Neuroprotective potential of Mentha piperita extract prevents motor dysfunctions in mouse model of Parkinson's disease through anti-oxidant capacities.

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world. Neurodegeneration of the substantia nigra (SN) and diminished release of dopamine are prominent causes of this progressive disease. The current study aims to evaluate the protective potential of ethanolic extract of Mentha piperita (EthMP) against rotenone-mediated PD features, dopaminergic neuronal degeneration, oxidative stress and neuronal survival in a mouse model. Swiss albino male mice were assigned to five groups: control (2.5% DMSO vehicle), PD (rotenone 2.5 mg/kg), EthMP and rotenone (200mg/kg and 2.5mg/kg, respectively), EthMP (200 mg/kg), and Sinemet, reference treatment containing levodopa and carbidopa (20 mg/kg and rotenone 2.5mg/kg). Behavioral tests for motor functional deficit analysis were performed. Anti-oxidant capacity was estimated using standard antioxidant markers. Histopathology of the mid-brain for neurodegeneration estimation was performed. HPLC based dopamine level analysis and modulation of gene expression using quantitative real-time polymerase chain reaction was performed for the selected genes. EthMP administration significantly prevented the rotenone-mediated motor dysfunctions compared to PD group as assessed through open field, beam walk, pole climb down, stepping, tail suspension, and stride length tests. EthMP administration modulated the lipid peroxidation (LPO), reduced glutathione (GSH), and superoxide dismutase (SOD) levels, as well as glutathione-s-transferase (GST) and catalase (CAT) activities in mouse brain. EthMP extract prevented neurodegeneration in the SN of mice and partially maintained dopamine levels. The expression of genes related to dopamine, anti-oxidant potential and synapses were modulated in M. piperita (MP) extract treated mice brains. Current data suggest therapeutic capacities of MP extract and neuroprotective capacities, possibly through antioxidant capacities. Therefore, it may have potential clinical applications for PD management.

Effects of Chronic Roundup Exposure on Medaka Larvae.

The use of glyphosate-based herbicides is increasing yearly to keep up with the growing demands of the agriculture world. Although glyphosate-based herbicides target the enzymatic pathway in plants, the effects on the endocrine systems of vertebrate organisms, mainly fish, are widely unknown. Many studies with glyphosate used high-exposure concentrations (mg/L), and the effect of environmentally relevant or lower concentrations has not been clearly understood. Therefore, the present study examined the effects of very low, environmentally relevant, and high concentrations of glyphosate exposure on embryo development and the thyroid system of Japanese medaka (Oryzias latipes). The Hd-rR medaka embryos were exposed to Roundup containing 0.05, 0.5, 5, 10, and 20 mg/L glyphosate (glyphosate acid equivalent) from the 8 h post-fertilization stage through the 14-day post-fertilization stage. Phenotypes observed include delayed hatching, increased developmental deformities, abnormal growth, and embryo mortality. The lowest concentration of glyphosate (0.05 mg/L) and the highest concentration (20 mg/L) induced similar phenotypes in embryos and fry. A significant decrease in mRNA levels for acetylcholinesterase (ache) and thyroid hormone receptor alpha (thrα) was found in the fry exposed to 0.05 mg/L and 20 mg/L glyphosate. The present results demonstrated that exposure to glyphosate formulation, at a concentration of 0.05 mg/L, can affect the early development of medaka larvae and the thyroid pathway, suggesting a link between thyroid functional changes and developmental alteration; they also showed that glyphosate can be toxic to fish at this concentration.

Transcriptional Alterations Induced by Delta-9 Tetrahydrocannabinol in the Brain and Gonads of Adult Medaka.

With the legalization of marijuana smoking in several states of the United States and many other countries for medicinal and recreational use, the possibility of its release into the environment cannot be overruled. Currently, the environmental levels of marijuana metabolites are not monitored on a regular basis, and their stability in the environment is not well understood. Laboratory studies have linked delta 9-tetrahydrocannabinol (Δ9-THC) exposure with behavioral abnormalities in some fish species; however, their effects on endocrine organs are less understood. To understand the effects of THC on the brain and gonads, we exposed adult medaka (Oryzias latipes, Hd-rR strain, both male and female) to 50 ug/L THC for 21 days spanning their complete spermatogenic and oogenic cycles. We examined transcriptional responses of the brain and gonads (testis and ovary) to Δ9-THC, particularly molecular pathways associated with behavioral and reproductive functions. The Δ9-THC effects were more profound in males than females. The Δ9-THC-induced differential expression pattern of genes in the brain of the male fish suggested pathways to neurodegenerative diseases and pathways to reproductive impairment in the testis. The present results provide insights into endocrine disruption in aquatic organisms due to environmental cannabinoid compounds.

