Increasing dopamine synthesis in nigrostriatal circuits increases phasic dopamine release and alters dorsal striatal connectivity: implications for schizophrenia.

One of the most robust neurochemical abnormalities reported in patients with schizophrenia is an increase in dopamine (DA) synthesis and release, restricted to the dorsal striatum (DS). This hyper functionality is strongly associated with psychotic symptoms and progresses in those who later transition to schizophrenia. To understand the implications of this progressive neurobiology on brain function, we have developed a model in rats which we refer to as EDiPs (Enhanced Dopamine in Prodromal schizophrenia). The EDiPs model features a virally mediated increase in dorsal striatal (DS) DA synthesis capacity across puberty and into adulthood. This protocol leads to progressive changes in behaviour and neurochemistry. Our aim in this study was to explore if increased DA synthesis capacity alters the physiology of DA release and DS connectivity. Using fast scan cyclic voltammetry to assess DA release we show that evoked/phasic DA release is increased in the DS of EDiPs rats, whereas tonic/background levels of DA remain unaffected. Using quantitative immunohistochemistry methods to quantify DS synaptic architecture we show a presynaptic marker for DA release sites (Bassoon) was elevated within TH axons specifically within the DS, consistent with the increased phasic DA release in this region. Alongside changes in DA systems, we also show increased density of vesicular glutamate transporter 1 (VGluT1) synapses in the EDiPs DS suggesting changes in cortical connectivity. Our data may prove relevant in understanding the long-term implications for DS function in response to the robust and prolonged increases in DA synthesis uptake and release reported in schizophrenia.

Positive symptom phenotypes appear progressively in "EDiPS", a new animal model of the schizophrenia prodrome.

An increase in dopamine (DA) synthesis capacity in the dorsal striatum (DS) during the prodromal stage of schizophrenia becomes more pronounced as patients progress to the full disorder. Understanding this progression is critical to intervening in disease course. We developed an animal model-Enhanced Dopamine in Prodromal Schizophrenia (EDiPS)-which uses a genetic construct to increase DA synthesis capacity in the DS of male rats. We assessed pre-pulse inhibition (PPI) and amphetamine (AMPH)-induced locomotion (0.6 mg/kg) in EDiPS animals longitudinally after post-natal day 35 (when the EDiPS construct is administered). We also assessed their response to repeated acute restraint stress. In adult EDiPS animals, we measured baseline and evoked extracellular DA levels, and their stereotyped responses to 5 mg/kg AMPH. AMPH-induced hyperlocomotion was apparent in EDiPS animals 6-weeks after construct administration. There was an overall PPI deficit in EDiPS animals across all timepoints, however the stress response of EDiPS animals was unaltered. Adult EDiPS animals show normal baseline and potassium-evoked DA release in the DS. These findings suggest that key behavioural phenotypes in EDiPS animals show a progressive onset, similar to that demonstrated by patients as they transition to schizophrenia. The EDiPS model could therefore be used to investigate the molecular mechanisms underlying the prodrome of schizophrenia.

Ameliorative effects of jamun seed and orange peel extracts on microcystin LR induced alterations in calcitonin cells and parathyroid gland of rats.

This study investigated changes in calcitonin cells (C-cells) and parathyroid glands (PTG) induced by microcystin LR (MCLR) exposure to rats and evaluated ameliorative effects of jamun (Syzygium cumini) seed (JSE) and orange (Citrus sinensis) peel (OPE) extracts. Wistar rats were treated as-Group A (control), Group B (MCLR), Group C (MCLR + JSE), Group D (MCLT + OPE), Group E (OPE) and Group F (JSE). Microcystin dose was (10 µg/kg body wt/day whereas OPE and JSE dose was 200 mg/kg body wt/day. Thyroid and PTG were fixed on 15 and 30 days following the treatment. C-cells of treated rats for 15 days with MCLR; MCLR + JSE and MCLR + OPE exhibit degranulation, mitochondrial swelling and prominent RER. In MCLR treated rats few cells completely lack secretory granules. After 30 days MCLR treatment accumulation of secretory granules and degeneration were noticed in C-cells. C-cell nuclear volume (NV) of MCLR, MCLR + JSE and MCLT + OPE treated rats show an increase. In MCLR, MCLR + JSE and MCLR + OPE treated rats PTG exhibit hyperchromatic nuclei, nuclear elongation and increased NV after 15 days. After 30 days MCLR treatment nuclei of PTG become more hyperchromatic, more elongated, show degeneration of nuclei and increase in NV. NV is increased in Group C and Group D. PTG remain unaltered 30 days following treatment with OPE and JSE. Microcystin LR provoke physiological effects on the blood calcium and alterations in C cells and PTG, which cause serious threat to organism. These changes can be protected by JSE and OPE.

