Enhanced mitochondrial testicular antioxidant capacity in Goto-Kakizaki diabetic rats: role of coenzyme Q

Therapeutic Potential of 4-Hexylresorcinol in Preserving Testicular Function in Streptozotocin-Induced Diabetic Rats

It is known that many diabetic patients experience testicular atrophy. This study sought to investigate the effect of 4-hexylresorcinol (4HR) on testicular function in rats with streptozotocin (STZ)-induced diabetes, focusing on testicular weight, sperm motility, histological alterations, and serum testosterone levels to understand the efficacy of 4HR on testes. Our findings reveal that 4HR treatment significantly improves testicular health in diabetic rats. Notably, the STZ group exhibited a testicular weight of 1.22 ± 0.48 g, whereas the STZ/4HR group showed a significantly enhanced weight of 1.91 ± 0.26 g (p < 0.001), aligning closely with the control group's weight of 1.99 ± 0.17 g and the 4HR group's weight of 2.05 ± 0.24 g, indicating no significant difference between control and 4HR groups (p > 0.05). Furthermore, the STZ/4HR group demonstrated significantly improved sperm motility compared to the STZ group, with apoptotic indicators notably reduced in the STZ/4HR group relative to the STZ group (p < 0.05). These results underscore the therapeutic potential of 4HR for maintaining testicular function under diabetic conditions.

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Antidiabetic Effect of Fermented Mesembryanthemum crystallinum L. in db/db Mice Involves Regulation of PI3K-Akt Pathway

Type 2 diabetes (T2D) is a serious health issue with increasing incidences worldwide. However, current medications have limitations due to side effects such as decreased appetite, stomach pain, diarrhea, and extreme tiredness. Here, we report the effect of fermented ice plant (FMC) in the T2M mouse model of db/db mice. FMC showed a greater inhibition of lipid accumulation compared to unfermented ice plant extract. Two-week oral administration with FMC inhibited body weight gain, lowered fasting blood glucose, and improved glucose tolerance. Serum parameters related to T2D including insulin, glycosylated hemoglobin, adiponectin, and cholesterols were improved as well. Histological analysis confirmed the protective effect of FMC on pancreas and liver destruction. FMC treatment significantly increased the expression and phosphorylation of IRS-1, PI3K, and AKT. Additionally, AMP-activated protein kinase phosphorylation and nuclear factor erythroid 2-related factor 2 were also increased in the liver tissues of db/db mice treated with FMC. Overall, our results indicate the anti-diabetic effect of FMC; therefore, we suggest that FMC may be useful as a therapeutic agent for T2D.

Complementary effects of coenzyme Q10 and Lepidium sativum supplementation on the reproductive function of mice: An experimental study

Background

Coenzyme Q10 (CoQ10) and Lepidium sativum (LS) have therapeutic effects on infertility.

Objective

To evaluate the combined effects of LS and CoQ10 on reproductive function in adult male NMRI mice.

Materials and Methods

Eighty three-months-old male mice (35–40 gr) were divided into four groups (n = 10/each): control (treated with water), CoQ10-treated (200, 300, and 400 mg/kg/body weight), LS-treated (200, 400, 600 mg/kg/body weight), and co-treated (LS [600 mg/kg/body weight] + CoQ10 [200 mg/kg/body weight]) groups. Serum testosterone, luteinizing hormone, follicle-stimulating hormone, and gonadotropin realizing hormone (GnRH) levels were measured using ELISA method. The sperm quality was assessed using Sperm Class AnalyzerⓇ (SCA) CASA system and GnRH mRNA expression levels were evaluated by real-time polymerase chain reaction.

Results

The number of sniffing and following behavior was significantly higher in LS-treated (400 and 600 mg/ml/body weight) groups than the control group (p = 0.0007 and p = 0.0010, respectively). The number of mounting and coupling behaviors was significantly higher in the CoQ10 (300 and 400 mg/ml/body weight)-treated animals than the control group (p = 0.0170 and p = 0.0006, respectively). Co-treatment of CoQ10 (200 mg/ml/body weight) and LS (600 mg/ml/body weight) significantly increased all aspects of sexual behaviors as well as the levels of serum testosterone (p = 0.0011), luteinizing hormone (p = 0.0062), and follicle-stimulating hormone (p = 0.0001); sperm viability (p = 0.0300) and motility (p = 0.0010); and GnRH mRNA levels (p = 0.0016) compared to the control group.

Conclusion

The coadministration of CoQ10 and LS significantly improves the activity of the hypothalamic-pituitary-gonadal axis and enhances the reproductive parameters in adult male mice.

