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

Protective effect of antidiabetic drugs against male infertility: evidence from Mendelian randomization

BACKGROUND

The global prevalence of diabetes has been steadily increasing, with a growing number of younger individuals being affected. Over recent decades, various antidiabetic drugs have been repurposed for treating conditions beyond diabetes. However, the effects of antidiabetic drugs on male infertility (MIF) remain inadequately elucidated. This Mendelian randomization (MR) study aims to clarify the potential impact of antidiabetic drugs on the risk of MIF.

METHOD

We designed a comprehensive analytical workflow involving two-sample MR and summary-based MR (SMR) to assess the causal relationship between antidiabetic drug targets and MIF. First, instrumental variables were obtained based on HbA1c levels and gene expression levels. Then, MR analysis was performed after selecting positive target genes from four blood glucose level and type 2 diabetes (T2DM) datasets. Finally, we applied SMR analysis to validate and expand upon the previous conclusions. Additionally, sensitivity analyses were conducted to evaluate the robustness of the results.

RESULTS

Seven drug targets associated with five antidiabetic drugs were identified as significantly related to MIF. In the two-sample MR, the following drugs were found to reduce MIF risk through their respective significant targets: metformin (GPD1: IVW OR 0.007, 95% CI 0.000-0.204, P = 0.004), SGLT2 inhibitors (SGLT2i) (SLC5A1: IVW OR 0.048, 95% CI 0.004-0.585, P = 0.017), insulin and its analogs (IGF1R: IVW OR 0.773, 95% CI 0.648-0.922, P = 0.004), and sulfonylureas (TRPM4: IVW OR 0.869, 95% CI 0.766-0.985, P = 0.028; CTPA1: IVW OR 0.838, 95% CI 0.741-0.947, P = 0.005). In SMR analysis, antidiabetic drugs targeting the genes CPE (P = 0.03, HEIDI = 0.970) and TRPM4 (P = 0.028, HEIDI = 0.746) were found to significantly reduce the risk of MIF.

CONCLUSION

Our study indicates that metformin, SGLT2i, insulin and its analogs, as well as sulfonylureas, may offer potential therapeutic benefits for MIF. Specifically, six antidiabetic drug target genes GPD1, SLC5A1, IGF1R, TRPM4, CPT1 A, and CPE may play a role in the progression of MIF. These findings have significant implications for the development of personalized precision therapies for MIF.

The emergence of natural products as potential therapeutics for male infertility

Infertility is a major reproductive health problem. Approximately 50% of all documented cases of infertility are attributable to male factors, such as poor testicular function and semen quality. The recent significant global decline in sperm counts has serious implications for male fertility, but the armamentarium for improving testicular function and semen quality is limited. Natural products have a wide range of activities and are a major source of drugs for disease prevention and treatment. To provide ideas and a theoretical basis for the research and development of therapeutic drugs for male infertility, this review summarizes natural products (mostly monomers) that have been shown to improve testicular function and semen quality and their possible mechanisms of action. These natural products primarily improve testicular function and semen quality via antioxidant, antiapoptotic, and anti-inflammatory effects, in addition to increasing serum testosterone and reducing DNA damage in spermatozoa and testicular cells. Prospects for the application of natural products in the treatment of male infertility are discussed.

Propolis attenuates diabetes-induced testicular injury by protecting against DNA damage and suppressing cellular stress

