Acute effects of bisphenol a on testis tissue of guppy fish ( Poecilia reticulata )

Introduction Endocrine disrupting chemicals (EDCs) are compounds in the external environment that modulate the physiology of the endocrine system and often cause health disorders (Crews & McLachlan, 2006). Many studies have shown that xenoestrogens have serious damage to natural habitats (Colborn, 1995). Inspite of this, it’s not clear whether xenoestrogens are caused by abnormalities in reproductive system. Because, in the nature, many pollutings contaminate ecosystem at the same time so livings are exposed to mixture of many chemicals. Therefore, it’s difficult to determine the effect of each one of them. Many of the investigations into EDCs in the aquatic environment have involved fish because of similarities in the endocrine system to higher vertebrates (Bond, 1979), a demonstrated sensitivity to EDCs in both laboratory and field investigations, ease of working with fish, and the fact that wild populations in a number of locations have exhibited effects thought to be associated with exposure to EDCs (Noaa, 2002). Bisphenol A (2 bis(4-hydroxiphenyl) propane, BPA) is one of the most potent endocrine disrupting chemicals which mimics estrogen in vivo and in vitro (Kim et al., 2011) and therefore is classified as xenoestrogen. Chemicals that can mimic or antagonize the effects of endogenous hormones could potentially have and well serious effects not only on the development being of an individual organism, but perhaps more importantly on the ability of that organism to reproduce, and its offspring to survive and eventually reproduce (Noaa, 2002). BPA is widely used in industry for making plastics harder. It’s found in polycarbonate plastics (baby feeding bottles, carboys) (Cao & Corriveau, 2008) and inside of epoxy coated cans (Kang et al., 2006). Bisphenol A (BPA) is one of the highest production volume chemicals in the world. Nowadays, depending on the increasing the production of BPA, the rate of contamination of aquatic systems is increasing rapidly. BPA levels were reported between 0.02–21 ug/L in river water (Kang, 2007). The guppy (Poecilia reticulata), is a member of the Poeciliidae family , [1] is one of the most popular fish species in the world. They generally live in freshwater with a temperature between 25.5 and 27.8 °C Female and male individuals can be seperated easily because guppies exhibit sexual dimorphism. While wild-type females are grey in body colour, males have gonopodium and different colors of splashes, spots, or stripes. The aim of this study is to investigate the histopathological effects of BPA on the testis tissue of male guppy fishes. Testis histology, location and shape of the cells which belong to spermatogenic serial, structure of the tissue was investigated with light microscopy with this study. Materials and Methods Chemical: BPA, 2 bis(4-hydroxiphenyl), (Sigma Aldrich, CAS No: 5005-7) was dissolved in 1 % dimethylsulfoxide (DMSO) to generate desired concentrations for treatment of the guppy fishes. Fish Adult guppies were purchased from a local breeder in İstanbul with no water pollution. The fish were separated by sex into different aquariums. Fish system water, obtained by carbon/sand filtration of municipal tap water, was maintained at 26 ± 1 oC and pH 7.2-7.7 with a 14:10 h light:dark photoperiod. Test chambers were glass aquaria of about a 20-L capacity. The guppies were fed once daily in the morning with flake food (Tetra, Germany) Experimental Design Following the preliminary experiment, all determinations were repeated two times. The guppies are divided into three groups (n=30) concerning their different BPA doses. After 48 h of adaptation, the different concentrations of deltamethrin were added to the experimental aquaria. Mortality was controlled 24, 48, 72, and 96 h after the start of the tests. Dead individuals were removed immediately. Control group received 1% DMSO at its maximum volume used in dilution of the dosing concentrations (group I: 4 mg/L BPA, group II: 8 mg/L BPA, and group III: control group). After giving different doses of BPA, fishes were dissected on the fifth day of the study. The testis tissues of adults were fixed in Bouin’s fixative for 18 h