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In vivo MRI study of anoxia induced brain swelling in crucian and common carp
Abstracts / Comparative Biochemistry and Physiolog>, Part A 126 (2000) S1~163
S 149
METALLOTHIONEIN-LIKE PROTEIN LEVELS IN NATURAL POPULATIONS GUDGEON (GOBIO GOBIO): RELATIONSHIP WITH M E T A L L E V E L S I N T I S S U E S
OF AND
ENVIRONMENT V a n C a m p e n h o u t K., Bervoets L., Lodts M., D e S m e t H. a n d B l u s t R. D e p a r t m e n t o f B i o l o g y , U n i v e r s i t y o f A n t w e r p ( R U C A ) , G r o e n e n b o r g e r l a a n 171, 2 0 2 0 A n t w e r p Environmental or even tissue concentrations of metals only reflect the presence of these metals but not their biological effect or significance. So, there is a need to quantify a specific biological response closely linked to metal exposure. The present study investigates the relevance of metallothionein-like protein (MTLP) levels as a biomarker for environmental metal contamination. A field monitoring campaign was organised to investigate the suitability of tissue (Cd, Zn)-MTLP levels of the gudgeon as a biomarker for metal contamination. Gudgeons (Gobio gobio) were sampled at 10 sampling sites Oil a river system in Flanders (Belgium). Nine sampling sites were situated along a cadmium and zinc gradient with a nearby tributary as the reference site As with the environmental (water and sediments) and tissue Cd, Zn concentrations, there was a clear difference among the hepatic and gill (Cd, Zn)-MTLP levels across the different sampling sites. However, for the renal (Cd, Zn)-MTLP concentrations no significant differences between the sampling sites were found. Our data also revealed significantly positive correlations between the hepatic (Cd, Zn)-MTLP levels and metal concentrations in the environment and in the liver tissue. Surprisingly however, negative correlations between the metal concentrations environmental and gill tissue) and the (Cd, Zn)-MTLP levels in the gills were found. We can conclude that the (Cd, Zn)-MTLP synthesis and their correlations with environmental and tissue metal concentrations are tissue specific. It was demonstrated that the hepatic (Cd, Zn)-MTLP levels could be used as a biomarker for the Cd, Zn contamination in the selected study area. The gill (Cd, Zn)-MTLP levels however, were negatively correlated with the environmental and tissue metal concentrations. Therefore care must be taken when interpreting these (Cd, Zn)-MTLP levels as a biological response and biomarker of metal contamination.
IN VIVO MRI STUDY OF ANOXIA INDUCED COMMON CARP V a n d e r L i n d e n A. 1, V e r h o y e M . l, a n d N i l s s o n G. 2
BRAIN
SWELLING
IN CRUCIAN
AND
B i o I m a g i n g lab, U n i v e r s i t y o f A n t w e r p , B e l g i u m and 2 Division of General physiology, Dept. Biology, University of Oslo, Norway. Most vertebrate brains are irreversibly damaged by only a few minutes of anoxia. A well-documented event in the anoxic brain is cell swelling, i.e. an increase in intracellular volume and a decrease in extracellular volume. Cell volume regulation is highly dependent of ATP consuming ion pumps, and the fall in ATP levels that rapidly occurs in anoxia/ischemia is thought to be the immediate cause of cell swelling in brain. In mammals, the anoxic cell swelling causes an increase in the intracranial pressure, and when this pressure exceeds the blood pressure, blood flow to the brain will stop. At this stage the brain can not be saved even if the organism is reoxygenated. Still, some ectothermic animals can survive anoxia for hours or even days. The crucian carp is one of the most anoxia tolerant species known, having developed alternative anaerobic metabolic pathways and metabolic depression, which enables it to maintain brain ATP levels during more than 24 h of anoxia at room temperature. Using in-vivo T2 and diffusion-weighted magnetic resonance imaging (MRI), we have studied the effects of anoxia (up to 2 h) and subsequent normoxic recovery (up to 100 rain) on brain volume, brain free water content and brain water homeostasis (tissue water diffusion coefficient) in crucian carp and common carp. Both these species can survive 2 h of anoxia at 18 ° C, but we expect the response of their brains to anoxia to be quite different, and indicative to the fact that this time period is at the very limit of anoxic survival for the common carp, which shows a continuous decline in brain ATP levels during anoxia. The crucian carp did not show any signs of change in brain volume or brain tissue water homeostasis even upon 24 hours of anoxia (except for the optic lobe, where reversible cellular oedema was indicated). The entire common carp's brain suffered from cellular oedema, net water gain and a brain volume increase (by 6.5 %) which also proceeded during 100 rain of normoxic recovery (by 10 %). The reason that the common carp recovered uneventfully from this insult, proving the reversible nature of the observed changes, could be related to the oversized brain cavity which probably allows a significant brain swelling without a resultant increase in intracranial pressure and global ischemia The results also demonstrate that maintenance of brain volume is closely linked to the ability to maintain brain energy charge.
