The Effects Of Phthalate Acid Esters (Paes) On Green Mussel (Perna Viridis), Crimson Snapper (Lutjanus Erythropterus) And River Snapper (lutianus Argentimaculatus)

The phthalic acid esters (PAEs) is one of the most extensively used synthetic organic chemicals. More and more attention was paid to its toxicity to the aquatic organism. Recently, the study on the toxicity of PAEs is highlighted. The present study aimed to elucidate the toxic effect of dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) on Green mussel (Perna viridis), Crimson snapper (Lutjanus erythropterus) and River snapper (Lutianus argentimaculatus). The super oxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione Stransferase (GST), malondialdehyde (MDA) contents and acetylcholinesterase (AChE) in brain, EROD activity and CYP1A gene expressions were examined. In addition, the morphology of liver and gills of river snapper were analysized using routin histological technique and light microscope analysis.1,The SOD and CAT activities of green mussel were significantly influenced by the stresses of DBP and DEHP. When exposed to DBP, the activities of SOD and CAT of the visceral mass were significantly restrained. Whereas,the activity of SOD of the mantle was firstly significantly increased and then decreased. There was an obvious fluctuation inCAT activity and no regular changing pattern existed. When exposed to DEHP, the activity of SOD of the visceral mass was generally followed the same pattern as that of DBP. But CAT was adverse. In the beginning, the SOD activity of the mantle was decreased under a low dose of DEHP and increased under a high dose of DEHP. However, four days later, the mussel in all treatment groups recovered. The MDA content increased with increasing DBP, indicated that PAEs resulted to a lipid peroxidation (LPO) damage on shellfish in the ocean. During the period of purification, the time for the activities recovery of SOD, CAT and the content of MDA lowered to the controlled level was shorter than under DBP stress than that of DEHP.2,The 96h LC50 of DBP was 6.66 mg·L^-1, and the safe concentration (SC) in our study was 2.02 mg·L^-1 on crimson snapper; 96h LC50 of DEHP was10.73 mg·L^-1, the SC was 3.01 mg·L^-1. Thus, the two poisonous chemicals were highly toxic materials for crimson snapper. Furthermore, our data indicated that DBP was even worse than DEHP, due to its higher dissolvability in seawater.3,The SOD activity of the liver and gills of crimson snapper firstly increased and then inhibited by DBP. Under DEHP stress, SOD activity was increased in liver, but decreased in gills. With the, MDA activity significantly increased with increasing PAEs concentration, indicated oxidation stress to fish in a short time and leading to LPO. Moreover, it was demonstrated that the PAEs induced the activity of AChE as one of effective index, implying that it significantly stimulated the nerve conduction of marine fish.4,Under DBP stress, POD activity was increased in liver, but decreased in gills of river snapper; GST significantly fluctuated in these two tissues and dose was induced after 15d exposed 0.5 mg·L^-1.5,For crimson snapper, the EROD in the liver under DBP stress was higher than the controlled level after 7d and then decreased on the 15d. While, in the gills the EROD were lower than the control group on either 3d or 7d, but higher on the 15d. The results suggested that the activity of EROD in the liver was higher than in the gills and more sensitive. The CYP1A cDNA cloned from the tissues was one of the subfamily members. The quantitative examination by qRT-PCR showed that the change of the expression level of CYP1A mRNA was generally similar to the EROD activity.6,The results from the morphology of the two tissues of river snapper revealed that cells enlarged, vacuoles occurred in the cytoplasm, and the karyomorphism was changed in liver. Also, branch leaf was significantly swelled, blended, fused, necrotic and scaled in gill.7,For the green mussel, the toxic effects of DBP was less than that of DEHP. However, the toxic effects of DBP were higher than that of DEHP. Under the exposure of PAEs, the activity of enmity in the visceral mass was more sensitive than mantle forgreen mussel, and liver was better than gills. The antioxidase, EROD and CYP1A expressions in fish liver were more sensitive than in gills. AChE in brain was an early-warning index to PAEs exposure.