Unique morphological characteristics in the ovary of cotton rat (&lt;i&gt;Sigmodon hispidus&lt;/i&gt;)

Islam, Rashedul; Ichii, Osamu; Nakamura, Teppei; Irie, Takao; Masum, Abdul; Hosotani, Marina; Otani, Yuki; Elewa, Yaser Hosny Ali; Kon, Yasuhiro

doi:10.1262/jrd.2020-061

Cited by 4 publications

(21 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We found unique characteristics along with the developing follicles of neonatal CR ovary, DNOs (oocytes with two nuclei encased in a single follicle) at 6–8 weeks of age ( Islam et al, 2020 ). The appearance of DNOs varies among developing follicles.…”

Section: Resultsmentioning

confidence: 94%

“…For histomorphometry using HE-stained sections, ovarian follicles were classified, either in nest as cluster form or based on their stages, as primordial (PrF), primary (PF), secondary (SF), and tertiary follicles (TF), according to previously reported studies in rabbits ( Al-Mufti et al, 1988 ) and CRs ( Islam et al, 2020 ). Their numbers were counted every five sections.…”

Section: Methodsmentioning

confidence: 99%

“…Their numbers were counted every five sections. The number of various developing follicles was multiplied by five to determine the total number of follicles per ovary ( Su et al, 2013 ; Gaytán et al, 2014 ; Islam et al, 2020 ). Only follicles containing visible oocytes were counted to avoid double counting.…”

Section: Methodsmentioning

confidence: 99%

“…The developmental stage of ovarian follicles containing more than two oocytes (defined as MOFs) or two nuclei (defined as DNOs) were classified according to our previous study ( Islam et al, 2020 ). In neonates, DNOs appeared from PND0, and MOFs from PND4.…”

Section: Methodsmentioning

confidence: 99%

“…Female CRs also display significantly more features of severe chronic kidney disease than males, especially inflammatory cell infiltration and dilation of distal tubules ( Ichii et al, 2016 ). We also documented unique phenotypes in the CR ovary at 6–8 weeks of age, such as multi-oocyte follicles (MOFs) and double nucleated oocytes (DNOs) ( Islam et al, 2020 ). Based on the results, we considered the mechanism of development of MOFs or DNOs as a correlation between oocytes with incomplete cytoplasmic or nuclear division and GC expansion at 6–8 weeks of age.…”

Section: Introductionmentioning

confidence: 94%

See 4 more Smart Citations

Developmental Changes of the Ovary in Neonatal Cotton Rat (Sigmodon hispidus)

et al. 2021

Self Cite

View full text Add to dashboard Cite

The reproductive characteristics and ovarian development in cotton rats (Sigmodon hispidus, CRs) are unclear, although CRs are commonly used as animal models in biomedical research. We previously reported that young (6–8 weeks) CRs showed multi-oocyte follicles (MOFs) and double nucleated oocytes (DNOs) in different stages of follicles. The developmental changes in neonatal CR ovaries were investigated in the present study and were compared with our findings in previous studies of unique phenotypes, particularly in oocytes. CR ovaries at postnatal days (PND) 0, 4, and 7 were obtained from the Hokkaido Institute of Public Health. Samples were analyzed by light and transmission electron microscopy. The general histology and folliculogenesis in CR ovaries were similar to those in other experimental rodents. However, DNOs were observed in all age categories and were frequently observed in primordial follicles, whereas MOFs started to develop from PND4 with greater frequency in primary follicles. Almost all developing follicles expressed DEAD (Asp-Glu-Ala-Asp) box polypeptide 4 and forkhead box L2, which are representative markers of oocytes and follicular epithelial cells, respectively. Ki-67 staining demonstrated the proliferative activity of granulosa cells, but not of oocytes, in follicles. Moreover, rapid folliculogenesis of CR due to a small number of apoptotic oocytes was suggested, based on results of the terminal deoxynucleotidyl transferase dUTP nick end labeling assay, confirming the formation of DNOs or MOFs. These findings clarify the development of unique phenotypes of neonatal CR ovaries and support it as a useful model to better understand folliculogenesis and oocytogenesis as well as their abnormalities in humans and other animals.

show abstract

Section: Resultsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

See 3 more Smart Citations

Developmental Changes of the Ovary in Neonatal Cotton Rat (Sigmodon hispidus)

