INTERACTIVE EFFECTS OF ALCOHOL AND DIABETES - cIRcle

104 Pages·2008·2.45 MB·English

INTERACTIVE EFFECTS OF ALCOHOL AND DIABETES DURING
PREGNANCY ON THE RAT FETUS
By
Yi Lin
B. Sc. (Public Health) Tianjin Medical Institute, 1983
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF
THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE
in
THE FACULTY OF GRADUATE STUDIES
SCHOOL OF FAMILY AND NUTRITIONAL SCIENCES, DIVISION OF HUMAN NUTRITION
We accept this thesis as conforming
to the required standard
THE UNIVERSITY OF BRITISH COLUMBIA
August 1992
© Yi Lin, 1992
Inpresenting this thesisin partial fulfilment oftherequirements for an advanced degree at
the University of British Columbia, I agree that the Library shall make it freely available
for reference and study. I further agree that permission for extensive copying of this
thesis for scholarly purposes may be granted by the head of my department or by his
or her representatives. It is understood that copying or publication of this thesis for
financial gain shall not be allowed without my written permission.
Human Nutrition
The University of British Columbia
2075 Wesbrook Place
Vancouver, Canada
V6T 1Z1
Date:
7z
/
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Abstract
Substantialliterature indicates that maternal diabetes has teratogenic effects on the fetus
and that consumption of alcohol during gestation is also teratogenic to the fetus. In the
present study, Sprague-Dawley female rats were used to test whether small amounts of
alcohol administered during organogenesis has an effect on the outcome of pregnancy in
nondiabetic rats; to confirm the teratogenic effect of diabetes on fetuses; and to establish
whetherthereis an interactionbetween alcohol and diabetes on theoutcomeofpregnancy.
All rats were fed Purina rat chow and tap water ad libitum. Diabetes was induced by tail
vein administration of streptozotocin (60 mg/kg body weight) one week before mating.
Alcohol was administered during organogenesis (days 6-11 of gestation) intragastrically.
The incidence and types of external and skeletal malformations were recorded in the
fetuses of all treatment groups on day 21 of gestation. In addition, the fetal development
was followed by assessing the ossification of the skeleton on gestational day 21 with the
aid of alizarin red S and alcian blue 8GS staining.
The results of this investigation support the view of previous studies that maternal
diabetes is teratogenic to the offspring in terms of significantly increased malformation
rates, and retarded fetal development (smaller fetal weight, bigger placenta, and retarded
skeletal ossification compared to controls).
Consumption of a small amount of alcohol (2g/kg/day) during organogenesis (days
6-11 of gestation) did not seem to intoxicate the dams, the body weight gain was at
a normal rate, and there was a bigger fetal/placental ratio compared to controls. In
terms of skeletal development, alcohol exposure seemed to enhance bone development.
However, there were a few fetuses with absence of ossification centers in the hyoid bone
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and the short 13th rib which were significantly different from other treatment groups.
Whether this represents retarded skeletal development is not clear.
In the present study, a significant interaction between maternal diabetes and alcohol
administration during organogenesis was observed. The fetal external malformation rate
was significantly increased in diabetic rats exposed to alcohol compared to diabetic rats
not exposed to alcohol. Furthermore, more fetuses had poorly ossified thoracic vertebral
centers, poorly ossified cervical arches, and poorly ossified supraoccipital bone in diabetic
rats exposed to alcohol than in diabetic rats not exposed to alcohol. These observations
suggest that a small amount of alcohol consumption during organogenesis could possibly
exacerbate the embryotoxic effects of maternal diabetes.
