강도다리, Platichthys stellatus의 혈액, 항산화효소 및 면역 반응에 미치는 카드뮴과 미세플라스틱의 복합 영향

Abstract

Microplastics (MPs; > 5mm) which widely spread in aquatic environment have a large surface area, making it advantageous for adsorbing various environmental pollutants including heavy metals. Cadmium (Cd) is a toxic heavy metal used in a variety of industries and released into the aquatic environment. In this study, accumulation, blood physiology, antioxidant and immune response of P latichthys stellatus (length 14.884 ± 0.88cm, weight 49.288 ± 8.44g) exposed to MPs and Cd for 10 and 20 days were analyzed. The experimental concentrations were set at control, MPs 500㎍/L (MPs-L), MPs 1000㎍/L (MPs-H), Cd 50㎍/L, Cd-MPs combined exposure groups (Cd 50㎍/L plus MPs-L and Cd 50㎍/L plus MPs-H). The MPs accumulation in gills, intestine and liver of P. stellatus were significantly increased in the MPs-H and Cd 50㎍/L plus MPs-H groups. The MPs accumulation profile was in the order of intestine > gills > liver. The Cd accumulation in gills, intestine and liver of P. stellatus were significantly increased in the Cd-MPs combined exposure groups. The Cd accumulation profile was in the order of liver > gills > intestine. Growth rate were mesured in Body weight gain (BWG), Specific growth rate (SGR) and Hepatosomatic index (HSI). BWG and SGR were significantly decreased in the Cd-MPs combined exposure groups and HSI was significantly increased in the Cd 50㎍/L plus MPs-H groups. In the blood physiology, red blood cell (RBC) count and hemoglobin (Hb) were significantly decreased in the Cd-MPs combined exposure groups. Glutamic oxaloacetic transaminase (GOT), Glutamic pyruvic transaminase (GPT), Alkaline phosphatase (ALP), Glucose and magnesium were significantly increased in the Cd-MPs combined exposure groups. While, total protein (TP) and calcium were significantly decreased in the Cd-MPs combined exposure groups. In the antioxidant response, superoxide dismutase (SOD) and catalase (CAT) in gills, intestine and liver of P. stellatus were significantly increased in the Cd-MPs combined exposure groups. In the immune response, lysozyme (LZM) and immunoglobulin M (IgM) in gills, intestine and liver of P. stellatus were significantly decreased in the Cd 50㎍/L plus MPs-H groups. Our results suggest that the toxicity of Cd-MPs combined exposure is higher than single exposure, and that combined exposure may cause physiological changes and immune decline.