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Development of the glycogen body through the whole length of the chick spinal cord.

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T H E ANATOMICAL RECORD 202:511-519 (1982)
Development of the Glycogen Body Through the Whole
Length of the Chick Spinal Cord
MASAI'O U K H A I t A A ~ I ) ' I ' O S I I I H I K O
UI.:SHIMA
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ABSTRACT
The development of the glycogen body was studied throughout
the entire length of the chick spinal cord. The glycogen body cells first appeared a t
stage 31 on each side of the ependymal septum from the 26th to 28th segments of
the spinal cord. By stage 34 the paired primordia of the glycogen body extended
from the 25th to 29th segments. In the middle of the structure described classically as the glycogen body (i.e., the portion restricted to the level of the spinal nerves
26-29), these primordia were fused dorsally at stage 34 and had fused completely
by stage 37. The paired primordia extended from the cervical enlargement to the
lumbosacral portion of the spinal cord by stage 36 and extended to the upper
cervical segments by stage 38. They were totally fused throughout the entire
length of the spinal cord by stage 42. The glycogen containing cells, in the classical
glycogen body level, appeared ventrolateral to the central canal a t stage 35. Thereafter they increased in number and glycogen content, and extended rostrad and
caudad from the classical glycogen body level. They fused to each other and then
fused with the glycogen body. Therefore, the bilateral clusters of the glycogencontaining cells are considered a s the ventral paired primordia of the glycogen
body. The development of the glycogen body is essentially the same pattern as in
the classical glycogen body throughout the entire length of the spinal cord.
The avian spinal cord, in contrast to that of
other vertebrates, is characterized by the presence of the glycogen body, a mass containing
glycogen filled cells. In the chicken the glycogen body was originally defined as a structure
restricted to the level of spinal nerves 26-29.
The central canal of the spinal cord extends
through the substance of the glycogen body,
and the right and left sides of the spinal cord
are connected only by means of the ventral
commissure (Watterson, 1949). Recently,
Sansone (1977) and Uehara and Ueshima
(1981) have shown that the glycogen body is
not restricted to the level of the spinal nerves
26-29, but also extends rostrally and caudally
through all of the spinal segments. Most investigations on the development of the glycogen
body have been concerned with only the portion of the structure located a t the level of the
lumbosacral cord (Watterson, 1949, 1952,
1954; Watterson and Spiroff, 1949; Doyle and
Watterson, 1949; Watterson et al., 1958; De
Gennaro, 1959; Matulionis, 1972). According
to Watterson (1952)the glycogen body first ap-
pears as distinct paired primordia in 7 % day
chick embryos. These primordia lie on each
side of the ependymal septum, formed by the
roof plate of the spinal cord, and fuse progressively in the dorsoventral direction. But the
origin of the glycogen body cells in the ventral
portion of the central canal is unknown. The
development of the glycogen body, except for
the classically defined structure, has been
briefly reported histologically (Mori, 1934;
Bosch et al., 1968).The purpose of this investigation was to study the development of the
chick glycogen body in the whole length of the
spinal cord.
0003-276X/82/2024-0511$03.00 E 1982 ALAN R. LISS, INC.
MA'I'EKIALS A N D MI~XYIODS
White Leghorn eggs were incubated in a
forced draft incubator a t 38°C and constant
relatively humidity. Embryos were obtained
on each stage (except stage 33) from stage 30
to 46 (from 6V2 to 21 days of incubation, Ham-
512
M. UEHARA AND T. UESHIMA
burger and Hamilton, 1951). After the eggs
were opened, the spinal cords, or the vertebral
columns with the spinal cords, were removed
from the embryos and immersed in either l0Y0
formalin-alcohol or absolute alcohol, and
embedded in celloidin. Thirty micrometer
thick sections were cut transversely or frontally and stained with hematoxylin-eosin (H-E)or
periodic acid-Schiff (PAS).
K E S u I’TS
Stages 31 to 32 (ca. 7-7% days)
Using the PAS stain, the cells of the glycogen body appeared first a t stage 31. A small
number of glycogen body cells were identified
on each side of the ependymal septum, which
consisted of elongated ventricular cells of the
spinal cord’s roof plate. The glycogen body
cells within each primordium were spindle
shaped and radially arranged. The paired primordia extended from the 26th to 28th spinal
cord segments. These segments corresponded
with the location of the classical glycogen body
in the adult chicken. The glycogen body cells
increased in number a t stage 32, concentrating
in the dorsal area of the roof plate. Accordingly, each primordium had a broad base
against the external limiting membrane and
tapered almost t o a point a t the central canal
(Fig. 1).The nuclei of the ventricular cells were
corwded towards the external limiting membrane (Fig. 2). In the floor plate an accumulation of glycogen was found on the median line
(Fig. 1).
