The synthetic activity of primordial germ cells in normal and irradiated neonatal male rats

Development ◽  
1968 ◽  
Vol 19 (2) ◽  
pp. 239-249
Author(s):  
I. C. Lett
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Giant Cells ◽  
Male Rats ◽  
Synthetic Activity ◽  
X Rays ◽  
Short Term ◽  
Post Irradiation ◽  
Histological Appearance ◽  
Transitional Cells

Resting primordial germ cells or gonocytes, present in the testis of the rat at birth (Beaumont & Mandl, 1963), are highly radiosensitive. A dose of 50–100 r X-rays induces complete, or almost complete, sterility, as judged by the histological appearance of the testis at 25 days post parturn (Mandl et al. 1964). Studies of short-term post-irradiation changes have revealed that gonocytes, exposed to a sterilizing dose of X-rays at birth, do not degenerate immediately after exposure but differentiate normally into transitional cells (the immediate precursors of definitive germ cells; Beaumont & Mandl, 1963; Huckins, 1963; Franchi & Mandl, 1964) so that no histological abnormalities are detectable for 5 or 6 days. Subsequently, however, the irradiated transitional cells fail to divide; they increase markedly in size and form irregularly shaped giant cells which eventually become pyknotic (Franchi & Mandl, 1966; see also Sapsford, 1965a).

The population of germ cells in immature male rats following irradiation at birth

1966 ◽  
Vol 165 (998) ◽  
pp. 103-135 ◽  
Keyword(s):  
Germ Cells ◽  
Total Population ◽  
Primordial Germ Cells ◽  
Type A ◽  
Male Rats ◽  
Type B ◽  
The Absolute ◽  
The Difference ◽  
Transitional Cells ◽  
Type A Spermatogonia

Male rats were irradiated with 19 r on the day of birth, and killed at intervals ranging from 5 to 18 days. Estimates were made of the absolute and relative numbers of germ cells at different stages of spermatogenesis in 64 irradiated and 61 untreated specimens. In the normal rat, the calculated population of germ cells increased from about 160000 at 5 days to 30 million at 18 days. Only negligible numbers of primordial germ cells (gonocytes and transitional cells) persisted beyond the age of 10 days. Small numbers of spermatogonia type A appeared at 5 days (15000) and their population rose to about 1 million at 12 days, and 2 million at 18 days (7 % of all germ cells). Intermediate spermatogonia first occurred in appreciable numbers (23000 to 55000) at 8 or 9 days, when the population of type-A spermatogonia was 360000. The subsequent rise in the population of intermediate spermatogonia was more rapid than that of type A (4 million at 18 days). Spermatogonia type B and primary spermatocytes appeared at 9 to 10 days, and their numbers rose more steeply still (6.5 and 16 million at 18 days, respectively). Irradiation at birth exerted no rapid effect on the cytological appearance of primordial germ cells. Transformation from gonocytes to transitional cells appeared to proceed normally and the estimated total population of germ cells at 5 days was no smaller than in the controls. Subsequently, however, many of the transitional cells failed to divide: they enlarged to form giant cells, acquired bizarre nuclear outlines, and persisted for unusually long periods. Some degenerated at mitotic prophase or metaphase, while a few seemed to die at interphase, without entering division. The calculated total population of germ cells in irradiated rats rose from 160000 at 5 days to 9.4 million at 18 days. Small numbers of spermatogonia type A, presumably derived from such primordial germ cells as were able to complete mitosis, appeared some 2 to 3 days later than in controls. The number of type-A spermatogonia in 7-day-old irradiated rats was 44000, cf. 215000 in controls; the difference became less pronounced with time, and by the age of 18 days, the population of 1.9 million was comparable to that estimated for the controls. Small numbers of intermediate spermatogonia appeared on the 9th (8000) and 10th day (35000), when the population of type-A spermatogonia was about 110000 and 260000 respectively. By the 18th day, intermediate spermatogonia numbered 2 million. The populations of type-B spermatogonia and primary spermatocytes rose from 11000 to 13000 at 10 days to 1.6 and 3.4 million, respectively, at 18 days. The difference in the absolute and relative numbers of germ cells between normal and irradiated testes widened progressively with advance in the developmental stage of the germ cells. Analysis of the results indicates that in the reduced population of spermatogonia type A after irradiation, the pattern of spermatogonial mitoses is modified so as to favour the formation of more type-A, in preference to intermediate, spermatogonia.

