Shortened Daily Photoperiod Alleviates Anxiety-like Behaviour by Antioxidant Effect and Changes Serum Fatty Acid Profile in Diabetic Rats

The aim of our study was to investigate the effects of a shortened daily photoperiod on anxiety-like behaviour, brain oxidative stress, lipid status and fatty acid composition of serum lipids in a streptozotocin (STZ)-induced model of diabetes mellitus in rats. Male Wistar rats were divided into the following groups: first group—control group (C12/12); second group—diabetic group (DM12/12; 100 mg/kg STZ); third group—control group exposed to a light/dark cycle 6/18 h (C6/18); fourth group—diabetic group exposed to a light/dark cycle 6/18 h (DM6/18). Anxiety-like behaviour was tested three weeks following STZ injection by elevated plus maze (EPM) and open-field test (OFT). Oxidative stress parameters were measured in the cortex, hippocampus and thalamus, while lipid status and fatty acid methyl esters (FAMEs) were measured in the serum. Both EPM and OFT showed a lower degree of anxiety-like behaviour in the DM6/18 vs. DM12/12 group. Lipid peroxidation in the cortex, hippocampus and thalamus was significantly lower in the DM6/18 vs. DM12/12 group (p < 0.05), associated with an increased level of antioxidant enzymes and protein thiols in the cortex and thalamus. In the DM6/18 group, oleic, vaccenic, dihomo-γ-linolenic and docosahexaenoic acid concentrations were significantly higher in comparison to the DM12/12 group. A shortened daily photoperiod alleviates anxiety-like behaviour in diabetic rats by reduced lipid peroxidation and changes in the serum fatty acids profile

Behavioral and electroencephalographic manifestations of thioacetamide-induced encephalopathy: Possible mechanisms of neurotoxic effects

Although there is still no ideal experimental model of hepatic encephalopathy, thioacetamide is widely used for the induction of acute and chronic liver failure. Thioacetamide exerts hepatotoxic effects through the formation of toxic metabolites in hepatocytes, oxidative stress and calcium mobilization. An ideal experimental model of hepatic encephalopathy should have similar behavioral and electroencephalographic manifestations as human encephalopathy. Thioacetamide induces motor manifestations in a dose-dependent manner. Milder forms of thioacetamide-induced encephalopathy are associated with an increase in relative alpha power, while more severe forms are followed by a flattening of the electroencephalogram. liver failure-induced hyperammonemia has a pivotal role in the neurotoxic effects of thioacetamide. Hyperammonemia induces brain edema, alterations in neurotransmission, oxidative stress, mitochondrial dysfunction and neuronal death. The aim of this article is to review the behavioral and electroencephalographic manifestations of thioacetamide-induced encephalopathy, as well as to summarize potential mechanisms involved in thioacetamide neurotoxicity.[Acknowledgments. This work was supported by the Ministry of Education and Science of Serbia, Grant No 175032

The effect of N-methyl-D-aspartate receptor antagonists on D,L-homocysteine thiolactone induced seizures in adult rats

The aim of our study was to investigate the effects of ifenprodil and MK-801 on D,L-homocysteine thiolactone induced seizures in adult rats.Male Wistar rats were divided into following groups: 1. Saline-treated (C, n=10); 2. D,L-homocysteine thiolactone 8 mmol/kg, i.p. (H, n=7); 3. Ifenprodil 20 mg/kg i.p. (IF, n=8); 4. MK-801 0.5 mg/kg, i.p. (MK, n=8) and 5. Groups that received IF or MK 30 minutes prior to H (IFH, n=8 and MKH, n=8). Seizure behavior was assessed by incidence, latency, number and intensity of seizure episodes. Seizure severity was described by a descriptive scale with grades 0-4. Lethality in experimental group was recorded 90 min and 24 h upon D,L-homocysteine thiolactone administration.There were no behavioral signs of seizure activity in groups C, IF and MK.Pre-treatment with MK-801 (MKH) showed tendency to reduced incidence of convulsions, latency to the first seizure onset and the severity of seizure episodes, but statistical significance was not attained comparing to the H group. However, median number of seizure episodes was significantly decreased in MKH (p<0.05), comparing to the H group. On the other hand, ifenprodil (IFH) decreased the latency to the first seizure onset and increased the median number of seizure episodes (p<0.05). The majority of seizure episodes in IFH (72.1%, p<0.05) and MKH (73.1%, p<0.05) groups was grade 2 and significantly different comparing to the H (36.0%). Our findings suggest that MK-801 has a mild anticonvulsive effect on D,L-homocysteine thiolactone induced seizures in adult rats

Spectral analysis of thioacetamide-induced electroencephalographic changes in rats

Thioacetamide (TAA) is widely used as a model of hepatic encephalopathy (HE). The aim of our study was to investigate the effects of TAA on electroencephalographic (EEG) changes in rats and to compare them with human HE. Male Wistar rats were divided into groups: (1) saline-treated group and (2) TAA-treated groups: TAA(300) (300 mg/kg), TAA(600) (600 mg/kg), and TAA(900) (900 mg/kg). Daily dose of TAA (300 mg/kg) was administered intraperitoneally once (TAA(300)), twice (TAA(600)), or thrice (TAA(900)) in subsequent days. EEG changes were recorded about 24 h after the last dose of TAA. Absolute and relative power density in alpha bands were significantly higher in TAA(300) versus control group. In TAA(300), absolute beta power density was higher and relative beta power density was lower versus control group. Absolute alpha, theta, delta, and relative theta power were significantly lower, while relative power in delta band was significantly higher in TAA(900) versus control group (p LT 0.01). In conclusion, decrease in EEG voltage with an increase in delta relative power, which correspond to the EEG manifestations of severe HE in humans, was observed in TAA(900) group. Electrical activity in TAA(300) group correlates with mild HE in humans

