Drug and Chemical Toxicology
ISSN: 0148-0545 (Print) 1525-6014 (Online) Journal homepage: http://www.tandfonline.com/loi/idct20
Subacute and Subchronic Toxicity of Ethylene Glycol Administered in Drinking Water to SpragueDawley Rats Merrel Robinson, Cynthia L. Pond, R. Dana Laurie, J. Peter Bercz, Gerry Henningsen & Lyman W. Condie To cite this article: Merrel Robinson, Cynthia L. Pond, R. Dana Laurie, J. Peter Bercz, Gerry Henningsen & Lyman W. Condie (1990) Subacute and Subchronic Toxicity of Ethylene Glycol Administered in Drinking Water to Sprague-Dawley Rats, Drug and Chemical Toxicology, 13:1, 43-70, DOI: 10.3109/01480549009011069 To link to this article: http://dx.doi.org/10.3109/01480549009011069
Published online: 27 Sep 2008.
Submit your article to this journal
Article views: 22
View related articles
Citing articles: 2 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=idct20 Download by: [Australian National University]
Date: 07 November 2015, At: 06:28
DRUG AND CHEMICAL TOXICOLOGYy 13(1), 4 3 - 7 0 (1990)
Downloaded by [Australian National University] at 06:28 07 November 2015
SUBACUTE AND SUBCHRONIC TOXICITY OF ETHYLENE GLYCOL ADMINISTERED IN DRINKING WATER TO SPRAGUE-DAWLEY RATS
'
Merrel Robinsona, Cynthia L. Pondb, R. Dana Lauriec,
J . Peter Bercza, Gerry Henningsend , and Lyman W. Condiee
aEnvironmental Toxicology Division Health Effects Research Laboratory U.S. Environmental Protection Agency 26 West Martin Luther King Jr. Drive Cincinnati, Ohio 45268 bPathology Associates, Inc. 6217 Center Park Drive West Chester, Ohio 4 5 0 6 9 'Procter
and Gamble, Inc.
1 1 5 2 0 Reed Hartman Highway Cincinnati, Ohio 4 5 2 4 1
dToxic Hazards Division Air Force Aerospace Medical Research Laboratory Wright-Patterson AFB, Ohio 4 5 4 3 3 eU.S. Army Dugway Proving Ground Dugway, Utah 84022
Corresponding Author: Merrel Robinson Environmental Toxicology Division Health Effects Research Laboratory U.S. Environmental Protection Agency 26 West Martin Luther King Jr. Drive Cincinnati, Ohio 45268 43 Copyright 0 1990 by Marcel Dekker, Inc.
ROBINSON ET AL.
44 ABSTRACT
Subacute (10-day) and subchronic (90-day) toxicity studies of ethylene glycol (EG) were conducted in male and female
Downloaded by [Australian National University] at 06:28 07 November 2015
Sprague-Dawley rats to provide the U.S.
Environmental Protec-
tion Agency's (EPA) Office of Drinking Water with toxicity data for final preparation of a Health Advisory for the chemical. Ethylene glycol was administered in drinking water at concentrations of 0 . 5 , 1.0, 2.0, and 4 . 0 % for both sexes in the 10-day study. Based on a projected consumption rate of 100 ml/kg/day, the respective doses on a mg/kg/day basis would be 5 5 4 , 1108, 2 2 1 6 , and 4 4 3 2 .
These dose levels were also used in the 90-day
study for females, but dose levels for the males in the 90-day study were 0 . 2 5 , 0 . 5 , 1.0, and 2.0% ( 2 2 7 , 5 5 4 , 1108, and 2216 mg/kg/day).
At time of sacrifice necropsies were performed and
tissues were prepared for histological evaluation.
Blood sam-
ples were taken for hematology and clinical chemistry determinations.
Body weights were measured weekly.
consumption were determined three times weekly. occurred in the 10-day study.
Water and food No mortality
In the 90-day study 8/10 females
and 2/10 males in the high dose group died prior to sacrifice. Body weights were suppressed in a dose response fashion for males and females.
