. 2021; 92(7):550555.

NLRP1-Mediated Antidepressant Effect of Ketamine in Chronic Unpredictable Mild Stress Model in Rats.

OBJECTIVE: NOD-like receptor protein 1 (NLRP1) inflammasome complex has been recently associated with chronic unpredictable mild stress (CUMS) model of depression. Our aim was to investigate whether ketamine-induced antidepressant effect is associated with suppression of NLRP1. METHODS: Wistar albino rats were divided into control, CUMS, CUMS+acute ketamine (a single 10 mg/kg dose) and CUMS+chronic ketamine (daily 10 mg/kg injections for 3 weeks) groups (n=10 for each group). Sucrose preference test and forced swimming test were performed to assess anhedonia and immobility time respectively for the severety of depression symptoms. Brain tissues were dissected and prefrontal cortex and hippocampus regions were used for real-time polymerase chain reaction (PCR) and immunohistochemical analysis. RESULTS: CUMS procedure significantly induced depressive-like symptoms whereas both acute and chronic ketamine treatment ameliorated them. mRNA expression levels of NLRP1, caspase 1, apoptosis-associated speck-like protein containing a CARD (ASC), NF-κB, endothelial nitric oxide synthase, IL-1ß, IL-6, toll-like receptor 4 (TLR-4) and purinergic 2×7 receptor (P2X7R) and numbers of Iba- 1+and GFAP+glial cells were reduced by acute and/or chronic ketamine treatment. CONCLUSION: In the present study for the first time upstream and downstream elements of the NLRP1 inflammasome complex are shown to be suppressed by ketamine thus reinforcing the involvement of NLRP1 in the physiopathology of depression.

Nesfatin-1 ameliorates oxidative bowel injury in rats with necrotizing enterocolitis: The role of the microbiota composition and claudin-3 expression.

BACKGROUND AND PURPOSE: Ongoing high mortality due to necrotizing enterocolitis (NEC) necessitates the investigation of novel treatments to improve the outcome of the affected newborns. The aim was to elucidate the potential therapeutic impact of the nesfatin-1, a peptide with anti-inflammatory and anti-apoptotic effects in several inflammatory processes, on NEC-induced newborn rats. MATERIALS AND METHODS: Sprague-Dawley pups were separated from their mothers, fed with a hyperosmolar formula and exposed to hypoxia, while control pups had no intervention. NEC-induced pups received saline or nesfatin-1 (0.2 µg/kg/day) for 3 days, while some nesfatin-1 treated pups were injected with capsaicin (50 µg/g) for the chemical ablation of afferent neurons. On the 4th day, clinical state and macroscopic gut assessments were made. In intestines, immunohistochemical staining of cycloxygenase-2 (COX-2), nuclear factor (NF)-κB-p65 (RelA), vascular endothelial growth factor (VEGF), claudin-3 and zonula occludens-1 (ZO-1) were performed, while gene expressions of COX-2, occludin, claudin-3, NF-κB-p65 (RelA) and VEGF were determined using q-PCR. In fecal samples, relative abundance of bacteria was quantified by q-PCR. Biochemical evaluation of oxidant/antioxidant parameters was performed in both intestinal and cerebral tissues. RESULTS: Claudin-3 and ZO-1 immunoreactivity scores were significantly elevated in the nesfatin-1 treated control pups. Nesfatin-1 reduced NEC-induced high macroscopic and clinical scores, inhibited NF-κB-65 pathway and maintained the balance of oxidant/antioxidant systems. NEC increased the abundance of Proteobacteria with a concomitant reduction in Actinobacteria and Bacteroidetes, while nesfatin-1 treatment reversed these alterations. Modulatory effects of nesfatin-1 on microbiota and oxidative injury were partially reversed by capsaicin. Immunohistochemistry demonstrated that nesfatin-1 abolished NEC-induced reduction in claudin-3. Gene expressions of COX-2, NF-κB, occludin and claudin-3 were elevated in saline-treated NEC pups, while these up-regulated mRNA levels were not further altered in nesfatin-1-treated NEC pups. CONCLUSION: Nesfatin-1 could be regarded as a potential preventive agent for the treatment of NEC.

Intra-amygdaloid injection of kainic acid in rats with genetic absence epilepsy: the relationship of typical absence epilepsy and temporal lobe epilepsy.

We showed previously that genetic absence epilepsy rats from Strasbourg (GAERS) resist secondary generalization of focal limbic seizures after electrical kindling. We now investigate the effect of intra-amygdaloid injection of kainic acid, as another model of temporal lobe epilepsy, focusing on epileptogenesis, spike-and-wave discharges (SWDs), and the transition from basal to SWD states in GAERS. The EEG was recorded from the hippocampus and cortex of adult GAERS and Wistar rats before kainic acid injections into the basolateral amygdala and for 3 months thereafter. EEG and video recordings monitored SWDs and convulsive seizures. We analyzed spectral changes of the EEG during kainic acid-induced status epilepticus, SWDs, for 10 s before (silent period) and for 2 s before (transition period) SWDs. After the injection of kainic acid, all animals experienced convulsive seizures for at least 3 h. The first convulsive seizure was significantly delayed in GAERS compared with Wistar rats. SWDs and increases in power of the delta, alpha, and beta frequency ranges during the transition period disappeared after the kainic acid injection for 1-3 d and gradually reappeared. Power increases in the delta and alpha ranges were significantly correlated with the number of SWDs, in the beta and alpha ranges with their mean duration. Neo-Timm's staining at the end of experiments demonstrated that mossy fiber sprouting in GAERS is less pronounced than in Wistar rats. Our findings show that mechanisms underlying absence epilepsy and temporal lobe epilepsy interact with each other, although a site of this interaction remains to be defined.