A study of the aphrodisiac properties of Cordyceps militaris in streptozotocin-induced diabetic male rats

Background and Aim:

Cordyceps militaris (CM) is a fungus that has been used to enhance aphrodisiac activity in men, but to date, no studies have focused on its antidiabetic properties. This study aimed to investigate the effects of CM on reproductive performance of streptozotocin (STZ)-induced diabetic male rats.

Materials and Methods:

Six-week-old Wistar rats were randomly divided into four groups: control Group 1 consisting of healthy rats; Group 2, healthy rats treated with CM (100 mg/kg); Group 3, diabetic untreated rats; and Group 4, diabetic rats treated with CM (100 mg/kg). Rats were orally administered with vehicle or CM for 21 days. The body weight, blood glucose level, food intake, epididymal sperm parameter, sexual behavior, serum testosterone level, and antioxidant parameters were determined.

Results:

The results indicated that CM treatment in STZ-induced diabetic rats significantly improved the epididymal sperm parameter and serum testosterone level and, in turn, their copulatory behavior. CM treatment in diabetic rats significantly ameliorated malondialdehyde level and significantly improved the glutathione and catalase levels.

Conclusion:

These results provide new information on the pharmacological properties of CM in ameliorating testicular damage due to oxidative stress and improving sexual performance in diabetic male rats.

Chitosan-Stabilized Selenium Nanoparticles and Metformin Synergistically Rescue Testicular Oxidative Damage and Steroidogenesis-Related Genes Dysregulation in High-Fat Diet/Streptozotocin-Induced Diabetic Rats

BACKGROUND

this study examined the metformin (MF) and/or chitosan stabilized selenium nanoparticles (CH-SeNPs) efficacy to alleviate the male reproductive function impairment in a high-fat diet feed with low-dose streptozotocin (HFD/STZ) induced type 2 diabetes mellitus (T2DM) diabetic rat model.

METHODS

control non-diabetic, HFD/STZ diabetic, HFD/STZ+MF, HFD/STZ+CH-SeNPs, and HFD/STZ+MF+CH-SeNPs rat groups were used. After 60 days, semen evaluation, hormonal assay, enzymatic antioxidant, lipid peroxidation, testis histopathology, and the steroidogenesis-related genes mRNA expressions were assessed.

RESULTS

in the HFD/STZ diabetic rats, sperm count and motility, male sexual hormones, and testicular antioxidant enzymes were significantly reduced. However, sperm abnormalities and testicular malondialdehyde were significantly incremented. The steroidogenesis-related genes, including steroidogenic acute regulatory protein (StAr), cytochrome11A1 (CYP11A1), cytochrome17A1 (CYP17A1), and hydroxysteroid 17-beta dehydrogenase 3 (HSD17B3), and the mitochondrial biogenesis related genes, including peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGCα) and sirtuin (SIRT), were significantly downregulated in the HFD/STZ diabetic rats. However, CYP19A1mRNA expression was significantly upregulated. In contrast, MF and/or CH-SeNPs oral dosing significantly rescued the T2DM-induced sperm abnormalities, reduced sperm motility, diminished sexual hormones level, testicular oxidative damage, and steroidogenesis-related genes dysregulation. In the MF and CH-SeNP co-treated group, many of the estimated parameters differ considerably from single MF or CH-SeNPs treated groups.

CONCLUSIONS

the MF and CH-SeNPs combined treatment could efficiently limit the diabetic complications largely than monotherapeutic approach and they could be considered a hopeful treatment option in the T2DM.

Diabetes mellitus and the impairment of male reproductive function: Possible signaling pathways

BACKGROUND AND AIMS

Today, it has been shown that diabetes mellitus (DM) can affect male fertility. Glucose metabolism is a vital process in spermatogenesis that is impacted by diabetes condition. But the mechanisms by which DM causes male infertility are not wholly clarified. The aim of this review is to provide brief information about the influence of hyperglycemia on male fertility and specific emphasis on the molecular signaling pathway that is involved.

METHODS

Broad literature search in the electronic database "Pubmed", "Google Scholar", the website of "World Health Organization" (WHO) and Control Disease and Prevention (CDC) took place. There was no time restriction. A key criterion for the selection of articles was English and language. Finally, one hundred thirty seven articles were included in the review.

RESULTS

Diabetes mellitus affects many signaling pathways that involved in the spermatogenesis. It seems that increased ROS and oxidative stress in the diabetes is the beginning of all fertility problems and affects all of involved signaling pathways in the spermatogenesis.

CONCLUSIONS

It seems that there was strong interconnected between oxidative stress and all of involved signaling pathways in the reproductive problems in diabetes. So, approaches that diminish oxidative stress in the testis can be effective in improving diabetes related infertility complications.

