Subacute Administration Research Articles

Evaluation of Sub-acute Oral Toxicity of Lithium Carbonate Microemulsion (Nano Size) on Liver and Kidney of Mice.

The development of drug delivery systems has improved the therapeutic and toxic properties of existing drugs in therapy. Microemulsion systems are novel vehicles for drug delivery, which have been developed in recent years. These systems are currently of interest to the pharmaceutical scientist because of their considerable potential to act as drug delivery vehicles by incorporating into a wide range of drug molecules. Although these systems improved solubility and bioavailability of drugs, they may have potential toxic effects on the body organs. The purpose of this study was to examine a possible hepatotoxic and nephrotoxic effect of lithium carbonate microemulsion (LCME) in a mice model. Eighty male Swiss albino mice were randomly allocated to eight experimental groups, as follows: Group 1, as negative control group were treated orally with normal saline (0.9% NaCl); Group 2, received microemulsion base without drug as control group; Groups 3 to 5, received lithium carbonate (LC) solution in doses of 50, 100, and 200 mg/kg, respectively; Groups 6 to 8, received LCME orally in doses of 50, 100, and 200 mg/kg, respectively. All drugs were administered orally for ten consecutive days. Serum glutamate pyruvate aminotransferase (SGPT), serum glutamate oxaloacetate aminotransferase (SGOT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), and plasma creatinine (Cr), as markers of liver and kidney toxicity in treated mice, were measured. Furthermore, the changes of tissue were assessed by histopathologic examination. The findings showed that serum activity of ALP, SGOT, and SGPT and the levels of BUN and Cr in microemulsion base group was greater than normal saline group. However, this difference was not significant. Administration of LC and LCME in all doses resulted in a significant increase in the levels of BUN and serum activity of SGOT and SGPT in comparison to normal saline group (P < 0.05). Histopathological changes were observed in mice treated with LC or LCME. This study showed that subacute oral administration of different doses of LCME with severe toxicity in comparison to the same dose of LC.

Asenapine alters the activity of monoaminergic systems following its subacute and long-term administration: An in vivo electrophysiological characterization

Asenapine is a tetracyclic atypical antipsychotic used for treatment of schizophrenia and mania. Previous in vivo electrophysiological studies demonstrated antagonistic action of asenapine at dopamine D2, serotonin (5-HT)2A, and α2-adrenergic receptors. Here, we assessed monoamine system activities after two-day and 21-day asenapine administration at a dosage (0.1mg/kg/day) resulting in clinically relevant plasma levels. In the ventral tegmental area (VTA), asenapine increased the number of spontaneously active dopamine neurons, while firing parameters remained unchanged. Asenapine partially prevented the D2 autoreceptor-mediated inhibitory response to apomorphine after two days of administration. This effect was lost after 21 days of administration, suggesting adaptive changes leading to D2 receptor sensitization. Asenapine increased the firing activity of noradrenergic neurons in the locus coeruleus (LC) after 21, but not two days of administration. Furthermore, it potently blocked 5-HT2A receptors while α2-adrenergic receptors were unaffected by this drug regimen. Both acute and long-term asenapine administration partially blocked α2-adrenergic receptors in the CA3 region of the hippocampus, and noradrenergic tone on α1- and α2-adrenoceptors remained unchanged. In the dorsal raphe nucleus, asenapine increased the firing rate of 5-HT neurons after two, but not 21 days of administration. In addition, responsiveness of 5-HT1A autoreceptors was unaltered by asenapine. In the hippocampus, 21-day asenapine administration increased serotonergic tone by partial agonistic action on postsynaptic 5-HT1A and terminal 5-HT1B receptors. Taken together, asenapine had profound effects on both catecholamine systems, potently blocked 5-HT2A receptors, and enhanced 5-HT tone, effects that could be important in treatment of mood disorders and schizophrenia.

Effects of 4-hydroxyisoleucine from Fenugreek Seeds on Depression-like Behavior in Socially Isolated Olfactory Bulbectomized Rats.