S 149
METALLOTHIONEIN-LIKE PROTEIN LEVELS IN NATURAL POPULATIONS GUDGEON (GOBIO GOBIO): RELATIONSHIP WITH M E T A L L E V E L S I N T I S S U E S
OF AND
ENVIRONMENT V a n C a m p e n h o u t K., Bervoets L., Lodts M., D e S m e t H. a n d B l u s t R. D e p a r t m e n t o f B i o l o g y , U n i v e r s i t y o f A n t w e r p ( R U C A ) , G r o e n e n b o r g e r l a a n 171, 2 0 2 0 A n t w e r p Environmental or even tissue concentrations of metals only reflect the presence of these metals but not their biological effect or significance. So, there is a need to quantify a specific biological response closely linked to metal exposure. The present study investigates the relevance of metallothionein-like protein (MTLP) levels as a biomarker for environmental metal contamination. A field monitoring campaign was organised to investigate the suitability of tissue (Cd, Zn)-MTLP levels of the gudgeon as a biomarker for metal contamination. Gudgeons (Gobio gobio) were sampled at 10 sampling sites Oil a river system in Flanders (Belgium). Nine sampling sites were situated along a cadmium and zinc gradient with a nearby tributary as the reference site As with the environmental (water and sediments) and tissue Cd, Zn concentrations, there was a clear difference among the hepatic and gill (Cd, Zn)-MTLP levels across the different sampling sites. However, for the renal (Cd, Zn)-MTLP concentrations no significant differences between the sampling sites were found. Our data also revealed significantly positive correlations between the hepatic (Cd, Zn)-MTLP levels and metal concentrations in the environment and in the liver tissue. Surprisingly however, negative correlations between the metal concentrations environmental and gill tissue) and the (Cd, Zn)-MTLP levels in the gills were found. We can conclude that the (Cd, Zn)-MTLP synthesis and their correlations with environmental and tissue metal concentrations are tissue specific. It was demonstrated that the hepatic (Cd, Zn)-MTLP levels could be used as a biomarker for the Cd, Zn contamination in the selected study area. The gill (Cd, Zn)-MTLP levels however, were negatively correlated with the environmental and tissue metal concentrations. Therefore care must be taken when interpreting these (Cd, Zn)-MTLP levels as a biological response and biomarker of metal contamination.
IN VIVO MRI STUDY OF ANOXIA INDUCED COMMON CARP V a n d e r L i n d e n A. 1, V e r h o y e M . l, a n d N i l s s o n G. 2
BRAIN
SWELLING
IN CRUCIAN
AND
B i o I m a g i n g lab, U n i v e r s i t y o f A n t w e r p , B e l g i u m and 2 Division of General physiology, Dept. Biology, University of Oslo, Norway. Most vertebrate brains are irreversibly damaged by only a few minutes of anoxia. A well-documented event in the anoxic brain is cell swelling, i.e. an increase in intracellular volume and a decrease in extracellular volume. Cell volume regulation is highly dependent of ATP consuming ion pumps, and the fall in ATP levels that rapidly occurs in anoxia/ischemia is thought to be the immediate cause of cell swelling in brain. In mammals, the anoxic cell swelling causes an increase in the intracranial pressure, and when this pressure exceeds the blood pressure, blood flow to the brain will stop. At this stage the brain can not be saved even if the organism is reoxygenated. Still, some ectothermic animals can survive anoxia for hours or even days. The crucian carp is one of the most anoxia tolerant species known, having developed alternative anaerobic metabolic pathways and metabolic depression, which enables it to maintain brain ATP levels during more than 24 h of anoxia at room temperature. Using in-vivo T2 and diffusion-weighted magnetic resonance imaging (MRI), we have studied the effects of anoxia (up to 2 h) and subsequent normoxic recovery (up to 100 rain) on brain volume, brain free water content and brain water homeostasis (tissue water diffusion coefficient) in crucian carp and common carp. Both these species can survive 2 h of anoxia at 18 ° C, but we expect the response of their brains to anoxia to be quite different, and indicative to the fact that this time period is at the very limit of anoxic survival for the common carp, which shows a continuous decline in brain ATP levels during anoxia. The crucian carp did not show any signs of change in brain volume or brain tissue water homeostasis even upon 24 hours of anoxia (except for the optic lobe, where reversible cellular oedema was indicated). The entire common carp's brain suffered from cellular oedema, net water gain and a brain volume increase (by 6.5 %) which also proceeded during 100 rain of normoxic recovery (by 10 %). The reason that the common carp recovered uneventfully from this insult, proving the reversible nature of the observed changes, could be related to the oversized brain cavity which probably allows a significant brain swelling without a resultant increase in intracranial pressure and global ischemia The results also demonstrate that maintenance of brain volume is closely linked to the ability to maintain brain energy charge.