Germ cell abnormalities in streptozotocin induced diabetic mice do not correlate with blood glucose level

Effects of diabetes-induced hyperglycemia on epigenetic modifications and DNA packaging and methylation during spermatogenesis; A narrative review

The impact of diabetes on various organs failure including testis has been highlighted during the last decades. If on one hand diabetes-induced hyperglycemia has a key role in induced damages; on the other hand, glucose deprivation plays a key role in inducing male infertility. Indeed, glucose metabolism during spermatogenesis has been highlighted due to post-meiotic germ cells drastic dependence on glucose-derived metabolites, especially lactate. In fact, hyperglycemia-induced spermatogenesis arrest has been demonstrated in various studies. Moreover, various sperm maturation processes related to sperm function such as motility are directly depending on glucose metabolism in Sertoli cells. It has been demonstrated that diabetes-induced hyperglycemia adversely impacts sperm morphology, motility and DNA integrity, leading to infertility. However, fertility quality is another important factor to be considered. Diabetes-induced hyperglycemia is not only impacting sperm functions, but also affecting sperm epigenome. DNA packing process and epigenetics modifications occur during spermatogenesis process, determining next generation genetic quality transmitted through sperm. Critical damages may occur due to under- or downregulation of key proteins during spermatogenesis. Consequently, unpacked DNA is more exposed to oxidative stress, leading to intensive DNA damages. Moreover, epigenetic dysregulation occurred during spermatogenesis may impact embryo quality and be transmitted to next generations, increasing offspring genetic issues. Herein we discuss the mechanisms by which diabetes-induced hyperglycemia can affect epigenetic modifications and DNA packaging and methylation during spermatogenesis thus promoting long-lasting effects to the next generation.

Impact of Temperature and Time Interval Prior to Immature Testicular-Tissue Organotypic Culture on Cellular Niche

Cryopreservation of immature-testicular-tissue (ITT) prior to gonadotoxic treatment, while experimental, is the only recommended option for fertility preservation in prepubertal boys. The handling and manipulation of ITT before cryopreservation could influence the functionality of cells during fertility restoration, which this study explored by evaluating cellular niche and quality of mouse ITT subjected to various temperatures and time durations in vitro. ITT from 6-day-old mice were handled at ultraprofound-hypothermic, profound-hypothermic, and mild-warm-ischemic temperatures for varying time periods prior to 14-day organotypic culture. Viability, functionality, synaptonemal complex and chromatin remodeling markers were assessed. Results have shown that cell viability, testosterone level, and in vitro proliferation ability did not change when ITT were held at ultraprofound-hypothermic-temperature up to 24 h, whereas cell viability was significantly reduced (P < 0.01), when held at profound-hypothermic-temperature for 24 h before culture. Further, cell viability and testosterone levels in cultured cells from profound-hypothermic group were comparable to corresponding ultraprofound-hypothermic group but with moderate reduction in postmeiotic cells (P < 0.01). In conclusion, holding ITT at ultraprofound-hypothermic-temperature is most suitable for organotypic culture, whereas short-term exposure at profound-hypothermic-temperature may compromise postmeiotic germ cell yield post in vitro culture. This data, albeit in mouse model, will have immense value in human prepubertal fertility restoration research.

Comments on "The improvement Effects of Gordonia bronchialis on Male Fertility of Rats with Diabetes Mellitus Induced by Streptozotocin"

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Comparison of male reproductive parameters in mice with type 1 and type 2 diabetes

OBJECTIVE

The differences between type 1 and type 2 diabetes mellitus (T1DM and T2DM) in terms of their adverse effects on male reproductive parameters have never been elucidated. This study aimed to distinguish between the effects of the DM types in mice treated with multiple low doses of streptozotocin (STZ) to mimic human T1DM and coadministered a high-fat diet (HFD) to mimic human T2DM.

METHODS

The T1DM mice were intraperitoneally injected with STZ (40 mg/kg body weight) for 5 days. The T2DM mice received an HFD for 14 days prior to STZ injection (85 mg/kg body weight), followed by continuous feeding of an HFD. Male reproductive parameters were evaluated.