Context:Antidepressant-like effects of (2S, 3R, 4S)-4-hydroxyisoleucine (4-HI), a major amino acid from fenugreek seeds, has been reported in the animal model of acute depression.Aims:To evaluate effects of subacute administration of 4-HI in animal model of stress-induced depression namely socially isolated olfactory bulbectomized rats.Materials and Methods:Bilateral olfactory bulbectomy (OBX) were induced in 30 Sprague-Dawley rats. After recovery period of 14 days, rats were randomized into five groups of 6 rats each and stressed with social isolation (individual housing). The rats were orally treated with either vehicle (OBX-Iso), positive control, fluoxetine (30 mg/kg) or 4-HI (10, 30, 100 mg/kg) once a day from day 14 onward. Separate group of rats with social isolation but without OBX (Sham-Iso) was also maintained. The behavioral depression and anxiety related parameters using open field test (OFT), sucrose intake test, novelty suppressed feeding (NSF) and forced swim test (FST), and neurochemical estimation (brain monoamines viz., serotonin and nor-adrenaline, serotonin turnover, and serum cortisol) were performed.Statistical Analysis Used:Data was analyzed by either two-way ANOVA (OFT and FST) or one-way ANOVA (sucrose intake test, NSF, and neurochemical estimation) followed by Dunnett's multiple comparisons test. Differences were considered significant at P < 0.05.Results:The significant and dose-dependent protection from behavioral and neurochemical changes were observed in 4-HI co-administrated OBX-Iso rats.Conclusion:4-HI demonstrated the antidepressant and antianxiety effects in socially isolated stress-induced OBX rats with possible involvement of multiple stress relieving mechanisms.HIGHLIGHTS OF PAPERIn this study, the subacute pretreatment of 4-HI showed strong and dose-dependent prevention of isolation stress related behavioral and neurochemical responses in olfactory bulbectomized rats. The prevention of hyperactive HPA axis in OBX-Iso stress-induced rats can be envisaged as probable mechanism of antidepressant and antianxiety effects of 4-HI.SUMMARY Effect of 4-hydroxyisoleucine (4-HI) in olfactory bulbectomized and socially isolated (Iso) rats was evaluated4-HI showed significant and dose-dependent antidepressant effects during novelty suppressed feeding (NSF) and forced swim test (FST)4-HI showed significant and dose-dependent antianxiety effects during OFT (open field test) and sucrose intake test4-HI showed protection from OBX-Iso stress-induced brain monoamines, serotonin turnover, and serum cortisol level elevation. Abbreviations used: SSRI: Selective Serotonin Reuptake Inhibitor; 4-HI: (2S, 3R, 4S)-4-hydroxyisoleucine; OBX: Olfactory bulbectomy; CPCSEA: Committee for the Purpose of Control and Supervision of Experiments on Animals; OFT: Open Field Test; NSF: Novelty Suppressed Feeding; FST: Forced Swimming Test; 5HT: 5-Hydroxytryptamine; 5-HIAA: 5-Hydroxyindoleacetic Acid; NA: Nor-adrenaline; and HPA: Hypothalamic-Pituitary Adrenal.

New high-performance liquid chromatography-dad method for analytical determination of arbutin and hydroquinone in rat plasma

Natural substances present in herbal preparations should be carefully used because they can give toxic or therapeutic effects despite of their amount or the way of administration. The safety of products of vegetable origin must be assessed before commercialisation by monitoring the active ingredients and their metabolites. This study was therefore designed to identify and quantify arbutin and its metabolite hydroquinone, naturally present in Arctostaphylos uva-ursi (L.) Spreng plant in rat plasma, after an acute and subacute administration of aqueous arbutin solution in Wistar rats. For this purpose a reversed-phase high-performance liquid chromatography coupled with photodiode array detection was developed to assess the pharmacokinetic of arbutin and hydroquinone in plasma of female rats treated with aqueous arbutin solutions. The detection (arbutin: 0.0617 µg/ml and hydroquinone 0.0120 µg/ml) and quantification (arbutin: 0.2060 µg/ml and hydroquinone: 0.0400 µg/ml) limits were determined. At the arbutin concentration level of 10.7 µg/ml repeatability was 13.33% and its recovery 93.4±6.93%, while at the hydroquinone concentration level of 10.6 µg/ml repeatability was 11.66% and its recovery 92.9±7.75%. Furthermore the method was fully validated and the obtained data indicate that the new method provides good performances.