Halotolerant bacterial biofilms for desalination and water treatment: a pilot study.

Salinity has a significant impact on the water quality and crop yield. Physical desalination techniques were once thought to be expensive and time-consuming. Among biological techniques, halotolerant bacteria were thought to be the fastest and most effective way to reduce the salt content in brackish saltwater water. In the current study, halotolerant bacterial biofilms were used to desalinate saline water on abiotic substrates (such as sand, pebbles, glass beads, and plastic beads), and studied subsequently for the effects on Zea mays germination. Briefly, salt samples (SLT7 and SLT8) from the Khewra site in Punjab, Pakistan, as well as seawater and sea sand samples (USW1, USW3, USW6, DSW1, DSW4, SS1, and SS3) from Karachi, Sindh, Pakistan's Arabian Sea, were collected. Halotolerant bacteria were isolated and characterized. Crystal violet ring assays and capsule staining were used to estimate extracellular polymeric substance (EPS) and biofilm development, respectively. All halotolerant bacterial strains were spore formers and produced EPS and formed biofilms well. 16S rRNA gene sequencing of the best halotolerant bacteria, USW6, showed the closest (100%) similarity to Bacillus aerius strain G-07 (a novel species) (accession number ON202984). A pilot-scale experiment for desalinating the artificial water (supplemented with 1 M NaCl) using biofilm adhered abiotic beads showed declined level of NaCl from 1 M to 0.00003 M after 15 days in treated water. Also, Zea mays germination was observed in the plants using treated water compared to no growth in the non-treated saline water. Estimations of chlorophyll, total soluble sugar, and protein revealed that plants cultivated using elute collected from a desalinated pilot scale setup contained less chlorophyll (i.e., 5.994 and 116.76). Likewise, plants grown with elute had a total soluble protein and sugar content of 1.45 mg/ml and 1.3 mg/ml, respectively. Overall, in treated water plants, a minor drop in chlorophyll content, a slight increase in total soluble sugar content, and a slight increase in protein content were noted. The study concluded that biofilm-treated desalt water has the potential to significantly reduce the effects of droughts, soil salinization, and economic and environmental issues associated with agricultural drainage. The results specified the application of halotolerant bacteria biofilms (Bacillus aerius, a novel species, USW6) for water desalination to overcome the problem of water scarcity caused by global warming and the increased salinity.

Sustainable Ornamental Fish Aquaculture: The Implication of Microbial Feed Additives.

Ornamental fish trade represents an important economic sector with an export turnover that reached approximately 5 billion US dollars in 2018. Despite its high economic importance, this sector does not receive much attention. Ornamental fish husbandry still faces many challenges and losses caused by transport stress and handling and outbreak of diseases are still to be improved. This review will provide insights on ornamental fish diseases along with the measures used to avoid or limit their onset. Moreover, this review will discuss the role of different natural and sustainable microbial feed additives, particularly probiotics, prebiotics, and synbiotics on the health, reduction in transport stress, growth, and reproduction of farmed ornamental fish. Most importantly, this review aims to fill the informational gaps existing in advanced and sustainable practices in the ornamental fish production.

Moringa oleifera alleviated oxidative stress, physiological and molecular disruption induced by acute thermal stress in grass carp, Ctenopharyngodon idella.