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

Cotton rats (Sigmodon hispidus) with a high prevalence of hydrocephalus without clinical symptoms

et al. 2021

Self Cite

View full text Add to dashboard Cite

Normal-pressure hydrocephalus (NPH) is a condition in which the ventricle is enlarged without elevated cerebrospinal fluid pressure, and it generally develops in later life and progresses slowly. A complete animal model that mimics human idiopathic NPH has not yet been established, and the onset mechanisms and detailed pathomechanisms of NPH are not fully understood. Here, we demonstrate a high spontaneous prevalence (34.6%) of hydrocephalus without clinical symptoms in inbred cotton rats (Sigmodon hispidus). In all 46 hydrocephalic cotton rats, the severity was mild or moderate and not severe. The dilation was limited to the lateral ventricles, and none of the hemorrhage, ventriculitis, meningitis, or tumor formation was found in hydrocephalic cotton rats. These findings indicate that the type of hydrocephalus in cotton rats is similar to that of communicating idiopathic NPH. Histopathological examinations revealed that the inner granular and pyramidal layers (layers IV and V) of the neocortex became thinner in hydrocephalic brains. A small number of pyramidal cells were positive for Fluoro-Jade C (a degenerating neuron marker) and ionized calcium-binding adaptor molecule 1 (Iba1)-immunoreactive microglia were in contact with the degenerating neurons in the hydrocephalic neocortex, suggesting that hydrocephalic cotton rats are more or less impaired projections from the neocortex. This study highlights cotton rats as a candidate for novel models to elucidate the pathomechanism of idiopathic NPH. Additionally, cotton rats have some noticeable systemic pathological phenotypes, such as chronic kidney disease and metabolic disorders. Thus, this model might also be useful for researching the comorbidities of NPH to other diseases.

show abstract

The analysis of histological features and morphometric parameters of the ovaries in absenсe epilepsy

Садртдинова

Хисматуллина

2023

Morphology

View full text Add to dashboard Cite

Aim. Using histological and morphometric methods to assess the state of the ovaries of rats with absence epilepsy. Material and methods. The experiments were carried out on mature female Wistar and WAG/Rij rats (genetic model of human absence epilepsy). Animal ovaries were fixed in neutral buffered 10% formalin and embedded in paraffin according to the standard procedure. Sections obtained on a microtome were stained with hematoxylin and eosin. Results. When studying the morphological picture of the ovaries, destruction of the cortical and medulla of the ovary of WAG/Rij rats was found. It was noted that the layer of granulosa cells surrounding the oocyte has a looser structure. The observed changes in the follicular epithelium were probably accompanied by impaired functional activity. Morphometric analysis showed that in WAG/Rij rats the weight of the ovaries is almost 2 times less than in Wistar rats: 37.30.93 mg versus 55.842.36 mg. In addition, there are differences in the thickness of the epithelial layer - 7.810.25 m, which is 26.2% less than in Wistar rats (p0.05). This indicates possible morphological and functional disorders. In the ovaries of WAG/Rij rats, we noted that the layer of granulosa cells surrounding the oocyte has a looser structure. Sometimes destructive changes in follicular epithelium and apoptotic death of granulosa cells were observed, which was accompanied by impaired functional activity. When studying ovarian follicles, it was revealed that in WAG/Rij rats the follicles were irregular in shape, their diameter and area were smaller than in Wistar females. In addition, the numerical density of all types of follicles was lower, which indicates a violation of ovulation processes. Conclusions. The results obtained allowed us to conclude that rats with absence epilepsy exhibit structural and quantitative changes in the ovaries, which indicates certain disorders of the reproductive system.

show abstract

Unique morphological characteristics in the ovary of cotton rat (<i>Sigmodon hispidus</i>)

Cited by 4 publications

References 43 publications

Developmental Changes of the Ovary in Neonatal Cotton Rat (Sigmodon hispidus)

Developmental Changes of the Ovary in Neonatal Cotton Rat (Sigmodon hispidus)

Cotton rats (Sigmodon hispidus) with a high prevalence of hydrocephalus without clinical symptoms

The analysis of histological features and morphometric parameters of the ovaries in absenсe epilepsy

Contact Info

Product

Resources

About