Comparative toxicity profiles of Plumbago zeylanica L. root petroleum ether, acetone and hydroalcoholic extracts in Wistar rats.

Introduction:The root of Plumbago zeylanica Linn. is used in traditional medicine for the treatment of chronic inflammatory diseases and various disorders. The toxicity of this plant has not yet been extensively evaluated.Aim:To evaluate and compare the toxicity of P. zeylanica root petroleum ether (PZPE), acetone (PZAC), and the hydroalcoholic (PZHY) extracts.Materials and Methods:The acute and sub-acute toxicities of extracts were evaluated according to OECD guidelines 425 and 407, respectively in female rats.Results:PZPE was more toxic than PZAC and PZHA, based on LD50 values of 93.45, 928.4, and 928.4 mg/kg, respectively. This potency difference directly correlates with the plumbagin content of extracts. With regard to sub-acute toxicity, a significant increase in organ weights (liver, adrenal glands, and/or heart) was observed in PZPE and PZAC treated groups. All extracts produced a significant increase in serum aspartate aminotransferase and urea, and PZAC produced a significant increase in serum creatinine as compared to control. A decrease in hematocrit was observed in the highest dose PZPE group, and a decrease in leukocytes was observed in all PZAC groups. Hepatic and renal changes were observed in all extract treated groups.Conclusion:The findings of our study, thus demonstrate that liver and kidney are the primary organs being adversely affected following sub-acute administration of P. zeylanica root extract in rats.

Prophylactic Subacute Administration of Zinc Increases CCL2, CCR2, FGF2, and IGF-1 Expression and Prevents the Long-Term Memory Loss in a Rat Model of Cerebral Hypoxia-Ischemia.

Prophylactic subacute administration of zinc decreases lipoperoxidation and cell death following a transient cerebral hypoxia-ischemia, thus suggesting neuroprotective and preconditioning effects. Chemokines and growth factors are also involved in the neuroprotective effect in hypoxia-ischemia. We explored whether zinc prevents the cerebral cortex-hippocampus injury through regulation of CCL2, CCR2, FGF2, and IGF-1 expression following a 10 min of common carotid artery occlusion (CCAO). Male rats were grouped as follows: (1) Zn96h, rats injected with ZnCl2 (one dose every 24 h during four days); (2) Zn96h + CCAO, rats treated with ZnCl2 before CCAO; (3) CCAO, rats with CCAO only; (4) Sham group, rats with mock CCAO; and (5) untreated rats. The cerebral cortex-hippocampus was dissected at different times before and after CCAO. CCL2/CCR2, FGF2, and IGF-1 expression was assessed by RT-PCR and ELISA. Learning in Morris Water Maze was achieved by daily training during 5 days. Long-term memory was evaluated on day 7 after learning. Subacute administration of zinc increased expression of CCL2, CCR2, FGF2, and IGF-1 in the early and late phases of postreperfusion and prevented the CCAO-induced memory loss in the rat. These results might be explained by the induction of neural plasticity because of the expression of CCL2 and growth factors.

Subacute administration of fluoxetine prevents short-term brain hypometabolism and reduces brain damage markers induced by the lithium-pilocarpine model of epilepsy in rats.

The role of serotonin (5-hydroxytryptamine; 5-HT) in epileptogenesis still remains controversial. In this regard, it has been reported that serotonergic drugs can alter epileptogenesis in opposite ways. The main objective of this work was to investigate the effect of the selective 5-HT selective reuptake inhibitor (SSRI) fluoxetine administered subacutely (10mg/kg/day×7 days) on the eventual metabolic impairment induced by the lithium-pilocarpine model of epilepsy in rats. In vivo 2-deoxy-2-[(18)F]fluoro-d-glucose ([(18)F] FDG) positron emission tomography (PET) was performed to assess the brain glucose metabolic activity on days 3 and 30 after the insult. In addition, at the end of the experiment (day 33), several histochemical and neurochemical assessments were performed for checking the neuronal functioning and integrity. Three days after the insult, a marked reduction of [(18)F] FDG uptake (about 30% according to the brain region) was found in all brain areas studied. When evaluated on day 30, although a hypometabolism tendency was observed, no statistically significant reduction was present in any region analyzed. In addition, lithium-pilocarpine administration was associated with medium-term hippocampal and cortical damage, since it induced neurodegeneration, glial activation and augmented caspase-9 expression. Regarding the effect of fluoxetine, subacute treatment with this SSRI did not significantly reduce the mortality rate observed after pilocarpine-induced seizures. However, fluoxetine did prevent not only the short-term metabolic impairment, but also the aforementioned signs of neuronal damage in surviving animals to lithium-pilocarpine protocol. Finally, fluoxetine increased the density of GABAA receptor both at the level of the dentate gyrus and CA1-CA2 regions in pilocarpine-treated animals. Overall, our data suggest a protective role for fluoxetine against pilocarpine-induced brain damage. Moreover, this action may be associated with an increase of GABAA receptor expression in hippocampus.