Short-term culture of porone primordial germ cells

1998 ◽  
Vol 49 (1) ◽  
pp. 237
Author(s):  
G. Durcova-Hills ◽  
K. Prelle ◽  
S. Müller ◽  
E. Wolf ◽  
G. Brem
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Short Term ◽  
Short Term Culture

The ultrastructure of male germ cells in rats X-irradiated at birth

1966 ◽  
Vol 165 (998) ◽  
pp. 136-154 ◽  
Keyword(s):  
Golgi Apparatus ◽  
Electron Micrographs ◽  
Germ Cells ◽  
Giant Cells ◽  
Simple Type ◽  
X Irradiation ◽  
Pinocytotic Vesicles ◽  
Radiation Induced ◽  
Partial Body ◽  
Transitional Cells

A histological and ultrastructural study was made of the testes of rats, aged 1 to 15 days, which had received partial-body X-irradiation ( ca . 100 r) on the day of birth. Nineteen serially sectioned testes were subjected to a quantitative analysis including counts of germ cells and measurements of nuclear volume. The type, position and general form of germ cells, together with the incidence of various organelles, was assessed semi-quantitatively from 533 electron micrographs of irradiated (370) and normal (163) tissues. Exposure to 100 r at birth has no marked effect on the total population of germ cells during the first 5 days. The transformation of gonocytes into transitional cells is not affected. Subsequently, the treated testes differ from those of coeval controls by the almost complete absence of germinal mitoses and, consequently, of spermatogonia type A. Many of the transitional cells grow into irregularly-shaped giant cells, usually with a highly lobed nucleus and enlarged nucleoli. Although some cells show condensation of chromatin which may indicate the onset of mitotic prophase, the majority appear to degenerate at interphase. By 10 days, the testes contain only a fraction of the original population of germ cells. No significant changes are detectable in the ultrastructure of germ cells up to 4 days after irradiation. The treatment only induces the sporadic appearance of two minor features (pinocytotic vesicles containing electron-dense material; peripheral granular bodies with some internal organization) which are normally absent from corresponding cells in the controls. Electron micrographs of giant transitional cells confirmed the cytological observations of irregularity of nuclear outline and nucleolar enlargement. The nucleoli are frequently irregular in shape and contain material of two distinct electron densities. In general, the organelles of giant transitional cells are normal and healthy in appearance. With advancing age, an increasing proportion of germ cells show degenerative changes leading to pyknosis. Dead cells appear to be engulfed by neighbouring somatic cells. In both normal and irradiated testes, the simple form of Golgi apparatus in the gonocyte changes to a more complex type in the transitional cells. The persistence of giant cells is associated with a tendency for the Golgi apparatus to revert to the simple type, or to disperse into a number of small simple units. The most striking feature is the relatively high incidence of centrioles, suggesting that radiation-induced mitotic inhibition and gigantism may be accompanied by endomitosis. Irradiation does not markedly affect the appearance and incidence of A- and B-bodies (Franchi & Mandl 1964). These organelles tend, however, to persist over a longer period in irradiated than in untreated young rats.

