Diabetes and Sperm DNA Damage: Efficacy of Antioxidants

Protective Effect of Black Rice Cyanidin-3-Glucoside on Testicular Damage in STZ-Induced Type 1 Diabetic Rats

Diabetic testicular damage is quite a common and significant complication in diabetic men, which could result in infertility. The natural fertility rate of type 1 diabetes men is only 50% because of testicular damage. This research first aimed to explore the intervention effect of C3G on testicular tissue damage induced by diabetes. Here, a streptozotocin-induced type 1 diabetic rat model was established, and then C3G was administered. After 8 weeks of C3G supplementation, the symptoms of diabetes (e.g., high blood glucose, lower body weight, polydipsia, polyphagia) were relieved, and at the same time that sperm motility and viability increased, sperm abnormality decreased in C3G-treated diabetic rats. Furthermore, the pathological structure of testis was restored; the fibrosis of the testicular interstitial tissue was inhibited; and the LH, FSH, and testosterone levels were all increased in the C3G-treated groups. Testicular oxidative stress was relieved; serum and testicular inflammatory cytokines levels were significantly decreased in C3G-treated groups; levels of Bax, Caspase-3, TGF-β1 and Smad2/3 protein in testis decreased; and the level of Bcl-2 was up-regulated in the C3G-treated groups. A possible mechanism might be that C3G improved antioxidant capacity, relieved oxidative stress, increased anti-inflammatory cytokine expression, and inhibited the apoptosis of spermatogenic cells and testicular fibrosis, thus promoting the production of testosterone and repair of testicular function. In conclusion, this study is the first to reveal that testicular damage could be mitigated by C3G in type 1 diabetic rats. Our results provide a theoretical basis for the application of C3G in male reproductive injury caused by diabetes.

Aubergine stem restores reproductive damages following diabetes mellitus induction in male mice

Diabetes mellitus unbalances cellular antioxidant levels. This phenomenon can potentially lead to cellular damage and apoptosis in the male reproductive system. Besides, herbal-based antioxidants can prevent these detrimental changes. Thus, we assessed the probable role of Aubergine stems with antioxidant and anti-hyperlipidemic characteristics on reproductive damage following diabetes mellitus induction. Forty male NMRI mice were categorized into groups of control and treatments. Diabetes was induced by a single dose of streptozotocin (60 mg/kg), and the extract was administered at various doses (100, 300, and 500 mg/kg) daily for 4 weeks. Antioxidative features of the extract were approved by phytochemical assays and ferric-reducing ability of plasma. Side-effects of diabetes were also assessed by the malondialdehyde (MDA) and Griess techniques. Sperm parameters, LH, FSH, and testosterone levels, the TUNEL assay, histopathologic alteration, and apoptotic genes (p53, caspase-3, Bcl-2) were evaluated. Results showed that diabetes increased oxidation levels and the extract accelerated total antioxidant capacity status. Sperm parameters and hormone levels were restored following extract administration in diabetic animals. Also, the apoptosis rate decreased following extract administration in diabetic animals. We concluded that diabetes can elevate the levels of oxidation and suppress the antioxidant power. These pathologic changes were restored by Aubergine stem, leading to decreased levels of apoptosis and normal serum levels of testosterone, LH, and FSH.

Gut-Gonad Perturbations in Type-1 Diabetes Mellitus: Role of Dysbiosis, Oxidative Stress, Inflammation and Energy-Dysbalance

Type 1 diabetes mellitus is a major metabolic disorder that affects people of all age groups throughout the world. It is responsible for the alterations in male gonadal physiology in experimental models as well as in clinical cases. On the other side, diabetes mellitus has also been associated with perturbations in the gut physiology and microbiota dysbiosis. The accumulating evidence suggests a link between the gut and gonad as evident from the i) experimental data providing insights into type 1 diabetes mellitus induced gut perturbations, ii) link of gut physiology with alterations of testicular health, iii) role of gut microbiota in androgen metabolism in the intestine, and iv) epidemiological evidence linking type 1 diabetes mellitus with inflammatory bowel disease and male infertility. Considering all the pieces of evidence, it is summarized that gut dysbiosis, oxidative stress, inflammation and energy dys-balance are the prime factors involved in the gonadal damage under type 1 diabetes mellitus, in which the gut contributes significantly. Identification of novel biomarkers and intervention of suitable agents targeting these prime factors may be a step forward to restore the gonadal damage in diabetic conditions.