Keystone Flap as a Reconstructive Option for selected areas; A Prospective Study.

OBJECTIVE: A very few flaps would be described as versatile as the Keystone Flap. There is an increasing demand for coverage of defects in lower limb due to traumatic defects as well as other parts of the body. Keystone flap is one of its kind, which is simple and easy to perform. It is a safe option for conditions where microsurgery may not be a viable option. The relative simplicity of this flap makes it a to go option at many places. METHODS: A prospective study was developed from October 2017 to December 2019 at SMS Hospital, Jaipur. We assessed the size of the flap, operation time, average hospital stay and the complications. Perforators over the leg were Doppler marked preoperatively over which the flap was raised. RESULTS: 50 patients were taken into the study. 30 key stone flaps were done to cover lower limb defects, 10 flaps were done for upper limb defects and the remaining 10 were for trunk defects. The average intraoperative time from skin incision to final suture was 50 min (range 20-90 min). The largest defect covered by keystone flap in our series measured 50 × 20 cm and the smallest defect covered was 8 × 4 cm. The average hospital stay was 3 days. We observed partial flap necrosis in 2 cases which required skin grafting. 3 other cases had wound infection leading to wound dehiscence, which required secondary suturing. The overall success rate was 95%. CONCLUSION: The Keystone flap being a versatile flap with its qualities of replacing "like with like", easy to perform, use of local tissue, good vascularity and a low complication rate makes it an excellent flap for a variety of defects. The KeyStone flap allows reconstruction in a single stage and is a relatively easy and fast technique for the beginner as well as the experienced surgeon. We believe it should be incorporated more into a surgeons practice.

Probiotics mixture increases butyrate, and subsequently rescues the nigral dopaminergic neurons from MPTP and rotenone-induced neurotoxicity.

Microbiota in the gut affect brain physiology via various pathways, and dysbiosis seems to play a role in the pathogenesis of Parkinson's disease (PD). Probiotics showed pleiotropic effects on functions of the central nervous system via microbiota-gut-brain axis. However, no studies displayed the neuroprotective effects of probiotics in the Parkinson's disease. This study aimed to test the neuroprotective effects of probiotics in two different models of PD. We evaluated neuroprotective effects of a probiotic cocktail containing Lactobacillus rhamnosus GG, Bifidobacterium animalis lactis, and Lactobacillus acidophilus in PD models induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or rotenone utilizing behavioral tests, immunohistochemistry and neurochemical analysis. To assure the neuroprotection came from increased production of butyrate, we further determined beneficial effects of butyrate in the MPTP-mediated PD model. The probiotic mixture overtly protected the dopaminergic neurons against MPTP neurotoxicity. However, the probiotics downregulated expression of monoamine oxidase (MAO) B in the striatum, which was accompanied by a lower level of 1-methyl-4-phenylpyridinium (MPP+), the main neurotoxic metabolite of MPTP. Thus, we extended the investigation into the rotenone-induced PD model. Rescuing effects of the probiotics were observed in the setup, which came with increased levels of neurotrophic factors and butyrate in the brain. Lactobacillus rhamnosus GG was identified to be a major contributor to the induction of neurotrophic factors and downregulation of MAO B. Finally, we demonstrated that sodium butyrate attenuated MPTP-induced neuronal loss in the nigrostriatal pathway. Probiotics could ameliorate neurodegeneration at least partially by increasing butyrate level. These data highlight the role of probiotics for brain health, and their potential as a preventive measure for neurodegenerative diseases such as PD.