P.1.h.011 The effects of subacute administration of buprenorphine and the novel opioid modulator samidorphan on home-cage locomotor activity in rats

Considerable evidences show that the VTA, as a major source of dopamine neurons projecting to cortical and limbic regions, has a major role in cognitive and motivating aspects of addiction. The current study assessed the ability of the selective D1 receptor antagonist SCH 23390 and D2 receptor antagonist sulpiride administrated into the CA1 region of hippocampus (dorsal hippocampus) to alter the rewarding effects of intra-VTA administration of morphine using the conditioned place preference (CPP). After bilaterally implantation of cannulae into the CA1 and/or VTA in adult male Wistar rats weighing 210–310 g, dose–response effects of different doses of intra-VTA morphine (0.03, 0.1, 0.3, 1 and 3 μg/side) on CPP paradigm were evaluated and animal displacement, conditioning score and locomotor activity were recorded by Ethovision software. In the next experiments, SCH 23390 (0.02, 0.05, 0.2 and 0.5 μg/side) or sulpiride (0.25, 0.75, 1.5 and 3 μg/side) were injected into the CA1, 5 min after intra-VTA injection of morphine during 3 days conditioning phase. Our results showed that intra-VTA morphine dose-dependently induces CPP in rats. Moreover, the blocking D1 and D2 receptors in the dorsal hippocampus decreased intra-VTA morphine-induced CPP significantly (P < 0.01). Intra-CA1 administration of these antagonists alone, in all doses, could not induce CPP. We suggest that D1 and D2 receptors in the CA1 region of hippocampus have a key role in the development of CPP induced by morphine at the level of the VTA. It seems that there is an interaction between dopaminergic and opioidergic systems in these areas in reward circuit.

Hypotensive effects of omentin-1 related to increased adiponectin and decreased interleukin-6 in intra-thoracic pericardial adipose tissue

BackgroundOmentin is an adipokine expressed in visceral adipose tissue (VAT). In vitro studies demonstrated that omentin induces vasorelaxation in isolated rat mesenteric arteries, and in vivo studies showed inhibition of agonist-induced increases in blood pressure, possibly mediated by nitric oxide (NO)-dependent mechanisms. MethodsWe investigated, in normotensive rats, the effects of subacute omentin-1 administration [8μg/kg, intraperitoneally (ip), once daily for 14 days] on cardiac activity, blood pressure, plasma concentration of l-citrulline (as a marker of NO production from l-arginine), and the gene expression of adiponectin, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in intra-thoracic pericardial adipose tissue (PAT). Electrocardiography (ECG), heart rate (HR), mean blood pressure (MBP), pulse pressure (PP) were monitored before and after treatment with omentin-1 or vehicle. ResultsWith respect to baseline and vehicle, we found a significant decrease of MBP (p<0.005) and PP (p<0.05) after treatment with omentin-1, while ECG and HR were not modified. Omentin-1 significantly increased l-citrulline levels in plasma (p<0.05), and the gene expression of adiponectin in PAT (p<0.05). On the other hand, we found decreased gene expression of IL-6 (p<0.005), while TNF-α mRNA in PAT was not affected. ConclusionWe conclude that the hypotensive effects of omentin-1 could be driven by stimulated production of NO in the vascular system, possibly related to increased adiponectin and decreased IL-6 mRNA in PAT.

