Protective effects of sodium nitrate against testicular apoptosis and spermatogenesis impairments in streptozotocin-induced diabetic male rats

Modulatory effects of Moringa oleifera leaf extract on sodium nitrate-induced experimental colitis via regulation of P53, Ki-67 and PCNA biomarkers

BACKGROUND

Ulcerative colitis is a risk factor for colorectal carcinoma. Different mechanisms are related to colitis like apoptosis and hyperproliferation. Moringa oleifera leaves extract (MO) provides a promising option to overcome the risk.

PURPOSE

To examine the colonic changes in a rat model of colitis induced by sodium nitrate (SN) and study the effects of MO.

STUDY DESIGN

Eight adult male rats were allocated in each of the three group; control (distilled water), SN (100 mg/kg/day, orally via gastric gavage), and SN + MO (100 mg/kg/day, orally via gastric gavage).

METHODS

Body weight was measured after the end of the experiment. Colonic homogenates were tested for levels of oxidative stress indicators. Immunohistochemistry for P53, PCNA and Ki-67 was performed. Fresh colon specimens were used for quantitative real-time PCR for assessment of P53, PCNA and Ki-67 gene expression.

RESULTS

SN group revealed a significant decreased weight (p = 0.002). MDA and NO levels were higher with SN administration than with MO co-administration (p= 0.04, 0.01 respectively). GSH level was reduced in SN group (p = 0.02) and significantly increased with MO intake (p = 0.04). SN-induced colonic destructive changes were reversed with MO. P53, PCNA and Ki-67 levels of gene expression were reduced in SN + MO group than SN group (P = 0.007, 0.02, 0.001 respectively).

CONCLUSION

MO protected the colonic mucosa against SN-induced changes regulating apoptosis, and cell proliferation.

Atg7 senses ATP levels and regulates AKT1-PDCD4 phosphorylation-ubiquitination axis to promote survival during metabolic stress

We report that autophagy-related gene 7 (ATG7) modulates p53 activity to regulate cell cycle and survival during metabolic stress, and that indicates Atg7 is functionally involved in cellular homeostasis in autophagy independent fashion. As a protein translation inhibitor, Programmed cell death 4 (PDCD4) expression is regulated by AKT1 phosphorylation. Here, we find that Atg7 interacts with PDCD4 and AKT1 to regulate AKT1-PDCD4 phosphorylation-ubiquitination axis during metabolic stress. We demonstrate that Atg7 senses decrease of ATP levels to suppress AKT-mediated PDCD4 phosphorylation at Ser67, which inhibits PDCD4 ubiquitinating during metabolic stress. Finally, PDCD4 accumulates and functions as a protein translation inhibitor to conserve energy, thus reducing apoptosis and allowing cells to survive stress periods. These results suggest that the ATP-Atg7-PDCD4 axis acts as a metabolic adaptation pathway which dictates cells to overcome metabolic stress.

Oral administration of Turnera diffusa willd. ex Schult. extract ameliorates steroidogenesis and spermatogenesis impairment in the testes of rats with type-2 diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Turnera diffusa Willd. ex Schult. (T. diffusa) has traditionally been used to treat male reproductive dysfunction and have aphrodisiac properties.

AIMS OF THE STUDY

This study aims to investigate the ability of T. diffusa to ameliorate the impairment in testicular steroidogenesis and spermatogenesis in DM that might help to improve testicular function, and subsequently restore male fertility.

MATERIALS AND METHODS

DM-induced adult male rats were given 100 mg/kg/day and 200 mg/kg/day T. diffusa leaf extract orally for 28 consecutive days. Rats were then sacrificed; sperm and testes were harvested and sperm parameter analysis were performed. Histo-morphological changes in the testes were observed. Biochemical assays were performed to measure testosterone and testicular oxidative stress levels. Immunohistochemistry and double immunofluorescence were used to monitor oxidative stress and inflammation levels in testes as well as Sertoli and steroidogenic marker proteins' expression.

RESULTS

Treatment with T. diffusa restores sperm count, motility, and viability near normal and reduces sperm morphological abnormalities and sperm DNA fragmentation in diabetic rats. T. diffusa treatment also reduces testicular NOX-2 and lipid peroxidation levels, increases testicular antioxidant enzymes (SOD, CAT, and GPx) activities, ameliorates testicular inflammation via downregulating NF-ΚB, p-Ikkβ and TNF-α and upregulating IκBα expression. In diabetic rats, T. diffusa treatment increases testicular steroidogenic proteins (StAR, CYP11A1, SHBG, and ARA54, 3 and 17β-HSD) and plasma testosterone levels. Furthermore, in diabetic rats treated with T. diffusa, Sertoli cell marker proteins including Connexin 43, N-cadherin, and occludin levels in the testes were elevated.