Hemoglobin, hematocrit, erythrocytes, and
leukocytes were all significantly decreased in female rats receiving 4% EG for 10 days.
The most significant histo-
45
TOXICITY OF ETHYLENE GLYCOL IN DRINKING WATER
pathological findings, seen predominantly in males, were kidney lesions which included calcium oxalate crystals in tubules and pelvic epithelium; tubular dilation and degeneration; intratubular proteinaceous material; and inflammation in tubules and
Downloaded by [Australian National University] at 06:28 07 November 2015
pelvic epithelium.
At the same dose of ethylene glycol, males
had more kidney lesions and much higher incidence and severity of lesions than the females.
INTRODUCTION Ethylene glycol (EG) is an important industrial chemical with many commercial applications. In 1983, 4.5 billion pounds of EG were produced in the United States1.
It is used as an
antifreeze in cooling and heating systems, a solvent in paint and plastic
industries, an industrial humectant, hydraulic
fluid, and an ingredient o f electrolytic condensers.
EPA is
currently attempting to assess the risk to human health posed by environmental contamination of EG.
Releases of the chemical
to the environment can occur during production, commercial use and disposal or accidental spills. While release to the atmosphere and persistence in surface water is minimal because of its low vapor pressure and its rapid biodegradation, contamination o f ground water is possible'.
.
Laug et al., presented an in-depth discussion of earlier toxicological investigations of EG
and reported oral LD50
ROBINSON ET AL.
46
values of 6100 mg/kg in the rat and 14,528 mg/kg in the mouse? Smyth et al., reported an oral ID50 of 8540 mg/kg in the rat4. Toxicity resulting from chronic exposure to EG in the diet of rats and mice has been reported by various investigators5* 6 *
Downloaded by [Australian National University] at 06:28 07 November 2015
71
8 * 9 * lo.
mented"*
The toxicity of EG to humans has been docu-
12* 13* l4
EG
was
reported by
d.,
Clark
to demonstrate no significant mutagenic activity in the Ames test15.
However, Bose and Naskar"
d., 17
and Alam &
reported EG to be a mutagen in cluster beans and wheat respectively.
Mutagenic activity in mammalian cells has also been
reported18, 19.
Price et al., reported teratogenic effects in
mice and rats that received from 0.75 to 5.0 g/kg/day
EG2'.
Lamb et al., reported reproductive effects of reduced litter size and skeletal anomalies in mice given 1.0% EG in drinking water in a protocol involving continuous breeding21.
DePass
et al., found EG to be without effect in three-generation reproduction and dominant lethal mutagenesis studies wherein rats received 1.0, 0 . 2 ,
and 0.04 g/kg/day22.
The mechanisms of
toxicity have been investigated exten~ively'~, 23*
241
25*
Gessner et al., found that EG is converted to glycolaldehyde, glycolic acid and glyoxylic acid prior to its ultimate elimination as respiratory C02 (primarily) or urinary oxalate (secondarily)26.
Bove confirmed these findings23.
The present studies were performed to assess the subacute and subchronic toxicity of EG in rats when administered via
TOXICITY OF ETHYLENE GLYCOL IN DRINKING WATER
47
drinking water in order to finalize a health advisory for the chemical. METHODS
Downloaded by [Australian National University] at 06:28 07 November 2015
Ethvlene Glvcol Ethylene glycol (Lot: 2-852019) was obtained from Fisher Scientific, (Cincinnati, OH).
The chemical was analyzed for
purity using gas chromatography and its composition confirmed by mass spectrometry. There were no impurities present within the detectable limits of the instrumentation. EG was administered via drinking water solutions which were prepared weekly by the addition of EG to distilled water.
The solutions were
delivered in amber colored glass bottles with rubber stoppers and stainless steel sipper tubes with ball bearings to avoid loss of test material. The concentrations of solutions adminis-
tered to animals was confirmed and the stability of EG in the drinking water was verified. Vehicle controls received distilled water. Animals and Maintenance The test animals were male and female Sprague-Dawley (SD) rats from Charles River Laboratories, Inc. (Portage, MI).