La localisation du matériel germinal dans le blastoderme non incube de l'oeuf de cane: étude à l'aide des irradiations aux rayons X

Development ◽  
1975 ◽  
Vol 34 (1) ◽  
pp. 171-177
Author(s):  
Par Noël Fargeix
Keyword(s):  
Germ Cells ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
X Rays ◽  
X Ray ◽  
Somite Stage ◽  
Population Decrease ◽  
Anterior Half ◽  
Duck Egg

Germinal material localization in the non-incubated duck egg blastoderm studied by means of X-ray irradiations Primordial germ cells (CGP) have been numbered from the 7-somite to the 14-somite stage in embryos formed from blastoderms the anterior or posterior halves of which have been irradiated with X-rays at the non-incubated stage or after 10 h of incubation. The germinal population decrease is almost the same for irradiations of the anterior or posterior halves at the non-incubated stage. At 10 h of incubation, this decrease is very marked for irradiations of the anterior halves while it is slight for irradiations of the posterior halves. These results seem to indicate that at the non-incubated stage, the germinal material is localized in the anterior half of the blastoderm as well as in the posterior one with a slight anterior predominance, and tends to accumulate in the anterior part only as early as the first hours of incubation.

scholarly journals Whole brain proton irradiation in adult Sprague Dawley rats produces dose dependent and non-dependent cognitive, behavioral, and dopaminergic effects

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michael T. Williams ◽  
Chiho Sugimoto ◽  
Samantha L. Regan ◽  
Emily M. Pitzer ◽  
Adam L. Fritz ◽  
...  
Keyword(s):  
Water Maze ◽  
Swimming Performance ◽  
Reference Memory ◽  
Cognitive Outcomes ◽  
Male Rats ◽  
X Rays ◽  
Proton Radiotherapy ◽  
Sprague Dawley ◽  
Post Irradiation ◽  
Dose Rates

AbstractProton radiotherapy causes less off-target effects than X-rays but is not without effect. To reduce adverse effects of proton radiotherapy, a model of cognitive deficits from conventional proton exposure is needed. We developed a model emphasizing multiple cognitive outcomes. Adult male rats (10/group) received a single dose of 0, 11, 14, 17, or 20 Gy irradiation (the 20 Gy group was not used because 50% died). Rats were tested once/week for 5 weeks post-irradiation for activity, coordination, and startle. Cognitive assessment began 6-weeks post-irradiation with novel object recognition (NOR), egocentric learning, allocentric learning, reference memory, and proximal cue learning. Proton exposure had the largest effect on activity and prepulse inhibition of startle 1-week post-irradiation that dissipated each week. 6-weeks post-irradiation, there were no effects on NOR, however proton exposure impaired egocentric (Cincinnati water maze) and allocentric learning and caused reference memory deficits (Morris water maze), but did not affect proximal cue learning or swimming performance. Proton groups also had reduced striatal levels of the dopamine transporter, tyrosine hydroxylase, and the dopamine receptor D1, effects consistent with egocentric learning deficits. This new model will facilitate investigations of different proton dose rates and drugs to ameliorate the cognitive sequelae of proton radiotherapy.

Hexachlorobenzene toxicity in the rat ovary: II. Ultrastructure induced by medium (10 mg/kg) dose exposure

1992 ◽  
Vol 50 (1) ◽  
pp. 668-669
Author(s):  
Amreek Singh ◽  
Warren G. Foster ◽  
Anna Dykeman ◽  
David C. Villeneuve
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Surface Epithelium ◽  
Morphological Parameters ◽  
Comprehensive Investigation ◽  
Ovary Surface Epithelium ◽  
Rat Ovary ◽  
High Doses

Hexachlorobenzene (HCB) is a known toxicant that is found in the environment as a by-product during manufacture of certain pesticides. This chlorinated chemical has been isolated from many tissues including ovary. When administered in high doses, HCB causes degeneration of primordial germ cells and ovary surface epithelium in sub-human primates. A purpose of this experiment was to determine a no-effect dose of the chemical on the rat ovary. The study is part of a comprehensive investigation on the effects of the compound on the biochemical, hematological, and morphological parameters in the monkey and rat.

Transfusion of Chick Primordial Germ Cells into Quail Embryos and their Settlement in Gonads

1998 ◽  
Vol 69 (10) ◽  
pp. 911-915 ◽  
Author(s):  
Tamao ONO ◽  
Ryohei YOKOI ◽  
Seishi MAEDA ◽  
Takao NISHIDA ◽  
Hirohiko AOYAMA
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells
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