Seasonal changes of mitochondrial autophagy and oxidative response in the testis of the wild ground squirrels (Spermophilus dauricus)

Author(s):  
Yuhan Wang ◽  
Ruting Su ◽  
Pinxuan Liu ◽  
Zhengrong Yuan ◽  
Yingying Han ◽  
...  

Mitochondria are the main organelles for mammalian energy metabolism and have been implicated in the regulation of germ cell maintenance and spermatogenesis. However, little is known about the changes in the mitochondria of the testis of seasonal breeders. Here, we characterized the seasonal changes in the mitochondria in the testis of the wild ground squirrels. Increased testicle weight, seminiferous tubule diameter and sperm count were observed in the wild ground squirrels at the breeding season. RNA-seq analysis of the wild ground squirrel testes revealed that mitochondrial-related genes were expressed differentially between the breeding and non-breeding seasons. Immunohistochemical staining showed that key mitophagy factors including PINK1, MFN2, and PARKIN were highly expressed in various cell types of testis during the breeding season. In addition, the abundance and enzymatic activities of mitochondrial-localized antioxidative enzymes SOD2 (Superoxide dismutase 2) and Catalase were decreased in the testis during the breeding season, suggesting a tightly controlled redox balance at least partially facilitated by mitophagy during the seasonal breeding. Taken together, our study reveals that mitochondrial autophagy and oxidative stress may be implicated in the seasonal reproductive recrudescence of the wild ground squirrels, which deepens our understanding of the mitochondrial regulation of seasonal reproductivity in wildlife and provides new insights into the development of potential therapeutic interventions of male infertility.

2021 ◽  
Vol 65 (2) ◽  
Author(s):  
Yuchen Yao ◽  
Wenqian Xie ◽  
Di Chen ◽  
Yingying Han ◽  
Zhengrong Yuan ◽  
...  

As a vital male accessory reproductive gonad, the prostate requires vascular endothelial growth factors for promoting its growth and development. In this study, we investigated the localizations and expressions of vascular endothelial growth factor (VEGF) and its receptors including VEGF-receptor1 (VEFGR1) and VEGF-receptor2 (VEGFR2) in the prostate of the wild ground squirrels during the breeding and the non-breeding seasons. The values of total prostate weight and volume in the breeding season were higher than those in the non-breeding season. Histological observations showed that the exocrine lumens of the prostate expanded in the breeding season and contracted in the non-breeding season. The mRNA expression levels of VEGF and VEGFR2 in the prostate were higher in the breeding season than those in the non-breeding season, but the mRNA expression level of VEGFR1 had no significant change between the breeding and non-breeding seasons. Immunohistochemical results revealed that VEGF, VEGFR1 and VEGFR2 were presented in epithelial and stromal cells during the breeding and non-breeding seasons. In addition, the microvessels of the prostate were widely distributed and the number of microvessels increased obviously in the breeding season, while decreased sharply in the non-breeding season. These results suggested that expression levels of VEGF and VEGFR2 might be correlated with seasonal changes in morphology and functions of the prostate, and VEGF might serve as pivotal regulators to affect seasonal changes in the prostate functions of the wild male ground squirrels via an autocrine/paracrine pathway.


Author(s):  
Yu Wang ◽  
Ziyi Wang ◽  
Wenyang Yu ◽  
Xia Sheng ◽  
Haolin Zhang ◽  
...  

The reproductive tissues including the uterus undergo dramatic changes in seasonal breeders from the breeding to non-breeding seasons. Classically, sex steroid hormones play important roles in the uterine morphology and functions. To clarify the relationship between sex steroid hormones and seasonal changes in the uterine morphology and functions, the wild Daurian ground squirrels (Spermophilus dauricus) were used as seasonal breeder model. And the immunolocalizations and expression levels of androgen receptor (AR), estrogen receptors α and β (ERα and ERβ) and cytochrome P450 aromatase (P450arom) were investigated in the uteri of the wild Daurian ground squirrels in the breeding (April) and the non-breeding (June) seasons via immunohistochemistry, Western blot and RT-PCR. Histologically, the uterine weight, the thickness of endometrium and the glandular density were significantly higher in the uteri of the breeding season than those of the non-breeding season. In both seasons, the immunostaining of AR was only presented in stromal cells of the uteri; the positive staining of ERα and ERβ were localized in stromal cells and glandular cells; P450arom was merely immunolocalized in glandular cells. The protein and mRNA expression levels of ERα, ERβ and P450arom were higher in the uteri of the breeding season than those of the non-breeding season; conversely, the expressions of AR were higher in the uteri of the non-breeding season comparing with those of the breeding season in both protein and mRNA levels. The AR: ER ratio in the uteri of the non-breeding season exceeded the AR: ER ratio in the uteri of the breeding season in the wild Daurian ground squirrels. These results suggested that seasonal changes in the expression levels of AR, ERs and P450arom might be correlated with the uterine morphology and histology changes, and estrogen may play an important autocrine/paracrine role in regulating the uterine functions of the wild Daurian ground squirrels.