The
rats were 85 days old when started on study. The average body weight was 350 grams for the males and 245 grams for the females.
4a
ROBINSON ET AL.
After a week quarantine the rats were randomized and housed, two per cage, in plastic cages with hardwood bedding (Ab-SorbDri, Inc., Maywood, NJ) in an animal room maintained at 21-24'C and 40-60% relative humidity with 12 hour light-dark cycles.
Downloaded by [Australian National University] at 06:28 07 November 2015
Rodent Chow No. 5001 (Ralston Purina Co., St. Louis, MO) and treatment solutions were available
libitum.
There were 10 animals per sex for each dose level. In the 10 day study animals drank either a 0.5, 1.0, 2.0, or 4 . 0 % EG solution.
The same dose levels were used for females in the
90-day study but lesser concentrations of 0.25, 0.5, 1.0, and 2.0% were administered to the males because of the severe body weight loss in the high dose group in the 10-day study (average loss of 45g per animal, while controls gained an average of 9g).
Controls in both studies received distilled water. Water
bottles were changed on Monday, Wednesday and Friday of each week and consumption was measured at each change. Total doses for both studies are shown in Table 1. Animals were weighed on the first day of dosing and weekly, thereafter.
Rats were
observed twice daily for clinical signs of changes in health. Necrovsv. Hematolow and Clinical Chemistry Complete postmortem examinations were completed on all animals unless they were severely autolyzed.
Terminal body
weights and organ weights (heart, kidney, liver, lung, spleen,
10 N.T.‘
9
2
527921251 205+ 407+ 947+ 212 31342 440
N.T.
10
10
10
10
8
N.T
4.00
90 Day 0.25
0.50
1.00
2.00
4.00
10
63
(139)
(103)
(108)
N.T.
(165)
(133)
(136)
(143)
5744 (3699-7789) (130)
3 0 8 7 ~676
1145+ 153
597+
29532 265
15062 201
x Theor. Dose
-
aValues are mean It Standard Deviation, except for high dose females in the 90 day study (range is given). Consumption data for early death animals are excluded from not tested these values. NT bNumbers in parenthesis show X of theoretical projected dose by assuming 100 ml/kg/day fluid consumption.
34 10
N.T.
10
26152 231
10
2.00
20
732721500
10
13432 190
10
1.00
794+ 123
10
6492 49
Female
10
N
10 day 0.50
Projected Dose
Male
N
Concentration ( X )
Xb
Table 1 Average Consumption of Ethylene Glycol (ng/kg/day) for SD Rats in 10 and 90 Day Studies”
Downloaded by [Australian National University] at 06:28 07 November 2015
z
r m
T
0
4 4
H
n
H
X
50
ROBINSON ET AL.
brain, gonads and thymus) were measured at necropsy.
Tissues
were fixed in 10% neutral buffered formalin and later trimmed, processed, embedded in paraffin, sectioned and stained with hematoxylin and eosin. The following tissues were examined for
Downloaded by [Australian National University] at 06:28 07 November 2015
histological changes from all animals in the control group (10 day study), five animals from control group (90 day study) and all animals in highest dose group having at least 60% of the animals surviving until terminal sacrifice: skin, mandibular and mesenteric lymph nodes, mammary glands, thigh muscle, sciatic nerve, femur and bone marrow, thymus, trachea, lungs, duodenum, jejunum, salivary gland, ileum, colon, cecum, rectum, liver, pancreas, spleen, kidneys, adrenals, urinary bladder, seminal vesicles, prostate, testes, epididymides, ovaries, uterus, nasal cavity and nasal turbinates, brain, pituitary, preputial and clitoral glands, Zymbal’s gland and any gross lesions. The target organ and any gross lesions were examined histologically from all remaining animals that survived until the terminal sacrifice.
Lungs and any gross lesions were
examined from all animals that died prior to the terminal sacrifice. Blood samples were taken via cardiac puncture from all animals for hematology and serum chemistries
at
sacrifice.
