Dose- and time-related effects of caffeine on the testis in immature male rats

Caffeine attenuates spermatogenic disorders in mice with induced chronic scrotal hyperthermia

OBJECTIVE

Chronic scrotal hyperthermia (SHT) can lead to serious disorders of the male reproductive system, with oxidative stress playing a key role in the onset of these dysfunctions. Thus, we evaluated the impact of caffeine, a potent antioxidant, on cellular and tissue disorders in mice with chronic SHT.

METHODS

In this experimental study, 56 adult male NMRI mice were allocated into seven equal groups. Apart from the non-treated control group, all were exposed to heat stress. Two groups, termed "preventive" and "curative," were orally administered caffeine. The preventive mice began receiving caffeine immediately prior to heat exposure, while for the curative group, a caffeine regimen was initiated 15 consecutive days following cessation of heat exposure. Each treated group was subdivided based on pairing with a positive control (Pre/curative [Cur]+PC) or a vehicle (Pre/Cur+vehicle). Upon conclusion of the study, we assessed sperm characteristics, testosterone levels, stereological parameters, apoptosis, antioxidant and oxidant levels, and molecular markers.

RESULTS

Sperm parameters, testosterone levels, stereological parameters, biochemical factors (excluding malondialdehyde [MDA]), and c-kit gene expression were significantly elevated in the preventive and curative groups, especially the former, relative to the other groups. Conversely, expression levels of the heat shock protein 72 (HSP72) and nuclear factor kappa beta (NF-κβ) genes, MDA levels, and apoptotic cell density were markedly lower in both caffeine-treated groups relative to the other groups, with more pronounced differences observed in the preventive group.

CONCLUSION

Overall, caffeine attenuated cellular and molecular abnormalities induced by heat stress in the testis, particularly in the mice treated under the preventive condition.

How Food Choices Impact on Male Fertility

PURPOSE OF REVIEW

Increasing evidence on the significance of nutrition in reproduction is emerging from both animal and human studies, suggesting an association between nutrition and male fertility. Here, we have highlighted the impact of the various food groups on reproductive hormones and on spermatogenesis, and the effects of classical and latest dietary patterns such as Mediterranean diet, Western diet, intermittent fasting, ketogenic diet, and vegan/vegetarian diet on male fertility.

RECENT FINDINGS

Nutrients are the precursors of molecules involved in various body's reactions; therefore, their balance is essential to ensure the correct regulation of different systems including the endocrine system. Hormones are strongly influenced by the nutritional status of the individual, and their alteration can lead to dysfunctions or diseases like infertility. In addition, nutrients affect sperm production and spermatogenesis, controlling sexual development, and maintaining secondary sexual characteristics and behaviors. The consumption of fruit, vegetables, fish, processed meats, dairy products, sugars, alcohol, and caffeine importantly impact on male fertility. Among dietary patterns, the Mediterranean diet and the Western diet are most strongly associated with the quality of semen. Nutrients, dietary patterns, and hormonal levels have an impact on male infertility. Therefore, understanding how these factors interact with each other is important for strategies to improve male fertility.

Effects of Exercise on Testosterone and Implications of Drug Abuse: A Review

OBJECTIVE

Research points to exercise having a positive effect in fighting relapse and use of drugs of abuse. Through conducting this research, differences have been observed in the effects of exercise on drug abuse between sexes. Many of the studies found that exercise tends to cause a more profound effect in blocking drug relapse or reinstatement in males when compared with females.

METHODS

Our hypothesis is that these differences in response to drugs of abuse after an exercise regimen could in part be attributed to variations in testosterone levels between males and females.

RESULTS

Testosterone has been shown to have a modulatory impact on the dopaminergic activity in the brain, causing an effect on the brain's response to drugs of abuse. Exercise has demonstrated a causal effect on increasing testosterone levels in males, whereas drugs of abuse decrease testosterone levels in males.

CONCLUSIONS

Thus, exercise raising testosterone levels in males helps to decrease the dopaminergic response in the brain to drugs of abuse causing attenuation to drugs. To find sex-specific exercise treatments for drugs of abuse, it is important to continue researching exercise's efficacy against drugs of abuse.

Fluted pumpkin seeds protect the spermatogenesis score index and testicular histology of caffeine treated rats

The present study was designed to evaluate the protective effect of fluted pumpkin seeds (FPS) against caffeine (CAFF) induced testicular toxicity in rats. Thirty young healthy male Wistar rats (196 ± 12 g) were randomly organized into five sets of six animals per each group: control, caffeine (CAFF; 50 mg kg-1 bw) and FPS co-treatment groups (CAFF + 50 mg FPS, CAFF + 100 mg FPS and CAFF + 200 mg FPS kg-1  bw). CAFF and FPS were administered daily and twice per week respectively by oral gavage for 40 days. CAFF treatment decreased testicular lactate dehydrogenase enzyme activity level, which was attenuated on co-administration with FPS at 50 and 100 mg kg-1  bw. Furthermore, CAFF decreased seminiferous epithelia thickness and spermatogenesis score index and increased the number of tubules with abnormal histological features, which were attenuated on co-administration with FPS at 50 mg kg-1  bw much more than at the higher doses (p < 0.05). CAFF did not affect malondialdehyde and glutathione concentrations and glutathione peroxidase (GSH-Px) activity in the testes whereas FPS co-treatment at the higher doses elevated glutathione level and GSH-Px activity and did not affect spermatogenesis score index at the highest dose (200 mg kg-1  bw). Testicular malondialdehyde concentrations remained unaffected in all FPS co-treatment groups. Overall, FPS is able to minimize the CAFF-induced testicular injury at lower than at the higher tested doses.

