Seawater Polluted with Highly Concentrated Polycyclic Aromatic Hydrocarbons Suppresses Osteoblastic Activity in the Scales of Goldfish,Carassius auratus

Abstract

We have developed an original in vitro bioassay using teleost scale that has osteoclasts, osteoblasts, and bone matrix as each marker: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Using this scale in vitro bioassay, we examined the effects of seawater polluted with highly concentrated polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) on osteoblastic and osteoclastic activities in the present study. Polluted seawater was collected from 2 sites (the Alexandria site on the Mediterranean Sea and the Suez Canal site on the Red Sea). Total levels of PAHs in the seawater from the Alexandria and Suez Canal sites were 1364.59 and 992.56 ng/l, respectively. We can detect NPAHs in both seawater samples. Total levels of NPAHs were detected in the seawater of the Alexandria site (12.749 ng/l) and the Suez Canal site (3.914 ng/l). Each sample of polluted seawater was added into culture medium at dilution rates of 50, 100, and 500 and incubated with the goldfish scales for 6 hrs. Thereafter, ALP and TRAP activities were measured. As a result, ALP activity was significantly suppressed by both polluted seawater samples diluted at least 500 times, although TRAP activity did not change. In addition, mRNA expressions of osteoblastic markers (ALP, osteocalcin, and the receptor activator of the NF-B ligand) decreased significantly, as did the ALP enzyme activity. Actually, ALP activity decreased with selected PAHs and NPAHs treatments. We conclude that seawater polluted with highly concentrated PAHs and NPAHs influenced bone metabolism in teleosts.

Toxicities of Polycyclic Aromatic Hydrocarbons for Aquatic Animals

“…At both sites, crude oil is often contained in the ballast water thrown away by ships, and the marine pollution of the Mediterranean Sea coast and the Suez Canal worsens even if there is no ship or oil tanker accident. We have reported that the concentrations of PAHs, including the PAHs shown in Figure 1, in these areas (Suez Canal: 992.56 ng/L; Alexandria port: 1364.59 ng/L) were remarkably high, around 100 times that of the Sea of Japan [95]. Furthermore, we demonstrated that they were more likely caused by PAHs included in crude oil [95].…”

“…We have reported that the concentrations of PAHs, including the PAHs shown in Figure 1, in these areas (Suez Canal: 992.56 ng/L; Alexandria port: 1364.59 ng/L) were remarkably high, around 100 times that of the Sea of Japan [95]. Furthermore, we demonstrated that they were more likely caused by PAHs included in crude oil [95]. Each sample of polluted seawater was added into culture medium at dilution rates of 50, 100, and 500 times and incubated with goldfish scales for 6 h. Thereafter, ALP and TRAP activities in the scales of goldfish were measured.…”

Influence of Benz[a]anthracene on Bone Metabolism and on Liver Metabolism in Nibbler Fish, Girella punctata

“…In the present study, we found that a low concentration of BaA has toxicity for the bone and liver of nibbler fish (marine teleost). As highly polluted seawater in the natural environment included BaA [18], we call for the prevention of PAH pollution.…”

“…These results indicate that BaA may affect liver diseases in addition to bone diseases. As BaA is included in highly polluted seawater [18], we should emphasize the prevention of aquatic PAH pollution.…”

“…Nibbler fish were divided into three groups (eight individuals each) and anesthetized with 0.04% of a 2-phenoxyethanol (FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan), and BaA (FUJIFILM Wako Pure Chemical Corporation) (low dose: 1 ng/g of body weight, n = 8; high dose: 10 ng/g body weight, n = 8) was injected intraperitoneally. These concentrations were determined based on the sea water which is highly contaminated with PAHs (total PAHs: 0.99-1.36 ng/mL) [18]. The injection was performed four times (on days 1, 3, 6, and 9).…”