NorCal Open Access Publications Journal of Aquatic Research and NORCAL Marine Sciences OPEN ACCESS PUBLICATION Volume 2; Issue 2 Asifa KP and Chitra KC Research Article ISSN 2639-4618 Effect of Chlordecone on the Reproductive Potential of the Cichlid Fish, Pseudetroplus Maculatus (Bloch, 1795) Asifa KP, Chitra KC* Endocrinology and Toxicology Laboratory, Department of Zoology, University of Calicut, Kerala, India. *Corresponding author: Chitra KC, Endocrinology and Toxicology Laboratory, Department of Zoology, University of Calicut, Kerala, India. Email: [email protected] Received Date: 16 March, 2019; Accepted Date: 03 May, 2019; Published Date: 17 May, 2019 Abstract Introduction The present study was undertaken to evaluate that chlordecone, During the past few decades, large number of environmental an organochlorine pesticide, possessing estrogenic properties contaminants such as, pesticides, pharmaceutical drugs, plas- are known to influence the reproductive potential of the cich- tic products, natural phytochemicals etc. has been continu- lid fish, Pseudetroplus maculatus. Chlordecone at two sublethal ously released into various compartments of both terrestrial concentrations, 3.5 and 7µg/L, were exposed to fish for 4, 7, 15 and aquatic ecosystems, which are known to disrupt the en- and 30 days in order to evaluate the level of vitellogenin, main- docrine system of animals, including humans. Such chemicals taining the control groups. Vitellogenin concentrations were are called endocrine-disrupting chemicals (EDCs), which can measured in both male and female fishes by using indirect end- interfere with biosynthesis, transport, action, metabolism and points, such as alkali-labile phosphoprotein (ALP), total pro- removal of various hormones in the body resulting in varia- tein and calcium concentrations in the blood plasma. Increase tion from normal homeostasis or reproduction [1]. Generally, in the concentrations of plasma protein, phosphoprotein, and EDCs are known to mimic or block the transcriptional activa- calcium were time-dependant showing positive correlation tion of endogenous hormones by binding to its corresponding when compared with the control groups. The remarkable raise receptors. Other new mode of action for EDCs includes dis- in the level of vitellogenin in male fish indicated the estrogenic ruption of steroid hormone metabolism, proteasome-mediated effects of chlordecone. However, gonadosomatic index was sig- degradation of receptor proteins, sensitization of hormones, nificantly decreased after the pesticide exposure, which could and altered DNA methylation [2]. Persistence of several EDCs be due to gonadal-specific chlordecone toxicity. Sperm param- in various aquatic ecosystems have been associated to cause en- eters such as sperm concentrations, viability and motility were docrine disruption and lead to several reproductive as well as evaluated at both sublethal concentrations for 24, 72 and 96 h developmental anomalies in fishes and other aquatic organisms maintaining the control groups. The significant decrease in the [3,4]. Chlordecone is a synthetic chlorinated pesticide, com- sperm parameters indicated that chlordecone affected normal monly used for the control of various pests on tobacco, banana, functions of male gamete. The present results suggested that citrus trees and ornamental shrubs. Structurally it is similar to chlordecone influenced adverse effects on fish reproduction as mirex which is another insecticide widely used for the control evidenced by the elevated vitellogenin level in males with al- of fire ants [5]. Chlordecone has been detected in those areas teration in sperm functional parameters, which can be served where mirex was applied as it is a photodegradation product of as biomarker for the estrogenic effects of chlordecone in the mirex [6]. Chlordecone is the more prominent persistent or- cichlid fish. ganic pollutant found in the environment, where it stick to sus- pended solids and sediments in water, and also has the ability to bioaccumulate in fish and other aquatic organisms thereby Keywords undergoes biomagnification through the food chain [7]. Chlor- decone has been proven toxic to fish, in-terfering with antiox- Alkali-labile phosphoprotein; Chlordecone; Gonadosomatic in- idant system of various tissues as gill, liver, brain [8] as well as dex; Plasma calcium; Sperm motility; Sperm viability muscle [9]. Acute exposure of chlordecone has been shown to NorCal Open Access Publications .01. Citation: Asifa KP and Chitra KC (2019) Effect of Chlordecone on the Reproductive Potential of the Cichlid fish, Pseudetroplus maculatus (Bloch, 1795). J Aquat Res Mar Sci 2019: 163-177. induce the formation of micronucleus and other nuclear ab- vitellogenin and sperm