Mechanistic comparison between MPTP and rotenone neurotoxicity in mice.

Animal models for Parkinson's disease (PD) are very useful in understanding the pathogenesis of PD and screening for new therapeutic approaches. 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP) and rotenone are common neurotoxins used for the development of experimental PD models, and both inhibit complex I of mitochondria; this is thought to be an instrumental mechanism for dopaminergic neurodegeneration in PD. In this study, we treated mice with MPTP (30 mg/kg/day) or rotenone (2.5 mg/kg/day) for 1 week and compared the neurotoxic effects of these toxins. MPTP clearly produced dopaminergic lesions in both the substantia nigra and the striatum as shown by loss of dopaminergic neurons, depletion of striatal dopamine, activation of glial cells in the nigrostriatal pathway and behavioral impairment. In contrast, rotenone treatment did not show any significant neuronal injury in the nigrostriatal pathway, but it caused neurodegeneration and glial activation only in the hippocampus. MPTP showed no such deleterious effects in the hippocampus suggesting the higher susceptibility of the hippocampus to rotenone than to MPTP. Interestingly, rotenone caused upregulation of the neurotrophic factors and their downstream PI3K-Akt pathway along with adenosine monophosphate-activated protein kinase (AMPK) activation. These results suggest that MPTP-induced dopaminergic neurotoxicity is more acute and specific in comparison to rotenone toxicity, and compensatory brain-derived neurotrophic factor (BDNF) induction and AMPK activation in the rotenone-treated brain might suppress the neuronal injury.

Enhanced neuroinflammatory responses after systemic LPS injection in IL-32ß transgenic mice.

IL-32 is a proinflammatory cytokine, and involved in various diseases including infection, inflammation, and cancer. However, effects of IL-32 on neuroinflammation remain obscure. Herein, we examined the effects of IL-32ß on systemic LPS-induced neuroinflammation using IL-32ß transgenic (Tg) mice. IL-32ß wild type (WT) and Tg mice received LPS injection (5 mg/kg, i.p.), and then neuroinflammatory responses were evaluated. Systemic LPS caused remarkable gliosis in the brain at 12 h regardless of genotypes. The gliosis in WT mice was sustained by 24 h, whereas it became more severe in Tg mice by 24 h. Proinflammatory cytokines and proteins were increased at 12 h both in WT and Tg brains. The elevated levels of TNFα and VCAM-1were not altered over time, while levels of IL-6, IL-1ß and iNOS were dropped in WT mice. In contrast, elevated levels IL-6, IL-1ß, iNOS and VCAM-1 were sustained, and level of TNFα was augmented in Tg brains by 24 h. Interestingly, level of IL-10 mRNA in Tg mice was remarkably higher than in WT mice at 0 h, which was decreased at 12 h and maintained by 24 h. In WT brain, mRNA level of IL-10 was raised at 12 h after LPS injection, and further increased at 24 h. Activation of NF-κB signaling pathway was detected in glia cells after LPS injection which was exaggerated at 24 h in Tg mice in comparison to WT mice. These results indicate that IL-32ß enhances neuroinflammatory responses caused by systemic LPS, and this might be attributable to prolonged activation of NF-κB signaling pathway.

Methylene blue protects dopaminergic neurons against MPTP-induced neurotoxicity by upregulating brain-derived neurotrophic factor.

The relatively old, yet clinically used, drug methylene blue (MB) is known to possess neuroprotective properties by reducing aggregated proteins, augmenting the antioxidant response, and enhancing mitochondrial function and survival in various models of neurodegenerative diseases. In this study, we aimed to examine the effects of MB in Parkinson's disease (PD) in vivo and in vitro models by using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP+ ) with a focus on possible effects on induction of neurotrophic factors. Our results indicate that pretreatment with MB significantly attenuated MPTP-induced loss of dopaminergic neurons, glial cell activation, and depletion of dopamine. We also found that MB upregulated brain-derived neurotrophic factor (BDNF) and activated its downstream signaling pathways, suggesting that BDNF might be a contributor to MB-associated neuroprotection. Specific inhibition of the BDNF receptor or extracellular signal-regulated kinase (Erk) reversed the MB-mediated protection against MPP+ toxicity, thus implying a role for BDNF and the Erk pathway in the neuroprotective effects. Taken together, our data suggest that MB protects neurons from MPTP neurotoxicity via induction of BDNF. Further study to determine whether MB preserves dopaminergic neurons in the brains of PD patients is warranted.