Impact of Coenzyme Q10 Administration on Lead Acetate-Induced Testicular Damage in Rats

Exposure to lead (Pb) causes multiorgan dysfunction including reproductive impairments. Here, we examined the protective effects of coenzyme Q10 (CoQ10) administration on testicular injury induced by lead acetate (PbAc) exposure in rats. This study employed four experimental groups (n = 7) that underwent seven days of treatment as follows: control group intraperitoneally (i.p.) treated with 0.1 ml of 0.9% NaCl containing 1% Tween 80 (v : v), CoQ10 group that was i.p. injected with 10 mg/kg CoQ10, PbAc group that was i.p. treated with PbAc (20 mg/kg), and PbAc+CoQ10 group that was i.p. injected with CoQ10 2 h after PbAc. PbAc injection resulted in increasing residual Pb levels in the testis and reducing testosterone, luteinizing hormone, and follicle-stimulating hormone levels. Additionally, PbAc exposure resulted in significant oxidative damage to the tissues on the testes. PbAc raised the levels of prooxidants (malondialdehyde and nitric oxide) and reduced the amount of endogenous antioxidative proteins (glutathione and its derivative enzymes, catalase, and superoxide dismutase) available in the cell. Moreover, PbAc induced the inflammatory response as evidenced by the upregulation of inflammatory mediators (tumor necrosis factor-alpha and interleukin-1 beta). Further, PbAc treatment induced apoptosis in the testicular cells, as indicated by an increase in Bax and caspase 3 expression, and reduced Bcl2 expression. CoQ10 supplementation improved testicular function by inhibiting Pb accumulation, oxidative stress, inflammation, cell death, and histopathological changes following PbAc exposure. Our findings suggest that CoQ10 can act as a natural therapeutic agent to protect against the reproductive impairments associated with PbAc exposure.

The Effects of Folic Acid Administration on Cardiac Oxidative Stress and Cardiovascular Biomarkers in Diabetic Rats

The aim of this study was to examine the effects of folic acid administration on the antioxidant enzyme (superoxide dismutase (SOD) and catalase (CAT)) activities, lactate and malate dehydrogenase (LDH and MDH) activities, and certain LDH and MDH isoform distribution in the cardiac tissue of diabetic Wistar male rats. Diabetes mellitus (DM) was induced by streptozotocin (STZ). There were five groups: C1-control (physiological saline 1 ml/kg, i.p. one day), C2-control with daily physiological saline treatment (1 ml/kg, i.p. 28 days), DM-diabetes mellitus (STZ 100 mg/kg in physiological saline, i.p. one day), FA-folic acid (5 mg/kg in physiological saline, i.p. 28 days), and DM+FA-diabetes mellitus and folic acid group (STZ 100 mg/kg in physiological saline, i.p. one day, and folic acid 5 mg/kg in physiological saline, i.p. 28 days). After four weeks, animal hearts were isolated for measurement of enzyme activities, as well as for histomorphometry analyses. An elevated glucose level and a decreased insulin level were obtained in the DM group. SOD, CAT, and MDH activities were elevated in the DM group, while there was no difference in LDH activity among the groups. In all tested groups, four LDH and three MDH isoforms were detected in the heart tissue, but with differences in their relative activities among the groups. Left ventricular cardiomyocyte transversal diameters were significantly smaller in both diabetic groups. Folic acid treatment of diabetic rats induced a reduced glucose level and reduced CAT, SOD, and MDH activities and alleviated the decrease in cardiomyocyte diameters. In conclusion, increased activities of antioxidant enzymes and MDH may be the consequence of oxidative stress caused by DM. Administration of the folic acid has a protective effect since it leads to reduction in glycemia and activities of the certain examined enzymes in the rats with experimentally induced DM.

Effect of Coenzyme Q10 Supplementation on Testosterone

Enhancing testosterone production in males is a continuous research direction for many scientists in the field, due to its role as a principal sex hormone and as a crucial modulator of well-being and general health in humans. Since 1978, there have been more than 30 studies that have connected coenzyme Q₁₀ and testosterone. Such a link is attributable to the vigorous biological role of coenzyme Q₁₀ as a crucial member in the energy production route in humans and animals, which is thought to have a positive influence on testosterone production, and hence on infertility, particularly male infertility. However, this connection has not yet been deliberated. The present work systematically reviews and summarizes the influence of coenzyme Q₁₀ supplementation on testosterone. To accomplish this purpose, the Scopus, PubMed, and Web of Science databases were searched using the keywords “coenzyme Q₁₀” versus “testosterone” for English language papers from November 1978 through October 2018. Relevant articles were also discussed and included to address an integral discussion. In summary, to date the studies conducted on human males reveal insignificant effects of coenzyme Q₁₀ supplementation on testosterone. Similarly, rather than the reproductive toxicity studies, the studies conducted on animals did not show any positive influence of coenzyme Q₁₀ on testosterone. However, coenzyme Q₁₀ supplementation was found to ameliorate the reduction in testosterone induced by chemical reproductive toxicants, mainly by neutralizing the damaging effect of the generated free radicals. However, collectively these findings require further confirmation by additional research studies.