Biochemical and hematological effects of acute and sub-acute administration to ethyl acetate fraction from the stem bark Scutia buxifolia Reissek in mice

Ethnopharmacological relevanceScutia buxifolia is a native tree of Southern Brazil, Uruguay, and Argentina, which is popularly known as “coronilha” and it is used as a cardiotonic, antihypertensive and diuretic substance. The aim of this study was to assess the acute and sub-acute toxicity of the ethyl acetate fraction from the stem bark Scutia buxifolia in male and female mice. Materials and methodsThe toxicity studies were based on the guidelines of the Organization for Economic Cooperation and Development (OECD-guidelines 423 and 407). In an acute study, a single dose of 2000mg/kg of Scutia buxifolia was administered orally to male and female mice. Mortality, behavioral changes, and biochemical and hematological parameters were evaluated. In the sub-acute study, Scutia buxifolia was administered orally to male and female mice at doses of 100, 200, and 400mg/kg/day for 28 days. Behavioral changes and biochemical, hematological, and histological analysis were evaluated. ResultsThe acute administration of Scutia buxifolia did not cause changes in behavior or mortality. Male and female mice presented decreased levels of platelets. Female mice presented decreased levels of leukocytes. On the other hand, in a sub-acute toxicity study, we observed no behavioral changes in male or female mice. Our results demonstrated a reduction in glucose levels in male mice treated to 200 and 400mg/kg of Scutia buxifolia. Aspartate aminotransferase (ASAT) activity was increased by Scutia buxifolia at 400mg/kg in male mice. In relation to the hematological parameters, male mice presented a reduction in hemoglobin (HGB) and hematocrit (HCT) when treated to 400mg/kg of plant fraction. Female mice showed no change in these parameters. Histopathological examination of liver tissue showed slight abnormalities that were consistent with the biochemical variations observed. ConclusionScutia buxifolia, after acute administration, may be classified as safe (category 5), according to the OECD guide. However, the alterations observed, after sub-acute administration with high doses of ethyl acetate fraction from the stem bark Scutia buxifolia, suggest that repeated administration of this fraction plant can cause adverse hepatic, renal, and hematological effects.

Subacute administration of crude khat (Catha edulis F.) extract induces mild to moderate nephrotoxicity in rats.

BackgroundAlthough various studies have been conducted to shed light on the pharmacological actions of khat, little or no data are available regarding khat’s effect on the renal redox system. The aim of this study was therefore to investigate the potential of nephrotoxicity associated with khat exposure in rats.MethodsSprague Dawely rats were randomly assigned into eight experimental groups. Animals were treated with Tween80, gentamicin 100 mg/kg and khat at various doses (100, 200 and 400 mg/kg) alone or in combination with gentamicin for ten days. The animals were then sacrificed to obtain blood and renal tissues for subsequent analysis. Renal markers, including creatinine, blood urea nitrogen, antioxidant enzymes as well as markers for lipid peroxidation were determined using established protocols. In addition, histopathological changes were evaluated with hematoxilin and-eosin staining technique.ResultsLower and moderate doses of khat did not alter the measured parameters compared to controls. By contrast, higher dose (400 mg/kg) of khat not only increased levels of serum creatinine and blood urea nitrogen (p < 0.001) but also levels of malondialdehyde (p < 0.01). Moreover, 400 mg/kg of khat significantly decreased enzymatic activities of superoxide dismutase (p < 0.01) and catalase (p < 0.001). When khat was administered with gentamicin, it was again the higher dose that significantly accentuated gentamicin-induced alterations in the renal system.ConclusionsKhat treatment at high dose is demonstrated to induce mild to moderate renal damage. Moreover, it creates synergy when combined with nephrotoxic drugs such as gentamicin.