Combination Therapy with Enalapril and Paricalcitol Ameliorates Streptozotocin Diabetes-Induced Testicular Dysfunction in Rats via Mitigation of Inflammation, Apoptosis, and Oxidative Stress

BACKGROUND

As the impacts of diabetes-induced reproductive damage are now evident in young people, we are now in urgent need to devise new ways to protect and enhance the reproductive health of diabetic people. The present study aimed to evaluate the protective effects of enalapril (an ACE inhibitor) and paricalcitol (a vitamin D analog), individually or in combination, on streptozotocin (STZ)-diabetes-induced testicular dysfunction in rats and to identify the possible mechanisms for this protection.

MATERIAL AND METHODS

This study was carried out on 50 male Sprague-Dawley rats; 10 normal rats were allocated as a non-diabetic control group. A total of 40 rats developed diabetes after receiving a single dose of STZ; then, the diabetic rats were divided into four groups of equivalent numbers assigned as diabetic control, enalapril-treated, paricalcitol-treated, and combined enalapril-and-paricalcitol-treated groups. The effects of mono and combined therapy with paricalcitol and enalapril on testicular functions, sperm activity, glycemic state oxidative stress, and inflammatory parameters, as well as histopathological examinations, were assessed in comparison with the normal and diabetic control rats.

RESULTS

As a result of diabetes induction, epididymal sperm count, sperm motility, serum levels of testosterone, follicle-stimulating hormone (FSH) as well as luteinizing hormone (LH), and the antioxidant enzyme activities, were significantly decreased, while abnormal sperm (%), insulin resistance, nitric oxide (NO), malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly increased, along with severe distortion of the testicular structure. Interestingly, treatment with paricalcitol and enalapril, either alone or in combination, significantly improved the sperm parameters, increased antioxidant enzyme activities in addition to serum levels of testosterone, FSH, and LH, reduced insulin resistance, IL-6, and TNF-α levels, and finally ameliorated the diabetes-induced testicular oxidative stress and histopathological damage, with somewhat superior effect for paricalcitol monotherapy and combined therapy with both drugs compared to monotherapy with enalapril alone.

CONCLUSIONS

Monotherapy with paricalcitol and its combination therapy with enalapril has a somewhat superior effect in improving diabetes-induced testicular dysfunction (most probably as a result of their hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic properties) compared with monotherapy with enalapril alone in male rats, recommending a synergistic impact of both drugs.

Dapagliflozin Mitigated Elevated Disomic and Diploid Sperm in a Mouse Model of Diabetes and Recover the Disrupted Ogg1, Parp1, and P53 Gene Expression

Increases in numerical chromosomal syndromes were observed in children of diabetic mothers. However, the effects of diabetes on male reproduction, specifically numerical chromosomal aberrations (aneuploidy), have not been studied. Furthermore, despite the increasing use of dapagliflozin for diabetes treatment, no data exists on its ability to affect aneuploidy levels in germ cells. Thus, our investigation aimed to evaluate the effects of diabetes on spontaneous sperm aneuploidy and whether treatment with dapagliflozin influences the frequency of aneuploidy in the sperm of an experimental diabetic animal model. Our findings show that dapagliflozin has no aneugenic effects on the meiotic stages of spermatogenesis. In contrast, diabetes raised the frequency of aneuploidy, and dapagliflozin administration decreased the elevated levels of disomic and diploid sperm. The level of oxidative stress was markedly increased in diabetic mice, but were reduced by dapagliflozin treatment. Furthermore, the expression of some of DNA repair genes was disrupted in diabetic animals, whereas dapagliflozin therapy restored these disruptions and significantly enhanced DNA repair. Thus, dapagliflozin may effectively ameliorate diabetes-induced aneugenic effects on male meiosis and treating diabetic patients with dapagliflozin may effectively mitigate the transmission of diabetes-induced chromosomal defects to offspring.