2020 ◽  
Vol 64 (2) ◽  
Author(s):  
Wenyang Yu ◽  
Ziwen Zhang ◽  
Pei Liu ◽  
Xiaoying Yang ◽  
Haolin Zhang ◽  
...  

Sperm-associated antigen 11A (SPAG11A) is expressed exclusively in the epididymis, which can specifically regulate sperm maturation. The aim of this study was to investigate the seasonal expressions of beta-defensin (SPAG11A) and androgen receptor (AR) in the epididymis of the wild ground squirrels (Citellus dauricus Brandt). Morphologically, the results showed that epididymis length and weight in the breeding season were significantly higher than those of the non-breeding season. Histologically, the results revealed that enlarged lumen diameters, thickened epithelial and abundant sperm in the breeding season while reduced lumen diameters and epithelial with no sperm in the non-breeding season. SPAG11A was intensely expressed in cytoplasm and nucleus of epithelial cells in the breeding season, and weaker staining in the non-breeding season. The immunostaining of AR was only presented in nucleus of smooth muscle cells and epithelial cells in the whole epididymis with stronger staining in the breeding season. The results of real-time quantitative PCR also showed that the mRNA levels of SPAG11A and AR in the epididymis during the breeding season were significantly higher than those of the non-breeding season. In addition, the levels of testosterone (T), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the serum were higher during the breeding season. Taken together, these results suggested that SPAG11A might play an important role to regulate seasonal changes in epididymal function of the wild ground squirrels.


1980 ◽  
Vol 7 (3) ◽  
pp. 385 ◽  
Author(s):  
CM Kemper

A total of 291 P. novaehollandiae were observed during a 4-y study in the Nelson Bay and Smith Lake regions of New South Wales. Reproductive organs were examined from males and females, May 1972-May 1974; reproductive condition of females was noted during a CMR study, August 1974-July 1976. Breeding seasons (conceptions and births) occurred between August and early January (4-5 months) in the first 3 years and between September and March (7 months) in the last year. Second-year females produced three or four litters in short seasons, four or five litters in the long season and up to 20 offspring per season. First-year females produced one litter in short seasons and one or two litters in the long season. Mean litter size was 4.56 (2-6). Ovarian follicles were largest in September and smallest in May. Small, inactive CL persisted in parous females until May. Placental scars were present in all sampled months. Vaginae remained closed during the non-breeding season. In mature males testes and epididymides contained sperm from July to March. Vesicular, prostate and preputial glands were enlarged and secretory from September to December. Testes were smallest and least developed in May and June. Males were divided into five categories depending on age and overall reproductive condition. Sexual maturity was reached in the breeding season of birth by some males (33%) and females (13-88%). More females matured early when population density was low. Food abundance and quality may have been important variables in regulating the timing of the breeding season.


2001 ◽  
Vol 72 (1) ◽  
pp. 55-64 ◽  
Author(s):  
C. McG. Argo ◽  
M.G. R. Collingsworth ◽  
J. E. Cox