111
Table of Contents
ii
Abstract
viii
List of Tables
x
List of Figures
xi
Acknowledgement
1
1 Introduction
1.1 Evidence that alcohol is teratogenic 1
1.1.1 Studies in humans 1
1.1.2 Studies in animals 5
1.2 Evidence that diabetes is teratogenic 11
11
1.2.1 Studies in humans
1.2.2 Studies in animals • . 13
1.2.3 The teratogenic period of diabetic pregnancy 14
1.2.4 The proposed mechanisms • • 15
1.3 Evidence for an interaction between alcohol and other factors • 17
1.4 Evidence for an interaction between alcohol and diabetes • . 20
1.5 Skeletal examination in experimental teratology studies 21
1.6 The purpose of the study 23
24
2 Methods
24
2.1 Preliminary experiments
iv
2.2 Experimental methods • 25
2.2.1 Chemicals and reagents • 25
2.2.2 Animals and diets • 25
2.2.3 Induction of diabetes 25
2.2.4 Breeding 26
2.2.5 Administration of alcohol 26
2.2.6 Blood alcohol assay 27
2.2.7 Body weight record 27
2.2.8 Blood glucose measurement 27
. .
2.2.9 Termination of gestation 28
2.2.10 Skeletal staining 28
2.2.11 Skeletal examination 29
2.2.12 Food record 31
2.2.13 Statistical analysis 32
34
3 Results
3.1 Calorie and water consumption 34
3.2 Reproductive performance 38
3.3 Body weight and weight gain of dams during pregnancy 39
3.4 Blood glucose concentrations 42
3.5 Peak blood alcohol levels 44
3.6 Outcome of pregnancy 44
3.7 Fetal weight, placental weight and fetal weight/placental weight ratio 45
3.8 External malformations 49
3.9 Skeletal malformations 52
3.10 Skeletal ossification and variants 54
V
3.10.1 Metacarpus, metatarsus 54
3.10.2 Sternum 56
3.10.3 Vertebrae 60
3.10.4 Skull 66
3.10.5 Other skeletal variants 69
3.10.6 Bone areas 69
4 Discussion 71
4.1 Calorie and water consumption 71
4.2 Reproductive performance 72
4.3 Weight gain 73
4.4 Outcome of pregnancy 74
4.5 Fetal and placental weights 76
4.6 Malformations 78
4.7 The proposed mechanisms for malformations 79
4.8 Skeletal ossification 82
4.8.1 Number of ossification centers 83
4.8.2 Skeletal variations 84
4.8.3 Ossification of the skull 86
4.8.4 Bone areas 87
4.9 The effect of alcohol consumption 89
4.10 Summary and conclusion 89
91
Appendices
A Photographs 91
B Chi-square tests, P values 102
vi
C Two way ANOVA statistical effects diabetes vs alcohol, P values 104
D Tests of Simple Effect, P values 106
Bibliography 108
vii
List of Tables
1.1 Principal Features of the Fetal Alcohol Syndrome Observed in 245 People
Affected 3
1.2 Associated Features ofthe Fetal Alcohol Syndrome Observed in 245 People
Affected 4
3.3 Average water and calorie intake per day during gestation in each treat
ment group (Mean ± SD) 35
3.4 Breeding and pregnancy rates of animals in each treatment group 38
. . .
3.5 Body weight and weight gain of dams during gestation in each treatment
group (mean + SD) 40
3.6 Blood glucose concentration of dams at different times during the experi
ment, in each treatment group (mmol/L) 44
3.7 Reproductive variables on day 21 of gestation in each treatment group. 45
3.8 Fetal and placental weights on day 21 ofgestation in each treatment group
(mean ± SD) 46
3.9 Numbers of fetuses with external malformations iii each treatment group 51
3.10 Numbers of fetuses with skeletal malformations in each treatment group 52
3.11 Development of ossification centers in metacarpus, metatarsus, and ster
num in each treatment group 55
3.12 Skeletal variants observed in fetuses of each treatment group 58
3.13 Mean numbers of poorly ossified centers in sternum, thoracic and lumbar
vertebrae in each group (mean ± SD) 59
vii’
3.14 Frequencies of fetuses according to the most cephalic and most caudal
vertebral ossification centers and the most caudal vertebral arches 61
. . .
3.15 Ossification centers and foramen in skull 67
3.16 Ossified tissue areas (2)mm measured in the selected bones (mean ± SD) 70
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