Effect of simultaneous coffee/caffeine and ethanol administration on sperm quality and reproductive hormones: an experimental study in Sprague Dawley rats

Chronic alcohol or coffee/caffeine consumption has been associated with negative effects on male reproductive system. The present study evaluated the possible interaction (combination treatment) of coffee/caffeine and alcohol and its resultant consequence on sperm parameters in rats. Ten groups of adult Sprague Dawley rats (n = 5 per group) were orally gavaged with different quantities of coffee (≈5, 10, and 20 mg/kg caffeine); 30% v/v ethanol (0.5, 1, and 2 g/kg); coffee + ethanol or vehicle (distilled water) daily for 60 days. Sperm parameters, serum sex hormone levels, together with antioxidants and lipid peroxidation status of testis homogenate were evaluated. Single and combined administration of coffee/caffeine and ethanol caused a reduction in sperm count dose-dependently (p = 0.0002), but this effect was highest in the combined treatment. Sperm viability, motility, and morphology were unaffected by coffee or ethanol administration, but the combination produced detrimental effects on them. While changes in follicle stimulating hormone were not significant, testosterone and luteinizing hormone levels were decreased significantly and dose-dependently in all experimental groups (p < 0.05-0.0001). This effect was most pronounced in the groups that received the combination. Testicular superoxide dismutase and catalase activities, and reduced glutathione and malondiadehye (MDA) levels were not affected by coffee/caffeine, but ethanol decreased (p < 0.05) the antioxidants and elevated MDA levels mostly at 2 g/kg. The combination reduced (p < 0.0001) the antioxidants and increased MDA levels in testis homogenates at all doses. Combination of coffee/caffeine and ethanol potentiates their detrimental effects on sperm quality and reproductive hormones via reduction in testicular antioxidants activities and elevation of lipid peroxidation in rats.

Do lifestyle practices impede male fertility?

Alongside an increasing prevalence of couple and male infertility, evidence suggests there is a global declining trend in male fertility parameters over the past few decades. This may, at least in part, be explained through detrimental lifestyle practices and exposures. These include alcohol and tobacco consumption, use of recreational drugs (e.g., cannabis, opioids and anabolic steroids), poor nutritional habits, obesity and metabolic syndrome, genital heat stress (e.g., radiation exposure through cell phones and laptops, prolonged periods of sitting, tight-fitting underwear and recurrent hot baths or saunas), exposure to endocrine-disrupting chemicals (e.g., pesticide residue, bisphenol A, phthalates and dioxins) and psychological stress. This review discusses these lifestyle practices and the current evidence associated with male infertility. Furthermore, known mechanisms of action are also discussed for each of these. Common mechanisms associated with a reduction in spermatogenesis and/or steroidogenesis due to unfavourable lifestyle practices include inflammation and oxidative stress locally or systemically. It is recommended that relevant lifestyle practices are investigated in clinical history of male infertility cases, particularly in unexplained or idiopathic male infertility. Appropriate modification of detrimental lifestyle practices is further suggested and recommended in the management of male infertility.

Metabolic Response of Adult Male Offspring Rats to Prenatal Caffeine Exposure

Caffeine is the most widely consumed psychoactive substance, with recommendations from health associations and regulatory bodies for limiting caffeine consumption during pregnancy being increasingly common. Prenatal exposure to caffeine has been shown to increase the risk of developing abnormalities in lipid metabolism in adult life. We further investigated the effect of prenatal caffeine exposure (PCE) (20 mg/kg of body weight) on the metabolic "reserve" of male Sprague Dawley offspring fed on a high fructose diet in adult life. Male adult PCE offspring were assigned to four groups; Nw and Nf: offspring of control mothers (N group of mothers), having received tap water or high fructose water respectively; Cw and Cf: offspring exposed to caffeine during gestation (C group of mothers) and receiving tap water or a high fructose water solution, respectively. Cf rats presented increased serum triglyceride level, as well as raised systolic and diastolic blood pressure levels, together with extensive renal tissue oedema in adulthood, compared to the other groups (p<0.05 for all comparisons). These findings show further evidence for potential detrimental metabolic effects of prenatal caffeine exposure during adulthood in this animal model.