Hemoglobin, hematocrit, erythrocytes and leukocyte measurements were made with a Model ZBI Coulter Counter (Coulter Electronics, Inc., Hialeah, Fla.).
Differential counts were evaluated by
TOXICITY OF ETHYLENE GLYCOL IN DRINKING WATER the Wright-Giemsa staining procedure.
51
All serum chemistries
were measured using an Encore Chemistry System (Baker Instruments, Allentown, PA).
Parameters measured were AST, ALT, LDH,
Downloaded by [Australian National University] at 06:28 07 November 2015
cholesterol, phosphorus, calcium, glucose, BUN and creatinine. Statistical analysis. In both
the subacute and subchronic studies, Tukey's
multiple comparison procedure was used for body weights, organ weights and organbody weight ratio data2'.
Kruskal-Wallis
Rank Sum was used for the clinical chemistry and hematology data2'.
Overall analyses were done by one factor analysis of
variance. Values which differed from the vehicle control group at p cO.05 were considered significant. Statistical evaluation of the 'incidence of renal histopathological lesions was performed using Fisher's Exact Test. The significance of the severity of the lesions was determined by Pearson's Correlation Coefficient and Correlation Analysis.
RESULTS
10-DAY TOXICITY STUDY Fluid/EG consumDtion There was a general trend of partiality to EG throughout all groups in both males and females. The concentrations administered ( 0 . 5 , 1.0, 2.0 and 4.0%)were selected to give theoretical
52
ROBINSON ET AL.
doses of 554, 1108, 2216, and 4432 mg/kg/day, respectively, or 10, 20, 40 and 80 mM/kg/day, based on projected water consumption of 100 ml/kg/day.
The rate of consumption was higher than
anticipated and the actual doses ranged from 117% (0.5% group)
Downloaded by [Australian National University] at 06:28 07 November 2015
to 121% (1.0% group) of theoretical dose in the males and from 133% (2.0% group) to 165% (4.0% group) in the females (Table 1). Final Body and Oraan Weivhts The only significant effect that EG had on body weight was in the high dose male group animals which lost an average of 45 grams (p
ISSN: 0148-0545 (Print) 1525-6014 (Online) Journal homepage: http://www.tandfonline.com/loi/idct20
Subacute and Subchronic Toxicity of Ethylene Glycol Administered in Drinking Water to SpragueDawley Rats Merrel Robinson, Cynthia L. Pond, R. Dana Laurie, J. Peter Bercz, Gerry Henningsen & Lyman W. Condie To cite this article: Merrel Robinson, Cynthia L. Pond, R. Dana Laurie, J. Peter Bercz, Gerry Henningsen & Lyman W. Condie (1990) Subacute and Subchronic Toxicity of Ethylene Glycol Administered in Drinking Water to Sprague-Dawley Rats, Drug and Chemical Toxicology, 13:1, 43-70, DOI: 10.3109/01480549009011069 To link to this article: http://dx.doi.org/10.3109/01480549009011069
Published online: 27 Sep 2008.
Submit your article to this journal
Article views: 22
View related articles
Citing articles: 2 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=idct20 Download by: [Australian National University]
Date: 07 November 2015, At: 06:28
DRUG AND CHEMICAL TOXICOLOGYy 13(1), 4 3 - 7 0 (1990)
Downloaded by [Australian National University] at 06:28 07 November 2015
SUBACUTE AND SUBCHRONIC TOXICITY OF ETHYLENE GLYCOL ADMINISTERED IN DRINKING WATER TO SPRAGUE-DAWLEY RATS
'
Merrel Robinsona, Cynthia L. Pondb, R. Dana Lauriec,
J . Peter Bercza, Gerry Henningsend , and Lyman W. Condiee
aEnvironmental Toxicology Division Health Effects Research Laboratory U.S. Environmental Protection Agency 26 West Martin Luther King Jr. Drive Cincinnati, Ohio 45268 bPathology Associates, Inc. 6217 Center Park Drive West Chester, Ohio 4 5 0 6 9 'Procter
and Gamble, Inc.