Neuroprotective Effects of Antidepressants via Upregulation of Neurotrophic Factors in the MPTP Model of Parkinson's Disease.

Neurotrophic factors are essential for neuronal survival, plasticity, and development and have been implicated in the action mechanism of antidepressants. In this study, we assessed the neurotrophic factor-inducing and neuroprotective properties of antidepressants. In the first part of the study, we found that fluoxetine, imipramine, and milnacipran (i.p., 20 mg/kg/day for 1 week or 3 weeks) upregulated brain-derived neurotrophic factor in the striatum and substantia nigra both at 1 week and 3 weeks. In contrast, an increase in the glial-derived neurotrophic factor was more obvious at 3 weeks after the antidepressants treatment. Specifically, it was found that fluoxetine and imipramine are more potent in raising the levels of neurotrophic factors than milnacipran. Furthermore, antidepressants elevated the phosphorylation of extracellular signal-regulated-protein kinase (ERK1/2) and the serine/threonine kinase Akt. In the second part of the study, we compared the neuroprotective effects of fluoxetine, imipramine, and milnacipran in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson's disease. Pretreament with fluoxetine, imipramine or milnacipran for 3 weeks reduced MPTP-induced dopaminergic neurodegeneration and microglial activation in the nigrostriatal pathway. Neurochemical analysis by HPLC exhibited that antidepressants attenuated the depletion of striatal dopamine. In consistent, beam test showed that behavioral impairment was ameliorated by antidepressants. Neuroprotective effects were more prominent in the fluoxetine or imipramine treatment group than in milnacipran treatment group. Finally, we found that neuroprotection of the antidepressants against 1-methyl-4-phenylpyridinium neurotoxicity in SH-SY5Y cells was attenuated by ERK or Akt inhibitor. These results indicate that neuroprotection by antidepressants might be associated with the induction of neurotrophic factors, and antidepressant could be a potential therapeutic intervention for treatment of Parkinson's disease.

Metformin lowers α-synuclein phosphorylation and upregulates neurotrophic factor in the MPTP mouse model of Parkinson's disease.

In spite of the massive research for the identification of neurorestorative or neuroprotective intervention for curing Parkinson's disease (PD), there is still lack of clinically proven neuroprotective agents. Metformin, a common anti-hyperglycemic drug has been known to possess neuroprotective properties. However, specific mechanisms by which metformin protects neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity remain to be elucidated. In this study, we assessed the neuroprotective effects of metformin in the subchronic MPTP model of PD, and explored its feasible mechanisms for neuroprotection. Animals received saline or MPTP injection (30 mg/kg/day) for the first 7 days, and then saline or metformin (200 mg/kg/day) for the next 7 days. Immunohistochemical stainings showed that metformin rescued the tyrosine hydroxylase-positive neurons and attenuated astroglial activation in the nigrostriatal pathway. In parallel, metformin restored dopamine depletion and behavioral impairments exerted by MPTP. Western blot analysis revealed that metformin ameliorated MPTP-induced α-synuclein phosphorylation which was accompanied by increased methylation of protein phosphatase 2A (PP2A), a phosphatase related to α-synuclein dephosphorylation. Moreover, the metformin regimen significantly increased the level of brain derived neurotrophic factor in the substantia nigra, and activated signaling pathways related to cell survival. Proof of concept study revealed that inhibition of PP2A or tropomyosin receptor kinase B reversed neuroprotective property of metformin in SH-SY5Y cells. Our results indicate that metformin provides neuroprotection against MPTP neurotoxicity, which might be mediated by inhibition of α-synuclein phosphorylation and induction of neurotrophic factors.