Lifestyle and fertility: the influence of stress and quality of life on male fertility

BACKGROUND

Male infertility is a widespread condition among couples. In about 50% of cases, couple infertility is attributable to the male partner, mainly due to a failure in spermatogenesis. In recent times, the crucial role that modifiable lifestyle factors play in the development of infertility have generated a growing interest in this field of study, i.e. aging, psychological stress, nutrition, physical activity, caffeine, high scrotal temperature, hot water, mobile telephone use. Several studies have investigated associations between semen quality and the presence of lifestyle stressors i.e. occupational, life events (war, earthquake, etc.) or couple infertility; overall, these studies provide evidence that semen quality is impaired by psychological stress. In this review, we will discuss the impact of quality of life (modifiable lifestyle factors) and psychological stress on male fertility. In addition, the role that increased scrotal temperature along with inappropriate nutritional and physical exercise attitudes exert on male fertility will be presented.

CONCLUSION

The decline of male fertility, particularly associated with advancing age, incorrect lifestyles and environmental factors plays an important role on natality, and its consequences on the future on human population makes this an important public health issue in this century. Thus, modification of lifestyle through a structured program of educational, environmental, nutritional/physical exercise and psychological support, combined with the use of nutraceutical antioxidants can prevent infertility and therefore, may help couples to obtain better quality of life and improved possibility to conceive spontaneously or optimize their chances of conception.

Aging and chromatoid body assembly: Are these two physiological events linked?

The chromatoid body is a cytoplasmic male germ cell structure that plays a role in the regulation of mRNA transcription during spermatogenesis. A proteomic analysis of this structure has identified the presence of its classic molecular markers (MVH and MIWI), as well as a significant number of transient proteins. Circadian locomotor output cycles protein kaput (CLOCK) and brain and muscle ARNT-like 1 (BMAL1), which are molecular components of the circadian clock, are likely located in the chromatoid body in a transient fashion. This study sought to determine whether aging produces morphological changes in the chromatoid bodies of round spermatids similar to those previously observed in BMAL1 knockout mice. A sample of 30 male mice was divided into three groups: juvenile mice (45 days old), adult mice (120 days old), and old mice (+180 days old). Aging was confirmed by viability and sperm count analyses and testosterone dosage. Squash slides prepared with fragments of seminiferous tubules were immunostained for MVH, MIWI, BMAL1, and CLOCK detection. In juvenile and adult specimens, single round chromatoid bodies were observed using MVH/BMAL1 and MIWI/CLOCK immunostaining. In old specimens, many chromatoid bodies displayed changes in number and morphology, as well as an increase in the interactions between MVH and BMAL1; MIWI and CLOCK. Changes in chromatoid body morphology increased interactions between the proteins analyzed herein, and decreased amounts of these proteins in seminiferous tubules of older mice may indicate that aging influences the assembly and physiology of chromatoid bodies, which may, in turn, affect fertility. Impact statement The results discussed in this paper indicate that aging compromises the structure and physiology of chromatoid bodies (CBs) in post-meiotic male cells. Since CB is a fundamental structure for the differentiation of the mature male germ cell it is possible that this imbalance in CB physiology may play a role in the reduction of fertility in older men. It is important to note that not only the classic CB markers (such as the MIWI and MVH proteins) were used to showcase the structural changes in the CBs but also the main components of circadian cycle control (the CLOCK and BMAL1 proteins), indicating that the reduction of circadian control in aged males may contribute to these changes in CBs as well. Therefore, it is intriguing to evaluate the hypothesis that controlling these physiological/structural changes in CBs may be a way of delaying the effects of aging in males.

The Effects of Caffeine on the Long Bones and Testes in Immature and Young Adult Rats

This study was to evaluate the age-dependent effects of caffeine exposure on the long bones and reproductive organs using male rats. A total of 15 immature male rats and 15 young adult male rats were allocated randomly to three groups: a control group and two groups fed caffeine with 120 and 180 mg/kg/day for 4 weeks. Exposure to caffeine at either dose significantly reduced body weight gain; a proportional reduction in muscle and fat mass in immature animals, whereas a selective reduction in fat mass with relatively preserved muscle mass in young adult animals. The long bones of immature rats exposed to caffeine were significantly shorter and lighter than those of control animals along with decreased bone minerals. However, there was no difference in the length or weight of the long bones in young adult rats exposed to caffeine. Exposure to caffeine reduced the size and absolute weight of the testes significantly in immature animals in comparison to control animals, but not in young adult animals exposed to caffeine. In contrast, the adrenal glands were significantly heavier in caffeine-fed young adult rats in comparison to control animals, but not in caffeine-fed immature rats. Our results clearly show that the negative effects of caffeine on the long bones and testes in rats are different according to the age of the rat at the time of exposure, and might therefore be caused by changes to organ sensitivity and metabolic rate at different developmental stages. Although the long bones and testes are more susceptible to caffeine during puberty, caffeine has negative effects on body fat, bone minerals and the adrenal glands when exposure occurs during young adulthood. There is a need, therefore, to educate the public the potential dangers of caffeine consumption during puberty and young adulthood.