- Email: [email protected]
The rate of dominant lethals after low X-ray doses given to mouse spermatozoa
Mutation Research
Elsevier Publishing Company, Amsterdam Printed in The Netherlands
234
The rate of dominant lethals after low X-ray doses given to mouse spermatozoa In a previous study 2 we showed that the relation between the X-ray dose and the rate of dominant lethals induced by irradiation of mouse spermatozoa was linear for increasing doses from ioo to 15oo R. This work has now been completed for X-ray doses from io to ioo R. Male mice from the BALB/c strain, 11-13 weeks old, received whole-body irradiation with doses of IO, 20, 30, 40, 50, 60, 7 o, 80, 9 ° and IOO R of X-rays (300 kV, 20 mA, filtration through 2 mm Cu, dose rate IOO R/min). For X-irradiation, male mice were taped individually on to a Plexiglass plate. A group received the same treatment without X-irradiation. Immediately after treatment, each male was allowed to mate with 3 virgin females for a period of 7 days. The females were killed 17 days after the beginning of the mating, and the number of corpora lutea, and living and dead embryos were counted. From our previous experiments ~ it was concluded that X-ray doses from IOO to 60o R mainly increase the number of deaths after implantation, whereas above 70o R we observed an increase in the number of spermatozoa carrying more than one lethal together with a drop in the number of spermatozoa carrying only one lethal. Our present results (Tables I and II) similarly show that a low X-ray dose given to mouse spermatozoa mainly increases the rate of intrauterine deaths. Whereas the mean number of implantations is only slightly altered by X-ray doses from IO to IOO R, the number of dead embryos per female increases regularly from IO to IOO R. Fig. I gives the distribution of the females according to the number of dead embryos and the X-rays dose, and shows that the increase in the mean number of dead embryos is the result of an increase in the number of females with one or two dead embryos instead of a small increase in the number of females with many intrauterine deaths. After X-ray doses from IO to IOO R, the rate of dominant lethal mutations, calculated according to the method of EDWARDSAND SEARLE1 appears to be slightly higher than expected from previous experiments 5, since the regression coefficient was found to be b -~ 0.001498 instead of b = 0.001142 after X-ray doses from IOO to 15oo R (Fig. 2). TABLE
I
GENERAL RESULTS OF THE DISSECTIONS
X-ray dose (R)
Total females
Pregnant females
Corpora lutea
Implantations
Live embryos IO20
Dead embryos
O
152
125
I212
IIOI
IO 20
I53 152
IO9 I18
IO45 1124
956 lO38
868 936
8I
88 Io2
3°
153
116
1121
1OO 4
895
109
4° 50 60 7° 80 90 IOO
153 153 i52 153 153 I53 154
112 118 114 I23 1IO io 3 125
Io6o 1138 lO58 1214 lO59 977 I194
933 967 944 1o65 935 861 lO77
815 851 8o5 924 777 717 912
118 116 139 141 158 144 165
Mutation Res., 4 (I967) 234-236
SHORT COMMUNICATIONS TABLE
235
II
ANALYSIS
OF RE;SULTS IN TABLE
X-ray dose (R)
Pregnant females (%)
lrnplantations/~_
Live embryos/~
Dead embryos/~
Live embryos Corpora l~tea
o Io 2o 3° 4° 5° 6o 7° 80 9O ioo
82.2 71.2 77.6 75 .8 73 -2 77.~ 75.o 80"4 71.9 67.3 81.2
8.8 8.8 8.8 8.7 8.3 8.2 8. 3 8"7 8. 5 8"4 8.6
8.2 7.9 7.9 7.7 7.3 7.2 7. [ 7"5 7.1 7-O 7.3
0.65 0.8[ 0.80 0.94 1-o5 0.98 1.22 I. 15 1.44 L40 1.32
o.84~6 0.8306 o.8327 0.7984 0.7688 0.7478 o.76o8 O.761 I 0.7337 O.7338 0.7638
@;
J
10
II
J
R
60
R
70
R
o 4
o~
E
,
,
,
,
---., ~ ?
o
J
20
,0j\
I
R
O
o
j
%.N.