Introduction: Propolis has a wide range of biological and pharmacological actions, including antioxidant properties-particularly its phenolic and flavonoid constituents-that could potentially protect the reproductive system from oxidative damage. Method: Four groups were allocated 40 male Wistar rats each. The vehicle was given to the first group's normal control rats negative control. The second, third, and fourth groups of diabetic rats were given vehicle (diabetic control) and propolis orally at 50 and 100 mg/kg, respectively, for 8 weeks. Diabetes was induced in rats via injection of nicotinamide and streptozotocin (STZ). Fasting blood glucose (FBG) and insulin levels, homeostatic model assessment for insulin resistance (HOMA-IR), and semen analysis were assessed. In addition, assessments of serum reproductive hormones, including total testosterone (TTST), estradiol (E2), follicle-stimulating hormone luteinizing hormone (LH), and prolactin (PRL), were measured at the end of the study. Tissue total testosterone, E2, and dihydrotestosterone were also evaluated. Serum and tissue oxidative enzymes, including catalase (CAT), superoxide dismutase, and glutathione peroxidase activities, were examined, and malondialdehyde content was determined. The pancreatic and testicular tissues were histopathologically examined, and proliferating cell nuclear antigen (PCNA) and B-cell lymphoma 2 (Bcl-2) in testicular tissue were immunohistochemically analyzed. Testicular tissue was examined for DNA integrity using a comet assay. Results: Compared to the STZ-control group, propolis greatly decreased FBG levels and improved the glycemic status of diabetic rats. In comparison to the STZ-DC group, propolis increased the number of sperm cells and the percent of morphologically normal and viable sperm in male rats, improving their fertility. Propolis also restored the pancreatic islets, protected the testis from oxidative stress, and increased levels of reproductive hormones in the blood, especially testosterone. Moreover, propolis at high doses demonstrated a strong positive response for Bcl-2 and a negative expression of proliferating cell nuclear antigen in spermatogenic cells. Conclusion: The data obtained strongly indicate that STZ causes severe impairments to the testis whereas propolis, acting as an antioxidant, protects against the adverse effects of STZ on the testis.

Physiological roles of propolis and red ginseng nanoplatforms in alleviating dexamethasone-induced male reproductive challenges in a rat model

BACKGROUND

Red ginseng and propolis are well-known antioxidants that have been related to a reduction in oxidative stress.

OBJECTIVE

This study evaluated the efficiency of red ginseng and propolis, either in powder or as nano-forms against dexamethasone-induced testicular oxidative challenges in adult male albino rats.

METHODS

Forty rats were divided into 8 equal groups including control negative group that was given vehicle (DMSO), control positive group that was administered dexamethasone in addition to the nano-propolis, nano-ginseng, nano-propolis + dexamethasone, nano ginseng+dexamethasone, propolis+dexamethasone and ginseng + dexamethasone groups. Serum, semen and tissue samples were obtained.

RESULTS

Lower testosterone levels, higher levels of MDA, and lower levels of total antioxidant capacity in serum, as well as impaired semen quality and a disturbed histopathological picture of both the testis and seminal glands, were all observed as significant negative effects of dexamethasone. These findings were confirmed by lower gene expression profiles of CYP11A1, StAR, HSD-3b, Nrf-2 and ACTB-3b in testicular and seminal gland tissues. The most powerful anti-dexamethasone effects were obtained with either propolis in nanoform or conventional ginseng.

CONCLUSION

Propolis nano-formulation and ginseng in conventional form could be considered excellent candidates to ameliorate the oxidative stress provoked by dexamethasone, however, neither nano-ginseng nor conventional propolis showed such effects.

An Innovative Use of Propolis in the Production of Dipping Sauce Powder as a Functional Food to Mitigate Testicular Toxicity Induced by Cadmium Chloride: Technological and Biological Evidence

Propolis is a common natural ingredient used in food production, food packaging, and pharmaceutical products. Therefore, the aim of our study was to prepare dipping sauce powders as an innovative functional product with a regular and spicy taste from economical raw materials with high nutritional value. The developed products were fortified with propolis powder at 250, 500, and 750 mg/kg. All studied dipping sauces were subjected to a palatability test, a nutritional evaluation, and a microbiological assay performed during 6 months of storage. In addition, an in vivo study was designed to evaluate the efficacy of these products in preventing the testicular toxicity disorders induced by cadmium chloride (CdCl2) in albino rats. Based on the palatability test, the dipping sauces supplemented with propolis at 250 mg/kg and 500 mg/kg were preferred. Moreover, all samples were safe to consume within 6 months. Biological results showed that all investigated propolis-enriched dipping sauce samples caused an improvement in all CdCl2-induced testicular histopathological and biochemical changes, especially the spicy dipping sauce powder fortified with 500 mg/kg of propolis.