CONCLUSION

T. diffusa treatment could help to ameliorate the detrimental effects of DM on the testes, thus this plant has potential to be used to restore male fertility.

Asparagus Fructans as Emerging Prebiotics

Commercial fructans (inulin and oligofructose) are generally obtained from crops such as chicory, Jerusalem artichoke or agave. However, there are agricultural by-products, namely asparagus roots, which could be considered potential sources of fructans. In this work, the fructans extracted from asparagus roots and three commercial ones from chicory and agave were studied in order to compare their composition, physicochemical characteristics, and potential health effects. Asparagus fructans had similar chemical composition to the others, especially in moisture, simple sugars and total fructan contents. However, its contents of ash, protein and phenolic compounds were higher. FTIR analysis confirmed these differences in composition. Orafti^®GR showed the highest degree of polymerization (DP) of up to 40, with asparagus fructans (up to 25) falling between Orafti^®GR and the others (DP 10-11). Although asparagus fructan powder had a lower fructan content and lower DP than Orafti^®GR, its viscosity was higher, probably due to the presence of proteins. The existence of phenolic compounds lent antioxidant activity to asparagus fructans. The prebiotic activity in vitro of the four samples was similar and, in preliminary assays, asparagus fructan extract presented health effects related to infertility and diabetes diseases. All these characteristics confer a great potential for asparagus fructans to be included in the prebiotics market.

The role of vasopressin V1A and oxytocin OTR receptors in protective effects of arginine vasopressin against H2O2-induced oxidative stress in H9C2 cells

BACKGROUND

Oxidative stress, has been shown to play an important role in the pathophysiology of cardiac remodelling and heart failure. The aim of study is effect of arginine vasopressin (AVP) on apoptosis of cardiomyocyte via its receptors.

MATERIALS AND METHODS

The cell viability effect of AVP in H9C2 cardiomyocytes was assayed using the MTT method. The transcription and translation level of apoptosis genes (Bax, Bcl-2, caspase-3) were discovered with qRT-PCR and western blotting.

RESULTS

The results showed that vasopressin could reduce apoptosis in cardiomyocytes cell line through downregulation of caspase-3, BAX and upregulation of Bcl-2 (p < .001). Also, there was a decrease in anti-apoptosis effect of vasopressin when V1A and OTR receptors were blocked with their antagonists.

DISCUSSION

These results suggest that activation of V1A and OTR receptors in H9C2 cells mediate protective effect of vasopressin via regulating apoptosis marker that lead to cell survival under conditions of stress oxidative.Key pointAVP may contribute to the improvement of heart ischaemia through its actions on V1A and OTR receptors.

The Effect of Chlorogenic Acid on Endoplasmic Reticulum Stress and Steroidogenesis in the Testes of Diabetic Rats: Study of mRNA Expressions of GRP78, XBP1s, 3β-HSD, and 17β-HSD

Diabetes mellitus (DM) is a chronic endocrine metabolic disorder that can increase the incidence of infertility. Excessive production of reactive oxygen species (ROS) can trigger oxidative stress reactions and reduce antioxidant content. The increase of ROS can exert an impact on the endoplasmic reticulum (ER) stress conditions and inhibit the steroidogenesis of the testes. The objectives of the current study were to determine the effect of chlorogenic acid (CGA) as an antioxidant in reducing ER stress conditions (mRNA expressions of GRP78, XBP1s), and to increase steroidogenesis (mRNA expressions of 3β-HSD and 17β-HSD) in the testis of DM rats. A total of 24 rats were randomly divided into six groups, namely: control group, DM1.5 months, DM2 months, and DM group were treated with CGA with three different doses (12.5 mg/kgBW, 25 mg/kgBW, and 50 mg/kgBW), respectively. Testicular tissue was isolated for examination of GRP78, XBP1s, 3β-HSD, and 17β-HSD mRNA expressions using RT-PCR. In the CGA1 group, GRP78 mRNA expression level was lower than in the DM2 group and was statistically different (p=0.021). XBP1s mRNA expression in the CGA1 group was lower and significantly different when compared to the DM2 group (p=0.018). The mRNA expression of 3β -HSD in the CGA1 group was higher than that in the DM1.5 and DM2 groups, which were statistically significant with p=0.000 and p=0,008. The comparison of 17β - HSD mRNA expression in the CGA1 group was higher than the DM1,5 and DM2 groups with p=0.013 and p=0.012. Administration of CGA at a dose of 12.5 mg/kgBW can reduce ER stress conditions and increase testicular steroidogenesis in DM rat models. These results were seen based on low GRP78 and XBP1s mRNA expressions, and high 3β-HSD and 17β-HSD mRNA expressions after CGA administration.