The present study was designed to investigate the protective effect of dietary Moringa oleifera leaf meal (MLM) supplementation against high temperature-induced stress in grass carp (Ctenopharyngodon idella). A total of 180 apparent healthy juvenile grass carp (15.48 g ± 0.054) were divided into three groups in triplicate (20 fish in each replicate). Fish were fed with diets containing 0, 1, and 5% MLM for 60 days and then subjected to a high-temperature challenge for 48 h (32-33 °C). The results revealed that feeding fish with 1 and 5% MLM resulted in a significant increase in weight gain and specific growth rate compared to the control. In addition, feed conversion ratio was significantly reduced in groups fed with MLM. No significant difference was reported in the serum cortisol level among different experimental groups before heat stress while serum glucose level significantly decreased in fish fed with 5% MLM. Serum alanine transaminase, aspartate transaminase, and alkaline phosphatase significantly decreased in fish fed with 1 and 5% MLM before and after heat stress. Hepatic lipid peroxidation significantly decreased in fish fed with MLM for 60 days. A non-significant increase in hepatic reduced glutathione level was reported in fish fed with 1 and 5% MLM before heat stress. Catalase and superoxide dismutase activities increased significantly in the liver of fish fed with 5% MLM. No significant change was observed in the expression profile of heat shock protein (hsp) 70 and 90 before heat stress. Meanwhile, after heat stress, up to a fivefold increase was recorded in mRNA level of hsp 70 and fourfold increase in the expression level of hsp 90 in the liver of the control fish which were not fed with MLM-supplemented diets. Fish fed with 1 and 5% MLM showed a significant decrease in the expression of hsp 70 and a non-significant decrease in the expression of hsp 90. Results of the present study suggest that supplementing the diet of grass carp with 5% MLM could improve growth and physiological performance and provide resistance against high temperature-induced stress.

Assessment of Avermectins-Induced Toxicity in Animals.

Macrocyclic lactones, particularly the avermectins, have completely revolutionized the approaches aimed at control of parasites. These avermectins are the most widely used anti-parasitic drugs in veterinary field with sales exceeding one billion US dollars annually. However, before clinical usage, their safety evaluation in the animals is a major critical factor that must be considered. Many studies have reported the negative effects of avermectins like ivermectin, abamectin, doramectin, and eprinomectin on the host animals. These harmful effects arise from avermectins targeting GABA and glutamate-gated chloride channels present both in the parasites and the host animals. In this review, various modes of avermectins action along with the negative effects on the host like nephrotoxicity, hepatotoxicity, neurotoxicity, reproductive toxicity, and endocrine disruption were discussed in detail. Furthermore, other important issues like ecotoxicity, drug resistance, and drug residues in milk associated with avermectins usage were also discussed, which need special attention.

The Effects of Dietary Thyme Oil (Thymus vulgaris) Essential Oils for Common Carp (Cyprinus carpio): Growth Performance, Digestive Enzyme Activity, Antioxidant Defense, Tissue and Mucus Immune Parameters, and Resistance against Aeromonas hydrophila.

This study evaluated the effects of dietary supplementation of thyme (Thymus vulgaris) essential oil (TVO) on growth performance, digestive enzymes, biochemical parameters, hematological indices, liver enzymes, and pathogen resistance in common carp (Cyprinus carpio). Triplicate groups of fish (15.36 ± 0.10 g) were fed daily with diets supplemented with TVO at 0, 0.5, 1, and 2 percent for 60 days then challenged with Aeromonas hydrophila. The results determined that supplementation of thyme resulted in significantly higher final body weights (FBW) and lower feed conversion ratios (FCR). Furthermore, no mortality was observed in the thyme-supplemented treatments. Regression analysis showed that fish growth parameters were polynomially related to dietary TVO levels. The optimum dietary TVO level, based upon the varied growth parameters, was 1.344 to 1.436%. Digestive enzymes activity, including amylase and protease, significantly increased in fish fed the supplemented diets. The thyme-supplemented diets also significantly increased the biochemical parameters, including total protein, albumin, and acid phosphatase (ACP), compared to the control group. We also observed significant increases in hematological indices, including red blood cells (RBC), white blood cells (WBC), hematocrit (Hct), and hemoglobin (Hb) in common carp fed diets containing thyme oil (P < 0.05). Liver enzymes activity including alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) was also reduced (P < 0.05). Immune parameters, including total protein and total immunoglobulin (total Ig) levels, alternative complement pathway hemolytic (ACH50), lysozyme, protease, and ALP in the skin mucus, and lysozyme, total Ig, and ACH50 in the intestine were higher (P < 0.05) in TVO-supplemented fish. Catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) in the liver were also elevated (P < 0.05) in TVO administered groups. Lastly, thyme-supplementation resulted in higher survival rates after the A. hydrophila challenge compared to the control (P < 0.05). In conclusion, dietary inclusion of thyme oil (1 and 2%) effectively improved fish growth, immune systems, and resistance to A. hydrophila.