Ameliorative effect of Stevia rebaudiana Bertoni on sperm parameters, in vitro fertilization, and early embryo development in a streptozotocin-induced mouse model of diabetes

Diabetes mellitus (DM) is a common metabolic disease characterized by high blood sugar levels. It is well known that men with diabetes frequently experience reproductive disorders and sexual dysfunction. In fact, sperm quality has a significant effect on fertilization success and embryo development. The current study aimed to investigate the effect of Stevia rebaudiana hydroalcoholic extract on serum testosterone levels, sperm parameters, in vitro fertilization (IVF) success, and in vitro embryonic developmental potential to reach the blastocyst stage in a streptozotocin (STZ)-induced mouse model of diabetes. In this research, 30 male mice were distributed randomly into control, diabetic (streptozotocin 150 mg/kg) and diabetic + Stevia (400 mg/kg) groups. The results revealed a decrease in body and testis weight and elevated blood fasting blood sugar (FBS) levels in the diabetic group, compared with the control. However, Stevia treatment significantly increased body and testis weight, while serum FBS levels were decreased compared with the diabetic group. In addition, Stevia significantly increased blood testosterone levels compared with the diabetic group. Moreover, sperm parameters were improved considerably by Stevia treatment compared with the diabetic group. Furthermore, Stevia administration significantly promoted IVF success rate and in vitro development of fertilized oocytes compared with the diabetic group. In summary, our data indicated that Stevia enhanced sperm parameters, IVF success, and in vitro embryonic developmental competency in diabetic mice, probably because of its antioxidant effects. Therefore, Stevia could ameliorate sperm parameters that, in turn, increase fertilization outcomes in experimental-induced diabetes.

Actinidia deliciosa Extract as a Promising Supplemental Agent for Hepatic and Renal Complication-Associated Type 2 Diabetes (In Vivo and In Silico-Based Studies)

Type 2 diabetes (T2D) is a chronic metabolic condition associated with obesity, oxidative stress-mediated inflammation, apoptosis, and impaired insulin signaling. The utilization of phytochemical therapy generated from plants has emerged as a promising approach for the treatment of diabetes and its complications. Kiwifruit is recognized for its substantial content of antioxidative phenolics. Therefore, this work aimed to examine the effect of Actinidia deliciosa (kiwi fruit) on hepatorenal damage in a high-fat diet (HFD) and streptozotocin (STZ)-induced T2D in rats using in vivo and in silico analyses. An increase in hepatic and renal lipid peroxidation was observed in diabetic rats accompanied by a decrease in antioxidant status. Furthermore, it is important to highlight that there were observable inflammatory and apoptotic responses in the hepatic and renal organs of rats with diabetes, along with a dysregulation of the phosphorylation levels of mammalian target of rapamycin (mTOR), protein kinase B (Akt), and phosphoinositide 3-kinase (PI3K) signaling proteins. However, the administration of kiwi extract to diabetic rats alleviated hepatorenal dysfunction, inflammatory processes, oxidative injury, and apoptotic events with activation of the insulin signaling pathway. Furthermore, molecular docking and dynamic simulation studies revealed quercetin, chlorogenic acid, and melezitose as components of kiwi extract that docked well with potential as effective natural products for activating the silent information regulator 1(SIRT-1) pathway. Furthermore, phenolic acids in kiwi extract, especially syringic acid, P-coumaric acid, caffeic acid, and ferulic acid, have the ability to inhibit the phosphatase and tensin homolog (PTEN) active site. In conclusion, it can be argued that kiwi extract may present a potentially beneficial adjunctive therapy approach for the treatment of diabetic hepatorenal complications.