Protection of testis through antioxidant action of Mallotus roxburghianus in alloxan-induced diabetic rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Mallotus roxburghianus is used for its antihyperglycaemic properties in Southeast Asia especially in Northeast India (Mizoram) and is also recognized in traditional medicine. About 90% of diabetic patients have been associated with reproductive impairments. The primary aim of this investigation is to examine the effects of diabetes on oxidative stress, steroidogenesis, histopathology, proliferation of germ cells with proliferative cell nuclear antigen (PCNA) and antioxidant status, and alleviative effect of M. roxburghianus on the testis dysfunction.

MATERIALS AND METHODS

Methanolic leaf extract of M. roxburghianus was given to male albino Wistar rats by oral gavage to study the acute toxicity. Phyto-chemical composition of the methanol extract of M. roxburghianus was analyzed by GC-MS. Male Wistar rats were divided into six groups with seven animals in each group: untreated control; M. roxburghianus methanolic extract control (MRME, 400mg/kg); Alloxan diabetic control group (150 mg/kg); diabetic with 100mg/kg MRME treatment; diabetic with 400mg/kg MRME treatment; and diabetic with glibenclamide (0.1mg/kg) treatment. Diabetes was induced by a single intraperitoneal injection of 150 mg/kg alloxan and was confirmed by testing fasting plasma blood glucose levels 5 days after injection. MRME was administered orally for 28 days. Body and testis weights, serum testosterone, testis malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), glutathione S transferase (GST) and protein levels were measured, and testis tissue was examined histopathologically and immunohistochemically (PCNA).

RESULTS

No sign of mortality and organ toxicity was observed up to 3000 mg/kg in acute toxicity assay of MRME and inferred to be non-toxic and safe. Bergenin and betulinic acid are the major components of MRME with many biological activities. MRME treatment rendered significant increases in body weight, testis weight, testes-body weight ratio, down regulated the MDA levels, reduced the degeneration and disruption of seminiferous tubule structure, restored the antioxidant enzymes and serum testosterone levels, increased the PCNA activities and attenuated the testes injury.

CONCLUSION

MRME treatment to diabetic rats improves diabetes induced oxidative damage in testis as well as provides protection to testis. Phenols (Bergenin) and terpenes (Betulinic acid) were the main compounds of MRME that show antioxidant and antidiabetic activities and indeed validated its traditional use in the management of diabetes related testicular impairment.

Effects of hydro-alcoholic extract of Launaea acanthodes on serum gonadotropin and testosterone levels and the structure of seminiferous tubules in hyperglycemic rats

OBJECTIVE

To investigate the effects of hydro-alcoholic extract of Launaea acanthodes, a blood glucose lowering plant in folk medicine of Iran, on the structure of seminiferous tubules and serum gonadotropin and testosterone levels in hyperglycemic rats.

METHODS

Twenty-four Wistar rats were randomly allocated into 4 groups (n=6): control, streptozotocin (STZ), STZ + insulin [STZ + Ins, 5 IU/(kg•day)], and STZ + Launaea acanthodes extract [STZ + Ext, 150 mg/(kg•day)]. Blood samples were collected at the 2nd and 4th weeks for detection of testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) with enzyme-linked immuno sorbent assay (ELISA), and the right testes of rats were removed at the 7th week for the evaluation of diameter and wall thickness of seminiferous tubules and number of Leydig cells using unbiased stereological techniques.

RESULTS

In comparison with the control group, at the 2nd week FSH (0.45 vs 0.03, 0.02, 0.02 IU/L in STZ, STZ + Ins and STZ + Ext groups, respectively) and LH (1.02 vs 0.37, 0.2, 0.29 IU/L) showed significant decreases (all P<0.05) and testosterone (4.2 vs 8.37, 7.78, 11.8 ng/mL) showed a remarkable increase (all P<0.05). The levels of these hormones became closer in the STZ + Ext and the STZ + Ins groups to the control at the 4th week. A significant decrease in diameter and wall thickness of seminiferous tubules and number of Leydig cells were observed in the STZ group as compared with the control (P<0.01).

CONCLUSIONS

Administration of Launaea extract demonstrated a beneficial impact on the protection of testis from pathogenic and degenerative effects of hyperglycemia which may be partly due to its potential antioxidative effects.