Toxicological effects of the chemical and green ZnO NPs on Cyprinus carpio L. observed under light and scanning electron microscopy.

Nanoparticles in aquatic bodies cause serious harm to the aquatic organisms when accumulated in high amounts. However, green nanoparticles synthesized using plants can be less toxic as compared to chemical nanoparticles. Hence, we designed our study to investigate the toxicological effects of chemical and green zinc oxide nanoparticles (ZnO NPs) on the biological activity of juvenile Cyprinus carpio. The green ZnO NPs were synthesized from Solieria robusta, and chemical ZnO NPs were synthesized using zinc chloride solution and ammonium hydroxide. Characterization was done by using light microscopy, scanning electron microscope (SEM), Fourier transmission infrared radiation, and X-ray diffraction (XRD) techniques. The highest absorbance of nanoparticles was observed at 360 which confirmed the synthesis of ZnO. The SEM analysis showed that green nanoparticles were hexagonal while the chemical nanoparticles were spherical to cubic in shape. Definite peaks were observed in XRD of green and chemical NPs at 2θ angles 45.84° and 32.18°, respectively. Oxidative stress was determined by chemical analysis of catalase, glutathione S-transferase (GST), glutathione (GSH), and lipid peroxidation (LPO) activities. The toxicological effects of chemical ZnO NPs on the catalase, LPO, GST, and GSH activities were more than green ZnO NPs. The histopathological investigation proved that the effect of chemical nanoparticles was worse than green ZnO NPs. More tissue damage was found in chemical nanoparticles than green synthesized nanoparticles. It was concluded that chemical nanoparticles can be replaced by green nanoparticles, as green nanoparticles are eco-friendly with less toxicological effects. This replacement can limit the toxic effect of nanoparticles when they get accumulated in high amounts in water bodies.

Role of modified diet and gut microbiota in metabolic endotoxemia in mice.

This study was aimed at investigating the effect of cultured gut microbiota (GM) from obese humans coupled HFD in inducing metabolic endotoxemia in humanized mice. In total, 30 strains were isolated from 10 stool samples of obese patients. Following morphological and biochemical characterization, 16S rRNA gene sequencing of six abundant isolates identified these Klebsiella aerogenes, Levilactobacillus brevis, Escherichia coli, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis (MZ052089-MZ052094). In vivo trial using above isolates, known as human gut microbiota (HGM), was performed for six months. Sixteen mice were distributed into four groups, i.e., G1 (control) mice fed with chow diet, group 2 (G2) with HFD, group 3 (G3) with HFD + HGM and group 4 (G4) with chow diet + HGM. Body mass index (BMI) and plasma endotoxins were measured pre- and post-experiment. In vivo study revealed that HFD + HGM caused significant increase (3.9 g/cm at 20 weeks) in the body weight and BMI (0.4 g/cm post-experiment) of G3 mice compared to the other groups. One-way ANOVA showed significantly higher level of endotoxins (2.41, 4.08 and 3.7 mmol/L) in mice groups G2, G3 and G4, respectively, indicating onset of metabolic endotoxemia. Cecal contents of experimental mice groups showed a shift in microbial diversity as observed by all isolates belonging to either Firmicutes or Bacteroidetes phyla, respectively. In conclusion, current study reported that minor alteration in GM composition through HFD feeding and cultured GM transfer has significant impact in development of metabolic endotoxemia, possibly via modified intestinal permeability.

Comparative evaluation of the toxicological effect of silver salt (AgNO3 ) and silver nanoparticles on Cyprinus carpio synthesized by chemicals and marine algae using scanning electron microscopy.