1 1 5 2 0 Reed Hartman Highway Cincinnati, Ohio 4 5 2 4 1
dToxic Hazards Division Air Force Aerospace Medical Research Laboratory Wright-Patterson AFB, Ohio 4 5 4 3 3 eU.S. Army Dugway Proving Ground Dugway, Utah 84022
Corresponding Author: Merrel Robinson Environmental Toxicology Division Health Effects Research Laboratory U.S. Environmental Protection Agency 26 West Martin Luther King Jr. Drive Cincinnati, Ohio 45268 43 Copyright 0 1990 by Marcel Dekker, Inc.
ROBINSON ET AL.
44 ABSTRACT
Subacute (10-day) and subchronic (90-day) toxicity studies of ethylene glycol (EG) were conducted in male and female
Downloaded by [Australian National University] at 06:28 07 November 2015
Sprague-Dawley rats to provide the U.S.
Environmental Protec-
tion Agency's (EPA) Office of Drinking Water with toxicity data for final preparation of a Health Advisory for the chemical. Ethylene glycol was administered in drinking water at concentrations of 0 . 5 , 1.0, 2.0, and 4 . 0 % for both sexes in the 10-day study. Based on a projected consumption rate of 100 ml/kg/day, the respective doses on a mg/kg/day basis would be 5 5 4 , 1108, 2 2 1 6 , and 4 4 3 2 .
These dose levels were also used in the 90-day
study for females, but dose levels for the males in the 90-day study were 0 . 2 5 , 0 . 5 , 1.0, and 2.0% ( 2 2 7 , 5 5 4 , 1108, and 2216 mg/kg/day).
At time of sacrifice necropsies were performed and
tissues were prepared for histological evaluation.
Blood sam-
ples were taken for hematology and clinical chemistry determinations.
Body weights were measured weekly.
consumption were determined three times weekly. occurred in the 10-day study.
Water and food No mortality
In the 90-day study 8/10 females
and 2/10 males in the high dose group died prior to sacrifice. Body weights were suppressed in a dose response fashion for males and females.
Hemoglobin, hematocrit, erythrocytes, and
leukocytes were all significantly decreased in female rats receiving 4% EG for 10 days.
The most significant histo-
45
TOXICITY OF ETHYLENE GLYCOL IN DRINKING WATER
pathological findings, seen predominantly in males, were kidney lesions which included calcium oxalate crystals in tubules and pelvic epithelium; tubular dilation and degeneration; intratubular proteinaceous material; and inflammation in tubules and
Downloaded by [Australian National University] at 06:28 07 November 2015
pelvic epithelium.
At the same dose of ethylene glycol, males
had more kidney lesions and much higher incidence and severity of lesions than the females.
INTRODUCTION Ethylene glycol (EG) is an important industrial chemical with many commercial applications. In 1983, 4.5 billion pounds of EG were produced in the United States1.
It is used as an
antifreeze in cooling and heating systems, a solvent in paint and plastic
industries, an industrial humectant, hydraulic
fluid, and an ingredient o f electrolytic condensers.
EPA is
currently attempting to assess the risk to human health posed by environmental contamination of EG.
Releases of the chemical
to the environment can occur during production, commercial use and disposal or accidental spills. While release to the atmosphere and persistence in surface water is minimal because of its low vapor pressure and its rapid biodegradation, contamination o f ground water is possible'.
.
Laug et al., presented an in-depth discussion of earlier toxicological investigations of EG
and reported oral LD50
ROBINSON ET AL.
46
values of 6100 mg/kg in the rat and 14,528 mg/kg in the mouse? Smyth et al., reported an oral ID50 of 8540 mg/kg in the rat4. Toxicity resulting from chronic exposure to EG in the diet of rats and mice has been reported by various investigators5* 6 *
Downloaded by [Australian National University] at 06:28 07 November 2015
71
8 * 9 * lo.
mented"*
The toxicity of EG to humans has been docu-
12* 13* l4
EG
was
reported by
d.,
Clark
to demonstrate no significant mutagenic activity in the Ames test15.