parameters in the cichlid fish, Pseude- normalities such as blebbed, notched and lobed nuclei in the troplus maculatus. erythrocytes of Etroplus maculatus [10]. Chlordecone has been known to activate estrogen receptor-α and promote angiogen- Materials and Methods esis in human endothelial cells [11], and impaired male repro- duction by the alteration in morphology of testes and arrest of Animal sperm maturation in catfish [12]. Adult male and female freshwater cichlid fish, Pseudetroplus Important biomarkers of endocrine disruption in fish includes maculatus, (7±1 g and 7±1.5 cm) were collected from KKF measurement of vitellogenin (VTG) protein, plasma steroid Nursery, Manjeri, Vaniyambalam, Kerala, India. Fishes were hormones, histopathology of gonads, vitelline envelope pro- brought to the laboratory with least disturbance and were accli- teins (VEPs), morphological features as facial tubercles and matized to the laboratory conditions for 15 days prior to exper- nuptial pads, male gender development, detection of enzymes iments in dechlorinated and well-aerated aquarium tanks (40 involved in the biosynthesis of sex hormones like cytochrome L capacity). Health status of fish was continuously monitored P450 (CYP)-19, aromatase and C17-lyase and genes involved in throughout the experiment. The physico-chemical features of estrogen response pathway [13]. Among these biomarkers, vi- the tap water were estimated as prescribed in APHA guidelines tellogenin is considered as a potential biomarker of endocrine [29] where water temperature (28 ± 2ºC), oxygen saturation (70 disruption by environmental estrogenic compounds in fish to 100%) and pH (6.5 to 7.5) were maintained in the standard [14]. Vitellogenin is a Glyco-lipophosphoprotein that serves as range throughout the treatment period. a major precursor of egg yolk proteins, normally expressed in females and functions as an essential source of nutrients during Chemicals early development of oviparous vertebrates and some inverte- brates [15]. It is synthesized in liver in response to endogenous Technical grade organochlorine pesticide, chlordecone (Kepone, estrogens and transported to the ovary through the blood- decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]-pen- stream, where it is taken up by oocytes and processed into yolk talen-2-one, 99.9% purity) was obtained from Supelco, USA. proteins [16]. In males, exogenous estrogenic compounds have Trichloroacetic acid, sodium hydroxide, methanol, acetone, hy- been shown to mimic the endogenous estrogens and act on he- drochloric acid, folin-ciocalteau reagent, lanthanum chloride, patic estrogen receptors which induce vitellogenin biosynthesis sucrose, eosin and nigrosin were obtained from Himedia Lab- [17]. oratories, Mumbai, India. All other chemicals were of analytical grade and obtained from local commercial sources. In order to detect the level of vitellogenin, several techniques have been developed globally, which includes enzyme-linked Treatment immunosorbent assay [18], non-competitive enzymatic immu- noassays [19,20], immune agglutination [21] and densitometry Chlordecone was dissolved in dimethyl sulfoxide (1% DMSO), following electrophoresis [22,23]. Owing to the complexity of which was used as solvent control (vehicle) in the experiment. The median lethal concentration (LC -96h) of chlordecone de- vitellogenin molecule and requirement of species-specific an- 50 tibodies, these assays are limited to single species. In addition, termined by probit analysis in the cichlid fish,Pseudetroplus these techniques are highly expensive and the use is restrict- maculatus was 35μg/ L [30]. After acclimatization, two suble- ed due to the lack of species-specific antibodies. Thus as an thal concentrations - 3.5µg/ L and 7µg/ L (1/10th and 1/5th of LC ) of chlordecone were exposed to fish for 24 h, 72 h and 96 alternative to the techniques, indirect endpoints such as plas- 50 ma protein, alkali labile phosphoprotein, plasma calcium and h (4 days), 7 days, 15 days and 30 days maintaining ten male gonadosomatic index were frequently used to study the induc- and female fishes in each group. tion of vitellogenin in fishes [24]. Thus in the present study the estrogenic activity of chlordecone were measured using vitello- Experimental protocol genin as biomarker by simple and reliable biochemical assays in At the end of every treatment period, fishes were caught very the blood plasma of Pseudetroplus maculatus. gently using a small dip net, one at a time with least disturbance and their body weights were noted. Blood and sperm samples Pseudetroplus maculatus is a cichlid fish indigenous to South were collected from control and treated groups and then the India and Sri Lanka, which inhabits both freshwater and brack- fishes were