The widespread use of silver nanoparticles (AgNPs) results in the unintentional release into the water body. Therefore, understanding of the potentially harmful impacts of AgNPs and Ag-salt on aquatic animals is a need of time. This study was design to analyze the oxidative stress and histopathological damages in Cyprinus carpio. The synthesis of AgNPs from Halymenia porphyraeformis and by reduction of chemical was done. Nanoparticles were characterized with UV-Visible spectroscopy, SEM, XRD, and FTIR analysis. The comparative toxicological effect of chemically synthesized silver nanoparticles (Ch-AgNPs), green silver nanoparticles (Gr-AgNPs), and Ag-salt on C. carpio was analyzed. For oxidative stress analysis, different tests Lipid peroxidation (LPO), catalase, glutathione reduction (GST), and glutathione S-transferase (GST) were performed. The highest LPO 245.168 ± 0.034 was recorded in Ch-AgNPs-treated gills and the lowest 56.4532 ± 0.02 was found in Gr-AgNPs-treated liver. Maximum GSH 56.4065 ± 0.13 was observed in Gr-AgNPs liver and minimum 40.781 ± 0.54 was recorded in Ag-salt gills. The maximum quantity of catalase 68.0162 ± 0.09 was noted in the Ag-salt-treated liver and the minimum was calculated 17.3665 ± 0.01 in the liver of Ch-AgNPs and highest values of GST 765.829 ± 0.11 were recorded in gills of Gr-AgNPs and lowest 633.08 ± 0.26 in the liver of Ch-AgNPs-treated fish. In conclusion, maximum destruction was found in the gills and liver of the fish treated with chemical and green AgNPs followed by Ag-salt as compared to control. The adverse effects of AgNPs and Ag-salt were probably related to the oxidative stress in the fish that lead to histopathological damage of its vital organs.

Detrimental Effects of Bisphenol Compounds on Physiology and Reproduction in Fish: A Literature Review.

Bisphenol-A is one of the most studied endocrine-chemicals, which is widely used all over the world in plastic manufacture. Because of its extensive use, it has become one of the most abundant chemical environmental pollutants, especially in aquatic environments. BPA is known to affect fish reproduction via estrogen receptors but many studies advocate that BPA affects almost all aspects of fish physiology. The possible modes of action include genomic, as well as and non-genomic mechanisms, estrogen, androgen, and thyroid receptor-mediated effects. Due to the high detrimental effects of BPA, various analogs of BPA are being used as alternatives. Recent evidence suggests that the analogs of BPA have similar modes of action, with accompanying effects on fish physiology and reproduction. In this review, a detailed comparison of effects produced by BPA and analogs and their mode of action is discussed.

Evaluation of Cadmium Chloride-Induced Toxicity in Chicks Via Hematological, Biochemical Parameters, and Cadmium Level in Tissues.

Cadmium is a heavy metal and a non-biodegradable environmental contaminant, and its omnipresence ensures its recurrent exposure to humans and animals. Its intake by chicks leads to fatal implications. Cadmium chloride (CdCl2) because of its bio-accumulative nature is an emerging threat to the poultry industry as well as to the humans which consumes these cadmium-intoxicated chickens. In the current study, the target was to elucidate the toxic effects of CdCl2on body weight, hematological, and biochemical parameters as well as its bioaccumulation in different organs of broiler chicks. Various concentrations of CdCl2 (0, 12, 24, 38, and 48 mg/kg body weight) were administered orally to five groups (A, B, C, D, and E) of broiler chicks, respectively. The biometric screening of the exposed birds was carried out by hematological parameters such as packed cell volume (PCV), total erythrocyte count (TEC), mean corpuscular hemoglobin concentration (MCHC), total protein, white blood cells (WBC), and hemoglobin (Hb), as well as biochemical parameters superoxide dismutase (SOD), low-density lipoprotein (LDL), glutathione peroxidase (GPx), and high-density lipoprotein (HDL) with commercially available kits. Metal accumulation in different organs was detected using atomic absorption spectrophotometer. The compound exposure produced a varied impact on broiler birds. Hematological parameters showed a significant decrease except for WBC. Biochemical parameters also decreased significantly in a dose-dependent manner. However, it was revealed that the body weight of chickens was not affected considerably after CdCl2 exposure. A direct relationship was detected between the accumulation of metal within tissues (lungs, heart, and flesh) and exposure frequency. It can be deduced that an increase in Cd deposition in tissues may lead to an alteration in hematological-biochemical markers which may significantly contribute to systemic toxicity in broilers.