J
30 R
Y = 0.001498
I
C
80 R
.-
'
J
~¢
E
/
0.10
•
9o R
/
•
•
°//~////
O
0
50-~,
,
-.o~_.
i
40 R
•
2
I
/,
5
o
50-.'~
X
1'•2 ~O., ' \"-~. ,
J
,
,
50
O
"0~=~.__.
,~_ E
I
loo R
o
,
R "
50 -t,
./,*, 000,,, x
c
I
o.o 5
0
l', ,
I
2
3
4 >4 Dead
1
2 3 embryos
4>4
,
20
,
,
40
,
,
60 X-ray
,
,
,
80
,
100 dose
Fig. I. D i s t r i b u t i o n of f e m a l e s a c c o r d i n g to t h e n u m b e r of d e a d e m b r y o s a n d to t h e X - r a y dose. ...... , f e m a l e s m a t e d w i t h control m a l e s ; - - , f e m a l e s m a t e d w i t h i r r a d i a t e d males. Fig. 2. D o m i n a n t l e t h a l m u t a t i o n rate. , regression coefficient c a l c u l a t e d f r o m p r e s e n t results; , regression coefficient c a l c u l a t e d f r o m p r e v i o u s e x p e r i m e n t s ~.
Mutation Res., 4 (I967) 234-236
236
SHORT COMMUNICATIONS
This w o r k was done t h a n k s to the c o n t r a c t E u r a t o m / C . E . N . No. 059-65- 7 B I O B a n d to g r a n t s from t h e F o n d s de la Recherche Scientifique F o n d a m e n t a l e Collective.
Laboratory of Genetics, Department of Radiobiology, Centre for Nuclear Energy Research, Mol (Belgium)
A.L~ONARD GH. DEKNUDT
I EDWARDS, V~. G., AND A. G. SEARLE, Genetic radiosensitivity of specific post-dictyate stages in
mouse o6cytes, Genet. Res., 4 (1963) 348-36o.
2 LEONARD, A., Relation between the X-ray dose and the rate of dominant lethals induced by
irradiation of mouse spermatozoa, Mutation Res., 3 (1966) 73-78. R e c e i v e d O c t o b e r 26th, 1966 R e v i s e d m a n u s c r i p t received N o v e m b e r 2Ist, 1966
Mutation Res., 4 (I967) 234-236
Elsevier Publishing Company, Amsterdam Printed in The Netherlands
234
The rate of dominant lethals after low X-ray doses given to mouse spermatozoa In a previous study 2 we showed that the relation between the X-ray dose and the rate of dominant lethals induced by irradiation of mouse spermatozoa was linear for increasing doses from ioo to 15oo R. This work has now been completed for X-ray doses from io to ioo R. Male mice from the BALB/c strain, 11-13 weeks old, received whole-body irradiation with doses of IO, 20, 30, 40, 50, 60, 7 o, 80, 9 ° and IOO R of X-rays (300 kV, 20 mA, filtration through 2 mm Cu, dose rate IOO R/min). For X-irradiation, male mice were taped individually on to a Plexiglass plate. A group received the same treatment without X-irradiation. Immediately after treatment, each male was allowed to mate with 3 virgin females for a period of 7 days. The females were killed 17 days after the beginning of the mating, and the number of corpora lutea, and living and dead embryos were counted. From our previous experiments ~ it was concluded that X-ray doses from IOO to 60o R mainly increase the number of deaths after implantation, whereas above 70o R we observed an increase in the number of spermatozoa carrying more than one lethal together with a drop in the number of spermatozoa carrying only one lethal. Our present results (Tables I and II) similarly show that a low X-ray dose given to mouse spermatozoa mainly increases the rate of intrauterine deaths. Whereas the mean number of implantations is only slightly altered by X-ray doses from IO to IOO R, the number of dead embryos per female increases regularly from IO to IOO R. Fig. I gives the distribution