Beyond the mean: Quantile regression to differentiate the distributional effects of ambient PM2.5 constituents on sperm quality among men

Ambient PM_2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter) constituents have been related to mean changes in semen quality, but focusing on the mean response may not well capture distributional and heterogeneous effects of PM_2.5 constituents on semen quality. In this study, 2314 semen samples of 622 men between Jan 1, 2019 and Dec 31, 2019 from Guangdong Human Sperm Bank were subjected to semen quality analysis. Daily average concentrations of PM_2.5 constituents including 4 water-soluble ions and 15 metals/metalloid were measured for 7 days per month at 3 fixed atmospheric pollutant monitoring stations. We used quantile regression for longitudinal data to examine whether the associations between PM_2.5 constituents and quality indicators of semen varied across quantiles of outcome distribution. Heterogeneous associations were found between PM_2.5 constituents and sperm quality across different quantiles. An interquartile range (14.0 μg/m³) increase in PM_2.5 mass was negatively associated with lower tails of sperm concentration and upper tails of sperm count distribution. PM_2.5 vanadium exposure was significantly related to the 90th percentile of sperm count distribution, but not to the lower quantiles. In addition, those subjects with relatively high sperm motility were more susceptible to sulfate, chromium, and manganese constituents in PM_2.5. Our results indicate that PM_2.5 and certain constituents were associated with sperm quality, especially sperm motility, and the associations are more pronounced in men with relatively high or low sperm motility.

Effect of Alpinia officinarum extract on reproductive damages in streptozotocin induced diabetic male rats

PURPOSE

Infertility is one of the systemic problems in diabetic men. The purpose of the present study is investigation of the effects of the Alpinia officinarum (AO) hydro-alcoholic extract on the reproductive system damages in diabetic male rats.

METHODS

Twenty four male rats were randomly assigned into 4 groups (n = 6); i.e., control, diabetic control, and diabetic rats treated orally with AO extract (200 and 500 mg kg-1). A single dose (60 mg kg-1) of streptozotocin (STZ) was injected intraperitoneally (IP) to induce diabetes. After 8 weeks of treatment, blood samples, testis, and cauda epididymis were excised to evaluate specific hormonal changes, sperm parameters, and testis morphology.

RESULTS

Diabetic control rats showed remarkably lower body and testicular weights, testicular volumes, and sperm parameters compared with the control group (p <0.05). Diabetic control rats also exhibited significantly decreased serum testosterone and follicle stimulating hormone (FSH). Sperm parameters were considerably enhanced in diabetic animals gavaged with AO extract. Testosterone levels were significantly elevated by administrating 500 mg kg-1 AO extract to the diabetic control rats (p <0.05). The morphological assessment of testis of treatment group (500 mg kg-1) indicated remarkable differences (p <0.05) by increasing the seminiferous tubules diameter (STD) and thickness of the seminiferous epithelium (TSE) compared with diabetic control rats.

CONCLUSION

As demonstrated by the results, AO extract ameliorated sperm damage and improved sperm morphology besides improving histological damage in the testis in diabetic rats. In addition, the dose of 500 mg kg-1 worked more efficiently than 200 mg kg-1.

Can troxerutin pretreatment prevent testicular complications in prepubertal diabetic male rats?

OBJECTIVE

The vast majority of type 1 diabetes leads to a higher prevalence of reproductive system's impairments. Troxerutin has attracted much attention owing to its favorable properties, including antihyperglycemic, anti-inflammatory, and antiapoptotic effects. This investigation was proposed to evaluate whether pretreatment with troxerutin could prevent apoptosis-induced testicular disorders in prepubertal diabetic rats.

METHODS

Fifty prepubertal male Wistar rats were randomly allocated into five groups: control (C), troxerutin (TX), diabetic (D), diabetic+troxerutin (DTX), and diabetic+insulin (DI). Diabetes was induced by 55 mg/kg of streptozotocin applied intraperitoneally. In TX and DTX groups, 150 mg/kg troxerutin was administered by oral gavage. Diabetic rats in DI group received 2-4 U NPH insulin subcutaneously. Troxerutin and insulin treatments were begun immediately on the day of diabetes confirmation. After 30 days, the testicular lipid peroxidation and antioxidant activity, apoptosis process, and stereology as well as serum glucose and insulin levels were assessed.

RESULTS

The results showed that diabetes caused a significant increase in the blood glucose, the number of TUNEL positive cells and tubules, and the malondialdehyde level as well as a significant decrease in serum insulin level compared to controls. The stereological analysis also revealed various alterations in diabetic rats compared to controls. Troxerutin treatment improved these alterations compared to the diabetic group.

CONCLUSION

Troxerutin-pretreatment may play an essential role in the management of the type-1 diabetes-induced testicular disorders by decreasing blood glucose and modulating apoptosis.

