Dietary cholesterol and oxidised cholesterol: effects on sperm characteristics, antioxidant status and hormonal profile in rats

Asparagus Fructans as Emerging Prebiotics

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

Low protein diet and methyl-donor supplements modify testicular physiology in mice

The link between male diet and sperm quality has received significant investigation. However, the impact diet and dietary supplements have on the testicular environment has been examined to a lesser extent. Here, we establish the impact of a sub-optimal low protein diet (LPD) on testicular morphology, apoptosis and serum fatty acid profiles. Furthermore, we define whether supplementing a LPD with specific methyl donors abrogates any detrimental effects of the LPD. Male C57BL6 mice were fed either a control normal protein diet (NPD; 18% protein; n = 8), an isocaloric LPD (LPD; 9% protein; n = 8) or an LPD supplemented with methyl donors (MD-LPD; choline chloride, betaine, methionine, folic acid, vitamin B12; n = 8) for a minimum of 7 weeks. Analysis of male serum fatty acid profiles by gas chromatography revealed elevated levels of saturated fatty acids and lower levels of mono- and polyunsaturated fatty acids in MD-LPD males when compared to NPD and/or LPD males. Testes of LPD males displayed larger seminiferous tubule cross section area when compared to NPD and MD-LPD males, while MD-LPD tubules displayed a larger luminal area. Furthermore, TUNNEL staining revealed LPD males possessed a reduced number of tubules positive for apoptosis, while gene expression analysis showed MD-LPD testes displayed decreased expression of the pro-apoptotic genes Bax, Csap1 and Fas when compared to NPD males. Finally, testes from MD-LPD males displayed a reduced telomere length but increased telomerase activity. These data reveal the significance of sub-optimal nutrition for paternal metabolic and reproductive physiology.

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

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

Oxidized-LDL inhibits testosterone biosynthesis by affecting mitochondrial function and the p38 MAPK/COX-2 signaling pathway in Leydig cells

Abnormal lipid/lipoprotein metabolism induced by obesity may affect spermatogenesis by inhibiting testosterone synthesis in Leydig cells. It is crucial to determine which components of lipoproteins inhibit testosterone synthesis. Circulating oxidized low-density lipoprotein (oxLDL), the oxidized form of LDL, has been reported to be an independent risk factor for decreased serum testosterone levels. However, whether oxLDL has a damaging effect on Leydig cell function and the detailed mechanisms have been rarely studied. This study first showed the specific localization of oxLDL and mitochondrial structural damage in testicular Leydig cells of high-fat diet-fed mice in vivo. We also found that oxLDL reduced the mitochondrial membrane potential (MMP) by disrupting electron transport chain and inhibited testosterone synthesis-related proteins and enzymes (StAR, P450scc, and 3β‑HSD), which ultimately led to mitochondrial dysfunction and decreased testosterone synthesis in Leydig cells. Further experiments demonstrated that oxLDL promoted lipid uptake and mitochondrial dysfunction by inducing CD36 transcription. Meanwhile, oxLDL facilitated COX2 expression through the p38 MAPK signaling pathway in Leydig cells. Blockade of COX-2 attenuated the oxLDL-induced decrease in StAR and P450scc. Our clinical results clarified that the increased serum oxLDL level was associated with a decline in circulating testosterone levels. Our findings amplify the damaging effects of oxLDL and provide the first evidence that oxLDL is a novel metabolic biomarker of male-acquired hypogonadism caused by abnormal lipid metabolism.

Effects of treatment with haloperidol and clozapine on the plasma concentrations of thyroid hormones in rats

OBJECTIVES

Psychoactive drugs are group of compounds used to treat severe mental problems, including psychosis, as well as other conditions. This study assessed clinically relevant side effects of haloperidol and clozapine on the thyroid hormones.

METHODS

Haloperidol (0.05 and 2 mg/kg) or clozapine (0.5 and 20 mg/kg) was intraperitoneally injected to male Wistar rats for 28 days. The control group received 2 ml of physiological saline. A chemiluminescent immunoassay was used to measure the plasma levels of thyroid hormones.

RESULTS

Plasma concentrations of thyroxine (T4) in rats treated with high-dose (2 mg/kg) of haloperidol decreased significantly compared to the control group (p=0.001). However, both low (0.5 mg/kg) and high clozapine (20 mg/kg) doses did not have a significant effect on the plasma concentrations of T4 and triiodothyronine (T3) (p>0.05). Neither of the compound had a significant effect on T3 plasma concentration levels (p>0.05).