Zingiber officinale and 6-gingerol alleviate liver and kidney dysfunctions and oxidative stress induced by mercuric chloride in male rats: A protective approach.

Mercury toxicity is an emerging problem in the world as its concentration is rising continuously due to increased industrial, medicinal and domestic uses. Exposure to mercury represents a serious challenge to humans and other living biomes. The aim of the present study was to assess the protective effect of natural products as Zingiber officinale extract and its active compound (6-gingerol) against mercuric chloride-induced hepatorenal toxicity and oxidative stress in male rats. Male Sprague-Dawley rats (150±10g, n=6 per group) were administered HgCl2 (12µmol/kg, ip; once only) the treatment of Zingiber officinale Rosc. extract (ZO: 125mg/kg, po) and 6-gingerol (GG: 50mg/kg, po) for three days after 24h of HgCl2 administration. Acute HgCl2 administration altered various biochemical parameters, including transaminases, alkaline phosphatase, lactate dehydrogenase, bilirubin, gamma-glutamyl transferase, triglycerides and cholesterol, urea, creatinine, uric acid and blood urea nitrogen contents with a concomitant decline in protein and albumin concentration in serum. In addition, a significant rise in lipid peroxidation level with concomitant decrease in reduced glutathione content and the antioxidant enzymes activities of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and glutathione-S-transferase after acute HgCl2 exposure. Results of the present investigation clearly showed that both treatments as Zingiber officinale extract and 6-gingerol provide protection against acute mercuric chloride-intoxication by preventing oxidative degradation of a biological membrane from metal mediated free radical attacks. Biochemical data were well supported by histopathological findings. In conclusion, natural products may be an ideal choice against oxidative damage induced by mercury poisoning.

Curcuma longa Linn. extract and curcumin protect CYP 2E1 enzymatic activity against mercuric chloride-induced hepatotoxicity and oxidative stress: A protective approach.

The present investigation has been conducted to evaluate the therapeutic potential of Curcuma longa (200mgkg-1, po) and curcumin (80mgkg-1, po) for their hepatoprotective efficacy against mercuric chloride (HgCl2: 12µmolkg-1, ip; once only) hepatotoxicity. The HgCl2 administration altered various biochemical parameters, including transaminases, alkaline phosphatase, lactate dehydrogenase, bilirubin, gamma-glutamyl transferase, triglycerides and cholesterol contents with a concomitant decline in protein and albumin concentration in serum which were restored towards control by therapy of Curcuma longa or curcumin. On the other hand, both treatments showed a protective effect on drug metabolizing enzymes viz. aniline hydroxylase (AH) and amidopyrine-N-demethylase (AND), hexobarbitone induced sleep time and BSP retention. Choleretic, 1,1-diphenyl-2-picryl-hydrazil (DPPH)-free radical scavenging activities and histological studies also supported the biochemical findings. The present study concludes that Curcuma longa extract or curcumin has the ability to alleviate the hepatotoxic effects caused by HgCl2 in rats.

Enhanced dopaminergic neurotoxicity mediated by MPTP in IL-32ß transgenic mice.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by prominent loss of the nigral dopaminergic neurons and motor symptoms, such as resting tremor and bradykinesia. Evidence suggests that neuroinflammation may play a critical role in PD pathogenesis. Interleukin (IL)-32 is a newly-identified proinflammatory cytokine, which regulates innate and adaptive immune responses by activating p38 MAPK and NF-κB signaling pathways. The cytokine has been implicated in cancers and autoimmune, inflammatory, and infectious diseases. In this study, we attempted to identify the effects of IL-32ß on dopaminergic neurotoxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), using IL-32ß transgenic mice. Male wild type and IL-32ß transgenic mice received intraperitoneal injections of vehicle or MPTP (15 mg/kg × 4). Immunohistochemistry showed that overexpression of IL-32ß significantly increased MPTP-mediated loss of dopaminergic neurons in the substantia nigra and deletion of tyrosine hydroxylase-positive fibers in the striatum. Dopamine depletion in the striatum and deficit in locomotor activity were enhanced in IL-32ß transgenic mice. These results were accompanied by higher neuroinflammatory responses in the brains of transgenic mice. Finally, we found that IL-32ß exaggerated MPTP-mediated activation of p38 MAPK and JNK pathways, which have been shown to be involved in MPTP neurotoxicity. These results suggest that IL-32ß exacerbates MPTP neurotoxicity through enhanced neuroinflammatory responses.