Voluntary exercise improves sperm parameters in high fat diet receiving rats through alteration in testicular oxidative stress, mir-34a/SIRT1/p53 and apoptosis

OBJECTIVES

High fat diet can lead to testicular structural and functional disturbances, spermatogenesis disorders as well as infertility. So, the present investigation was proposed to clarify whether voluntary exercise could prevent high fat diet induced reproductive complications in rats through testicular stress oxidative and apoptosis.

METHODS

Forty male Wistar rats were randomly divided into four groups; control (C), voluntary exercise (VE), high fat diet (HFD) and high fat diet and voluntary exercise (VE + HFD) groups. The rats in the VE and VE + HFD groups were accommodated in apart cages that had running wheels and the running distance was assessed daily for 10 weeks. In VE + HFD group, animals were fed with HFD for five weeks before commencing exercise. The sperm parameters, the expressions of testicular miR-34a gene, and P53 and SIRT1 proteins as well as testicular apoptosis were analyzed in all groups.

RESULTS

The results indicated that voluntary exercise in VE + HFD group led to significantly increased GPX and SOD activities, SIRT1 protein expression, sperm parameters, and decreased the expression of miR34a gene and Acp53 protein, and cellular apoptosis index compared to HFD group (p<0.001 to p<0.05). The SOD and catalase activities, SIRT1 protein expression, sperm parameters in VE + HFD group were lower than of those of VE group, however, MDA content, expression of Acp53 protein, apoptosis indexes in VE + HFD group was higher than that of VE group (p<0.001 to p<0.05).

CONCLUSION

This study revealed that voluntary exercise improved spermatogenesis, in part by decreasing the testicular oxidative stress status, apoptosis through alteration in miR-34a/SIRT1/p53 pathway.

A closer look at the role of insulin for the regulation of male reproductive function

While insulin demonstrates to have a considerable influence on the reproductive system, there are various unanswered questions regarding its precise sites, mechanisms of action, and roles for the developing and functioning of the adult male reproductive system. Apart from its effects on glucose level, insulin has an important role in the reproductive system directly by binding on insulin and IGF receptors in the brain and testis. To date, however, the effect of insulin or its alterations on blood-testis-barrier, as an important regulator of normal spermatogenesis and fertility, has not yet been studied. This review aimed to focus on the experimental and clinical studies to describe mechanisms by which insulin affects the hypothalamic-pituitary-gonadal (HPG) axis, testicular cells, spermatozoa, and sexual behavior. Moreover, we discussed the mechanism and impact of insulin changes in type 1 (insulin deficiency along with persisted or even increased sensitivity) and 2 (insulin resistance along with increased insulin level at the early stages of disease) diabetes and obesity on the male reproductive tract.

Voluntary exercise improves spermatogenesis and testicular apoptosis in type 2 diabetic rats through alteration in oxidative stress and mir-34a/SIRT1/p53 pathway

OBJECTIVES

This research was designed to demonstrate the impact of voluntary exercise on sperm parameters including sperm count, morphology, motility, viability, testicular apoptosis, oxidative stress, and the mir-34a/SIRT1/p53 pathway in type 2 diabetic rats.

MATERIALS AND METHODS

32 Wistar male rats were separated into four groups: control (C), voluntary exercise (VE), diabetic (D), and diabetic rats that performed voluntary exercise (VED). To induce diabetes, animals were injected with streptozotocin (35 mg/kg) after receiving a high-fat diet. The testicular protein levels of SIRT1 and P53, miR-34a expression, MDA, GPx, SOD, catalase, and sperm parameters were evaluated.

RESULTS

Diabetes caused increased testicular MDA content, miR-34a expression, acetylated p53 protein expression, and the percent of immotile sperm (P<0.01 to P<0.001) as well as reduced testicular GPx, SOD and catalase activities, SIRT1 protein expression, and sperm parameters (P<0.05 to P<0.001). Voluntary exercise reduced testicular MDA content, miR-34a, and acetylated p53 protein expression compared with the D group (P<0.001), however, GPx, SOD, catalase activities, and sperm parameters in voluntarily exercised rats were elevated compared with diabetic rats (P<0.05 to P<0.001).

CONCLUSION

It seems that voluntary exercise has significant positive impacts that can be employed to reduce the complications of type 2 diabetes in the testis of male rats.