Stage 34 (ca. 8 days)
By stage 34 the glycogen body extended
from the 25th to 29th segments. The glycogen
body cells, in the middle of the classical glycogen body level, had increased in nmber and became polygonal in shape. Each primordium of
the glycogen body was wedge shaped and no
longer contained PAS negative cells. The ventricular cells of the roof plate decreased in number, their nuclei had shifted away from the external limiting membrane, and the paired
primordia had begun to fuse in the dorsal portions (Fig. 3). The glycogen body cells progressively decreased in number from the middle of
the classical glycogen body level rostrad and
caud ad.
Stage ,?5 (ca. 8-9 days)
The rostrocaudal extent of the glycogen
body was the same as for the previous stage. In
the middle of the classical glycogen body level
the glycogen body cells increased in number.
The fusion of the paired primordia spread in a
dorsoventral direction and the ventral portions
of the primordia were slightly divided from one
another (Fig. 4). This fusion spread somewhat
rostrad and caudad from the middle of the classical glycogen body level. In the latter other
glycogen containing cells appeared in the ventrolateral portions of the central canal (Fig. 5).
Stage 36 (ca. 10 days)
The rostrocaudal extent of the glycogen
body was extremely stretched out from the
cervical enlargement to the caudal lumbosacral cord. In the cervical enlargement a few
glycogen body cells were detectable on each
side of the dorsal median and ependymal septum. These glycogen body cells stained pale,
ill-defined pink with the use of the PAS stain.
In the thoracic segments the distribution of
the glycogen body cells was similar to that of
the cervical enlargement but these contained
little glycogen, if any. In the middle of the classical glycogen body level, the glycogen body
expanded more dorsally and laterally than a t
the previous stage. Its dorsal surface had projected beyond the dorsal funiculi. The specimens stained with the PAS gave no indication
that the glycogen body arose from the paired
primordia (Fig. 6). But the specimens stained
with H-E indicated that a few elongated ventricular cells partially separated the ventral
portion of the formed glycogen body into right
and left halves (Figs. 7, 8).At the lumbosacral
segments, except a t the classical glycogen
body level, the glycogen body cells were identifiable as paired groups in the roof plate. A few
glycogen body cells were present in the caudal
lumbosacral segments. The number of glycogen-containing cells lying in the ventrolateral
portions of the central canal increased considerably in the classical glycogen body level
(Fig. 6).
Stage 37 (ca. 11 days)
The glycogen body cells appeared bilaterally
in the middle cervical segments. They were recognizable as paired groups on each side of the
ependymal septum by faint coloration with
PAS stain, but were not extended in the dorsal
median septum. In the cervical enlargement
the glycogen body cells were moderately glycogen positive (Fig. 9). In the classical glycogen
body level, the number of the glycogen body
cells increased faster than in the preceding
stage and the elongated ventricular cells of the
roof plate disappeared completely so the primordia had totally fused. In the lower lumbo-
513
DEVELOPMENT OF GLYCOGEN BODY
sacral segments the paired primordia were still
evident (Fig. 10).
Stages 38 and 39 (ca. 12 and 13 days)
The glycogen body cells were found along
t h e spinal cord from the rostral cervical to
caudal lumbosacral segments. In the cervical
segments the glycogen body cells were found
bilaterally on each side of the ependymal septum but were weak in glycogen reactivity (Fig.
11).In the cervical enlargement the glycogen
body cells extended bilaterally from the dorsolateral portion of the central canal to the dorsal
surface of the cord. The classical glycogen
body was larger than in the preceding stage.
The glycogen-containing cells lying in the ventrolateral portions of the central canal extended through the lumbosacral segments. The migration of the neuroglial cells into the ventral
commissure began in stage 38, later than the
other cord regions (Fig. 12). In the lower coccygeal segments only a few glycogen containing cells were found (Fig. 13).
