Co-administration of Selenium Nanoparticles and Metformin Abrogate Testicular Oxidative Injury by Suppressing Redox Imbalance, Augmenting Sperm Quality and Nrf2 Protein Expression in Streptozotocin-Induced Diabetic Rats

Advances in metformin-delivery systems for diabetes and obesity management

Metformin is a medication that is commonly prescribed to manage type 2 diabetes. It has been used for more than 60 years and is highly effective in lowering blood glucose levels. Recent studies indicate that metformin may have additional medical benefits beyond treating diabetes, revealing its potential therapeutic uses. Oral medication is commonly used to administer metformin because of its convenience and cost-effectiveness. However, there are challenges in optimizing its effectiveness. Gastrointestinal side effects and limitations in bioavailability have led to the underutilization of metformin. Innovative drug-delivery systems such as fast-dissolving tablets, micro/nanoparticle formulations, hydrogel and microneedles have been explored to optimize metformin therapy. These strategies enhance metformin dosage, targeting, bioavailability and stability, and provide personalized treatment options for improved glucose homeostasis, antiobesity and metabolic health benefits. Developing new delivery systems for metformin shows potential for improving therapeutic outcomes, broadening its applications beyond diabetes management and addressing unmet medical needs in various clinical settings. However, it is important to improve drug-delivery systems, addressing issues such as complexity, cost, biocompatibility, stability during storage and transportation, loading capacity, required technologies and biomaterials, targeting precision and regulatory approval. Addressing these limitations is crucial for effective, safe and accessible drug delivery in clinical practice. In this review, recent advances in the development and application of metformin-delivery systems for diabetes and obesity are discussed.

Metformin Ameliorates 2.856 GHz Microwave- Radiation-Induced Reproductive Impairments in Male Rats via Inhibition of Oxidative Stress and Apoptosis

The reproductive system has been increasingly implicated as a sensitive target of microwave radiation. Oxidative stress plays a critical role in microwave radiation -induced reproductive damage, though precise mechanisms are obscure. Metformin, a widely used antidiabetic drug, has emerged as an efficient antioxidant against a variety of oxidative injuries. In the present study, we hypothesized that metformin can function as an antioxidant and protect the reproductive system from microwave radiation. To test this hypothesis, rats were exposed to 2.856 GHz microwave radiation for 6 weeks to simulate real-life exposure to high-frequency microwave radiation. Our results showed that exposure to 2.856 GHz microwave radiation elicited serum hormone disorder, decreased sperm motility, and depleted sperm energy, and it induced abnormalities of testicular structure as well as mitochondrial impairment. Metformin was found to effectively protect the reproductive system against structural and functional impairments caused by microwave radiation. In particular, metformin can ameliorate microwave-radiation-induced oxidative injury and mitigate apoptosis in the testis, as determined by glutathione/-oxidized glutathione (GSH/GSSG), lipid peroxidation, and protein expression of heme oxygenase-1 (HO-1). These findings demonstrated that exposure to 2.856 GHz microwave radiation induces obvious structural and functional impairments of the male reproductive system, and suggested that metformin can function as a promising antioxidant to inhibit microwave-radiation-induced harmful effects by inhibiting oxidative stress and apoptosis.

Selenium nanoparticles: Properties, preparation methods, and therapeutic applications

Selenium nanoparticles (SeNPs) are a unique type of nano-sized elemental selenium that have recently found wide application in biomedicine. It has been shown that the properties of SeNPs can be varied by different fabrication methods. Moreover, SeNPs have various therapeutic effects in medical applications due to their excellent biological and adaptable physical properties. At the same time, SeNPs can be used as a carrier medium for various therapeutic substances, which can bring out the full curative effects of the drugs. In this review, the differences in bioactivity properties of SeNPs prepared from different substances were reviewed; the therapeutic effects and mechanisms of SeNPs in cancer, inflammation, neurodegenerative diseases, diabetes, reproductive diseases, cardiovascular diseases, and other diseases were discussed; and the importance of the development of SeNPs was further emphasized.