The Effects of Probiotic Soymilk Fortified with Omega-3 on Blood Glucose, Lipid Profile, Haematological and Oxidative Stress, and Inflammatory Parameters in Streptozotocin Nicotinamide-Induced Diabetic Rats

OBJECTIVE

The aim of the present study was to evaluate the effects of probiotic soymilk fortified with omega-3 in diabetic rats.

METHODS

Soymilk (SM), fermented soymilk (FSM), and fermented soymilk fortified with omega-3 (FSM + omega-3) were prepared. Rats were randomly assigned to five groups of 13 animals per group. Diabetes was induced by a single injection of streptozotocin (STZ) 15 min after the intraperitoneal administration of nicotinamide (NA). Normal control (NC) and diabetic control (DC) rats received 1 mL/day of distilled water and three groups of diabetic rats were given 1 mL/day of SM, FSM, and FSM + omega-3 products by oral gavage for 28 days.

RESULTS

Three products significantly (P < 0.05) reduced blood glucose, total cholesterol (TC), triglyceride (TG), and malondialdehyde (MDA) concentrations compared to the DC group, with the maximum reduction seen in the FSM + omega-3 group. Body weight, red blood cells (RBC), haemoglobin (Hb), haematocrit, and superoxide dismutase (SOD) also significantly increased in the FSM + omega-3 group. In the FSM + omega-3 group, MDA level compared with the SM and FSM groups and high sensitivity C-reactive protein (hs-CRP) concentrations compared with the DC and FSM groups were significantly lower (P < 0.05).

CONCLUSION

Fermented soymilk fortified with omega-3 may be beneficial in diabetes.

Experimental diabetes-induced testicular damage in prepubertal rats

BACKGROUND

There has been a marked increase in the prevalence of childhood and/or adolescent diabetes worldwide. Testicular dysfunction in adult-onset diabetes is well established, whereas the impact of early onset diabetes on the functional development of the testis remains elusive. In the present study we investigated early oxidative impairments and progressive histological changes in streptozotocin (STZ)-induced diabetic prepubertal rat testis.

METHODS

Testes were sampled from prepubertal rats injected with a single bolus of STZ (90 mg/kg, i.p.) on Days 1, 3, 5, 7 and 14 after STZ injection for quantitation of testicular oxidative stress parameters in isolated subcellular fractions and mitochondrial and microsomal functional efficiency, as well as at weekly intervals over a period of 8 weeks for histological and flow cytometry analyses.

RESULTS

Prepubertal diabetic rats were severely hyperglycemic with reduced testes size. At the subcellular level, a progressive increase in oxidative stress parameters was discernible in the cytosolic and microsomal compartments from Day 1 after STZ, together with decreased antioxidant defenses. Surprisingly, tissue ascorbate and free catalytic iron levels were notably increased in diabetic rat testis. Mitochondrial dysfunction was manifested from Day 5, as evidenced by a reduction in electron transport activity. Histologically, tissue sections showed distorted seminiferous tubules and extensive cell vacuolization with progressive disappearance of spermatids in the lumen by Week 7 after STZ injection, observations that were consistent with flow cytometry data.

CONCLUSIONS

Herein we provide evidence that the onset of diabetes brings about oxidative changes at the subcellular level that cumulatively affect the functional growth of testes.

Molecular mechanisms beyond glucose transport in diabetes-related male infertility

Diabetes mellitus (DM) is one of the greatest public health threats in modern societies. Although during a few years it was suggested that DM had no significant effect in male reproductive function, this view has been challenged in recent years. The increasing incidence of DM worldwide will inevitably result in a higher prevalence of this pathology in men of reproductive age and subfertility or infertility associated with DM is expected to dramatically rise in upcoming years. From a clinical perspective, the evaluation of semen parameters, as well as spermatozoa deoxyribonucleic acid (DNA) integrity, are often studied due to their direct implications in natural and assisted conception. Nevertheless, recent studies based on the molecular mechanisms beyond glucose transport in testicular cells provide new insights in DM-induced alterations in male reproductive health. Testicular cells have their own glucose sensing machinery that react to hormonal fluctuations and have several mechanisms to counteract hyper- and hypoglycemic events. Moreover, the metabolic cooperation between testicular cells is crucial for normal spermatogenesis. Sertoli cells (SCs), which are the main components of blood-testis barrier, are not only responsible for the physical support of germ cells but also for lactate production that is then metabolized by the developing germ cells. Any alteration in this tied metabolic cooperation may have a dramatic consequence in male fertility potential. Therefore, we present an overview of the clinical significance of DM in the male reproductive health with emphasis on the molecular mechanisms beyond glucose fluctuation and transport in testicular cells.