Stages 40 and 41 (ca. 14 and 15 days)
The rostrocaudal extent of the glycogen
body was similar to that of the preceding
stage. The most evident event of these stages
was the onset of fusion of the paired primordia
a t level rostral and caudal to the classically defined glycogen body. In addition, the number
of ventricular cells in the roof plate decreased
markedly. The glycogen body cells in the cervico-thoracic segments increased in number and
in glycogen content (Fig. 14). In the classical
glycogen body level many glycogen-containing
cells were located in the lateral and ventral portions of the central canal (Fig.15).The accumulation of glycogen in the median line of the
floor plate almost disappeared in stage 41 (Fig.
15). In the rostral coccygeal segments the glycogen-containing cells were few, while in the
lower ones they increased in number and glycogen content throughout the entire areas.
Stage 42 or more (ca. 16 days or more)
The fusion of the paired primordia went on
as in previous stages. In the classical glycogen
body level the glycogen-containing cells lying
lateral and ventral to the central canal had
fused completely with the glycogen body. Accordingly, the central canal is ensheathed by
the glycogen body (Fig. 16). In the rostral
coccygeal segments a few glycogen-containing
cells appeared, whereas in the lower ones they
increased over the previous stage (Fig. 17). In
the cervical enlargement and the thoracic seg-
ments a few glycogen-containing cells appeared in the ventrolateral portions of the central
canal (Fig. 18).
D I SC U SSI 0 N
This is the first description of the development of the chick glycogen body throughout
the length of the spinal cord from the cervical
to coccygeal segments.
According to Watterson (1952) the paired
primordia of the classical glycogen body
appear at 7% days of incubation in chick embryos, when sections are stained with Best’s
carmine. Similar results were obtained by
using the PAS stain or transmission electron
microscopy (De Gennaro, 1959; Matulionis,
1972).The results of the present study indicate
that the earliest stage at which the primordia
of the glycogen body could be stained with
PAS stain was stage 31 (ca. 7 days). They appeared a t the 26th through 28th segments,
which correspond to the place of the classical
glycogen body. The paired primordia appeared
progressively rostrad and caudad from these
segments.
The glycogen body cells are considered to be
a special type of astrocyte (Watterson, 1949,
1952; Welsch and Wachtler, 1969; Lyser, 1973;
Sansone, 1980).The glioblasts are found in the
gray matter of the cervical enlargement by
stage 32 (ca. 7% days) (Kanemitsu, 1972) and
the astrocytes are found by 13 or 14 days of incubation in the chick spinal cord (Imhof, 1905;
Fujita, 1965).The glioblasts frequently appear
as elongated cells originating from the ventricular cells by their migration and differentiation (Fujita, 1965, 1973). In the classical
glycogen body level the glycogen body cells appeared as the elongated cells a t the earliest
stage of development (stage 31, ca. 7 days). I t
seems to be that the glycogen body cells begin
to synthetize and store glycogen soon after
their differentiation from the ventricular cells.
The development of the classical glycogen
body of the chick embryos has been the object
of many investigations. But very little attention to the development of the glycogen body
beyond the classical level was given. Bosch et
al. (1968) showed that in stage 36 (ca. 10 days)
glycogen is detectable in the dorsal ependymal
lining, along the whole chick spinal cord. But
their observations were carried out only to
stages 36, 41, and 45 (ca. 10, 15, and 20 days).
Mori (1934) observed glycogen accumulation
in lumbar enlargement of the nine day chick
embryos on each side of the dorsal median
plate of the central canal. A t 11 days the glyco-
514
M. UEHARA AND T. UESHIMA
gen body cells could be demonstrated from the
cervical through lumbar enlargements, and by
1 4 days they appeared also in the lower lumbosacral cord. Mori (1934)and Bosch et al. (1968)
do not describe the course of fusion in the paired primordia. Thus, our study is the first to do
so. Furthermore, the present study showed
that the paired primordia of the chick glycogen
body were present from the cervical enlargement through the lumbosacral segments by
stage 36 (ca. 10 days), spread in the upper
cervical segments a t stage 38 (ca. 12 days),and
appeared in the coccygeal segments by stage
42 (ca. 16 days). Why the glycogen body cells,
which are considered to be a special type of astrocyte, appear in a progressive rostrad and
caudad direction from the classical glycogen
body level is obscure. The paired primordia of
the classical glycogen body are seen to be fused
between 8 and 10 days of incubation (Watterson, 1952; Matulionis, 1972). The present
study corroborates the above observations
with respect of the classical glycogen body
level. The fusion of the paired primordia paralleled the disappearance of the ependymal septum, which is composed of the ventricular cells
of the roof plate. The paired primordia, in the
classical glycogen body level, were totally
fused by stage 37 (ca. 11 days), but in other
segments the primordia were fused after stage
42 (ca. 16 days).