TMT-based quantitative proteomics analysis reveals the differential proteins between fresh and frozen-thawed sperm of yak (Bos grunniens)

Sperm cryopreservation is one of the most effective methods for the conservation of germplasm resources and used of superior sires widely. However, the motility of yak (Bos grunniens) sperm was low after thawing and the proteomics changes in sperm cryopreservation remain unknown. Therefore, the aim of this study was to explore the differences between fresh sperm and frozen sperm of yak through the proteomic analysis and thus improve the understanding of sperm cryodamage. The Tandem Mass Tags (TMT) technology was used to screen differentially expressed proteins (DEPs) before and after freezing. Then, GO and KEGG analysis were conducted to analyze the DEPs enriched signaling pathways. Finally, the DEPs, including superoxide dismutase 1 (SOD1) and NADH ubiquinone oxidoreductase core subunit S8 (NDUFS8) were verified by the immunofluorescence technique. The results showed that there were 229 DEPs between fresh and frozen-thawed yak sperm. Compared with the fresh sperm, 120 proteins were up-regulated and 109 proteins were down-regulated in frozen-thawed sperm. The GO annotation showed that the up-regulated proteins enriched in metabolic and cytoskeleton-related processes, including lipoprotein metabolic process, lipid transport, extracellular region and intermediate filament cytoskeleton organization. In contrast, the down-regulated proteins enriched in biological processes including single fertilization, sperm capacitation and response to unfolded protein. KEGG pathway analysis indicated that freezing and thawing affected the oxidative phosphorylation pathway, the fructose and mannose metabolic pathway and the glycerolipid metabolic pathway of yak sperm. Immunofluorescence results showed that the protein expression level of SOD1 protein in the frozen group was significantly lower than that in the fresh group (P < 0.01), and the protein expression level of NDUFS8 protein was significantly higher in frozen group (P < 0.01). This study revealed the DEPs between fresh and frozen-thawed sperm and provides a theoretical basis to further explore the exertion of normal biological functions of yak sperm after freezing and thawing.

Trifolium pratense extract increases testosterone and improves sperm characteristics and antioxidant status in diabetic rats

Male reproductive dysfunction is a common complication of diabetes mellitus. Trifolium pratense exhibits antioxidant and antidiabetic effects. We investigated the effects of an extract of T. pratense on serum antioxidant status, sperm characteristics, testicular tissue changes and testosterone level in diabetic rats. Male Wistar rats were divided into six groups: 1, untreated control; 2, diabetic; 3 and 4, 100 or 200 mg/kg T. pratense extract treated, respectively; 5 and 6, diabetic 100 or 200 mg/kg T. pratense extract treated, respectively. Diabetes was induced by intraperitoneal injection of streptozotocin. After 3 weeks, serum glucose, testosterone and nitric oxide (NO); sperm parameters; testicular histology and total antioxidant capacity (TAC) were evaluated. In diabetic rats treated with T. pratense extract, sperm motility, count and viability, as well as TAC and testosterone were increased significantly compared to untreated diabetic rats, while serum NO and bcl-2 and p53 expression was decreased significantly compared to untreated diabetic rats. T. pratense extract reduced testicular tissue destruction caused by diabetes.

Ellagic acid improved diabetes mellitus-induced testicular damage and sperm abnormalities by activation of Nrf2