N-acetyl cysteine and selenium protects mercuric chloride-induced oxidative stress and antioxidant defense system in liver and kidney of rats: a histopathological approach.

Mercury exposure is second-most common cause of metal poisoning which is quite stable and biotransformed to highly toxic metabolites thus eliciting biochemical alterations and oxidative stress. The aim of present study describes the protective effect of selenium either alone or in combination with N-acetyl cysteine (NAC) against acute mercuric chloride poisoning. The experiment was carried out in male albino Sprague Dawley rats (n=30) which was divided into five groups. Group 1 served as control. Groups 2-5 were administered mercuric chloride (HgCl2: 12mol/kg, i.p.) once only, group 2 served as experimental control. Animals of groups 3, 4 and 5 were received N-acetyl cysteine (NAC: 0.6mg/kg, i.p.) and selenium (Se: 0.5mg/kg, p.o.) and NAC with Se in combination. Acute HgCl2 toxicity caused significant rise in serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, albumin, bilirubin, γ-glutamyl transpeptidase, cholesterol, triglycerides, protein, urea, creatinine, uric acid and blood urea nitrogen content. Animals also showed significantly higher mercury content in liver and kidney, significant rise in lipid peroxidation level with concomitant decrease in reduced glutathione content and the antioxidant enzyme activities of superoxide dismutase and catalase after HgCl2 exposure. Results of the present investigation clearly showed that combination therapy with NAC+Se provide maximum protection against mercury toxicity than monotherapy (alone treated groups) by preventing oxidative degradation of biological membrane from metal mediated free radical attacks.

Methylmercury toxicity: amelioration by selenium and water-soluble chelators as N-acetyl cysteine and dithiothreitol.

The protective potential of chelators, i.e. N-acetyl cysteine (0.6 mg /kg, intraperitoneally) and dithiothreitol (15.4 mg kg(-1) , intraperitoneally) with selenium (0.5 mg kg(-1) , pre-oral) were evaluated individually and in combination against methylmercury-induced biochemical alterations and oxidative stress consequences. Forty-two male Sprague-Dawley rats were exposed with methylmercury (1.5 mg kg(-1) , pre-oral) daily for 21 days followed by different treatments for five consecutive days. Administration of methylmercury caused significant enhancement in the release of transaminases, alkaline phosphatases and lactate dehydrogenases in serum. A significant increased was observed in lipid peroxidation level with a concomitant decreased in glutathione content after methylmercury exposure in liver, kidney and brain. Hepatic microsomal drug metabolizing enzymes (aniline hydroxylase and amidopyrine N-demethylase) of cytochrome p4502E1 showed sharp depletion after methylmercury exposure. Alterations in histological changes in liver, kidney and brain were also noted in methylmercury administered group. All treated groups showed recovery pattern, but the combined treatments with N-acetyl cysteine and dithiothreitol in combination with selenium were more effective than that with either alone treatments in recovering blood biochemical changes after methylmercury toxicity. In conclusion, the results demonstrated that combination therapy may recover all blood biochemical alterations and offer maximum protection against methylmercury-induced toxicity.

Protective effect of combined therapy with dithiothreitol, zinc and selenium protects acute mercury induced oxidative injury in rats.