The glycogen body is found throughout
whole length of the cord and the central canal
is surrounded by the glycogen-containingcells
(Sansone and Lebeda, 1976; Sansone, 1977;
Uehara and Ueshima, 1982).Watterson (1949)
stated that the glycogen body surrounds the
central canal and its ependyma, and the exact
mechanism by which this is accomplished is
not clear. There is no report about the development of the glycogen body cells that are located laterally and ventrally to the central
canal. The glycogen-containing cells, in the
classical glycogen body level, appeared bilaterally along the borderline between the floor and
basal plates a t stage 35 (ca. 9 days). In other
segments they appeared by stage 43 (ca. 17
days). Both the number of these cells and their
glycogen content increased parallel to the developmental stages, and they migrated to the
ventral portion of the ventricular zone. By
stage 42 (ca. 16 days) they were completely
fused with the dorsal glycogen body in theclassical glycogen body level. The bilateral
clusters of the glycogen-containing cells lying
ventrolateral to the central canal are considered a s the ventral primordia of the glycogen
body. Therefore, the major portion of the glycogen body is composed of cells that derived
from the roof plate, but the cells of the floor
plate also contribute to its formation. The glycogen body essentially develops in the same
pattern as in the classically described glycogen
body through the whole length of the spinal
cord.
1,1'1'ERA'I'URE C I T E D
Bosch. K.,H . 0 Buschiazzo, O.M. De Huschiazzo. and R.H
Rodriguez (1968) Histochemical evidence of glycogen con^
tent in the dorsal ependymal lining of the spinal cord of
chick embryo Acta Physiol. Lat. Am.. 18: 110-1 13.
De tiennaro. L.D. (1959) Differentiation of the glycogen
body of the chick embryo under normal and experimental
conditions. Growth, 2.? 235-249.
Doyle. W.I,.. and K.1,. Watterson (1949) The accumulation
of glycogen in the "glycogen body"of the nerve cord of the
developing chick. J . Morphol..
Fujita. S. (1965) An autoradiographic study on the origin
and fate of the subpial glioblast in the embryonic chick
spinal cord. J . Comp. Neurol.. 124: 51-60.
Fujita. S. 11973) Genesis of glioblasts in the human spinal
cord as revealed by feulgen cytophotometry J. Comp.
Neurol., 151: 25-34.
Hamburger. V., and H.L. Hamilton I19511 A series of normal stage in the development of the chick embryo. 3. Morphol.. XN: 49-92
Imhof, ti. (1905) Anatomie und Entwicklungsgeshichite des
1,umbalmarkes bei den Vogeln. Arch. Mikrosk. Anat.
Entwicklungsmech 65: 498-610.
Kanemitsu. A. (19721Histogenesis of the chick spinal cord.
Adv. Neurol.. 16; .'ji9-387 (in Japanese).
Lyser. K.M. (1973) The tine structure of the glycogen body
of the chick. Acta Anat. 85 533-549.
Matulionis. D. (1972) Analysis of the developing avian glycogen body. I. Ultrastructural morphology. J . Morphol..
1.77: 463-482.
Mori. M . 11934) Developmental and histological studies of
Hofmann's nucleus of the spinal cord in birds and reptiles.
Igaku Kenkyu. N: 903-1015 (in Japanese).
Sansone, F.M., and F.J. Lebeda (1976) A brachial glycogen
body in the spinal cord of t h e domestic chicken. J . Morphol., 14X: 23-32.
Sansone, F.M. (19771The craniocaudal extent of the glycogen body in the domestic chicken. J. Morphol.. 155:
.
87-106.
Sansone. F.M. (1980) An ultrastructural study of the craniocaudal continuation of the glycogen body. J. Morphol..
163 45-58.
Uehara. >I.. and T. Ueshima 11982) Extent of the glycogen
body and the glycogen content of the chicken spinal cord.
Jpn. J. Vet. Sci., 44: 31-38.
Watterson. K.L. (1949) 1)evelopment of the glycogen body
of the chick spinal cord I . Normal morphogenesis. vasculogenesis. and anatomical relationships. J. Morphol.. 85:
337-390.
Watterson. R.1,. 11952) Development of the glycogen body
of the chick spinal cord I I I . The paired primordia a s revealed by glycogen-specific stains. Anat. Kec., I /,'? 29-52.