Effects of soybean isoflavone extract on the plasma lipid profiles and antioxidant enzyme activity in streptozotocin-induced diabetic rats

The present study evaluated the effects of various dosages of soybean isoflavone extract on lipid profiles, lipid peroxidation and antioxidant activities in streptozotocin-induced diabetic rats. The one normal control group was fed an AIN-76-based experimental diet and four diabetic groups were fed the same diet, supplemented with four different levels of soybean isoflavone extract for seven weeks. The daily dosages of pure isoflavone for four diabetic groups were set to be 0 mg (diabetic control), 0.5 mg (ISO-I), 3.0 mg (ISO-II) and 30.0 mg (ISO-III) per kilogram of body weight, respectively. The plasma total cholesterol levels and the TBA-reactive substances contents in the liver and kidney were significantly lowered in ISO-II and ISO-III groups compared to those in the diabetic control group. The levels of plasma HDL-cholesterol, plasma vitamin A and hepatic superoxide dismutase were significantly increased in those two groups compared with the diabetic control group. The present study demonstrated the possibility that the diets supplemented with 3.0 mg and 30.0 mg of soybean isoflavone extract may have beneficial effects on the plasma lipids, tissue lipid peroxidation and partly on antioxidant system in diabetic animals and there were no significant differences between the ISO-II and ISO-III groups. The results suggest that the effective daily dosage level of isoflavone for improving lipid metabolism in diabetic rats may be above 3.0 mg per kilogram body weight.

Testicular mitochondrial alterations in untreated streptozotocin-induced diabetic rats

Diabetes-induced complications are associated with mitochondrial dysfunction and increasing evidence suggests that diabetes has an adverse effect on male reproductive function. The STZ-induced diabetic rat was used as an animal model for the type 1 form of the disease with the aim of determining its effects in spermatogenesis and testicular mitochondrial function. Several aspects of mitochondrial function were measured, including respiratory and electric potential function, as well as mitochondrial calcium loading capacity. Additionally oxidative stress production, antioxidant levels and possible apoptotic alterations were also evaluated. We observed that diabetic animals present alterations in spermatogenesis in both the testis and epidydimus. However, and surprisingly, the overall results in mitochondrial parameters failed to reveal severe testicular mitochondrial dysfunction in diabetic animals, with the exception of a decrease in calcium load. Taken together, results suggest that in animal models that mimic untreated type 1 diabetes the severe effects of the condition on spermatogenesis are not directly mitochondrial-mediated.

Antioxidant level and redox status of coenzyme Q10 in the plasma and blood cells of children with diabetes mellitus type 1

Hyperglycaemia has been reported to cause increased production of oxygen free radicals. Oxidative stress may contribute to the pathogenesis of diabetic complications. Coenzyme Q(10) (CoQ(10)) is known for its key role in mitochondrial bioenergetics and is considered as a potent antioxidant and free radical scavenger. This study was conducted to evaluate plasma and blood cell concentrations of CoQ(10) in accordance to its redox capacity in children with diabetes mellitus type 1. CoQ(10) plasma and blood cell concentrations and redox status were measured using high-performance liquid chromatography with electrochemical detection in 43 children with diabetes mellitus type 1 and compared with 39 healthy children. In addition, the diabetic patients were subdivided according to their haemoglobin A1c (HbA1c) values into two groups, that is, those with good control (<8%) and those with poor control (>8%), and the CoQ(10) status was compared between the two groups. Children with type 1 diabetes showed increased plasma levels of CoQ(10) in comparison to healthy children. While CoQ(10) erythrocyte and platelet concentrations did not differ, in the diabetes group, the platelet redox status differed with a significantly increased part of reduced CoQ(10). This difference in concentration and redox status in comparison to healthy controls may be attributed to the subgroup of patients with poor control, as the subdivision of diabetic patients according to their HbA1c values shows. In diabetic children, especially in those with poor control, an increase in plasma concentration and intracellular redox capacity of the antioxidant CoQ(10) may contribute to the body's self-protection during a state of enhanced oxidative stress.

Effects of melatonin on lipid peroxidation and antioxidant enzymes in streptozotocin-induced diabetic rat testis

AIM

To examine the effects of melatonin treatment on lipid peroxidation (LPO) and the activities of antioxidant enzymes in the testicular tissue of streptozotocin (STZ)-induced diabetic rats.

METHODS

Twenty-six male rats were randomly divided into three groups as follows: group I, control, non-diabetic rats (n = 9); group II, STZ-induced, untreated diabetic rats (n = 8); group III, STZ-induced, melatonin-treated (dose of 10 mg/kg . day) diabetic rats (n = 9). Following 8-week melatonin treatment, all rats were anaesthetized and then were killed to remove testes from the scrotum.