Modulatory role of Coriandrum sativum (coriander) extract against diabetic complications on the gonads of female rats and their offspring

It is well known that diabetes is associated with impairment of ovarian and testicular structure and function. Coriander (Coriandrum sativum L.) is identified as one of the oldest herbal plants valued for its nutritional and medicinal properties. This work is mainly designed to evaluate the possible modulatory role of dry coriander fruit extract against gonadal impairments associated with diabetes in female rats and their pups. Twenty-four pregnant rats were divided into four groups (n = 6): group I served as control, group II was administered daily with coriander fruit extract (250 mg/kg b.wt), group III was injected interaperitoneally with a single dose of streptozotocin (STZ) (80 mg/kg b.wt), and group IV was injected with single dose of STZ and post administered coriander extract. The experiment was conducted from the 4th day of gestation till the end of weaning. At the end of the experiment, the mothers' rats and their offspring were weighed, sacrificed, the ovaries from mothers as well as ovaries and testes from offspring were immediately excised, and processed for histological, immunohistochemical and evaluation of apoptosis and transforming growth factorβ (TGF-β). Also, blood samples were collected and analyzed to estimate the levels of sex hormones as well as antioxidants.In STZ induced diabetes in mother's rats and their offspring, the ovarian sections revealed severe histopathological signs included several atretic follicles, dilated and congested blood capillaries. Additionally, the testicular sections of offspring appeared with destructive seminiferous tubules. Immunohistochemically, the ovarian sections displayed weak to negative expression for calretinin marker however the testicular sections showed strong expression for Bax protein (apoptotic marker) and weak to negative expression for Ki67 protein (proliferative marker). Also, the mean % values of positively expressed cells for TGF-β and annexin-v markers (late and early apoptosis indicator) were significantly elevated in the ovarian and testicular tissues of STZ-induced group of mother's rats and their pups if compared with control. Further results revealed that the levels of insulin, FSH, LH, estrogen, SOD and CAT were significantly decreased if compared with control however the levels of MDA and NO were significantly elevated. Administration of coriander fruit extract to diabetic rats successfully alleviated most of the altered histological, immunohistochemical, biochemical, and apoptotic changes induced by diabetes. Coriandrum sativum fruit extract has a powerful ameliorative role against STZ-induced diabetic gonadal dysfunctions in female rats and their offspring.

Ameliorative effects of propolis upon reproductive toxicity in males

Propolis is a sticky natural product produced by honeybees. Research studies have discussed the effectiveness of propolis, directly or indirectly, for ameliorating reproductive toxicity in males; however, this research has not yet been reviewed. The current paper presents an integrative summary of all research studies in Scopus and PubMed that investigated the effects of propolis on semen quality, and hence on male fertility, in conditions of reproductive toxicity. The consensus indicates that propolis ameliorates reproductive toxicity and enhances semen quality in vivo in test animals. These effects may be attributable to the ability of propolis to reduce testicular oxidative damage, enhance testicular antioxidant defense mechanisms, increase nitric oxide production, reduce testicular apoptotic injury, and boost testosterone production. However, to generalize these effects in humans would require further research.

Metformin alleviates the dysregulated testicular steroidogenesis and spermatogenesis induced by carbimazole in levothyroxine-primed rats

Most of the published experiments about carbimazole (CMZ)-induced testicular injury are constructed in normal healthy animals, which lakes the translational identification. Despite metformin (MET) having advantageous effects on injured testicles, its impact on thyroid function is arguable. In the current levothyroxine (LT4)/CMZ model, Wistar rats were primed by LT4 for sixty days. CMZ was then given individually or simultaneously with different doses of MET, 100, 200, and 400 mg, daily for thirty days. Serum was assessed for thyroid profile panel, sex hormones, and gonadotropin levels. Testicular tissues were examined for steroidogenesis, spermatogenesis, inflammation, and apoptosis. Histopathology of thyroid and testes were examined, besides thyroidal nuclear factor (NF)-kB expression. MET in a dose-response manner improved the LT4/CMZ-induced testicular toxicity by increasing the steroidogenic acute regulatory protein (StAR), and 17-β-hydroxysteroid dehydrogenase (17βHSD) activities, the proliferating cell nuclear antigen (PCNA), sperm count and motility, sex hormones, and gonadotropin levels. MET-400 mg markedly decreased the elevated NF-kB expressions, tumour necrosis factor (TNF)-α, caspase-3, and BAX, and increased BCL-2. LT4/CMZ could be used as translational animal modelling. MET displayed a dose-dependent ameliorative effect on the LT4/CMZ model without significant harmful effects on thyroid functions. MET-testicular protective roles in diabetics with thyroidal diseases should be explored.