Programmed cell death factor 4 (PDCD4), a novel therapy target for metabolic diseases besides cancer

Programmed cell death factor 4 (PDCD4) is originally described as a tumor suppressor gene that exerts antineoplastic effects by promoting apoptosis and inhibiting tumor cell proliferation, invasion, and metastasis. Several investigations have probed the aberrant expression of PDCD4 with the progression of metabolic diseases, such as polycystic ovary syndrome (PCOS), obesity, diabetes, and atherosclerosis. It has been ascertained that PDCD4 causes glucose and lipid metabolism disorders, insulin resistance, oxidative stress, chronic inflammatory response, and gut flora disorders to regulate the progression of metabolic diseases. This review aims to summarize the latest researches to uncover the structure, expression regulation, and biological functions of PDCD4 and to elucidate the regulatory mechanism of the development of tumors and metabolic diseases. This review has emphasized the understanding of the PDCD4 role and to provide new ideas for the research, diagnosis, and treatment of tumors and metabolic diseases.

Ameliorative effect of selenium nanoparticles on the structure and function of testis and in vitro embryo development in Aflatoxin B1-exposed male mice

The purpose of the research was to investigate the therapeutic ability of selenium nanoparticles (Se-NPs) on the aflatoxin B1 (AFB1) toxicity induced in the male reproductive system. For this experiment, the mature male mice were put into four groups. Control (0.5 ml PBS, 60 days; IP, n = 7), Se-NPs (0.5 µg kg^-1  day^-1 for 60 days; IP), AFB1 (4.5 mg kg^-1  day^-1 for 60 days; IP) and AFB1 + Se-NPs (4.5 mg kg^-1  day^-1  + 0.5 µg kg^-1  day^-1 for 60 days; IP). After treatment, the histological structure of testis, serum testosterone level and sperm parameters, including concentration, motility, viability, morphology and DNA fragmentation, were examined. The results demonstrated that the AFB1 destroyed the testicular tissue structure and decreased the sperm concentration, motility, viability and normal morphology significantly. AFB1 also could significantly increase sperm DNA fragmentation and reduce in vitro fertilisation and embryo development compared to the control group (p < .001). Our data show that Se-NPs could inhibit AFB1-induced damage to the testis and improve sperm parameters as well as in vitro fertilisation and embryo production in AFB1 exposed male mice. This study revealed that the administration of Se-NPs could attenuate the testicular injury of AFB1 and improve the male reproductive system function in AFB1 exposed mice.

Association between Drinking Water Nitrate and Adverse Reproductive Outcomes: A Systematic PRISMA Review

One in six couples experience fertility problems. Environmental factors may affect reproductive health; however, evidence is lacking regarding drinking water nitrates and outcomes of male and female fertility. The aim of this study was to investigate if exposure to nitrates in drinking water is associated with adverse reproductive outcomes in humans, and animals of fertile age. We conducted a systematic literature search and included case-control studies, cohort studies, and randomized control trials reporting on the association between drinking water nitrate exposure of men, women, or animals and adverse reproductive outcomes, specified as: Semen quality parameters, time to pregnancy (TTP), pregnancy rates, assisted reproductive technologies (ART), and spontaneous abortion. Findings were reported in a narrative synthesis. A total of 12 studies were included. The only human study included reported a decrease in spontaneous abortion at any detectable nitrate level. Overall, the 11 included animal studies support a potential negative effect on semen quality parameters but report equivocal results on TTP and number of offspring produced, and higher risk of spontaneous abortion. In conclusion, animal studies indicate possible effects on semen quality parameters and spontaneous abortion. However, with a few studies, including some with methodological limitations and small sample sizes, caution must be applied when interpreting these results.

Green Coffea arabica Extract Ameliorates Testicular Injury in High-Fat Diet/Streptozotocin-Induced Diabetes in Rats

Diabetes mellitus (DM) is a chronic endocrine disease characterized by persistent hyperglycemia. Oxidative damage, inflammatory cytokines, and apoptotic cell death play a major role in the induction and progression of male testicular damage. Plant-derived phytochemicals such as green coffee (Coffea arabica) can possess antidiabetic effects with little toxicity. The current study is aimed at investigating the therapeutic roles of green coffee in diabetic testicular injury stimulated by high-fat diet/streptozotocin administration. Diabetes mellitus was induced by a high-fat diet and a single dose of streptozotocin (STZ) (35 mg kg-1) in male albino rats. Diabetic animals were orally given two different concentrations of green coffee (50 mg kg-1 and 100 mg kg-1) for 28 days. The levels of testosterone, luteinizing hormone, and follicle-stimulating hormone and parameters of oxidative stress, inflammation, and apoptosis were measured. mRNAs and protein levels were detected quantitatively by real-time PCR and ELISA, respectively. In the diabetic group, the levels of testosterone, luteinizing hormone, and follicle-stimulating hormone showed a significant reduction while they increased significantly after green coffee treatment. A significant increase of antioxidant markers glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase along with decreased levels of lipid peroxides and nitric oxide was observed after green coffee treatment in the diabetic group. Finally, the levels of IL-1β, TNF-α, Bax, and caspase-3 were also decreased in both treated groups (metformin and green coffee) when compared to the diabetic group. We conclude that testicular oxidative impairment induced by a high-fat diet (HFD) and STZ can be reversed by green coffee. Administration of green coffee could represent a promising therapeutic agent which can help the treatment of type 2 DM-induced testicular dysfunction.