The present study was undertaken to establish mode of action, comparative therapeutic efficacy and safety evaluation of dithiothreitol (DTT) supplemented with Zn and Se against dimethylmercury in rats. Adult male albino rats of Sprague-Dawley strain (150±10 g, n=6 per group) were exposed a bolus dose of dimethylmercury (10 mg/kg, p.o.) for once only followed by DTT (15.4 mg/kg, i.p.) along with the combination of antioxidants Zn and Se (2 mmol/kg and 0.5 mg/kg, p.o.) after 72 h of toxicant administration for three days. The results showed a significant (P≤0.05) increase in the activities of AST, ALT, alkaline phosphatase, lactate dehydrogenase, in serum after toxicant administration. This was accompanied by histopathological observations. A significant rise was observed in lipid peroxidation level and mercury ion concentration however reduced glutathione content decreased in liver, kidney and brain. A significant (P≤0.05) decrease in the activity of acetyl cholinesterase was also seen in different regions of brain. Combined treatment of DTT along with Zn and Se significantly (P≤0.05) recouped the alterations in the enzymatic activities of serum and reversed the tissue biochemical and histopathological changes of liver, kidney and brain. Our results demonstrate that combined treatment of thiol chelator (DTT) along with antioxidants (Zn and Se) plays an important role against dimethylmercury induced tissue damage and hepatic, nephro and neurotoxicity.

Nerium indicum, a botanical pesticide affects ultimobranchial gland of the catfish Heteropneustes fossilis.

Heteropneustes fossilis were subjected to 11.27 mg L(-1) (80% of 96 h LC50 ) and 2.81 mg L(-1) (20% of 96 h LC50 ) of Nerium indicum leaf extract for short-term and long-term, respectively. After sacrificing the fish, blood was collected on 24, 48, 72, and 96 h in short-term and after 7, 14, 21, and 28 days in long-term experiment and analyzed for plasma calcium levels. Also, ultimobranchial glands (UBG) were fixed on these intervals. Serum calcium levels of H. fossilis exhibited a decline after 48 h following exposure to Nerium indicum leaf extract. This decrease continued till the end of the experiment (96 h). Ultimobranchial cells exhibited a decrease in the cytoplasmic staining response after 72 h following the treatment. The nuclear volumes of these cells were slightly decreased. These changes were exaggerated after 96 h following the treatment. Chronically exposed fish exhibited a decline in serum calcium levels of H. fossilis on day 14. The level progressively declined till the end of the experiment. Up to day 14 following the treatment there was no change in the histological structure of UBG. A decrease in the nuclear volume of ultimobranchial cells was noticed on day 21. Moreover, the cytoplasm of these cells displayed weakstaining response. The nuclear volume of these cells recorded a further decrease following 28-day treatment. Also there was noticed vacuolization and degeneration at certain places. To the best of our knowledge, the effects of any botanical pesticides on fish UBG have not been reported yet.

Morpho-toxicology of chlorpyrifos to prolactin cells of a freshwater catfish, Heteropneustes fossilis / Morfotoxicologia de clorpirifos para as células de prolactina de bagre de água doce Heteropneustes fossilis

In the present study, an organophosphorus compound Coroban (active ingredient chlorpyrifos ­ E.C. 20%) was used. In short-term exposure the fish were subjected to 0.8 of 96h LC50 value of chlorpyrifos (1.76 mg L-1) for 96h. In long-term exposure the experiment was performed for 28 days by using 0.2 of 96h LC50 value of chlorpyrifos (0.44 mg L-1). Fish were killed on each time intervals from control and experimental (chlorpyrifos) groups after 24, 48, 72, and 96h in short-term exposure and after 7, 14, 21, and 28 days in long-term experiment. Blood samples were collected and sera were analyzed for calcium. Pituitary glands were fixed for histological studies and stained with Herlant tetrachrome and Heidenhain's azan techniques. Short-term exposure of chlorpyrifos caused decrease in the serum calcium levels. No change was noticed in the prolactin cells of chlorpyrifos treated fish. Long-term treatment with chlorpyrifos provoked hypocalcemia. The prolactin cells of treated fish exhibited slight degranulation after 21 days whereas the nuclear volume remained unchanged. After 28 days, the prolactin cells exhibited further degranulation and the nuclear volume recorded an increase. Cytolysis and vacuolization were also visible.