The effects of metformin and forskolin on sperm quality parameters and sexual hormones in type II diabetic male rats

This study aimed to investigate the effects of metformin and forskolin independently and in combinations on the sperm quality parameters and sexual hormones of diabetic male rats. Fifty adult male rats were divided randomly into five identical groups, and diabetes mellitus was induced to the rats, except for the rats in the control group, using a high-fat diet and injection of Streptozotocin. Daily administration of metformin and forskolin independently and in combinations were performed for 8 weeks in different groups. Sperm quality parameters (including sperm count, morphology, sperm motility and Johnson score), testosterone, blood sugar level, Bax to Bcl-2 ratio mRNA expression level and oxidative stress levels were measured and compared between the investigated groups. Treating diabetic rats with metformin and forskolin resulted in significant improvement in sperm quality parameters, increased testosterone levels, reduced oxidative stress in blood and testicular tissue, and decreased blood sugar, and Bax to Bcl-2 ratio level. Although the combination of metformin with forskolin had a higher effect in some parameters such as testosterone levels compared to treatment with metformin or forskolin alone, this combination had not shown a synergistic effect in all the sperm quality parameters. Metformin and forskolin are effective anti-diabetic agents, which significantly improve the sperm quality and sexual hormone levels in diabetic rats. Combining metformin and gorskolin resulted in significantly better testosterone level and antioxidant activity in blood serum without significant effect on sperm quality of diabetic rats.

An Overview of the Evidence and Mechanism of Drug-Herb Interactions Between Propolis and Pharmaceutical Drugs

With the growing interest in the medicinal use of propolis, numerous studies have reported significant interactions between propolis extract and pharmaceutical drugs which may result in great clinical benefits or risks. The present study aims to review the drug-herb interactions of the full-spectrum propolis extract and main pharmaceutical drugs from the pharmacodynamic and pharmacokinetic aspects and elucidate the underlying pharmacological mechanisms. A literature search was conducted between June 2021 and February 2022 in Google Scholar, PubMed, MEDLINE, and EMBASE databases to include English studies from years 2000 to 2022 that evaluated the interaction of full-spectrum propolis extract and standard pharmaceutical drugs/cytochromes P450s. Studies that looked into geopropolis, propolis fractions, and isolated compounds, or interaction of propolis with foods, bioactive molecules, or receptors other than standard pharmaceutical drugs were excluded. From a pharmacodynamic perspective, propolis extract exhibited positive or synergistic interaction with several chemotherapeutic drugs by enhancing antitumor activity, sensitizing the chemoresistance cell lines, and attenuating multi-organ toxicity. The molecular mechanisms were associated with upregulating the apoptotic signal and immunomodulatory activity and attenuating oxidative damage. Propolis extract also enhanced the anti-bacterial and antifungal activities of many antimicrobial drugs against sensitive and resistant organisms, with an effect against the gram-positive bacteria stronger than that of the gram-negative bacteria. The synergistic action was related to strengthened action on interfering cell wall integrity and protein synthesis. The strong antioxidant activity of propolis also strengthened the therapeutic effect of metformin in attenuating hyperglycemia and pancreatic damage, as well as mitigating oxidative stress in the liver, kidney, and testis. In addition, propolis showed a potential capacity to enhance short-term and long-term memory function together with donepezil and improve motor function with levodopa and parasite killing activity with praziquantel. Pharmacokinetic studies showed inhibitory activities of propolis extracts on several CYP450 enzymes in vitro and in vivo. However, the effects on those CYP450 were deemed insignificant in humans, which may be attributed to the low bioavailability of the contributing bioactive compounds when administered in the body. The enhanced bioactivities of propolis and main pharmaceutical drugs support using propolis in integrative medicine in anti-cancer, anti-microbial, antidiabetic, and neurological disorders, with a low risk of altered pharmacokinetic activities.