Effect of Vitamins C &amp; E on Aspirin Induced Gastric Mucosal Damage and Oxidative Stress

The effects of Vitamins C & E on Aspirin - induced gastric mucosal damage on gastric ulcer parameters and stomach oxidative stress markers were determined in acute and sub-acute studies in Wistar rats. Aspirin produced a significant (p<0.05) increase in gastric ulcer score in both studies. Vitamins C & E conferred protection in acute and sub-acute studies with preventive indices of 54 and 60% respectively. Histologically the gastric mucosa of animals in the sub-acute study showed a severe necrosis of the epithelial cells than observed in the acute study. Acute aspirin administration did not increase the stomach tissue Malondialdehyde (MDA) but sub-acute administration significantly (p<0.05) increased MDA, while vitamins C & E caused a significant (p<0.05) decrease below the level seen in normal controls. Aspirin in both studies significantly decreased Catalase activity. While acute aspirin exposure had no effect on Superoxide Dismutase (SOD) activity, sub-acute exposure raised it significantly (p<0.05). Administration of Vitamins C and E significantly increased SOD activity only in the acute study. Aspirin significantly decreased reduced Glutathione (GSH) in both studies and was reversed by Vitamin C and E. The level of GSH reductase (GSHRD) in the acute study was significantly decreased by aspirin but sub- acutely and prior treatment with vitamins C and E had no significant effect. Combine administration of vitamins C & E prior to intake of aspirin significantly prevented aspirin-induced gastric ulceration with decrease in some oxidative stress markers.

Sub-acute intravenous administration of silver nanoparticles in male mice alters Leydig cell function and testosterone levels

The aim of this study was to determine whether short-term, in vivo exposure to silver nanoparticles (AgNPs) could be toxic to male reproduction. Low dose (1mg/kg/dose) AgNPs were intravenously injected into male CD1 mice over 12 days. Treatment resulted in no changes in body and testis weights, sperm concentration and motility, fertility indices, or follicle-stimulating hormone and luteinizing hormone serum concentrations; however, serum and intratesticular testosterone concentrations were significantly increased 15 days after initial treatment. Histologic evaluation revealed significant changes in epithelium morphology, germ cell apoptosis, and Leydig cell size. Additionally, gene expression analysis revealed Cyp11a1 and Hsd3b1 mRNA significantly upregulated in treated animals. These data suggest that AgNPs do not impair spermatogonial stem cells in vivo since treatment did not result in significant decreases in testis weight and sperm concentrations. However, AgNPs appear to affect Leydig cell function, yielding increasing testicular and serum testosterone levels.

Can TiC nanoparticles produce toxicity in oral administration to rats?

BackgroundTitanium carbide (TiC) is used for ceramic metal composites in several industries and is regarded as a nanomaterial for catalyst and battery applications. However, there are very few studies in regard to the toxicological potential of TiC nanoparticles (NPs). ObjectiveTo study the toxicodynamics and toxicokinetics of TiC NPs in Sprague Dawley rats in acute (24 h) and subacute (28 days) oral administrations. The acute doses were 0.5, 5, 50, 300 and 1000 mg kg−1; the subacute doses were 0.5 and 50 mg kg−1. ResultsOrgan histopathological examination (esophagus, stomach, intestines, spleen, liver, and kidneys) indicates the absence of damage at all applied doses, in both assessments. In the acute administration, alkaline phosphatases increased (5, 300 and 1000 mg kg−1), ASAT increased (1000 mg kg−1) and bile salts decreased (0.5 mg kg−1). No alterations in urine parameters (sodium, potassium, osmolarity) were found. Acute administration of TiC caused mineral changes in organs (liver, spleen, kidneys). TiC was mostly cleared by feces excretion 24 h after administration, in subacute administration causing variations in mineral absorption (Mg, Al, P, S, Ca, Zn). TiC could pass the intestinal barrier as TiC traces were detected in urine. ConclusionNo sign of toxicity was found after oral administration. TiC was excreted mostly in feces producing mineral absorption alterations. Low traces were retrieved in urine, indicating that TiC can cross the intestinal barrier.

Cute and Sub-Acute Toxicity Studies of Plumeria alba Linn. (Apocynaceae) Hydroalcoholic Extract in Rat

Plumeria alba Linn (Apocynaceae) is used in Togolese traditional medicine to treat diabetes mellitus and wounds. The present investigation was carried out to evaluate the toxicity of hydroalcoholic extract of Plumeria alba roots in Sprague Dawley rats. The acute toxicity test was conducted by administering orally dose of 5 g/Kg. General behavior and mortality were examined for up to 14 days. The sub-acute toxicity test was performed by daily gavage at 250, 500 and 1000 mg/Kg for 28 days. Body weight and blood glucose were measured weekly. Hematological and biochemical parameters, relative organ weight were determined at the end of the 28 days administration. In acute study, no adverse effect of the extract was observed at 5.0 g/Kg. Sub-acute oral administration of the extract at the dose up to 1000 mg/Kg did not induce death or significant changes in body weight, relative weight of vital organs, hematological parameters and was not associated with liver and kidney toxicity.