Modulatory Role of Curcumin on Cobalt-Induced Memory Deficit, Hippocampal Oxidative Damage, Astrocytosis, and Nrf2 Expression

Chemical overexposure is a growing environmental risk factor for many medical issues. Cobalt toxicity from environmental, industrial, and medical exposure has previously been linked to neurological impairment. Hence, the current study looked into the neuroprotective potential of curcumin, a natural polyphenol contained in the spice turmeric, against cobalt-induced neurotoxicity. Adult rats were randomly divided into six groups as follows: control, 40 mg/kg cobalt chloride (CoCl₂) only, 240 mg/kg curcumin only, 120 mg/kg or 240 mg/kg curcumin, or 100 mg/kg vitamin C co-administered with CoCl₂. The administration was via oral route daily for 4 weeks. After that, neurobehavioral tests were undertaken to evaluate short-term spatial memory. Biochemical investigation was performed to determine the hippocampal levels of status via measures of SOD, CAT, GST, and LPO. Furthermore, immunohistochemical assessment of the expression of GFAP and Nrf2 in the hippocampus was carried out. In the CoCl₂ group, the results showed altered behavioral responses, a decrease in antioxidant activities, increased expression of GFAP and the number of activated astrocytes, and decreased immunoexpression of Nrf2. These effects were mitigated in the curcumin- and vitamin C-treated groups. These results collectively imply that curcumin enhances memory functions in rats exposed to cobalt possibly by attenuating oxidative responses, mitigating astrocytosis, and modulating Nrf2 signaling.

Selenium in Bodily Homeostasis: Hypothalamus, Hormones, and Highways of Communication

The ability of the body to maintain homeostasis requires constant communication between the brain and peripheral tissues. Different organs produce signals, often in the form of hormones, which are detected by the hypothalamus. In response, the hypothalamus alters its regulation of bodily processes, which is achieved through its own pathways of hormonal communication. The generation and transmission of the molecules involved in these bi-directional axes can be affected by redox balance. The essential trace element selenium is known to influence numerous physiological processes, including energy homeostasis, through its various redox functions. Selenium must be obtained through the diet and is used to synthesize selenoproteins, a family of proteins with mainly antioxidant functions. Alterations in selenium status have been correlated with homeostatic disturbances in humans and studies with animal models of selenoprotein dysfunction indicate a strong influence on energy balance. The relationship between selenium and energy metabolism is complicated, however, as selenium has been shown to participate in multiple levels of homeostatic communication. This review discusses the role of selenium in the various pathways of communication between the body and the brain that are essential for maintaining homeostasis.

Histomorphometric and oxidative evaluation of the offspring's testis from type 2 diabetic female rats treated with metformin and pentoxifylline

Type 2 diabetes mellitus (T2D) during pregnancy is characterized by high levels of reactive oxygen species and pro-inflammatory factors in the placenta. Once these reactive species reach the foetus, they trigger physiological adaptations that allow the foetus to survive, but programme the organism to develop metabolic disorders in adulthood. The male reproductive system is highly susceptible to foetal programming. This study aimed to investigate the effects of intrauterine exposure to T2D on testicular histomorphometry and redox homeostasis of adult rats and evaluate the effects of maternal treatment with metformin and pentoxifylline. Female rats were induced to T2D, then treated with metformin and pentoxifylline, or co-treated with both drugs. The females were mated, the male offspring were sacrificed on postnatal day 90, and the testicles were collected for analysis. Metformin protected the tubular compartment, with the maintenance of the Sertoli cell population and daily sperm production. Pentoxifylline attenuated the effects of diabetes on Leydig cells, in addition to stimulating testosterone production and lowering lipid peroxidation. Intrauterine exposure to T2D results in important testicular alterations that compromise gonadal function, and the co-treatment with metformin and pentoxifylline may represent a promising therapy that attenuates these effects by combining the positive influences in both the tubular and interstitial compartments of the testicular parenchyma.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

The efficacy and safety of metformin combined with simvastatin in the treatment of polycystic ovary syndrome: A meta-analysis and systematic review

BACKGROUND

Several previous randomized controlled trials (RCTs) evaluated the efficacy of metformin combined with simvastatin in the treatment of polycystic ovary syndrome (PCOS), yet the results of the researches are not consistent. It is necessary to conduct a meta-analysis to explore the efficacy and safety of metformin combined with simvastatin in the treatment of PCOS, to provide evidence supports for the treatment of PCOS.