Watterson H.1,. (19541Development of the glycogen hody of
the chick spinal cord. IV. Effects of mechanical manipulation of the roof plate a t the lumbosacral level. J. Exp.
Zool., 125: 285-330.
Watterson. ILI,.. and 13.B.N. Spiroff (1949) Development of
glycogen hody of the chick spinal cord. I I Kffects of unilateral and bilateral leg~hudextirpation. I'hysiol. Zool..
2 2 318-337.
Watterson. ILL.. 1'. Veneziano. and D.A. 13rown (1958) Development of the glycogen body of the chick spinal cord.
V. Effects of hypophysectoniy on its glycogen content.
I'hysiol. Zoo1 .71: 49-59.
Welsch. U..and K Wachtler (1969)Zum Feinbau des t i l y k o ~
genkorpers im Ruckenmarkes der Taube. 2. Zellforsch..
.
97: 160-168.
In all plates the photomicrographs illustrate transverse
sectionsof thespinal cord. Fikwres 1-8. 12.and I f i a r e c u t a t
t h e middle of the classically described glycogen body level in
t h e lumbosacral cord.
Fig. 1. Stage 32 Ica. 7 ' 2 d a y s ) Paired primordia of the
glycogen body can he seen bilateral t o each side of the ependymal septum. PAS. X 50
Fig. 2. Stage 3 2 (ca. 7 ' 7 days). The nuclei of the ventricular cells in the roof plate are located towards the external
limiting membrane. 11-E. X 200.
Fig. 3. Stage 34 (ca. 8 days). Fusion of the paired primordia has commenced dorsally. P A S X 36.
Fig. 4. Stage 3.5 (ca. 8-Y days). Fusion of the paired primordia spreads in a dorsoventral direction. PAS. X 36.
Fig. 5. Stage 35 (ca 8-9 days). Ifigher magnification of
the floor plate shown in the previous photomicrograph.
Note t h a t the glycogen-containing cells extend ventrolaterally from the central canal (arrows).Accumulation of the
glycogen granules IS seen along the midline of the floor
plate. PAS. X 200.
516
M. U E H A R A A N D T. U E S H I M A
Figs. 6 and 7. Stage 36 Ica. 10 days). The dorsal surface
of the glycogen body has projected beyond the dorsal funiculi. The glycogen-containing cells of the ventrolateral portions of the central canal have increased in number and size.
Figure 6 is stained with PAS and Figure 7 with H-E. X 33.
Fig. 8. Stage 36 Ica. 10 days). Higher magnification of
the ventral portion of the glycogen body shown in Figure 7.
A few ventricular cells (arrows) in the roof plate partially
separate the ventral portion of the glycogen body into right
and left halves. H-E. X 200.
Fig. 9. Stage 37 (ca. 11 days). Transverse section
through the cervical enlargement. PAS. X 40.
Fig. 10. Stage 37 (ca. 11 days). Transverse section
through the lower lumbosacral cord. PAS. X 53.
Fig. 11. Stage 38 (ca. 12 days). Transverse section
through the upper cervical cord. Note paired primordia of
the glycogen body. C, central canal. PAS. X 100.
Fig. 12. Stage 38 Ica. 12 days). Detail of the floor plate
showing the migration of the neuroglial cells into the ventral commissure. H-E. X 100.
DEVELOPMENT OF GLYCOGEN BODY
517
518
M. UEHARA AND T. UESHIMA
Fig. 13. Stage 38 (ca. 12 days). Transverse section
through the lower coccygeal cord. The glycogen-containing
cells appear a t a earlier stage than in the upper coccygeal
cord. PAS. X 200.
Fig. 14. Stage 40 (ca. 14 days). Transverse section
through the cervical enlargement. PAS. X 40.
Fig. 15. Stage 41 (ca. 15 days). Many glycogen-containing cells are located in the lateral and ventral portions of the
central canal (C). PAS. X 200.
Fig. 16. Stage 42 Ica. 16 days).The central canal IC)is ensheathed by the glycogen body. PAS. X 200.
Fig. 17. Stage 43 (ca. 17 days) Transverse section
through the lower coccygeal cord. Glycogen is seen throughout the entire section. PAS. X 130.
Fig. 18. Stage 43 (ca. 17 days). Transverse section
through the cervical enlargement showing the glycogen-containing cells (arrows) of the ventrolateral portions of t h e
central canal. PAS. X 200.
DEVELOPMENT O F GLYCOGEN BODY
519
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