AbstractPony colts (~12 m) are generally infertile during the breeding season of mature stallions. The mechanism which ‘delays’ puberty beyond the first potential breeding opportunity has not been described. Four pre- and four post-pubertal colts were monitored from November for 13 (group 1, 6 to 19 months of age) and 9 months (group 2, 18 to 27 months of age). Fortnightly, 15 blood samples were collected at hourly intervals from each colt to determine concentrations of prolactin (PRL), LH, FSH and testosterone (T). Testicular biopsies were collected monthly to evaluate spermatogenic activity. Puberty occurred between 17 and 19 months, and at the onset of the 2-year-old breeding season, all colts were fertile. Seasonal changes in the concentrations of all four hormones were observed in both groups. Prolactin concentrations were correlated with changes in day length (r = 0·88) in both groups, but a biphasic profile was noted in group 1. Moulting of the winter coat was coincident with seasonally increased PRL concentrations (P < 0·001). Seasonal changes in FSH, LH and T concentrations were similarly timed between groups and levels were maximal in mid April, mid March and mid May, respectively. However, overall mean concentrations of LH and T in group 1 animals were only 0·33 and 0·22 of group 2 values (P < 0·001). Suppression of gonadal activity during the colts’ first ‘quiescent’ breeding season was associated with low concentrations of circulating LH. Appropriately timed changes in plasma PRL, FSH and T concentrations and pelage indicated that the photoperiodic mechanism was functional in the pre-pubertal colt but pituitary LH release may be blocked by immaturity or active suppression.


2018 ◽  
Vol 96 (3) ◽  
pp. 205-211 ◽  
Author(s):  
Jumpei Tomiyasu ◽  
Yojiro Yanagawa ◽  
Yoshikazu Sato ◽  
Michito Shimozuru ◽  
Masashi Nagano ◽  
...  

Adult male brown bears (Ursus arctos Linnaeus, 1758) display tree-marking behavior to chemically signal their dominance throughout the nondenning period, and this behavior peaks during the breeding season. Within the scent-marking sequence, back rub is a core marking posture. The present study investigated (i) seasonal changes in sebaceous glands in the back skin of brown bears and (ii) the relationship between those changes and testosterone levels. Back skin tissue samples and blood were collected from captive adult intact and castrated males during prebreeding, transitional, breeding, and postbreeding seasons, which were concurrent with back skin observations. In intact males, during the transitional and breeding seasons, an oily secretion from the back skin was observed along with enlarged sebaceous glands. The plasma testosterone concentrations during the transitional and breeding seasons were increased compared with the pre- and post-breeding seasons. Secretions and enlarged sebaceous glands were not found in castrated males, and the plasma testosterone concentrations remained at baseline levels. Oily secretions of the back skin glands that appear more abundant during the breeding season are rubbed against trees. Changes in size and volume of sebaceous glands, and thus their secreting capacity, are likely testosterone-regulated.


2021 ◽  
Author(s):  
Yue Song ◽  
Xiaoying Yang ◽  
Xueying Zhang ◽  
Jueyu Zhu ◽  
Yixin Chen ◽  
...  

Abstract Background: The aim of this study was to explore the localization and expression of extracellular signal regulated kinase/phospho-extracellular signal regulated kinases (ERK/pERK) in the colonic tissue of wild ground squirrels (Spermophilus dauricus) in the breeding season and the non-breeding season. Methods and Results: Hematoxylin-eosin staining, immunohistochemistry, real-time quantitative PCR and Western blot were used in this study. The histological results showed that the diameter of the colon lumen in the non-breeding season was larger than that in the breeding season, and the number of glandular cells in the non-breeding season was also more than those in the breeding season. The immunochemical results showed that ERK1/2 was expressed in the cytoplasm of goblet cells and intestinal epithelial cells, while pERK1/2 was expressed in the cytoplasm and nucleus of goblet cells and intestinal epithelial cells. The immunolocalization of ERK1/2 and pERK1/2 expression were more obvious in the non-breeding season, especially in intestinal epithelial cells. The results of real-time quantitative PCR and Western blot showed that the expression of ERK1/2 and pERK1/2 in the breeding season was significantly lower than that in the non-breeding season.Conclusions: The expression of ERK1/2 and pERK1/2 in the colons of the wild ground squirrels had seasonal changes, which had significant increases in the non-breeding season comparing to those in the breeding season. This study revealed the potential role of ERK1/2 in colon to the adaptation of seasonal changes in wild ground squirrel.


2021 ◽  
Vol 33 (2) ◽  
pp. 124
Author(s):  
C. S. Sarswat ◽  
S. Sharma ◽  
K. Nehra ◽  
P. C. Sharma ◽  
M. C. Parashar ◽  
...  