A bioinformatic search for correspondence between differentially expressed genes of domestic versus wild animals and orthologous human genes altering reproductive potential

One of the greatest achievements of genetics in the 20th century is D.K. Belyaev’s discovery of destabilizing selection during the domestication of animals and that this selection affects only gene expression regulation (not gene structure) and inf luences systems of neuroendocrine control of ontogenesis in a stressful environment. Among the experimental data generalized by Belyaev’s discovery, there are also f indings about accelerated extinc tion of testes’ hormonal function and disrupted seasonality of reproduction of domesticated foxes in comparison with their wild congeners. To date, Belyaev’s discovery has already been repeatedly conf irmed, for example, by independent observations during deer domestication, during the use of rats as laboratory animals, after the reintroduction of endangered species such as Przewalski’s horse, and during the creation of a Siberian reserve population of the Siberian grouse when it had reached an endangered status in natural habitats. A genome-wide comparison among humans, several domestic animals, and some of their wild congeners has given rise to the concept of self-domestication syndrome, which includes autism spectrum disorders. In our previous study, we created a bioinformatic model of human self-domestication syndrome using differentially expressed genes (DEGs; of domestic animals versus their wild congeners) orthologous to the human genes (mainly, nervous-system genes) whose changes in expression affect reproductive potential, i. e., growth of the number of humans in the absence of restrictions caused by limiting factors. Here, we applied this model to 68 human genes whose changes in expression alter the reproductive health of women and men and to 3080 DEGs of domestic versus wild animals. As a result, in domestic animals, we identif ied 16 and 4 DEGs, the expression changes of which are codirected with changes in the expression of the human orthologous genes decreasing and increasing human reproductive potential, respectively. The wild animals had 9 and 11 such DEGs, respectively. This difference between domestic and wild animals was signif icant according to Pearson’s χ2 test (p < 0.05) and Fisher’s exact test (p < 0.05). We discuss the results from the standpoint of restoration of endangered animal species whose natural habitats are subject to an anthropogenic impact.

The Effect of Metformin on Male Reproductive Function and Prostate: An Updated Review

Metformin is the first-line oral antidiabetic drug that shows multiple pleiotropic effects of anti-inflamation, anti-cancer, anti-aging, anti-microbia, anti-atherosclerosis, and immune modulation. Metformin's effects on men's related health are reviewed here, focusing on reproductive health under subtitles of erectile dysfunction (ED), steroidogenesis and spermatogenesis; and on prostate-related health under subtitles of prostate specific antigen (PSA), prostatitis, benign prostate hyperplasia (BPH), and prostate cancer (PCa). Updated literature suggests a potential role of metformin on arteriogenic ED but controversial and contradictory effects (either protective or harmful) on testicular functions of testosterone synthesis and spermatogenesis. With regards to prostate-related health, metformin use may be associated with lower levels of PSA in humans, but its clinical implications require more research. Although there is a lack of research on metform's effect on prostatitis, it may have potential benefits through its anti-microbial and anti-inflammatory properties. Metformin may reduce the risk of BPH by inhibiting the insulin-like growth factor 1 pathway and some but not all studies suggest a protective role of metformin on the risk of PCa. Many clinical trials are being conducted to investigate the use of metformin as an adjuvant therapy for PCa but results currently available are not conclusive. While some trials suggest a benefit in reducing the metastasis and recurrence of PCa, others do not show any benefit. More research works are warranted to illuminate the potential usefulness of metformin in the promotion of men's health.

The Effects of Separate and Combined Treatment of Male Rats with Type 2 Diabetes with Metformin and Orthosteric and Allosteric Agonists of Luteinizing Hormone Receptor on Steroidogenesis and Spermatogenesis

In men with type 2 diabetes mellitus (T2DM), steroidogenesis and spermatogenesis are impaired. Metformin and the agonists of luteinizing hormone/human chorionic gonadotropin(hCG)-receptor (LH/hCG-R) (hCG, low-molecular-weight allosteric LH/hCG-R-agonists) can be used to restore them. The aim was to study effectiveness of separate and combined administration of metformin, hCG and 5-amino-N-tert-butyl-2-(methylsulfanyl)-4-(3-(nicotinamido)phenyl)thieno[2,3-d]pyrimidine-6-carboxamide (TP3) on steroidogenesis and spermatogenesis in male rats with T2DM. hCG (15 IU/rat/day) and TP3 (15 mg/kg/day) were injected in the last five days of five-week metformin treatment (120 mg/kg/day). Metformin improved testicular steroidogenesis and spermatogenesis and restored LH/hCG-R-expression. Compared to control, in T2DM, hCG stimulated steroidogenesis and StAR-gene expression less effectively and, after five-day administration, reduced LH/hCG-R-expression, while TP3 effects changed weaker. In co-administration of metformin and LH/hCG-R-agonists, on the first day, stimulating effects of LH/hCG-R-agonists on testosterone levels and hCG-stimulated expression of StAR- and CYP17A1-genes were increased, but on the 3-5th day, they disappeared. This was due to reduced LH/hCG-R-gene expression and increased aromatase-catalyzed estradiol production. With co-administration, LH/hCG-R-agonists did not contribute to improving spermatogenesis, induced by metformin. Thus, in T2DM, metformin and LH/hCG-R-agonists restore steroidogenesis and spermatogenesis, with metformin being more effective in restoring spermatogenesis, and their co-administration improves LH/hCG-R-agonist-stimulating testicular steroidogenesis in acute but not chronic administration.

