Pigmented Macrophage Aggregates: A Toxic Response in Fish Exposed to Bleached-Kraft Mill Effluent?

Abstract

An epidemiological study was conducted to evaluate whether the density of pigmented macrophage aggregates (PMAs) and the prevalences of preneoplastic and neoplastic lesions increased in fish captured downstream from a bleached‐kraft pulp mill, causing induction of cytochrome P4501A enzymes (CYP1A). White suckers (Catostomus commersoni) sampled 10 and 95 km downstream from a bleached‐kraft pulp mill in the St. Maurice River, Quebec, Canada, exhibited higher densities of PMAs relative to age in liver, spleen, and kidney than fish sampled 10 km upstream. White suckers were also sampled at three sites in the Gatineau River, Quebec, Canada, a reference river with a similar upstream/downstream ecological gradient but no pulp mill. In the Gatineau, density of PMAs was lower in the liver of fish sampled at the most downstream site, and there was no difference among sites in spleen and kidney. Higher growth rates have been documented at downstream sites of both rivers and thus cannot explain the increased density of PMAs observed at downstream sites of the St. Maurice River only. Density of PMAs did not differ between sexes or between fish with or without grossly visible parasites or granulomatous histological lesions. Although we cannot exclude the involvement of unknown infectious agents, density of PMAs appears to be a useful marker of bleached‐kraft mill effluent (BKME) toxicity. Several known toxic effects of BKME could contribute to this response, including increased rates of lipid peroxidation associated with induced CYP1A and toxic hemolysis. Further field and laboratory studies are needed to evaluate whether the association between BKME exposure, induction of CYP1A, and increased density of PMA is consistent. Preneoplastic lesions were not observed in fish captured downstream of the pulp mill in the St. Maurice River, and only one case of biliary carcinoma was observed, at the most contaminated site.

Liver histology and ultrastructure of the Italian newt (Lissotriton italicus): Normal structure and modifications after acute exposure to nonylphenol ethoxylates

“…In mammalian non-estrogenic effects of nonylphenolic compounds include the production of ions and free radicals (ROS) (Obata and Kubota, 2000;Chitra and Mather, 2004;Okai et al, 2004;Gong and Han, 2006); moreover it has been shown that CYP-lA induction causes oxidant damage of cellular membranes (Couillard and Hodson, 1996). Therefore, the increase in melanin content reported herein may be interpreted as a reaction induced by oxidative stress and well correlated with CYP-1A induction.…”

Histologic, immunologic and endocrine biomarkers indicate contaminant effects in fishes of the Ashtabula River

“…Elevated prevalence or size of macrophage aggregates have previously been used as an indicator of environmental degradation in a number of monitoring programs (Zdanowicz et al 1987;Bucke et al 1992;Long et al 1995;Fournie et al 2001). Exposure to heavy metals such as mercury (Meinelt et al 1997), pulp mill effluent (Couillard andHodson 1996), dioxins (van der Weiden et al 1994), crude oil (Khan and Kiceniuk 1984), polybrominated flame retardants (Raldúa et al 2008) and PCBs (Pierce et al 1980;Anderson et al 2003;Fisher et al 2008) leads to an increase in MAs. Bowser et al (1990) observed increased hepatic macrophage aggregates in brown bullhead collected at a site contaminated with PCBs and metals when compared to a reference site.…”

Macrophage aggregates in gilthead sea bream fed copper, iron and zinc enriched diets

“…Couillard & Hodson (1996) reported a positive correlation between hepatic MA density and age in Catostomus commersoni (Lacépède) and proposed a link between MA formation and cytochrome P4501A peroxidase activity. Chromolipoids are abundant in the MAs of the liver, an organ that is particularly stressed in intensively reared fish, which shows typical cryptopathological, subclinical or asymptomatic transformation: cytoplasmic and nuclear vacuolizations which are characteristic of steatosis.…”

“…Wolke, 1992). Some authors have also proposed the use of MAs as biomarkers of environmental degradation and pollution (Wolke, 1992;Couillard & Hodson, 1996).…”