CONCLUSIONS

Haloperidol and clozapine act via different mechanisms and may have dissociable effects on thyroid hormones. Following treatment with haloperidol, significant changes in T4, but not in T3, serum levels were observed. Haloperidol and clozapine had different effects on the thyroid hormone levels. These results indicate that antipsychotic treatment can contribute to the thyroid dysfunction. Therefore, greater caution should be applied to the antipsychotics use. The thyroid function of the patients should be closely monitored, while using these drugs.

Oxidized cholesterol exacerbates toll-like receptor 4 expression and activity in the hearts of rats with myocardial infarction

Introduction: The present study examined the effects of high cholesterol and high oxidized-cholesterol diets on the myocardial expression of TLR4 and pro-inflammatory cytokine in rats.

Methods: Male Wistar rats were allocated into 6 groups and fed with a normal diet, cholesterol, and oxidized-cholesterol rich diets with or without isoproterenol-induced myocardial infarction. TLR4 and MyD 88 expression and levels tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) were measured in the heart and serum.

Results: Oxidized cholesterol-fed animals had higher serum levels of oxidized low-density lipoprotein (LDL) (263 ± 13 ng/dL) than the cholesterol-fed animals (98 ± 8 ng/dL; P < 0.001). A high level of oxidized-LDL caused fibrotic cell formation and enhanced neutrophil infiltration in the absence of MI. Both cholesterol and oxidized-cholesterol upregulated TLR4 mRNA expression and increased TNF-α and IL-6 production in the hearts of rats with MI. In rats fed with oxidized-cholesterol the serum and myocardial levels of TNF-α (653 ± 42 pg/mL, 1375 ± 121 pg/100 mg, respectively) were higher than MI group (358±24 pg/mL, P < 0.001 and 885 ± 56 pg/100 mg, P < 0.01). A significant correlation was seen between TLR4 expression and infarct size.

Conclusion: These findings suggest that cardiac TLR4 is preferentially upregulated by oxidized cholesterol in rats. Oxidized cholesterol may have a critical role in cardiac toxicity in the absence of pathological conditions.

Dietary Cholesterol and Lipid Overload: Impact on Male Fertility

Lipid metabolic disorders due to poor eating habits are on the rise in both developed and developing countries, with a negative impact of the "Western diet" on sperm count and quality. Dietary lipid imbalance can involve cholesterol, fatty acids, or both, under different pathophysiological conditions grouped under the term dyslipidemia. The general feature of dyslipidemia is the development of systemic oxidative stress, a well-known deleterious factor for the quality of male gametes and associated with infertility. Sperm are particularly rich in polyunsaturated fatty acids (PUFA), an important characteristic associated with normal sperm physiology and reproductive outcomes, but also targets of choice for oxidative thrust. This review focuses on the effects of dietary cholesterol or different fatty acid overload on sperm composition and function in both animals and humans. The links between oxidative stress induced by dyslipidemia and sperm dysfunction are then discussed, including possible preventive or therapeutic strategies to preserve gamete quality, longevity when stored in cryobanking, and male fertility.

Rutin ameliorates carbon tetrachloride (CCl4)-induced hepatorenal toxicity and hypogonadism in male rats

Rutin, a food derived-polyphenolic bioflavonoid, has been acknowledged for several health benefits. This study aims to explore the ameliorative effects of rutin against carbon tetrachloride (CCl4) toxicity in male rats. Adult male rats were given either CCl4 (30% in olive oil, 3 ml/kg b.w. intraperitoneally) alone or in combination with rutin (70 mg/kg intragastrically) twice a week for 4 weeks. Our data showed that rutin mitigated CCl4 hepatorenal damage, as indicated by diagnostic markers (i.e., transaminases, alkaline phosphatase, total bilirubin, total protein, albumin, urea, uric acid and creatinine), and histopathological findings. In addition, CCl4 induced profound elevation of free radical generation and oxidative stress, as evidenced by increasing lipid peroxidation and reducing catalase, superoxide dismutase and glutathione peroxidase activities in liver, kidney and testicular tissues; these effects were suppressed by coexposure with rutin. Moreover, the increase in the levels of serum triglycerides, cholesterol, low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol induced by CCl4 was effectively counteracted by rutin. The decrease in the level of high-density lipoprotein cholesterol in the CCl4 group was also counteracted by rutin treatment. Interestingly, the decreased levels of hormonal mediators associated with sperm production, including serum testosterone, luteinizing hormone and follicle-stimulating hormone, and the impaired sperm quality induced by CCl4 were reversed by rutin. Data from the current study clearly demonstrated that rutin supplementation could at least partly overcome CCl4-induced hepatotoxicity, nephrotoxicity and reproductive toxicity by antioxidant and antidyslipidemic effects.