Nitrate ameliorates dextran sodium sulfate-induced colitis by regulating the homeostasis of the intestinal microbiota

Inflammatory bowel disease (IBD) involves chronic inflammation, loss of epithelial integrity, and gastrointestinal microbiota dysbiosis. Effective therapies for IBD have not been established. Accordingly, in this study, we evaluated the effects of inorganic nitrate, a potent nitric oxide (NO) donor and microbiota regulator, in a mouse model of dextran sodium sulfate (DSS)-induced colitis. Mice were pretreated with NaNO₃ (2 mM) in their drinking water for 5 days, and NaCl was used as a control. Feces were collected for microbiota analyses. The results showed that oral administration of dietary nitrate could maintained colon consistency, improved colon length, maintained body weight, decreased apoptosis in colon epithelial cells, and ameliorated inflammatory cell infiltration in both the colon and peripheral blood. Microbiota profiling revealed that nitrate regulated dysbiosis. Analysis of the top bacteria at the genus level showed that Bacteroidales_S24-7_group_unidentified, Lactobacillus, Bacteroides, and Prevotellaceae_UCG-001 decreased in the DSS group compared with that in the normal group, whereas Lactobacillus, Ruminococcaceae_UCG-014, and Prevotellaceae_UCG-001 were increased in the DSS + NaNO₃ group compared with that in the DSS group. The enriched bacteria in the nitrate group included Gordonibacter, Ureaplasama, and Lachnospiraceae_UCG-006. Moreover, microbiota analysis revealed that nitrate could partially decrease the enriched metabolic pathways (p53 signaling pathway and colorectal cancer pathway) compared with that in the DSS and DSS + NaCl groups. Overall, these findings indicated that nitrate could ameliorate DSS-induced colitis by decreasing inflammation, reducing apoptosis, and regulating the microbiota by activation of the NO₃^-/NO₂^-/NO pathway. Nitrate might be a potential treatment for colitis patients in the future clinical application.

The effect of prolonged dietary sodium nitrate treatment on the hypothalamus-pituitary-gonadal axis and testicular structure and function in streptozotocin-induced diabetic male rats

The aim of this study was to evaluate the effect of prolonged dietary nitrate supplementation on the gonadotropin level, testicular histology and morphometry, expression of miR-34b and p53 mRNA, and spermatogenesis in streptozotocin-induced diabetic male rats.

METHODS

Fifty male Wistar rats were divided into 5 groups: Control (C), control + nitrate (CN), diabetes (D), diabetes + insulin (DI), and diabetes + nitrate (DN). Diabetes was induced using 45 mg kg^-1 of streptozotocin intraperitoneally. Rats in the CN and DN groups were administered sodium nitrate in drinking water (100 mg L^-1). NPH insulin (2-4 U d^-1) was injected subcutaneously in the DI group for 2 months. Nitrate and insulin supplementation was started one month after confirmation of diabetes.

RESULTS

Nitrate supplementation in the DN group significantly increased the body weight (p < 0.05), sperm parameters (p < 0.001), indices of spermatogenesis (p < 0.001), and testis histopathology as well as decreased the blood glucose level (p < 0.001) compared to the untreated diabetic group, although it had no significant effect on testicular parameters, LH and FSH levels. Nitrate administration in the DN group also decreased miR-34b (p < 0.001) and p53 mRNA (p < 0.001) expression, and increased serum insulin and NOx levels compared to the untreated diabetic rats.

CONCLUSIONS

Chronic nitrate supplementation in streptozotocin-induced diabetic rats improved fertility parameters, which may be associated with increased miR-34b and decreased p53 mRNA.

Evaluation of ameliorative effect of sodium nitrate in experimental model of streptozotocin-induced diabetic neuropathy in male rats

OBJECTIVE

Diabetes induces sensory symptoms of neuropathy as positive (hyperalgesia), negative (hypoalgesia), or both.

METHODS

In the present study, fifty male Wistar rats were allocated to five groups: control, control+nitrate, diabetes, diabetes+insulin, and diabetes+nitrate. Thirty days after diabetes confirmation, insulin (2-4 U/day) was injected subcutaneously in diabetes+insulin group and nitrate (100 mg/l) was added into drinking water of the control+nitrate and diabetes+nitrate groups for a period of 2 months. In order to assess the mechanical and thermal algesia, tail immersion, hot plate, and von Frey tests were performed. The serum insulin levels were determined with insulin ELISA Kit. Serum level of NOx was determined by the Griess method.