Effect of exposure to diazinon on adult rat’s brain

Diazinon (DZN), a commonly used agricultural organophosphate insecticide, is one of the major concerns for human health. This study was planned to investigate neurotoxic effects of subacute exposure to DZN in adult male Wistar rats. Animals received corn oil as control and 15 and 30 mg/kg DZN orally by gastric gavage for 4 weeks. The cerebrum malondialdehyde and glutathione (GSH) contents were assessed as biomarkers of lipid peroxidation and nonenzyme antioxidants, respectively. Moreover, activated forms of caspase 3, -9, and Bax/Bcl-2 ratios were evaluated as key apoptotic proteins. Results of this study suggested that chronic administration of DZN did not change lipid peroxidation and GSH levels significantly in comparison with control. Also, the active forms of caspase 3 and caspase 9 were not significantly altered in DZN-treated rat groups. Moreover, no significant changes were observed in Bax and Bcl-2 ratios. This study indicated that generation of reactive oxygen species was probably modulated by intracellular antioxidant system. In conclusion, subacute oral administration of DZN did not alter lipid peroxidation. Moreover, apoptosis induction was not observed in rat brain.

Influence of Clonidine and Ketamine on m-RNA Expression in a Model of Opioid-Induced Hyperalgesia in Mice

BackgroundWe investigated the influence of morphine and ketamine or clonidine in mice on the expression of genes that may mediate pronociceptive opioid effects.Material and MethodsC57BL/6 mice received morphine injections thrice daily using increasing doses (5-20mg∙kg-1) for 3 days (sub-acute, n=6) or 14 days (chronic, n=6) and additionally either s-ketamine (5mg∙kg-1, n=6) or clonidine (0.1mg∙kg-1, n=6). Tail flick test and the assessment of the mechanical withdrawal threshold of the hindpaw was performed during and 4 days after cessation of opioid treatment. Upon completion of the behavioural testing the mRNA-concentration of the NMDA receptor (NMDAR1) and β-arrestin 2 (Arrb2) were measured by PCR.ResultsChronic opioid treatment resulted in a delay of the tail flick latency with a rapid on- and offset. Simultaneously the mice developed a static mechanical hyperalgesia with a delayed onset that that outlasted the morphine treatment. Sub-acute morphine administration resulted in a decrease of NMDAR1 and Arrb2 whereas during longer opioid treatment the expression NMDAR1 and Arrb2 mRNA increased again to baseline values. Coadministration of s-ketamine or clonidine resulted in a reversal of the mechanical hyperalgesia and inhibited the normalization of NMDAR1 mRNA expression but had no effect on the expression of Arrb2 mRNA.ConclusionIn the model of chronic morphine therapy the antinociceptive effects of morphine are represented by the thermal analgesia while the proniceptive effects are represented by the mechanical hyperalgesia. The results indicate that the regulation of the expression of NMDAR1 and Arrb2 may be associated to the development of OIH in mice.PerspectiveThe results indicate that co-administration of clonidine or ketamine may influence the underlying mechanisms of OIH.

Does propylthiouracil increase the gentamicin-induced nephrotoxicity in rat?

