Histological Effect of Lead Chloride on The Brain of Gambusia Affinis

Heavy material pollution is one of the most critical threats to fish stocks around the world. Lead is one of the essential heavy elements that directly or indirectly affect fish. The purpose of this study is to investigate the effects of sublethal concentration of lead chloride PbCl₂ on the brain of Gambusia affinis. For this purpose, 90 fish were used, which were divided into nine groups, each group containing ten fish. They divided into a control group, the acute treatment groups included four groups exposed to concentrations of 20 and 25 mg/L of PbCl₂ for 24 and 96 hours, respectively. At the same time, the chronic treatment included four groups exposed to concentrations of 5 and 10 mg/L of PbCl₂ for 15 and 30 days, respectively. The results showed that there were histological lesions that appeared in all the treated fish compared to the control group. These lesions appeared in different degrees of concentration and duration of use. Among the most prominent of these tissue changes that were repeated in the treatments were degeneration, vacuolar degeneration, necrosis, hemorrhage, congestion and oedema as well as disintegration between different brain tissues. The study concluded that lead chloride has a very harmful effect on brain tissues and that chronic exposure leads to irreversible histological lesions.