Diabetes mellitus induces testicular damage, increases sperm abnormalities, and impairs reproductive dysfunction due to induction of endocrine disturbance and testicular oxidative stress. This study evaluated the reproductive protective effect of ellagic acid (EA) against testicular damage and abnormalities in sperm parameters in Streptozotocin (STZ)-induced diabetic rats (T1DM) and examined some possible mechanisms of protection. Adult male rats were segregated into 5 groups (n = 12 rat/each) as control, control + EA (50 mg/kg/day), T1DM, T1DM + EA, and T1DM + EA + brusatol (an Nrf-2 inhibitor) (2 mg/twice/week). All treatments were conducted for 12 weeks, daily. EA preserved the structure of the seminiferous tubules, prevented the reduction in sperm count, motility, and viability, reduced sperm abnormalities, and downregulated testicular levels of cleaved caspase-3 and Bax in diabetic rats. In the control and diabetic rats, EA significantly increased the circulatory levels of testosterone, reduced serum levels of FSH and LH, and upregulated Bcl-2 and all steroidogenic genes (StAr, 3β-HSD1, and 11β-HSD1). Besides, it reduced levels of ROS and MDA but increased levels of GSH and MnSOD and the transactivation of Nrf2. All these biochemical alterations induced by EA were associated with increased activity and nuclear accumulation of Nrf2. However, all these effects afforded by EA were weakened in the presence of brusatol. In conclusion, EA could be an effective therapy to alleviated DM-induced reproductive toxicity and dysfunction in rats by a potent antioxidant potential mediated by the upregulation of Nrf2.

The molecular mechanism behind insulin protective effects on testicular tissue of hyperglycemic rats

AIMS

The present study assessed the possible mechanisms by which the insulin regulates the heat shock (HSPs) and transitional proteins expression and consequently ameliorates the oxidative stress-induced damages in germ and sperm cells DNA contents.

MAIN METHODS

Mature male Wistar rats were distributed into control, Hyperglycemia-induced (HG) and insulin-treated HG-induced (HG-I) groups. Following 8 weeks from HG induction, testicular total antioxidant capacity (TAC), immunoreactivity of 8-oxodG, germ cells mRNA damage, Hsp70-2a, Hsp90, transitional proteins 1 and 2 (TP-1 and -2) mRNA and protein expressions were analyzed. Moreover, the sperm chromatin condensation was assessed by aniline-blue staining, and DNA integrity of germ and sperm cells were analyzed by TUNEL and acrdine-orange staining techniques.

KEY FINDINGS

The HG animals exhibited significant (p < 0.05) reduction in TAC, HSp70-2a, TP-1 and TP-2 expression levels, and increment in 8-oxodG immunoreactivity, mRNA damage, and Hsp90 expression. However, insulin treatment resulted in (p < 0.05) enhanced TAC level, Hsp70-2a, Hsp90, TP-1 and TP-2 expressions, besides reduced 8-oxodG immunoreactivity and mRNA damage compared to the HG group (p < 0.05). The chromatin condensation and the germ and sperm cells DNA fragmentation were decreased in HG-I group.

SIGNIFICANCE

Insulin treatment amplifies the testicular TAC level, improves the Hsp70-2a, TP-1, and TP-2 expressions, and boosts the Hsp90-mediated role in DNA repairment process. Consequently, altogether could maintain the HG-induced DNA integrity in the testicular and sperm cells.

Momordica cymbalaria improves reproductive parameters in alloxan-induced male diabetic rats

Male reproductive dysfunction is one of the common complications of diabetes mellitus that causes infertility. This study was designed to investigate the protective effect of Momordica cymbalaria (M. cymbalaria) extracts on diabetes mediated reproductive toxicity in male Wistar rats. The induction of diabetes was performed using a single intraperitoneal injection of alloxan (120 mg/kg). Skin and seed extracts (250 and 500 mg/kg) of M. cymbalaria were orally administered to alloxan-induced diabetic male rats for 28 days. Postprandial blood glucose (PBG) levels were recorded at 7-day interval for four weeks. The effects of the treatment on blood glucose, weight of reproductive organs, sperm count, testosterone levels, antioxidant capacity, and histomorphology were evaluated. Treatment with the above extracts of M. cymbalaria significantly (p < 0.05) improved the reproductive parameters as well as the antioxidant levels superoxide dismutase (SOD) and glutathione-s-transferase (GST) in the diabetic rats. Also, oral treatment with M. cymbalaria extracts significantly reduced the PBG and malondialdehyde (MDA) levels. Further, it revived the histomorphology of reproductive organs in diabetic rats. Interestingly, skin extract at a dose of 500 mg/kg was found to be more efficient in elevating the level of testosterone and sperm count in the diabetic rats. Based on the results, it is clear that M. cymbalaria not only regulates the postprandial blood glucose levels but also improves the reproductive health in the diabetic state.