RESULTS

As compared to group I, in rat testicular tissues of group II , increased levels of malondialdehyde (MDA) (P < 0.01) and superoxide dismutase (SOD) (P < 0.01) as well as decreased levels of catalase (CAT) (P < 0.01) and glutathione peroxidase (GSH-Px) (P > 0.05) were found. In contrast, as compared to group II, in rat testicular tissues of group III, levels of MDA decreased (but this decrease was not significant, P > 0.05) and SOD (P < 0.01) as well as CAT (P < 0.05) increased. GSH-Px was not influenced by any of the treatment. Melatonin did not significantly affect the elevated glucose concentration of diabetic group. At the end of the study, there was no significant difference between the melatonin-treated group and the untreated group by means of body and testicular weight.

CONCLUSION

Diabetes mellitus increases oxidative stress and melatonin inhibits lipid peroxidation and might regulate the activities of antioxidant enzymes of diabetic rat testes.

The evaluation of altered redox status in plasma and mitochondria of acute and chronic diabetic rats

OBJECTIVES

An increase in plasma oxidative stress and decreased mitochondrial lipid hydroperoxides may contribute to the imbalance in the redox status between intramitochondrial and extramitochondrial milieu in chronic experimental diabetic rats.

DESIGN AND METHODS

To determine the effect of hyperglycemia in promoting redox imbalance, we determined lipid hydroperoxides (LHP), protein carbonyl (PCO), total antioxidant activity (ferric reducing/antioxidant power; FRAP) and albumin as markers of redox status of plasma, and mitochondrial lipid hydroperoxide levels as a marker of lipid peroxidation in liver, pancreas and kidney tissue of acute and chronic diabetic male Sprague-Dawley rats and their controls. The levels of the studied markers were determined by colorimetric methods.

RESULTS

Plasma and mitochondrial oxidative stress parameter levels of acute diabetic rats were not significantly different from their controls. Plasma LHP and PCO levels of chronic diabetic rats were increased significantly as compared to those of both acute diabetic rats and the controls. Plasma FRAP levels of chronic diabetic animals were decreased significantly as compared to those of the controls. On the other hand, LHP levels in liver, pancreas and kidney mitochondria of chronic diabetic rats were decreased significantly as compared to those of both acute diabetic rats and the controls. We observed a negative correlation between LHP levels in liver mitochondria of chronic diabetic rats, and PCO and fructosamine levels in plasma of chronic diabetic rats were correlated. LHP levels in the pancreatic mitochondria of chronic diabetic rats and plasma oxidative stress parameters of chronic diabetic rats were not significantly correlated. LHP levels in kidney mitochondria of chronic diabetic rats were significantly correlated with serum albumin. There was no correlation between LHP levels in kidney mitochondria and other plasma oxidative stress parameters in chronic diabetic rats.

CONCLUSIONS

Our data suggest that redox imbalance between plasma and liver mitochondria might become a major threat to chronic diabetic rats.

Diabetes and mitochondrial function: role of hyperglycemia and oxidative stress

Hyperglycemia resulting from uncontrolled glucose regulation is widely recognized as the causal link between diabetes and diabetic complications. Four major molecular mechanisms have been implicated in hyperglycemia-induced tissue damage: activation of protein kinase C (PKC) isoforms via de novo synthesis of the lipid second messenger diacylglycerol (DAG), increased hexosamine pathway flux, increased advanced glycation end product (AGE) formation, and increased polyol pathway flux. Hyperglycemia-induced overproduction of superoxide is the causal link between high glucose and the pathways responsible for hyperglycemic damage. In fact, diabetes is typically accompanied by increased production of free radicals and/or impaired antioxidant defense capabilities, indicating a central contribution for reactive oxygen species (ROS) in the onset, progression, and pathological consequences of diabetes. Besides oxidative stress, a growing body of evidence has demonstrated a link between various disturbances in mitochondrial functioning and type 2 diabetes. Mutations in mitochondrial DNA (mtDNA) and decreases in mtDNA copy number have been linked to the pathogenesis of type 2 diabetes. The study of the relationship of mtDNA to type 2 diabetes has revealed the influence of the mitochondria on nuclear-encoded glucose transporters, glucose-stimulated insulin secretion, and nuclear-encoded uncoupling proteins (UCPs) in beta-cell glucose toxicity. This review focuses on a range of mitochondrial factors important in the pathogenesis of diabetes. We review the published literature regarding the direct effects of hyperglycemia on mitochondrial function and suggest the possibility of regulation of mitochondrial function at a transcriptional level in response to hyperglycemia. The main goal of this review is to include a fresh consideration of pathways involved in hyperglycemia-induced diabetic complications.