of the females according to the number of dead embryos and the X-rays dose, and shows that the increase in the mean number of dead embryos is the result of an increase in the number of females with one or two dead embryos instead of a small increase in the number of females with many intrauterine deaths. After X-ray doses from IO to IOO R, the rate of dominant lethal mutations, calculated according to the method of EDWARDSAND SEARLE1 appears to be slightly higher than expected from previous experiments 5, since the regression coefficient was found to be b -~ 0.001498 instead of b = 0.001142 after X-ray doses from IOO to 15oo R (Fig. 2). TABLE
I
GENERAL RESULTS OF THE DISSECTIONS
X-ray dose (R)
Total females
Pregnant females
Corpora lutea
Implantations
Live embryos IO20
Dead embryos
O
152
125
I212
IIOI
IO 20
I53 152
IO9 I18
IO45 1124
956 lO38
868 936
8I
88 Io2
3°
153
116
1121
1OO 4
895
109
4° 50 60 7° 80 90 IOO
153 153 i52 153 153 I53 154
112 118 114 I23 1IO io 3 125
Io6o 1138 lO58 1214 lO59 977 I194
933 967 944 1o65 935 861 lO77
815 851 8o5 924 777 717 912
118 116 139 141 158 144 165
Mutation Res., 4 (I967) 234-236
SHORT COMMUNICATIONS TABLE
235
II
ANALYSIS
OF RE;SULTS IN TABLE
X-ray dose (R)
Pregnant females (%)
lrnplantations/~_
Live embryos/~
Dead embryos/~
Live embryos Corpora l~tea
o Io 2o 3° 4° 5° 6o 7° 80 9O ioo
82.2 71.2 77.6 75 .8 73 -2 77.~ 75.o 80"4 71.9 67.3 81.2
8.8 8.8 8.8 8.7 8.3 8.2 8. 3 8"7 8. 5 8"4 8.6
8.2 7.9 7.9 7.7 7.3 7.2 7. [ 7"5 7.1 7-O 7.3
0.65 0.8[ 0.80 0.94 1-o5 0.98 1.22 I. 15 1.44 L40 1.32
o.84~6 0.8306 o.8327 0.7984 0.7688 0.7478 o.76o8 O.761 I 0.7337 O.7338 0.7638
@;
J
10
II
J
R
60
R
70
R
o 4
o~
E
,
,
,
,
---., ~ ?
o
J
20
,0j\
I
R
O
o
j
%.N.
J
30 R
Y = 0.001498
I
C
80 R
.-
'
J
~¢
E
/
0.10
•
9o R
/
•
•
°//~////
O
0
50-~,
,
-.o~_.
i
40 R
•
2
I
/,
5
o
50-.'~
X
1'•2 ~O., ' \"-~. ,
J
,
,
50
O
"0~=~.__.
,~_ E
I
loo R
o
,
R "
50 -t,
./,*, 000,,, x
c
I
o.o 5
0
l', ,
I
2
3
4 >4 Dead
1
2 3 embryos
4>4
,
20
,
,
40
,
,
60 X-ray
,
,
,
80
,
100 dose
Fig. I. D i s t r i b u t i o n of f e m a l e s a c c o r d i n g to t h e n u m b e r of d e a d e m b r y o s a n d to t h e X - r a y dose. ...... , f e m a l e s m a t e d w i t h control m a l e s ; - - , f e m a l e s m a t e d w i t h i r r a d i a t e d males. Fig. 2. D o m i n a n t l e t h a l m u t a t i o n rate. , regression coefficient c a l c u l a t e d f r o m p r e s e n t results; , regression coefficient c a l c u l a t e d f r o m p r e v i o u s e x p e r i m e n t s ~.
Mutation Res., 4 (I967) 234-236
236
SHORT COMMUNICATIONS
This w o r k was done t h a n k s to the c o n t r a c t E u r a t o m / C . E . N . No. 059-65- 7 B I O B a n d to g r a n t s from t h e F o n d s de la Recherche Scientifique F o n d a m e n t a l e Collective.
Laboratory of Genetics, Department of Radiobiology, Centre for Nuclear Energy Research, Mol (Belgium)
A.L~ONARD GH. DEKNUDT
I EDWARDS, V~. G., AND A. G. SEARLE, Genetic radiosensitivity of specific post-dictyate stages in
mouse o6cytes, Genet. Res., 4 (1963) 348-36o.
2 LEONARD, A., Relation between the X-ray dose and the rate of dominant lethals induced by
irradiation of mouse spermatozoa, Mutation Res., 3 (1966) 73-78. R e c e i v e d O c t o b e r 26th, 1966 R e v i s e d m a n u s c r i p t received N o v e m b e r 2Ist, 1966
Mutation Res., 4 (I967) 234-236