However, Bose and Naskar"
d., 17
and Alam &
reported EG to be a mutagen in cluster beans and wheat respectively.
Mutagenic activity in mammalian cells has also been
reported18, 19.
Price et al., reported teratogenic effects in
mice and rats that received from 0.75 to 5.0 g/kg/day
EG2'.
Lamb et al., reported reproductive effects of reduced litter size and skeletal anomalies in mice given 1.0% EG in drinking water in a protocol involving continuous breeding21.
DePass
et al., found EG to be without effect in three-generation reproduction and dominant lethal mutagenesis studies wherein rats received 1.0, 0 . 2 ,
and 0.04 g/kg/day22.
The mechanisms of
toxicity have been investigated exten~ively'~, 23*
241
25*
Gessner et al., found that EG is converted to glycolaldehyde, glycolic acid and glyoxylic acid prior to its ultimate elimination as respiratory C02 (primarily) or urinary oxalate (secondarily)26.
Bove confirmed these findings23.
The present studies were performed to assess the subacute and subchronic toxicity of EG in rats when administered via
TOXICITY OF ETHYLENE GLYCOL IN DRINKING WATER
47
drinking water in order to finalize a health advisory for the chemical. METHODS
Downloaded by [Australian National University] at 06:28 07 November 2015
Ethvlene Glvcol Ethylene glycol (Lot: 2-852019) was obtained from Fisher Scientific, (Cincinnati, OH).
The chemical was analyzed for
purity using gas chromatography and its composition confirmed by mass spectrometry. There were no impurities present within the detectable limits of the instrumentation. EG was administered via drinking water solutions which were prepared weekly by the addition of EG to distilled water.
The solutions were
delivered in amber colored glass bottles with rubber stoppers and stainless steel sipper tubes with ball bearings to avoid loss of test material. The concentrations of solutions adminis-
tered to animals was confirmed and the stability of EG in the drinking water was verified. Vehicle controls received distilled water. Animals and Maintenance The test animals were male and female Sprague-Dawley (SD) rats from Charles River Laboratories, Inc. (Portage, MI).
The
rats were 85 days old when started on study. The average body weight was 350 grams for the males and 245 grams for the females.
4a
ROBINSON ET AL.
After a week quarantine the rats were randomized and housed, two per cage, in plastic cages with hardwood bedding (Ab-SorbDri, Inc., Maywood, NJ) in an animal room maintained at 21-24'C and 40-60% relative humidity with 12 hour light-dark cycles.
Downloaded by [Australian National University] at 06:28 07 November 2015
Rodent Chow No. 5001 (Ralston Purina Co., St. Louis, MO) and treatment solutions were available
libitum.
There were 10 animals per sex for each dose level. In the 10 day study animals drank either a 0.5, 1.0, 2.0, or 4 . 0 % EG solution.
The same dose levels were used for females in the
90-day study but lesser concentrations of 0.25, 0.5, 1.0, and 2.0% were administered to the males because of the severe body weight loss in the high dose group in the 10-day study (average loss of 45g per animal, while controls gained an average of 9g).
Controls in both studies received distilled water. Water
bottles were changed on Monday, Wednesday and Friday of each week and consumption was measured at each change. Total doses for both studies are shown in Table 1. Animals were weighed on the first day of dosing and weekly, thereafter.
Rats were
observed twice daily for clinical signs of changes in health. Necrovsv. Hematolow and Clinical Chemistry Complete postmortem examinations were completed on all animals unless they were severely autolyzed.
Terminal body
weights and organ weights (heart, kidney, liver, lung, spleen,
10 N.T.‘
9
2
527921251 205+ 407+ 947+ 212 31342 440
N.T.
10
10
10
10
8
N.T
4.00
90 Day 0.25
0.50
1.00
2.00
4.00
10
63
(139)
(103)
(108)
N.T.
(165)
(133)
(136)
(143)
5744 (3699-7789) (130)
3 0 8 7 ~676
1145+ 153
597+
29532 265
15062 201
x Theor. Dose
-
aValues are mean It Standard Deviation, except for high dose females in the 90 day study (range is given). Consumption data for early death animals are excluded from not tested these values. NT bNumbers in parenthesis show X of theoretical projected dose by assuming 100 ml/kg/day fluid consumption.