Antioxidants and total oxyradical scavenging capacity during grass shrimp, Palaemonetes pugio, embryogenesis

During embryogenesis in grass shrimp the capacity to scavenge oxyradicals increased as measured by the Total Oxyradical Scavenging Capacity (TOSC) assay. The increase in TOSC during embryogenesis was associated with increasing concentrations of a number of antioxidants, including coenzyme Q (ubiquinone), alpha-tocopherol and reduced glutathione. Glutathione concentrations ranged from 0.004 to 0.005 nmol/embryo in early embryo stages and reached concentrations between 0.16 to 0.23 nmol/embryo in late embryo stages. Ascorbate remained essentially constant (0.16-0.20 nmol/embryo) throughout embryogenesis and may provide the preponderance of TOSC during early embryo development. Carotenoids were associated with yolk lipovitellin and these antioxidants decreased as yolk was absorbed during embryogenesis. Astaxanthin and beta-carotene were identified in embryos with astaxanthin always the principal carotenoid. In early embryo stages there are maternally derived antioxidants but as embryogenesis proceeds there is an assembly of a complex antioxidant system by newly formed cells and tissues.

Coenzyme Q10 changes are associated with metabolic syndrome

BACKGROUND

The purpose of this study was to determine whether coenzyme Q10 (CoQ) concentrations and redox status are associated with components of the metabolic syndrome.

METHODS

This is a cross-sectional survey of 223 adults (28-78 years), who were drawn from the ongoing Princeton Follow-up Study in greater Cincinnati. Individuals were assessed for measures of fatness, blood pressure, glucose, lipid profiles, C-reactive protein (CRP), reduced CoQ (ubiquinol), oxidized CoQ (ubiquinone), total CoQ and CoQ redox ratio (ubiquinol/ubiquinone).

RESULTS

After adjusting for age, sex and race, we found that total CoQ, ubiquinol and CRP levels are significantly increased in metabolic syndrome. Comparison of minimal risk and high-risk metabolic syndrome groups indicates an increased CoQ redox ratio in the high risk group (p<0.05). Step-wise logistic regression analysis, using age, sex, race, (ln)CRP, total cholesterol, LDL, ubiquinol, ubiquinone and total CoQ as predictors, shows that only age (p=0.001), total CoQ adjusted for plasma lipids (p<0.0001) and (ln)CRP (p<0.005) were significant predictors of metabolic syndrome.

CONCLUSIONS

The presence of metabolic syndrome components are associated with increased plasma total CoQ and ubiquinol concentrations after adjusting for age, sex and race. An increase in CoQ redox ratio may indicate a gender-specific adaptive response to oxidative stress in females, but not males.

Metabolism and function of coenzyme Q

Coenzyme Q (CoQ) is present in all cells and membranes and in addition to be a member of the mitochondrial respiratory chain it has also several other functions of great importance for the cellular metabolism. This review summarizes the findings available to day concerning CoQ distribution, biosynthesis, regulatory modifications and its participation in cellular metabolism. There are a number of indications that this lipid is not always functioning by its direct presence at the site of action but also using e.g. receptor expression modifications, signal transduction mechanisms and action through its metabolites. The biosynthesis of CoQ is studied in great detail in bacteria and yeast but only to a limited extent in animal tissues and therefore the informations available is restricted. However, it is known that the CoQ is compartmentalized in the cell with multiple sites of biosynthesis, breakdown and regulation which is the basis of functional specialization. Some regulatory mechanisms concerning amount and biosynthesis are established and nuclear transcription factors are partly identified in this process. Using appropriate ligands of nuclear receptors the biosynthetic rate can be increased in experimental system which raises the possibility of drug-induced upregulation of the lipid in deficiency. During aging and pathophysiological conditions the tissue concentration of CoQ is modified which influences cellular functions. In this case the extent of disturbances is dependent on the localization and the modified distribution of the lipid at cellular and membrane levels.

Diabetes induces metabolic adaptations in rat liver mitochondria: role of coenzyme Q and cardiolipin contents

Several studies have been carried out to evaluate the alterations in mitochondrial functions of diabetic rats. However, results are sometimes controversial, since experimental conditions diverge, including age and strain of used animals. The purpose of this study was to evaluate the metabolic modifications in liver mitochondria, both in the presence of severe (STZ-treated rats) and mild hyperglycaemia [Goto-Kakizaki (GK) rats], when compared with control animals of similar age. Moreover, metabolic alterations were evaluated also at initial and advanced stages of the disease. We observed that both models of diabetes (type 1 and type 2) presented a decreased susceptibility of liver mitochondria to the induction of permeability transition (MPT). Apparently, there is a positive correlation between the severity of diabetes mellitus (and duration of the disease) and the decline in the susceptibility to MPT induction. We also found that liver mitochondria isolated from diabetic rats presented some metabolic adaptations, such as an increase in coenzyme Q and cardiolipin contents, that can be responsible for the observed decrease in the susceptibility to multiprotein pore (MPTP) opening.