Sperm parameters, DNA integrity, and protamine expression in patients with type II diabetes mellitus

Diabetes Mellitus (DM) is the most common endocrine disorder affecting many human physiological systems and tissues, including the reproductive organs in men. The age of individuals suffering from this disease has been falling rapidly in recent years. This study compared the effect of DM on sperm parameters, chromatin quality, and apoptosis, as well as the expression profile of protamine genes in men with and without DM using molecular and cytochemical assays. Sixty semen samples from the control group (N = 30) and case group (N = 30) were collected. There was a significant decrease in the percentages of sperm parameters in cases versus the controls (p˂0.05). Despite significantly higher percentages detected in spermatozoa with AB⁺, CMA3⁺, and TUNEL⁺, no change was demonstrated regarding protamines mRNA levels, as well as the P1/P2 ratios in cases in comparison with controls. In contrast, significant positive correlations were found between the quantity of P1 and P2 transcripts (r = 0.944, p < .001). The data indicated that DM not only caused a decrease in the quality of sperm parameters but also affected the sperm maturation process by increasing the substantial implications in the sperm DNA/chromatin levels of DM patients.IMPACT STATEMENTWhat is already known on this subject? Diabetes Mellitus (DM) is a chronic metabolic disorder affecting many human physiological systems and tissues, including the reproductive organs in men. The age of individuals suffering from this disease has been falling rapidly in recent years.What do the results of this study add? We found that DM not only caused a decrease in the quality of the sperm parameters, including motility and concentration, and an increase in morphological abnormalities but also affected the sperm maturation process by increasing the substantial implications in sperm DNA/chromatin levels of DM patients. Despite there being no significant difference in the mRNA levels of protamines between the two groups, our findings showed a positive correlation between the mRNA levels of P1 and progressive sperm motility.What are the implications of these findings for clinical practice and/or further research? Based on the results of this study, chromatin and DNA assessments can have important implications for increasing fertility, as complementary tests, in combination with routine laboratory tests. Since sperm standard parameters are not capable of examining the condition of the sperm nucleus, men with abnormal sperm DNA can also have normal spermatogram, and diabetes is prevalent in reproductive age.

Acquired Sperm DNA Modifications: Causes, Consequences, and Potential Solutions

DNA of human spermatozoa can be subject to various kinds of modifications acquired throughout life. Put simply, two basic types of acquired sperm DNA modifications can be distinguished: genetic and epigenetic. Genetic modifications cause alterations of the DNA sequence and mainly result from the formation of breakpoints leading to sperm DNA fragmentation. Epigenetic modifications include a vast spectrum of events that influence the expression of different genes without altering their DNA sequence. Both the genetic and the epigenetic modifications of sperm DNA can negatively influence embryonic development, cause miscarriages, and be the origin of different health problems for the offspring. As to sperm DNA fragmentation, reliable diagnostic methods are currently available. On the other hand, the detection of potentially harmful epigenetic modifications in spermatozoa is a much more complicated issue. Different treatment options can be chosen to solve problems associated with sperm DNA fragmentation. Some are relatively simple and noninvasive, based on oral treatments with antioxidants and other agents, depending on the underlying cause. In other cases, the recourse to different micromanipulation-assisted in vitro fertilisation techniques is necessary to select spermatozoa with minimal DNA damage to be injected into oocytes. The treatment of cases with epigenetic DNA modifications is still under investigation. Preliminary data suggest that some of the techniques used in cases of extensive DNA fragmentation can also be of help in those of epigenetic modifications; however, further progress will depend on the availability of more reliable diagnostic methods with which it will be possible to evaluate the effects of different therapeutic interventions.