(50
o—o 5000r
140
x
x 7200r
130
yo
Lt
O
10
20
Log
|
DAY 30
x
‘
30 40 50 60 70 80120 130 !40 150 I60 170
DAYS POSTIRRADIATION
Fig. 92.—A plot of the thickness of the proximal tibial epiphyseal cartilages of strain H C57 mice vs. time after partial
whole-body irradiation with 5000 and 7200 Rads. Irradiation
initially produced thinner cartilages after 3 to 5 days followed
by partial
recovery on
the
ninth
a000- or 7200-Rad surface doses on strain HW
were substantially different from those on H «1
mice (Figures 91-93). First, the time requiredt
rowthe cartilage plates after irradiation was pro
(9 days—7200 Rads; 14 days—as000 Rads). Seco
recovery time following 7200 Rads was almost
that observed after 5000 Rads, The graph (Figcu
also suggests that strain HWcartilages attemp
recover 7-8 days after irradiation, but that tlu
aborted. After partial recovery, it was impossi
distinguish one strain from the other on the bh:
GxmA
6 396
oo
oO Oo
CARTILAGE PLATE THICKNESS (,}
iGO
day. Less recovery was
achieved following 7200 Rads than after 5000 Racls.
190¢
1I8OH
o——e 50006r
170
x
x 7200r
cartilage plate thickness. Recovery in strain HW
as noted above, was more dependent upon the mm
ization of ossification patterns than on the abil
the cell populations in the eartilage to proli:
There was a general decrease in cartilage plate
ness in all mice after 60 days. which may havi
due to age changes.
Irregular endochondral ossification occurred
result of both 5000 and 7200 Rads irradiation, an
was due, in part, to the development of fibrillar n
and numerous foci of degenerate and probabl:
permineralized plugs of matrix in the growth
+ 160H
0
96
Ba
a
Oo
yp
Oo
|
°
oO
CARTILAGE PLATE THICKNES
fee]
90
BO
TO}
0
|| |
|
oo
| yt
{| |
19 20 30 40 50 60 70 80°'120 130 140 [50 160 I70
DAYS POSTIRRADIATION
Fic. 93.—A plot of the thickness of the proximal tibial epi-
physeal cartilages of strain HB C57 mice vs. time after partial
whole-body irradiation with 5000 and 7200 Rads. While the
thinning of the cartilages following 7200 Rads was more severe
than after 5000 Rads (after 5 davs), partial recovery had occurred in both groups bythe ninth day.
lages during the first days following irradiation with
5000 Rads or 7200 Rads. The sharp decrease in plate
thickness observed in strains H and HB during this
time, 3-5 days postirradiation, fairly well correlated
with histologic signs of chondroclastic activity in the
metaphysis. Table 55 summarizes the essentijal information from the graphs (Figures 91-93). In these
strains, recovery, measured by increased plate thick-
ness, began 6 days after irradiation and was completed
by the ninth day at both dose levels. The effects of
aps %,
Fic. 94—A photomicrograph of the proximal tibial
cartilage of an HWstrain C57 mouse 2 days after partial «
body irradiation with 5000 Rads. The cartilage plate degenerate plugs of acellular matrix 2nd unresorbed islan
chondrocytes in the metaphysis, which suggest impaired
esses of endochondral ossification. Hematoxylin and
250 X.