First Report of Stolbur Phytoplasma Associated with Maize Redness Disease of Maize in Bosnia and Herzegovina

Maize redness (MR), caused by stolbur phytoplasma (16SrXII-A, ‘Candidatus phytoplasma solani’) and vectored by the cixiid planthopper Reptalus panzeri (Löw), is a severe and emerging disease of maize in southeastern Europe (2). Symptoms of MR include midrib, leaf, and stalk reddening, followed by desiccation of the entire plant, abnormal ear development, and incomplete kernel set. MR may cause significant economic losses (2). During 2010, 2011, and 2012, the presence of MR-like symptoms on maize accompanied by significant yield losses were frequently observed in maize fields in the Semberija region of northeastern Bosnia and Herzegovina. From mid-June to early July, potential vectors were collected using mouth-aspirators from maize plants in fields at three locations in the Semberija region where MR-like symptoms were previously observed. At the end of July, symptomatic maize plants were collected from six fields in the same region for phytoplasma identification. In addition, we sampled asymptomatic johnsongrass (Sorghum halepense L.), bindweed (Convolvulus arvensis L.), and volunteer wheat (Triticum aestivum L.) in areas adjacent to maize fields with MR-like symptoms, as potential phytoplasma reservoirs (2,3). A total of 49 plants (38 maize, 6 johnsongrass, 3 bindweed, and 2 wheat) and 43 R. panzeri were tested for the presence of stolbur phytoplasma. Leaves of four maize seedlings, grown in insect-proof greenhouse conditions, were used as controls. Total DNA was extracted from roots of each plant and R. panzeri using the CTAB methods (2). Initial phytoplasma detection was conducted on 16S rRNA gene using nested PCR assay with phytoplasma universal primers P1/P7 and F2n/R2 (4). Subsequently, all phytoplasma positive samples were retested employing stolbur-specific Stol11 protocol with the f2r/f3r2 primer set (1). Molecular characterization of identified phytoplasmas was performed by PCR-RFLP analysis of the tuf gene (3) and by sequence analyses of the 16S rRNA nested PCR products (GenBank Accession No. KC852868). All samples that tested positive on 16S rRNA gene using phytoplasma generic primers gave positive reaction in assays with stolbur-specific primers. Stolbur phytoplasma was identified in 36 of 49 plant samples (34 of 38 symptomatic maize plants and in 2 of 6 johnsongrass) and in 2 of 43 R. panzeri individuals. None of the control plants, bindweed, or wheat samples were positive for the presence of any phytoplasma. Tuf gene RFLP analyses enabled affiliation of all isolates to the stolbur type tuf-b. Comparison of the 16S rRNA sequence using BLAST analyses further confirmed identification of the phytoplasmas as being ‘Candidatus phytoplasma solani.’ The obtained sequence showed 100% identity with ‘Candidatus phytoplasma solani’ from corn in Serbia (JQ730750). These data clearly demonstrated association of stolbur phytoplasma with MR symptoms on maize in Semberija, which represents the first report of the MR disease and stolbur phytoplasma in maize, R. panzeri, and johnsongrass in Bosnia and Herzegovina. In the Semberija region, maize-wheat crop rotation is a traditional practice, which is a key factor for MR occurrence and persistence (2). References: (1) D. Clair et al. Vitis 42:151, 2003. (2) J. Jović et al. Phytopathology 99:1053, 2009. (3) M. Langer and M. Maixner. Vitis 43, 191, 2004. (4) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. </jats:p

Brain and heart in hyperhomocysteinemia induced by methionine nutritional overload

Date: October 8th – 10th, 2015, Belgrade

Reduced light exposure mitigates streptozotocin-induced vascular changes and gliosis in diabetic retina by an anti-inflammatory effect and increased retinal cholesterol turnover

Diabetic retinopathy is not cured efficiently and changes of lifestyle measures may delay early retinal injury indiabetes. The aim of our study was to investigate the effects of reduced daily light exposure on retinal vascularchanges in streptozotocin (STZ)-induced model of DM with emphasis on inflammation, Aqp4 expression, visualcycle and cholesterol metabolism-related gene expression in rat retina and RPE. Male Wistar rats were dividedinto the following groups: 1. control; 2. diabetic group (DM) treated with streptozotocin (100 mg/kg); 3. groupexposed to light/dark cycle 6/18 h (6/18); 4. diabetic group exposed to light/dark cycle 6/18 h (DM+6/18).Retinal vascular abnormalities were estimated based on lectin staining, while the expression of genes involved inthe visual cycle, cholesterol metabolism, and inflammation was determined by qRT-PCR. Reduced light exposurealleviated vasculopathy, gliosis and the expression of IL-1 and TNF-α in the retina with increased perivascularAqp4 expression. The expression of genes involved in visual cycle and cholesterol metabolism was significantlyup-regulated in RPE in DM+6/18 vs. DM group. In the retina only the expression of APOE was significantlyhigher in DM+6/18 vs. DM group. Reduced light exposure mitigates vascular changes and gliosis in DM via itsanti-inflammatory effect, increased retinal cholesterol turnover and perivascular Aqp4 expression