METHODS

We searched PubMed, EMbase, Cochrane Library, China National Knowledge Infrastructure, Wanfang, and Chinese biomedical literature databases online to identify the RCTs evaluating the efficacy of metformin combined with simvastatin in the treatment of PCOS. Standardized mean difference (SMD) and 95% confidence interval (95% CI) were calculated to evaluate the synthesized effects.

RESULTS

Nine RCTs with a total of 746 PCOS patients were included. The synthesized results indicated that the combined use of metformin and simvastatin are more beneficial to reduce the total cholesterol (SMD -2.66, 95% CI -3.65 to -1.66), triglycerides (SMD -1.25, 95% CI -2.02 to -0.49), low density lipoprotein (SMD -2.91, 95% CI -3.98 to -1.84), testosterone (SMD -0.64, 95% CI -1.13 to -0.15), fasting insulin (SMD -1.17, 95% CI -2.09 to -0.26) than metformin alone treatment in PCOS patients (all P < .001), and there was no significant difference in the high density lipoprotein (SMD -0.05, 95% CI -0.56-0.46), luteinizing hormone (SMD -0.58, 95% CI -1.66 to -0.50), follicle stimulating hormone (SMD 0.41, 95% CI -0.78-1.59), prolactin (SMD -1.38, 95% CI -2.93-0.17), fasting blood sugar (SMD 0.23, 95% CI -0.52-0.97), and insulin sensitivity index (SMD -0.17, 95% CI -0.48-0.15) between experimental and control groups (all P > .05).

CONCLUSIONS

Metformin combined with simvastatin is superior to metformin alone in the treatment of PCOS patients with more advantages in improving the levels of sex hormones, blood lipids, and blood sugar. However, the safety of this therapy still needs to be further explored in clinical studies with high-quality and large samples.

Nω-nitro-L-arginine, a nitric oxide synthase inhibitor, attenuates nickel-induced neurotoxicity

The various mediums of exposure to nickel (Ni) compounds have raised enormous public health concerns, as it has been illustrated to exert toxic effects in biological organs, including the brain. We have previously implicated the involvement of elevated nitric oxide (NO) in Ni-induced oxidative stress in the brain. Hence, the present study investigated the ameliorative potential of N^ω-nitro-L-arginine (L-NA), a NO synthase inhibitor, following Ni-induced neurotoxicity. Adult male rats were divided into four groups; control (normal saline), 10 mg/kg Ni chloride (NiCl₂) only, 1 mg/kg L-NA, or 2 mg/kg L-NA co-administered with NiCl₂. The administration was via daily intraperitoneal injections for three weeks. Neurobehavioural assessments performed thereafter ascertained short-term spatial memory and anxiety. Furthermore, histological evaluations of the cortex, hippocampus, and striatum were carried out using routine hematoxylin and eosin technique, while the phosphotungstic acid hematoxylin method was used to express the degree of astrogliosis. Biochemical analysis of NO levels was examined along with other oxidative stress markers (superoxide dismutase, catalase, glutathione, glutathione S transferase, glutathione peroxidase, myeloperoxidase, and lipid peroxidation). The results illustrated altered behavioral responses, a higher population of degenerating neurons, and astrocytes in the NiCl₂ group. There was also an elevation in the NO level and a corresponding reduction in antioxidant activities. However, these debilitating changes were ameliorated in the L-NA treated groups. These results demonstrate an association between alterations in NO synthesis pathway and Ni neurotoxicity, which may render neuronal cells susceptible to damage by oxidative stress. This may yet be another mechanism and useful therapeutic marker in deciphering Ni-induced neurotoxicity.

Selenium nanoparticles and metformin ameliorate streptozotocin-instigated brain oxidative-inflammatory stress and neurobehavioral alterations in rats