No estudo presente, o composto organofosforo Coroban (ingrediente ativo clorpirifo ­ E.C. 20%) foi usado. Na exposição a curto prazo os peixes foram submetido a 0,8 de valor LC50 de 96h de clorpirifo (1,76 mg L-1) durante 96h. Na exposição a longo prazo o experimento foi executado durante 28 dias usando 0,2 de valor LC50 de 96h de clorpirifos (0,44 mg L-1). Os peixes foram mortos a cada intervalo dos grupos controle e experimental (clorpirifos) após 24, 48, 72, e 96h em exposição a curto prazo e após 7, 14, 21, e 28 dias no experimento a longo prazo. As amostras de sangue foram colhidas e o soro foi analisado para cálcio. As glândulas pituitárias foram fixadas para estudos histológicos e colorido por tetracromo de Herlant e por técnicas de azan do Heidenhain. A exposição a curto prazo do clorpirifo diminuiu os níveis de cálcio no soro. Nenhuma mudança foi observada nas células de prolactina nos peixes tratados com clorpirifo. O tratamento a longo prazo com clorpirifo causou hipocalcemia. As células de prolactina dos peixes tratados mostraram uma leve degranulação após 21 dias ao passo que o volume nuclear permaneceu inalterado. Depois de 28 dias, as células de prolactina mostraram mais degranulação e o volume nuclear registrou um aumento. Citólise e vacuolização também eram visíveis.

Morpho-toxicology of chlorpyrifos to prolactin cells of a freshwater catfish, Heteropneustes fossilis - doi: 10.4025/actascibiolsci.v34i4.9134

In the present study, an organophosphorus compound Coroban (active ingredient chlorpyrifos E.C. 20%) was used. In short-term exposure the fish were subjected to 0.8 of 96h LC50 value of chlorpyrifos (1.76 mg L-1) for 96h. In long-term exposure the experiment was performed for 28 days by using 0.2 of 96h LC50 value of chlorpyrifos (0.44 mg L-1). Fish were killed on each time intervals from control and experimental (chlorpyrifos) groups after 24, 48, 72, and 96h in short-term exposure and after 7, 14, 21, and 28 days in long-term experiment. Blood samples were collected and sera were analyzed for calcium. Pituitary glands were fixed for histological studies and stained with Herlant tetrachrome and Heidenhains azan techniques. Short-term exposure of chlorpyrifos caused decrease in the serum calcium levels. No change was noticed in the prolactin cells of chlorpyrifos treated fish. Long-term treatment with chlorpyrifos provoked hypocalcemia. The prolactin cells of treated fish exhibited slight degranulation after 21 days whereas the nuclear volume remained unchanged. After 28 days, the prolactin cells exhibited further degranulation and the nuclear volume recorded an increase. Cytolysis and vacuolization were also visible.

Acute toxicity of azadirachtin to a teleost, Heteropneustes fossilis / Toxicidade aguda da azadiractin para um teleósteo, Heteropneustes fossilis

The acute static renewal test of a botanical pesticide - azadirachtin for the freshwater catfish, Heteropneustes fossilis has been performed to determine the LC50 values at different exposure period. The LC50 values at various exposure periods are 173.06 mg L-1 for 24h; 80.69 mg L -1 for 48h; 58.57 mg L-1 for 72h and 52.35 mg L -1 for 96h. The upper confidence limits were 196.87, 86.91, 79.20 and 70.04 mg L-1 for 24, 48, 72 and 96 h and lower confidence limits were 154.01, 74.24, 37.33 and 33.83 mg L-1, respectively. These results indicate that azadirachtin exposure to the fish caused toxic effects.

A renovação do ensaio estático agudo de um pesticida botânico - azadiractin para o peixe de água doce, Heteropneustes fossilis foi realizada para determinar os valores de LC50 em diferentes períodos de exposição. Os valores de LC50 em diferentes períodos de exposição são 173,06 mg L-1 por 24h; 80,69 mg L-1 por 48h; 58,57 mg L-1 por 72 h e 52,35 mg L-1 por 96h. Os limites de confiança superiores foram 196,87; 86,91; 79,20 e 70,04 mg L-1 para 24, 48, 72 e 96h os limites inferior e confiança foram 154,01; 74,24; 37,33 e 33,83 mg L-1, respectivamente. Estes resultados indicam que a exposição do peixe à azadiractin causou efeitos tóxicos.