Toxicity of a cyanobacterial extract containing microcystins to mouse lungs

Abstract

Toxic cyanobacteria in drinking water supplies can cause serious public health problems. In the present study we analyzed the time course of changes in lung histology in young and adult male Swiss mice injected intraperitoneally (ip) with a cyanobacterial extract containing the hepatotoxic microcystins. Microcystins are cyclical heptapeptides quantified by ELISA method. Ninety mice were divided into two groups. Group C received an injection of saline (300 µl, ip) and group Ci received a sublethal dose of microcystins (48.2 µg/kg, ip). Mice of the Ci group were further divided into young (4 weeks old) and adult (12 weeks old) animals. At 2 and 8 h and at 1, 2, 3, and 4 days after the injection of the toxic cyanobacterial extract, the mice were anesthetized and the trachea was occluded at end-expiration. The lungs were removed en bloc, fixed, sectioned, and stained with hematoxylin-eosin. The percentage of the area of alveolar collapse and the number of polymorphonuclear (PMN) and mononuclear cell infiltrations were determined by point counting. Alveolar collapse increased from C to all Ci groups (123 to 262%) independently of time, reaching a maximum value earlier in young than in adult animals. The amount of PMN cells increased with time of the lesion (52 to 161%). The inflammatory response also reached the highest level earlier in young than in adult mice. After 2 days, PMN levels remained unchanged in adult mice, while in young mice the maximum number was observed at day 1 and was similar at days 2, 3, and 4. We conclude that the toxins and/or other cyanobacterial compounds probably exert these effects by reaching the lung through the blood stream after ip injection.

Distribution of microcystins in various organs (heart, liver, intestine, gonad, brain, kidney and lung) of Wistar rat via intravenous injection

“…MCs are known to be not only responsible for the damage of hepatic and renal function (Nobre et al, 2001(Nobre et al, , 2003, but also for the pathological changes of respiratory system (Ito et al, 2001;Pican et al, 2004;Soares et al, 2007). Pican et al (2004) reported that cyanobacterial compounds containing MCs caused various histological changes in the lung of Swiss mice after i.p.…”

“…Pican et al (2004) reported that cyanobacterial compounds containing MCs caused various histological changes in the lung of Swiss mice after i.p. injection.…”

Repeated intranasal exposure to microcystin-LR affects lungs but not nasal epithelium in mice

“…injection of MC-LR (Picanço et al, 2004;Soares et al, 2007;Carvalho et al, 2010;Casquilho et al, 2011). However, the functional and histological assessments following a sub-chronic exposure to low doses are still poorly documented in the literature.…”

Toxin mixture in cyanobacterial blooms – a critical comparison of reality with current procedures employed in human health risk assessment

“…treatment with MC contaminated dialysis water (Azevedo et al 2002;Fischer et al 2005;Jochimsen et al 1998;Pouria et al 1998), and for nephrotoxicity, as indicated by several animal experiments (Bhattacharya et al 1997;Fischer and Dietrich 2000;Khan et al Chapter 39: Toxin mixture in cyanobacterial blooms -a critical comparison of reality with current procedures employed in human health risk assessment 13 1996; Milutinovic et al 2002;Milutinovic et al 2003;Moreno et al 2005;Stotts et al 1997). Studies on organ distribution support these findings and suggest that, beside liver and kidney, the brain and the lungs (Picanco et al 2004) can also be affected to a varying extent Meriluoto et al 1990;Pace et al 1990;Robinson et al 1989;Robinson et al 1991;Stotts et al 1997).…”