Sustained In Vitro and In Vivo Delivery of Metformin from Plant Pollen-Derived Composite Microcapsules

We developed a dual microencapsulation platform for the type 2 diabetes drug metformin (MTF), which is aimed to increase its bioavailability. We report the use of Lycopodium clavatum sporopollenin (LCS), derived from their natural spores, and raw Phoenix dactylifera L. (date palm) pollens (DPP) for MTF microencapsulation. MTF was loaded into LCS and DPP via a vacuum and a novel method of hydration-induced swelling. The loading capacity (LC) and encapsulation efficiency (EE) percentages for MTF-loaded LCS and MTF-loaded DPP microcapsules were 14.9% ± 0.7, 29.8 ± 0.8, and 15.2% ± 0.7, 30.3 ± 1.0, respectively. The release of MTF from MTF-loaded LCS microcapsules was additionally controlled by re-encapsulating the loaded microcapsules into calcium alginate (ALG) microbeads via ionotropic gelation, where the release of MTF was found to be significantly slower and pH-dependent. The pharmacokinetic parameters, obtained from the in vivo study, revealed that the relative bioavailability of the MTF-loaded LCS-ALG beads was 1.215 times higher compared to pure MTF, following oral administration of a single dose equivalent to 25 mg/kg body weight MTF to streptozotocin (STZ)-induced diabetic male Sprague-Dawley rats. Significant hypoglycemic effect was obtained for STZ-induced diabetic rats orally treated with MTF-loaded LCS-ALG beads compared to control diabetic rats. Over a period of 29 days, the STZ-induced diabetic rats treated with MTF-loaded LCS-ALG beads showed a decrease in the aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides, cholesterol, and low-density lipoprotein-cholesterol (LDL-C) levels, as well as an increase in glutathione peroxidase (GPx) and a recovery in the oxidative stress biomarker, lipid peroxidation (LPx). In addition, histopathological studies of liver, pancreas, kidney, and testes suggested that MTF-loaded LCS-ALG beads improved the degenerative changes in organs of diabetic rats. The LCS-ALG platform for dual encapsulation of MTF achieved sustained MTF delivery and enhancement of bioavailability, as well as the improved biochemical and histopathological characteristics in in vivo studies, opening many other intriguing applications in sustained drug delivery.

Review on Bee Products as Potential Protective and Therapeutic Agents in Male Reproductive Impairment

Bee products are sources of functional food that have been used in complementary medicine to treat a variety of acute and chronic illnesses in many parts of the world. The products vary from location to location as well as country to country. Therefore, the aim of this review was to identify various bee products with potential preventive and therapeutic values used in the treatment of male reproductive impairment. We undertook a vigorous search for bee products with preventive and therapeutic values for the male reproductive system. These products included honey, royal jelly, bee pollen, bee brood, apilarnil, bee bread, bee wax, and bee venom. We also explained the mechanisms involved in testicular steroidogenesis, reactive oxygen species, oxidative stress, inflammation, and apoptosis, which may cumulatively lead to male reproductive impairment. The effects of bee pollen, bee venom, honey, propolis, royal jelly, and bee bread on male reproductive parameters were examined. Conclusively, these bee products showed positive effects on the steroidogenic, spermatogenic, oxidative stress, inflammatory, and apoptotic parameters, thereby making them a promising possible preventive and therapeutic treatment of male sub/infertility.