34 10
N.T.
10
26152 231
10
2.00
20
732721500
10
13432 190
10
1.00
794+ 123
10
6492 49
Female
10
N
10 day 0.50
Projected Dose
Male
N
Concentration ( X )
Xb
Table 1 Average Consumption of Ethylene Glycol (ng/kg/day) for SD Rats in 10 and 90 Day Studies”
Downloaded by [Australian National University] at 06:28 07 November 2015
z
r m
T
0
4 4
H
n
H
X
50
ROBINSON ET AL.
brain, gonads and thymus) were measured at necropsy.
Tissues
were fixed in 10% neutral buffered formalin and later trimmed, processed, embedded in paraffin, sectioned and stained with hematoxylin and eosin. The following tissues were examined for
Downloaded by [Australian National University] at 06:28 07 November 2015
histological changes from all animals in the control group (10 day study), five animals from control group (90 day study) and all animals in highest dose group having at least 60% of the animals surviving until terminal sacrifice: skin, mandibular and mesenteric lymph nodes, mammary glands, thigh muscle, sciatic nerve, femur and bone marrow, thymus, trachea, lungs, duodenum, jejunum, salivary gland, ileum, colon, cecum, rectum, liver, pancreas, spleen, kidneys, adrenals, urinary bladder, seminal vesicles, prostate, testes, epididymides, ovaries, uterus, nasal cavity and nasal turbinates, brain, pituitary, preputial and clitoral glands, Zymbal’s gland and any gross lesions. The target organ and any gross lesions were examined histologically from all remaining animals that survived until the terminal sacrifice.
Lungs and any gross lesions were
examined from all animals that died prior to the terminal sacrifice. Blood samples were taken via cardiac puncture from all animals for hematology and serum chemistries
at
sacrifice.
Hemoglobin, hematocrit, erythrocytes and leukocyte measurements were made with a Model ZBI Coulter Counter (Coulter Electronics, Inc., Hialeah, Fla.).
Differential counts were evaluated by
TOXICITY OF ETHYLENE GLYCOL IN DRINKING WATER the Wright-Giemsa staining procedure.
51
All serum chemistries
were measured using an Encore Chemistry System (Baker Instruments, Allentown, PA).
Parameters measured were AST, ALT, LDH,
Downloaded by [Australian National University] at 06:28 07 November 2015
cholesterol, phosphorus, calcium, glucose, BUN and creatinine. Statistical analysis. In both
the subacute and subchronic studies, Tukey's
multiple comparison procedure was used for body weights, organ weights and organbody weight ratio data2'.
Kruskal-Wallis
Rank Sum was used for the clinical chemistry and hematology data2'.
Overall analyses were done by one factor analysis of
variance. Values which differed from the vehicle control group at p cO.05 were considered significant. Statistical evaluation of the 'incidence of renal histopathological lesions was performed using Fisher's Exact Test. The significance of the severity of the lesions was determined by Pearson's Correlation Coefficient and Correlation Analysis.
RESULTS
10-DAY TOXICITY STUDY Fluid/EG consumDtion There was a general trend of partiality to EG throughout all groups in both males and females. The concentrations administered ( 0 . 5 , 1.0, 2.0 and 4.0%)were selected to give theoretical
52
ROBINSON ET AL.
doses of 554, 1108, 2216, and 4432 mg/kg/day, respectively, or 10, 20, 40 and 80 mM/kg/day, based on projected water consumption of 100 ml/kg/day.
The rate of consumption was higher than
anticipated and the actual doses ranged from 117% (0.5% group)
Downloaded by [Australian National University] at 06:28 07 November 2015
to 121% (1.0% group) of theoretical dose in the males and from 133% (2.0% group) to 165% (4.0% group) in the females (Table 1). Final Body and Oraan Weivhts The only significant effect that EG had on body weight was in the high dose male group animals which lost an average of 45 grams (p