RESULTS

The reproductive organs of the DM mice weighed significantly less than those of controls, and the seminal vesicles plus prostates of the T1DM mice weighed less than those of the T2DM mice. Increased sperm abnormalities and incomplete DNA packaging were observed in the DM groups. Sperm concentration and the proportion of normal sperm were significantly lower in the T1DM group. The seminiferous histopathology of DM mice was classified into seven types. The penises of the DM mice were smaller than those of the controls; however, tunica albuginea thickness and the amount of penile collagen fibers were increased in these mice. Round germ cells were abundant in the epididymal lumens of the mice with DM.

CONCLUSION

T1DM adversely affected reproductive parameters to a greater extent than T2DM.

The Oleo-Gum-Resin of Commiphora myrrha Ameliorates Male Reproductive Dysfunctions in Streptozotocin-Induced Hyperglycemic Rats

Background: The oleo-gum-resin of Commiphora myrrha (myrrh) has a long history of therapeutic use in traditional medicine. The aim of this study was to seek for the scientific evidence to determine whether the ethanolic extract of myrrh (EEM) has any beneficial effects on Streptozotocin (STZ) induced testicular impairments, and explore the possible mechanisms underlying such actions. Methods: Forty-eight severe and complicated diabetic rats (fasting blood glucose above 350 mg/dL), randomly were divided into six equal groups (n=8). Besides, eight healthy rats allocated as a normal control group and only treated with vehicle solution. The diabetic animals orally received the extract (100, 200, 300, and 500 mg/kg), metformin (500 mg/kg) or vehicle solution for 28 days. As a final point, plasma glucose and insulin, circulatory sex hormones, sperm parameters including sperm concentration, motility and viability and also testicular malondialdehyde (MDA) levels were assessed. Furthermore, quantitative histological evaluation of seminiferous tubules area and determination of germinal cells apoptosis were performed. Results: None of the studied doses of EEM showed anti-diabetic effects. However, the extract mainly at the maximum dose (500 mg/kg) exhibited beneficial effects on reproductive impairments. The EEM treated rats mainly at 500 mg/kg had significantly higher sperm concentration, sperm motility, sperm viability, sex hormones and lower testicular MDA and germ cell apoptosis index than untreated diabetic rats. Conclusion: These results indicated that EEM may have beneficial effects against reproductive dysfunction induced by diabetes. The mechanisms behind the effects might be associated with the EEM sex hormone booster potential, antioxidant and anti-apoptotic properties.

Expression of testicular phosphorylated proteins in types 1 and 2 diabetes mellitus in mice: An experimental study

Background

Types 1 and 2 diabetes mellitus (DM) are known to be the cause of sub/infertility. However, the comparisons of potential markers in spermatogenesis and steroidogenesis in DM males have never been elucidated.

Objective

This study aimed to examine the expressions of tyrosine-phosphorylated and steroidogenic acute regulatory (StAR) proteins in testis of DM mice.

Materials and Methods

Fifty-six male C57BL/6 mice were divided into four groups (n░=░14/ each): control of MLD-STZ (multiple low doses of streptozotocin), MLD-STZ, control of HFD-STZ (high-fat diet with STZ), and HFD-STZ. MLD-STZ mice (type 1 DM) were intraperitoneally (i.p.) injected with STZ at 40░mg/kg BW for five days. HFD-STZ mice (type 2 DM) received an HFD for 14 days and i.p.-induced by STZ at 85░mg/kg BW and fed with HFD. At the end of the experiment (days 36 and 72), the expressions of phosphorylated proteins and StAR were examined.

Results

Tyrosine phosphorylated proteins were localized in late spermatids, luminal fluid, and Leydig cells. The intensities of phosphorylated 110, 85, 72, 60, and 55░kDas were lower in the 36 day-DM mice. Although such intensities were present in both groups, only 85░kDa in the MLD-STZ mice was higher in HFD mice at 72 days. StAR expressions in both groups were decreased than that of the controls.