The aim of this study was to evaluate the effect of subacute administration of propylthiouracil (PTU) on gentamicin (GM)-induced nephrotoxicity in male rats. Male Wistar rats were divided into 4 experimental groups as follow: (1) CONTROL GROUP: isotonic saline (1 ml/kg, IP. for 18 d), (2) GM group: 100 mg/kg, IP for 8 d, (3) PTU group: PTU (10 mg/kg, IP for 18 d.) and (4) PTU + GM group: GM (100 mg/kg, IP. for 8d) and PTU (10 mg/kg, IP. for 18 d). Blood sample was taken from all animals and then the animals were sacrificed under light ether anesthesia on the day after the last injection. Sera were separated and were used to measure the urea and creatinine. Microscopic evaluation of renal injury was performed using a semiquantitative scale to evaluate the degree of tubular necrosis. GM markedly increased serum urea and creatinine, as well as acute tubular necrosis (ATN), glomerular atrophy, hyaline casts formation in tubular lumen, interstitial nephritis and infiltration of inflammatory cells. PTU administration alone caused hyperemia and interstitial nephritis and infiltration of lymphocytic inflammatory cells in cortex but it had no marked effect on glomerular and tubular morphology and function. Co-administration of PTU and GM potentiates the GM-induced nephrotoxicity characterized by diffuse ATN; diffuse hyaline cast formation in lumen and infiltration of inflammatory cell in kidney tissues. Our data indicate that PTU potentiates GM-induced nephrotoxicity. The underlying mechanism(s) via which PTU potentiates GM renal toxicity remains to be elucidated.

English

Terminalia fagifolia Mart & Zucc is a typical plant from Brazilian savanna, whose stem bark is used in popular medicine for relief of gastrointestinal discomfort. A phytochemical study showed the presence of large amounts of antioxidants (flavonoids and triterpenes). In acute toxicity tests, five groups of female mice were orally treated with stem bark extract from T. fagifolia or fractions by gavage at doses 2 g/kg/day (n = 5) and general behavior, adverse effects and mortality were recorded for up to 14 days. In sub-acute toxicity assays, animals received T. fagifolia ethanol extract or fractions at doses of 80, 240 or 720 mg/kg/day (n = 6) for 30 days and biochemical and morphological parameters were determined. The acute treatment in mice produced 40% of death. The estimate for the median lethal oral dose was 2 g/kg (LD50 <5 g/kg). Sub-acute treatment with T. fagifolia failed to change body weight gain, food and water consumption and biochemical profiles or reproductive parameters in female Wistar rats. In addition, no changes in macroscopical and microscopical aspect of organs were observed. Our results showed that acute or sub-acute administration of T. fagifolia has no significant toxicity, suggesting that it is safe for use as herbal medicine. Key words: Toxicity, herbal medicine, reproductive toxicity, rodents.

Anti-Hyperglycemic, Anti-Hyperlipidemic and Antioxidant Potential of Alcoholic-Extract of Sida cordifolia (Areal Part) in Streptozotocin-Induced-Diabetes in Wistar-Rats

Sida cordifolia is a shrub found throughout the tropical and sub-tropical plains. All parts of the plant are used as anti-rheumatic, antipyretic, anti-asthmatic, laxative, diuretic, vasorelaxative, hypotensive, central nervous system depressant, antioxidant, analgesic and hypoglycemic. The present study was aimed to evaluate the hypoglycemic, anti-hyperlipidemic and antioxidant potential of alcoholic-extract obtained from areal part of S. cordifolia in streptozotocin-induced-diabetes in wistar-rats. Diabetes was induced with streptozotocin at the intra-peritoneal dose of 55 mg/kg. Diabetic rats were treated with alcoholic extract of S. cordifolia at dosage of 200, 400 mg/kg and glibenclamide (5 mg/kg) after sub-acute administration for 28 days. Alcoholic extract of S. cordifolia at 400 mg/kg significantly improved the body-weight whereas significantly decreased the blood glucose level in diabetic rats. However at 400 mg/kg, the alcoholic extract of S. cordifolia showed beneficial effect indicating significant decrease in total cholesterol, triglycerides, low density lipids, plasma-creatinine, plasma-urea nitrogen and lipid-peroxidation and a significant increase in high density lipid-level in diabetic rats. Interestingly at 400 mg/kg, a significant increase in antioxidant enzymes such as catalase and superoxide-dismutase-activity was seen in the diabetic rats. The dose 200 mg/kg of alcoholic extract of S. cordifolia showed non-significant change in diabetic rats. The above therapeutic-potential of alcoholic extract of areal parts of plant may be because of the presence of bioactive compounds such as glycosides, resins, alkaloids, sterols, saponins and flavonoids. Thus, the findings of the present study indicate that the alcoholic extract of S. cordifolia at dosage level of 400 mg/kg produces anti-diabetic effect in the streptozotocin-induced diabetes in wistar-rats.