RESULTS

Both thermal and mechanical nociceptive thresholds showed a significant decrease (p<0.05) which was followed by a significant increase (p<0.01) in the thermal nociceptive threshold in the diabetes group. Chronic nitrate or insulin treatment led to a significant decrease (p<0.01) in blood glucose levels, as well as a significant (p<0.05) increase in the body weight and serum NOx. Moreover, nitrate treatment significantly increased serum insulin levels (p<0.001) compared to the other groups.

CONCLUSION

Chronic nitrate treatment modified the thermal and mechanical sensitivities in diabetic animals.

Total flavonoids of Epimedium ameliorates testicular damage in streptozotocin-induced diabetic rats by suppressing inflammation and oxidative stress

Testicular damage is the anomaly that will often accompany diabetes mellitus. Thus, this study aimed to investigate the role that total flavonoids of Epimedium (TFE) played against streptozotocin (STZ)-induced diabetic testicular dysfunction and to elucidate the mechanism of action. The diabetic rat model was induced by vein injection of STZ in healthy rats. Thirty male healthy Spraque-Dawley rats were randomly divided into following groups: the control group, the diabetic group, and the diabetic + TFE group. Gastrointestinal administration begins at fifth week of TFE for 6 weeks. After TFE administration, all animals were euthanized. Testicular tissue samples and blood samples of rats were collected for histopathological examination and for determination of levels of various biomarkers including blood glucose, testosterone, testicular enzymes, and oxidative stress indicators. All testes were weighted to calculate the testicular organ index. Hematoxylin-eosin staining was used for observing the testis and epididymis pathological changes. Protein expression (monocyte chemoattractant protein-1, transforming growth factor-beta-1, interleukin-6, and 3-beta-hydroxysteroid dehydrogenase) was detected by immunohistochemistry and western blot techniques. There was a significant difference in the changes between the diabetes group and the control group. As a result of treat with TFE, the blood glucose decreased but there was no significant difference, and other indicators showed significant improvement. TFE may protect against STZ-induced testicular injury by suppressing inflammation and oxidative stress.

Sodium nitrate preconditioning prevents progression of the neuropathic pain in streptozotocin-induced diabetes Wistar rats

Purpose

The purpose of the study was to evaluate the possible protective effects of low dose sodium nitrate preconditioning on the peripheral neuropathy in streptozotocin (STZ)-induced diabetic model.

Methods

Male Wistar rats were randomly divided into five groups: control (no intervention), control treated sodium nitrate (100 mg/L in drinking water), diabetic (no intervention), diabetic treated NPH insulin (2-4 U), and diabetic treated sodium nitrate (100 mg/L in drinking water). Diabetes was induced by intraperitoneal injection of STZ (60 mg/kg). All interventions were done for 60 days immediately following diabetes confirmation. Thermal and mechanical algesia thresholds were measured by means of hot-plate test, von Frey test, and tail-withdrawal test before the diabetic induction and after diabetes confirmation. At the end of the experiment, serum NOx level and serum insulin level were assessed. Blood glucose concentration and body weight have recorded at the base and duration of the experiment.

Results

Both hypoalgesia, hyperalgesia along with allodynia developed in diabetic rats. Significant alterations including, decrease in tail withdrawal latency (30th day), decreased mechanical threshold (60th day), and an increase in hot plate latency (61st day) were displayed in diabetic rats compared to control rats. Nitrate and insulin preconditioning produced protective effects against diabetes-induced peripheral neuropathy. Data analysis also showed a significant increase in glucose level as well as a considerable reduction in serum insulin and body weight of diabetic rats, which restored by both insulin and nitrate preconditioning.

Conclusion

Sodium nitrate preconditioning produces a protective effect in diabetic neuropathy, which may be mediated by its antihyperglycemic effects and increased serum insulin level.

Malaysian propolis and metformin mitigate subfertility in streptozotocin-induced diabetic male rats by targeting steroidogenesis, testicular lactate transport, spermatogenesis and mating behaviour

BACKGROUND

Diabetes mellitus is one of the risk factors for male subfertility/infertility. Malaysian propolis is reported to decrease hyperglycaemia in diabetic state.

OBJECTIVES

The present study investigated the protective effect of Malaysian propolis on diabetes-induced subfertility/infertility. Additionally, its combined beneficial effects with metformin were investigated.

MATERIALS AND METHODS

Forty adult male Sprague Dawley rats were randomly assigned into five groups, namely normal control, diabetic control, diabetic + Malaysian propolis (300 mg/k.g. b.w.), diabetic + metformin (300 mg/kg b.w.) and diabetic + Malaysian propolis + metformin. Diabetes was induced using a single intraperitoneal injection of streptozotocin (60 mg/kg b.w.) and treatment lasted for 4 weeks. During the 4th week, mating behavioural experiments were performed using sexually receptive female rats. Thereafter, fertility parameters were assessed in the female rats.