The aim of this work was to determine the effect of administration of exogenous melatonin on the testicular biometry, libido parameters, hormone levels, and freezability of semen during the non-breeding seasons in adult Sirohi bucks. Experiments of 4 and 8 weeks were carried out during non-breeding seasons at different times. Twelve bucks, 2 to 3 years of age, were split into melatonin-treated and control groups, with 6 bucks in each group. Throughout the 2 experimental periods, all bucks were permanently kept outdoors under conditions of natural daylength and at ambient temperature. Bucks in the treated group were subjected to single subcutaneous injection of a powder form of melatonin mixed with corn oil at the dose rate 18mg per 50kg on the first day of experiment; bucks in the control group received sterile corn oil injected subcutaneously in control group. Ejaculates were taken from the bucks by artificial vagina (AV) once per week and their reaction time (the elapsed time between exposure to stimuli and first ejaculation) was recorded. Testicular biometry, serum testosterone, and serum melatonin were determined weekly before semen collection. Ejaculates were cryopreserved and thawed weekly and the same quantitative and qualitative variables were measured as for fresh semen samples. Melatonin significantly (P&lt;0.05) improved testicular biometry, libido parameters, and hormone levels compared with the control group during weeks 3 and 4 of the first experiment and from week 5 onward of the second experiment (P&lt;0.05). Semen volume (mL) improved to 0.70±0.039 vs. 0.48±0.009 and 0.94±0.036 vs. 0.56±0.032 in first and second experiments. Greater (P&lt;0.05) progressive motility (%) was noted in the melatonin group (84.59±1.472 and 86.88±0.797) during experiments 1 and 2. Semen quality of each straw from each ejaculate was evaluated after proper thawing within 24h. Mean post-thaw live sperm percentage for experiments 1 and 2 was 69.25±0.382 and 66.90±0.779, progressive motility was 50.42±0.948 and 58.75±1.058, and curled tail sperm count were 51.00±0.715 and 61.36±0.773, respectively. In conclusion, the results of present experiments are novel regarding the use of single subcutaneous melatonin injection during the non-breeding season to improve variables associated with the fertility potential of the Sirohi buck and frozen-thawed seminal parameters.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Vasiliki Tsolaki ◽  
Demosthenes Makris ◽  
Konstantinos Mantzarlis ◽  
Epameinontas Zakynthinos

Cardiac dysfunction may complicate the course of severe sepsis and septic shock with significant implications for patient’s survival. The basic pathophysiologic mechanisms leading to septic cardiomyopathy have not been fully clarified until now. Disease-specific treatment is lacking, and care is still based on supportive modalities. Septic state causes destruction of redox balance in many cell types, cardiomyocytes included. The production of reactive oxygen and nitrogen species is increased, and natural antioxidant systems fail to counterbalance the overwhelming generation of free radicals. Reactive species interfere with many basic cell functions, mainly through destruction of protein, lipid, and nucleic acid integrity, compromising enzyme function, mitochondrial structure and performance, and intracellular signaling, all leading to cardiac contractile failure. Takotsubo cardiomyopathy may result from oxidative imbalance. This review will address the multiple aspects of cardiomyocyte bioenergetic failure in sepsis and discuss potential therapeutic interventions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jade Carver ◽  
Morgan Meidell ◽  
Zachary J. Cannizzo ◽  
Blaine D. Griffen

AbstractTwo common strategies organisms use to finance reproduction are capital breeding (using energy stored prior to reproduction) and income breeding (using energy gathered during the reproductive period). Understanding which of these two strategies a species uses can help in predicting its population dynamics and how it will respond to environmental change. Brachyuran crabs have historically been considered capital breeders as a group, but recent evidence has challenged this assumption. Here, we focus on the mangrove tree crab, Aratus pisonii, and examine its breeding strategy on the Atlantic Florida coast. We collected crabs during and after their breeding season (March–October) and dissected them to discern how energy was stored and utilized for reproduction. We found patterns of reproduction and energy storage that are consistent with both the use of stored energy (capital) and energy acquired (income) during the breeding season. We also found that energy acquisition and storage patterns that supported reproduction were influenced by unequal tidal patterns associated with the syzygy tide inequality cycle. Contrary to previous assumptions for crabs, we suggest that species of crab that produce multiple clutches of eggs during long breeding seasons (many tropical and subtropical species) may commonly use income breeding strategies.


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