Malaysian Propolis and Metformin Synergistically Mitigate Kidney Oxidative Stress and Inflammation in Streptozotocin-Induced Diabetic Rats

Diabetic nephropathy is reported to occur as a result of the interactions between several pathophysiological disturbances, as well as renal oxidative stress and inflammation. We examined the effect of Malaysian propolis (MP), which has anti-hyperglycemic, antioxidant and anti-inflammatory properties, on diabetes-induced nephropathy. Diabetic rats were either treated with distilled water (diabetic control (DC) group), MP (300 mg/kg b.w./day), metformin (300 mg/kg b.w./day) or MP + metformin for four weeks. We found significant increases in serum creatinine, urea and uric acid levels, decreases in serum sodium and chloride levels, and increase in kidney lactate dehydrogenase activity in DC group. Furthermore, malondialdehyde level increased significantly, while kidney antioxidant enzymes activities, glutathione level and total antioxidant capacity decreased significantly in DC group. Similarly, kidney immunoexpression of nuclear factor kappa B, tumor necrosis factor-α, interleukin (IL)-1β and caspase-3 increased significantly, while IL-10 immunoexpression decreased significantly in DC group relative to normal control group. Histopathological observations for DC group corroborated the biochemical data. Intervention with MP, metformin or both significantly mitigated these effects and improved renal function, with the best outcome following the combined therapy. MP attenuates diabetic nephropathy and exhibits combined beneficial effect with metformin.

Metabolic Syndrome and Reproduction

Metabolic syndrome (MetS) and infertility are two afflictions with a high prevalence in the general population. MetS is a global health problem increasing worldwide, while infertility affects up to 12% of men. Despite the high prevalence of these conditions, the possible impact of MetS on male fertility has been investigated by a few authors only in the last decade. In addition, underlying mechanism(s) connecting the two conditions have been investigated in few preclinical studies. The aim of this review is to summarize and critically discuss available clinical and preclinical studies on the role of MetS (and its treatment) in male fertility. An extensive Medline search was performed identifying studies in the English language. While several studies support an association between MetS and hypogonadism, contrasting results have been reported on the relationship between MetS and semen parameters/male infertility, and the available studies considered heterogeneous MetS definitions and populations. So far, only two meta-analyses in clinical and preclinical studies, respectively, evaluated this topic, reporting a negative association between MetS and sperm parameters, testosterone and FSH levels, advocating, however, larger prospective investigations. In conclusion, a possible negative impact of MetS on male reproductive potential was reported; however, larger studies are needed.

Improvement Effect of Metformin on Female and Male Reproduction in Endocrine Pathologies and Its Mechanisms

Metformin (MF), a first-line drug to treat type 2 diabetes mellitus (T2DM), alone and in combination with other drugs, restores the ovarian function in women with polycystic ovary syndrome (PCOS) and improves fetal development, pregnancy outcomes and offspring health in gestational diabetes mellitus (GDM) and T2DM. MF treatment is demonstrated to improve the efficiency of in vitro fertilization and is considered a supplementary drug in assisted reproductive technologies. MF administration shows positive effect on steroidogenesis and spermatogenesis in men with metabolic disorders, thus MF treatment indicates prospective use for improvement of male reproductive functions and fertility. MF lacks teratogenic effects and has positive health effect in newborns. The review is focused on use of MF therapy for restoration of female and male reproductive functions and improvement of pregnancy outcomes in metabolic and endocrine disorders. The mechanisms of MF action are discussed, including normalization of metabolic and hormonal status in PCOS, GDM, T2DM and metabolic syndrome and restoration of functional activity and hormonal regulation of the gonadal axis.

Normalization of Testicular Steroidogenesis and Spermatogenesis in Male Rats with Type 2 Diabetes Mellitus under the Conditions of Metformin Therapy

One of the complications of type 2 diabetes mellitus in men is steroidogenic and spermatogenic dysfunctions. There is evidence of a restoring effect of the antidiabetic drug metformin on them. We studied the effect of MF therapy (4 weeks, 200 mg/kg/day) on the hormonal parameters of the gonad axis and on the morphological characteristics of epididymal spermatozoa in male rats with a severe form of T2DM caused by a high-fat diet and a low-dose streptozotocin. It has been shown that MF therapy, along with the restoration of the metabolic parameters, normalizes the plasma levels of testosterone and leptin and the content of testosterone, its precursors, leptin and its receptors in the testes, and also increases sperm motility, which is reduced in T2DM. This is the result of both the systemic action of MF and its direct effect on testicular cells.