The toxicity of microcystin-LR in swine and mice

Lovell, Randall Anderson

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https://hdl.handle.net/2142/19889 Copy

Description

Title

The toxicity of microcystin-LR in swine and mice

Author(s)

Lovell, Randall Anderson

Issue Date

1989

Doctoral Committee Chair(s)

Beasley, Val Richard

Department of Study

Veterinary Biosciences

Discipline

Veterinary Biosciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Biology, Animal Physiology
• Health Sciences, Pathology
• Biology, Veterinary Science

Language

eng

Abstract

• Microcystin-LR (MCLR) is a monocyclic heptapeptide hepatotoxin produced by the cyanobacterium Microcystis aeruginosa. One gilt given whole M. aeruginosa cells ig containing 0.3% MCLR and des-methyl MCLR at 2.1 g/kg had severe panlobular hepatic necrosis and hemorrhage when euthanatized at 32.5 hr postdosing.
• Mean liver and kidney weights increased 50-64% and 20-32%, respectively, in two strains of male mice that died within 200 minutes after a single lethal ip dose of purified MCLR. Mice that survived an ip LD$\sb{23}$ or LD$\sb{30}$ of MCLR had significantly longer survival times and higher survival rates when given an approximate ip LD$\sb{100}$ minimum (40-75 $\mu$g/kg) 2 or 3 days later.
• The liver (34.01 IU/g), pancreas (5.43 IU/g), and kidney (3.24 IU/g) were the only swine tissues with mean arginase activity (ARG) greater than 0.52 IU/g. The serum t${1\over2}$ of ARG in a barrow and gilt were 85.8 and 128.0 minutes (min).
• Between 12 and 24 min after anesthetized gilts were given a lethal iv dose of purified MCLR (72 $\mu$g/kg), mean aortic and central venous pressures, and renal and hepatic perfusion decreased ($\downarrow$) significantly, while portal venous pressure increased ($\uparrow$) significantly. Significant changes at 45 min included $\uparrow$ bile acids, total bilirubin, lactate, K, and pO$\sb2$, and $\downarrow$ platelet count, base excess, Hct, HCO$\sb3-$, and pCO$\sb2$. At 90 min, significant changes included $\uparrow$ ARG, P, BUN, and creatinine, and $\downarrow$ pH and glucose. Significant changes 150 min postdosing included $\uparrow$ AST, AP, ALT, CPK, and LDH. Livers were markedly enlarged, dark purple-red in color, and readily exuded blood on cut surfaces. Significantly $\uparrow$ liver weights and liver Fe and Hb concentrations were suggestive that 37.9% of the estimated blood volume was present in the liver. The major cause of acute death ($<$5 hr) following iv MCLR dosing in swine is hypovolemic shock which results from massive intrahepatic hemorrhage.

Type of Resource

text

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http://hdl.handle.net/2142/19889

Copyright and License Information

Copyright 1989 Lovell, Randall Anderson

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