Bisphenol-A induced antioxidants imbalance and cytokines alteration leading to immune suppression during larval development of Labeo rohita.

Recently, the oxidative stress and immunotoxicity biomarkers have been extensively used in embryotoxicity using fish embryos as promising models especially after exposure to chemical-like environmental estrogens. Bisphenol-A (BPA) is an estrogenic endocrine disruptor and is ubiquitous in the aquatic environment. Larvae of Labeo rohita were exposed to low concentrations of BPA (10, 100, 1000 µg/l) for 21 days. Innate immune system, antioxidants parameters, and developmental alterations were used as biomarkers. Exposure to BPA caused developmental abnormalities including un-inflated swim bladder, delayed yolk sac absorption, spinal curvature, and edema of pericardium. Lipid peroxidation increased and activity of catalase (p < 0.05), superoxide dismutase (p < 0.05), and glutathione peroxidase (p < 0.01) decreased after exposure to BPA. Level of reduced glutathione also decreased (p < 0.05) in BPA-exposed group. Lower expression of tumor necrosis factor-α (p < 0.05) and interferon-γ (p < 0.001) was observed in BPA-exposed groups while expression of interleukin-10 increased (p < 0.05) in larvae exposed to 10 µg/l BPA. Moreover, exposure of BPA caused a concentration-dependent increase in expression of heat shock protein 70 (p < 0.05). The present study showed that the exposure to BPA in early life stages of Labeo rohita caused oxidative stress and suppress NF-κB signaling pathway leading to immunosuppression. The results presented here demonstrate the cross talk between heat shock protein 70 and cytokines expression.

Dietary Black Seed Effects on Growth Performance, Proximate Composition, Antioxidant and Histo-Biochemical Parameters of a Culturable Fish, Rohu (Labeo rohita).

This feeding trial was conducted to investigate the effects of dietary black seed (Nigella sativa) supplementation on the growth performance, muscles proximate composition, antioxidant and histo-biochemical parameters of rohu (Labeo rohita). Fingerlings (8.503 ± 0.009 g) were fed on 0.0%, 1% and 2.5% black seed supplemented diets for 28 days. Fish sampling was done on the 7th, 14th, 21st and 28th day of experiment. The results of the present study indicated that black seed supplementation significantly increased growth performance and muscles protein contents of rohu over un-supplemented ones. Lipid peroxidation levels significantly decreased in all the studied tissues (liver, gills, kidney and brain) of black seed fed rohu, whereas the antioxidant enzymes (catalase, glutathione-S-transferase, glutathione peroxidase and reduced glutathione) activities were increased in all the studied tissues of black seed supplemented rohu at each sampling day. The hepatic-nephric marker enzymes levels were decreased for black seed fed rohu. The present study showed that tested black seed levels are safe for rohu. Black seed is cheaply available in local markets of Pakistan; therefore, based on the results of the present study, it is suggested that black seed has potential to be used as natural growth promoter and antioxidant in the diet of rohu.

Validation of Housekeeping Genes for Gene Expression Profiling in Fish: A Necessity.

Real-time polymerase chain reaction (qPCR) is a reliable tool for gene expression analysis in various organisms. Its use in aquaculture and study of fish physiology is increasing day by day. Relative quantification of mRNA through real-time qPCR requires suitable housekeeping genes/reference genes. Expression of housekeeping genes were thought to be constant in different tissues under various physiological and experimental conditions. In light of the literature reviewed here, it is clear that expression of most of the genes varied in different physiological conditions, under different experimental conditions, and in different gender. Use of housekeeping genes without proper validation may lead to erroneous results and misinterpretation of data. To solve this problem, various types of user-friendly software are now available for validation of housekeeping genes. Moreover, it is recommended to use more than one housekeeping gene for relative quantification. Using the geometric mean of the three most stable genes as a housekeeping gene can also solve this problem to some extent. Therefore, there is a dire need to validate a set of housekeeping genes in the species under study and in various tissues depending on the experimental design to obtain valid and reproducible results.

Modulation of brain kisspeptin expression after bisphenol-A exposure in a teleost fish, Catla catla.