RESULTS

Malaysian propolis increased serum and intratesticular free testosterone levels, up-regulated the mRNA levels of AR and luteinizing hormone receptor, up-regulated the mRNA and protein levels of StAR, CYP11A1, CYP17A1, 3β-HSD and 17β-HSD in the testes of diabetic rats. Furthermore, Malaysian propolis up-regulated testicular MCT2, MCT4 and lactate dehydrogenase type C mRNA levels, in addition to improving sperm parameters (count, motility, viability and normal morphology) and decreasing sperm nDNA fragmentation in diabetic rats. Malaysian propolis improved mating behaviour by increasing penile guanosine monophosphate levels. Malaysian propolis also improved fertility outcome as seen with decreases in pre- and post-implantation losses, increases in gravid uterine weight, litter size per dam and foetal weight. Malaysian propolis's effects were comparable to metformin. However, their combination yielded better results relative to the monotherapeutic interventions.

CONCLUSION

Malaysian propolis improves fertility potential in diabetic state by targeting steroidogenesis, testicular lactate metabolism, spermatogenesis and mating behaviour, with better effects when co-administered with metformin. Therefore, Malaysian propolis shows a promising complementary effect with metformin in mitigating Diabetes mellitus-induced subfertility/infertility.

Beneficial treatment effects of dietary nitrate supplementation on testicular injury in streptozotocin-induced diabetic male rats

RESEARCH QUESTION

Do low doses of dietary nitrate help to attenuate the progression of diabetic reproductive disorders in streptozotocin-induced diabetic male rats?

DESIGN

Fifty male Wistar rats were divided into five groups: controls receiving distilled water; controls receiving 100 mg/l nitrate in distilled water; diabetic rats receiving distilled water; diabetic rats receiving insulin 2-4 U/day of neutral protamine hagedorn insulin; and diabetic rats receiving 100 mg/l nitrate in distilled water. Diabetes was induced by 45 mg/kg streptozotocin. Nitrate and insulin treatment were started 4 weeks after diabetes induction for 8 weeks. Serum insulin, nitrogen oxide, stereology of testis, apoptosis, sperm parameters, and mRNA expression of Pdcd4, Pacs2, p53 and miR-449a were assessed at the end of the study.

RESULTS

Blood glucose, apoptotic index of seminiferous tubules and expression of p53, Pdcd4, and Pacs2 mRNA were significantly higher in the diabetic rats (P < 0.001). Decreased body weight, serum insulin and nitrogen oxide level, and miR-449a were observed in the diabetic group (P < 0.01 for insulin; P < 0.001 for others). Most sperm parameters and stereological results differed between diabetic and control rats; nitrate recovered almost all these alterations, including dead spermatozoa, sperm motility grade, sperm deformity index, spermatozoa with damaged DNA, malformations in abnormal spermatozoa, total volume of seminiferous tubule, germinal epithelium, capsule, lumen, interstitial tissue, seminiferous tubule diameter, germinal epithelium height, the number of spermatogenic, Sertoli and Leydig cells.

CONCLUSIONS

Treatment with sodium nitrate could modulate apoptosis, which is a major cause of diabetic testicular disorder. These experiments suggest that nitric oxide plays an important role in the function of the reproductive system.

Grape seed proanthocyanidin extract alleviates high-fat diet induced testicular toxicity in rats

The present study aimed to investigate the protective effects of grape seed proanthocyanidin extract (GSPE) on high-fat diet (HFD) induced testicular damage, oxidative stress, and apoptotic germ cell death. Male rats (n = 40) were randomly divided into four groups: the control group (treated with physiological saline), HFD group, HFD + GSPE (100 mg kg⁻¹) group and HFD + GSPE (300 mg kg⁻¹) group. Compared with the HFD group the rats of the GSPE-treated group showed improved serum testosterone levels, sperm quality and histological appearance of the testis tissue. Significant elevation of antioxidant enzyme (SOD, GSH, and GSH-Px) activities and remarkable reduction in MDA were also observed by GSPE administration, indicating that GSPE can decrease testicular oxidative stress. Finally, a significant reduction in spermatogenic cell apoptosis was detected by TUNEL assay. In summary, these results indicated that GSPE can suppress testicular dysfunction and this effect may be attributed to its antioxidant and anti-apoptotic properties. The current study indicates that GSPE can be considered a promising candidate for use as a drug or a food supplement to alleviate HFD-induced testicular dysfunction.

GSPE alleviates high-fat diet induced testicular toxicity in rats by promoting anti-apoptotic activity.