Biochemical biomarkers of skin mucus in Neogobius melanostomus for assessing lead pollution in the Gulf of Gorgan (Iran)

The present study was conducted to provide basic information on the physiological damages (mucosal indicators) of Round Goby under laboratory and environmental conditions of lead contamination. The other goal was to find mucosal biomarkers of lead contamination in the Gulf of Gorgan. In the laboratory study, 400 pieces of fish with an average the weight of 35 ± 7.16 g were caught alive and were exposed to lead concentrations of 0, 3.75, 7.5 and 15 mg / l for 14 days. Once the experiment was completed, the samples of mucus and liver were collected from the fish samples with the samples being surveyed by analyses of SDS-PAGE, mucus safety and toxicology. In the field test, the samples of fish, water, and sediment were prepared from four stations. In addition to measuring the lead in water, sediment and liver tissue, the samples of mucus from the caught fish were similarly analyzed under the laboratory conditions mentioned. According to the results under laboratory conditions, obvious differences were observed between the protein pattern of samples of treatment with the control group. Further, among innate immune parameters of the mucus, only lysozyme showed a significant correlation with the concentrations of lead accumulated in the liver of Round Goby (P < 0.05). Under environmental conditions, obvious differences were also observed between the protein pattern of samples of contaminated stations with the control station. Further, among innate immune parameters of the mucus, lysozyme indicated a positive correlation while alkaline phosphatase showed a negative correlation with lead contamination in the liver of Round Goby (P < 0.05). In total, in the pattern of mucus protein, the intensity of the band within the range of 25 kDa was enhanced in both conditions, suggesting the presence of proteases in this region. Also, among the immune parameters, lysozyme enzyme showed a significant and positive correlation with liver lead contamination in both conditions (P < 0.05). These can be considered as the biomarkers of protein pattern and safety in Round Goby mucus for assessing lead pollution in Gulf of Gorgan.