Endocrine-disrupting chemicals (EDCs) affect the neuroendocrine system which in turn influences the reproductive regulation. Neuronal genes disrupted by EDCs are the gonadotropin-releasing hormone (gnrh2), the Kiss/GPR54 system that regulates gonadotropin release and cyp19b gene encoding brain aromatase. In the present study, pubertal Catla catla expected to spawn for first the time in the coming season were exposed to graded concentration of bisphenol-A (10, 100, 1000 µg/l) for 14 days. Messenger RNA (mRNA) levels of neuroendocrine genes, i.e., kisspeptins and their receptors, gonadotropin-releasing hormone type II and brain aromatase were studied after 14 days exposure. Results showed that bisphenol-A (BPA) strongly upregulated expression of kiss1, kiss2, gpr54a, and gnrh2 in fish exposed to 10 µg/l BPA. Fish exposed to 1000 µg/l BPA, expression of kiss1 and gnrh2 were comparable to control while kiss2 mRNA increased compared to controls. Brain aromatase (cyp19b) mRNA expression increased in fish exposed to both 10 and 1000 µg/l BPA. These results indicate that BPA exposure can disrupt organization of the kisspeptin signaling pathways. This neuroendocrine disruption may be the underlying mechanism by which a suite of reproductive abnormalities are induced.

Disruption of the Reproductive Axis in Freshwater Fish, Catla catla, After Bisphenol-A Exposure.

Environmental estrogens such as bisphenol-A (BPA) cause reproductive disorders in many vertebrate species, especially fish. BPA is used extensively in the manufacture of plastic and plastic products, epoxy resins, and dental sealants. The presence of BPA in sewage and surface water raises a potential threat to aquatic populations. In the present study, we investigated the effects of BPA on ovarian histology and transcription of key genes involved in reproduction. Adult female Catla catla were exposed to graded concentrations of BPA (10, 100, 1000 µg/l) for 14 days. Ovary histology and expression of steroidogenic acute regulatory protein (star), ovary aromatase (cyp19a), follicle-stimulating hormone receptor (fshr), and luteinizing hormone receptor (lhr) were evaluated in ovary of female fish after 14 days. Fish ovaries from the control and 10 µg/l BPA exposed groups included primary oocytes (POCs), while fish exposed to higher concentrations of BPA (100 and 1000 µg/l) contained tertiary and mature oocytes with increased numbers of atretic follicles. Significant increases in mRNA transcripts of star were observed in fish exposed to 100 and 1000 µg/l BPA. A 15-fold increase in the expression of ovary aromatase (cyp19a) was detected in fish exposed to 100 µg/l BPA. fshr increased in a dose-dependent manner. Increases in the expression of lhr, although not statistically significant, were observed in fish exposed to 100 and 1000 µg/l BPA when compared to control. The results of the present study indicate that BPA causes alterations in the expression patterns of genes involved in the reproductive pathway, which may lead to negative effects on the reproductive system in female fish.

Oxidative stress and histopathologic biomarkers of exposure to bisphenol-A in the freshwater fish, Ctenopharyngodon idella

ABSTRACT Bisphenol-A (BPA) belongs to the family of endocrine disrupting chemicals (EDCs) and it is used in the production of polycarbonate plastic and epoxy resins. The reproductive toxicity of BPA is well documented but it also exerts its toxic effects through multiple pathways especially by inducing a state of oxidative stress and causing damage to the vital organs. In the present study, histopathologic and oxidative damage caused by BPA in liver and kidneys of fresh water cyprinid, Ctenopharyngodon idella was evaluated. LC50 of BPA for Ctenopharyngodon idella was determined by probit regression analysis. Fish were exposed to a sublethal concentration of BPA i.e. 3.2 ppm (1/2 LC50) for 14 days. Histologic studies revealed that BPA caused degenerative changes in liver and kidneys and exposure of sublethal concentration of BPA caused oxidative damage in both organs. Lipid peroxidation significantly increased in liver and kidneys of treated group. Catalase activity and reduced glutathione content significantly decreased in the group exposed to BPA compared to control and glutathione-S-transferase activity increased significantly in both organs exposed to the sublethal concentration of BPA. From this study it is concluded that BPA caused toxic effects in fish species by changing oxidative balance and damaging the vital organs.