Selenium nanoparticles (SeNPs) are well reported to exhibit pharmacological activities both in vitro and in vivo. However, literature is devoid of studies on the impact of SeNPs and/or metformin (M) against streptozotocin (STZ)-mediated oxidative brain injury and behavioral impairment. Consequently, to fill this gap, diabetes was induced in male Wistar rats by feeding with 10% fructose solution for 2 weeks, followed by a single dose intraperitoneal injection of STZ (40 mg/kg body weight [bwt]). After rats were confirmed diabetic, they were treated orally with 0.1 mg/kg bwt of SeNPs ± M (50 mg/kg bwt), and normal control (NC) received citrate buffer (2 mg/mL) for 5 weeks. In comparison with the diabetic control (DC), SeNPs, and/or M significantly (p < 0.05) lowered blood glucose levels, but increased insulin secretion and pancreatic β-cell function. An increase in locomotor and motor activities evidenced by improved spontaneous alternation, locomotor frequency, hinding, and increased mobility time were observed in treated groups. In addition, there was enhanced brain antioxidant status with a lower acetylcholinesterase (AChE) activity and oxidative-inflammatory stress biomarkers. A significant downregulation of caspase 3 and upregulation of parvalbumin and Nrf2 protein expressions was observed in treated groups. In some of the studied parameters, treated groups were statistically (p < 0.05) insignificant compared with the normal control (NC) group. Overall, co-treatment elicited more efficacy than that of the individual regimen.

Targeting Nrf2-Mediated Oxidative Stress Response Signaling Pathways as New Therapeutic Strategy for Pituitary Adenomas

Oxidative stress and oxidative damage are the common pathophysiological characteristics in pituitary adenomas (PAs), which have been confirmed with many omics studies in PA tissues and cell/animal experimental studies. Nuclear factor erythroid 2 p45-related factor 2 (Nrf2), the core of oxidative stress response, is an oxidative stress sensor. Nrf2 is synthesized and regulated by multiple factors, including Keap1, ERK1/2, ERK5, JNK1/2, p38 MAPK, PKC, PI3K/AKT, and ER stress, in the cytoplasm. Under the oxidative stress status, Nrf2 quickly translocates from cytoplasm into the nucleus and binds to antioxidant response element /electrophile responsive element to initiate the expressions of antioxidant genes, phases I and II metabolizing enzymes, phase III detoxifying genes, chaperone/stress response genes, and ubiquitination/proteasomal degradation proteins. Many Nrf2 or Keap1 inhibitors have been reported as potential anticancer agents for different cancers. However, Nrf2 inhibitors have not been studied as potential anticancer agents for PAs. We recommend the emphasis on in-depth studies of Nrf2 signaling and potential therapeutic agents targeting Nrf2 signaling pathways as new therapeutic strategies for PAs. Also, the use of Nrf2 inhibitors targeting Nrf2 signaling in combination with ERK inhibitors plus p38 activators or JNK activators targeting MAPK signaling pathways, or drugs targeting mitochondrial dysfunction pathway might produce better anti-tumor effects on PAs. This perspective article reviews the advances in oxidative stress and Nrf2-mediated oxidative stress response signaling pathways in pituitary tumorigenesis, and the potential of targeting Nrf2 signaling pathways as a new therapeutic strategy for PAs.

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.

Effects of curcumin on sperm quality, lipid profile, antioxidant activity and histopathological changes in streptozotocin-induced diabetes in rats

In this study, the effect of low-dose curcumin on sperm parameters, reproductive hormones, lipid profile, biochemical antioxidant parameters and the histopathological structure of the testis in diabetic male rats were evaluated. In the study, 28 male Wistar albino rats weighing 300-370 g and aged 8-10 weeks were used. Four groups of equal numbers have been created. Diabetes mellitus was induced with 45 mg/kg streptozotocin (STZ) in seven rats. Curcumin was administered to the rats in curcumin and the diabetes + curcumin group by gavage for 15 days at a dose of 10 mg/kg. Then, the rats were sacrificed. Blood samples and testis tissues were obtained, while the rats were under anaesthesia. Glucose, lipid profile, reproductive hormones, sperm parameters, biochemical antioxidant parameters and histopathological examination of the testis were performed. Abnormal sperm ratio, malondialdehyde, glucose, cholesterol, low-density lipoprotein, and triglyceride levels and caspase-3 expression were increased in diabetic rats, while the sperm motility and intensity and reduced glutathione, catalase and testosterone levels were decreased. When low-dose curcumin (10 mg/kg) was administered to diabetic rats, we found that curcumin significantly increased sperm motility and density, and decreased abnormal sperm rate according to the diabetic group. Moreover, curcumin significantly suppressed the lipid profile and increased follicle-stimulating hormone (FSH) and testosterone levels compared to the diabetic group. On testicular damage and decreased reproductive hormones caused by diabetes, curcumin may have a protective effect with indirect effect of glycaemic control by curcumin.