Conclusion

Decreased expressions of StAR and tyrosine-phosphorylated proteins may be directly involved in low testosterone levels and impaired spermatogenesis. These findings support the notion that both DM types play a role in male infertility.

The effects of diabetes on male fertility and epigenetic regulation during spermatogenesis

The effects of diabetes mellitus include long-term damages, dysfunctions, and failures of various organs. An important complication of diabetes is the disturbance in the male reproductive system. Glucose metabolism is an important event in spermatogenesis. Moreover, glucose metabolism is also important for maintaining basic cell activity, as well as specific functions, such as motility and fertilization ability in mature sperm. Diabetic disease and experimentally induced diabetes both demonstrated that either type 1 diabetes or type 2 diabetes could have detrimental effects on male fertility, especially on sperm quality, such as sperm motility, sperm DNA integrity, and ingredients of seminal plasma. Epigenetic modifications are essential during spermatogenesis. The epigenetic regulation represents chromatin modifications including DNA methylation, histone modifications, remodeling of nucleosomes and the higher-order chromatin reorganization and noncoding RNAs. If spermatogenesis is affected during the critical developmental window, embryonic gonadal development, and germline differentiation, environmentally-induced epigenetic modifications may become permanent in the germ line epigenome and have a potential impact on subsequent generations through epigenetic transgenerational inheritance. Diabetes may influence the epigenetic modification during sperm spermatogenesis and that these epigenetic dysregulation may be inherited through the male germ line and passed onto more than one generation, which in turn may increase the risk of diabetes in offspring.

DNA methylation in spermatogenesis and male infertility

Infertility is a significant problem for human reproduction, with males and females equally affected. However, the molecular mechanisms underlying male infertility remain unclear. Spermatogenesis is a highly complex process involving mitotic cell division, meiosis cell division and spermiogenesis; during this period, unique and extensive chromatin and epigenetic modifications occur to bring about specific epigenetic profiles in spermatozoa. It has recently been suggested that the dysregulation of epigenetic modifications, in particular the methylation of sperm genomic DNA, may serve an important role in the development of numerous diseases. The present study is a comprehensive review on the topic of male infertility, aiming to elucidate the association between sperm genomic DNA methylation and poor semen quality in male infertility. In addition, the current status of the genetic and epigenetic determinants of spermatogenesis in humans is discussed.

Effects of Hydro-Alcoholic Extract of Rhus coriaria (Sumac) Seeds on Reproductive Complications of Nicotinamide-Streptozotocin Induced Type-2 Diabetes in Male Mice

PURPOSE

The purpose of this study was to investigate the effects of the hydro-alcoholic extract of Rhus coriaria seeds on the reproductive system of nicotinamide-streptozotocin-induced type-2 diabetic mice.

MATERIALS AND METHODS

In this experimental study, 56 male Naval Medical Research Institute mice were randomly divided into seven groups (n=8): control; diabetic mice; diabetic mice administered glibenclamide (0.25 mg/kg); diabetic mice who received the hydro-alcoholic extract of R. coriaria seeds (200 and 400 mg/kg groups); and normal mice who received this extract (200 and 400 mg/kg groups). Diabetes was induced by intraperitoneal administration of streptozotocin (65 mg/kg) 15 minutes after an injection of nicotinamide (120 mg/kg). Then, glibenclamide and the above mentioned extract were administered orally for 28 consecutive days. Twenty-four hours after the last treatment, serum samples, the testes, and the cauda epididymis were removed immediately for hormonal, testis morphology, and sperm parameter assessments.

RESULTS

Body and testicular weight, sperm count and viability, and serum luteinizing hormone, follicle-stimulating hormone and testosterone levels were significantly lower in the diabetic mice (p<0.05). The diabetic mice treated with 400 mg/kg of the hydro-alcoholic extract of R. coriaria seeds recovered from these reductions (p<0.05). Further, glibenclamide alleviated hormonal and sperm count depletion in diabetes-induced mice (p<0.05).

CONCLUSIONS

The present results indicated that the hydro-alcoholic extract of R. coriaria seeds has anti-infertility effects in diabetic males.