Application of computer-assisted sperm analysis system to elucidate lack of effects of cyclophosphamide on rat epididymal sperm motion

Alkylating agents-induced gonadotoxicity in prepubertal males: Insights on the clinical and preclinical front

Rising cure rates in pediatric cancer patients warrants an increased attention toward the long-term consequences of the diagnosis and treatment in survivors. Chemotherapeutic agents can be gonadotoxic, rendering them at risk for infertility post-survival. While semen cryopreservation is an option that can be provided for most (post)pubertal boys before treatment, this is unfortunately not an option prepubertal in age, simply due to the lack of spermatogenesis. Over the last couple of years, studies have thus focused on better understanding the testis niche in response to various chemotherapeutic agents that are commonly administered and their direct and indirect impact on the germ cell populations. These are generally compounds that have a high risk of infertility and have been classified into risk categories in curated fertility guidelines. However, with it comes the lack of evidence and the challenge of using informative models and conditions most reflective of the physiological scenario, in short, the appropriate study designs for clinically relevant outcomes. Besides, the exact mechanism(s) of action for many of these "risk" compounds as well as other agents is unclear. Understanding their behavior and effect on the testis niche will pave the way for incorporating new strategies to ultimately combat infertility. Of the various drug classes, alkylating agents pose the highest risk of gonadotoxicity as per previously established studies as well as risk stratification guidelines. Therefore, this review will summarize the findings in the field of male fertility concerning gonadotoxicity of akylating agents as a result of chemotherapy exposure.

Chemoprotective effects of inositol hexaphosphate against cyclophosphamide-induced testicular damage in rats

Cyclophosphamide (CP) is commonly used as an anticancer agent but has been associated with high toxicity in several animal organs, including the testes. Inositol hexaphosphate (IP6) is a polyphosphorylated carbohydrate that is present in foods with high fibre contents and has a wide range of essential physiological and pathological activities. Thus, we estimated the defensive effects of IP6 against CP-related testicular toxicity in rats. Sperm counts, motilities, viabilities and abnormalities and levels of testosterone, luteinising hormone and follicle-stimulating hormone were evaluated. Testicle specimens were also processed for histological and biochemical analyses, including determinations of malondialdehyde, nitric oxide, total antioxidant capacity, alkaline phosphatase, acid phosphatase, gamma glutamyl transferase, ß-glucuronidase, c-reactive protein, monocyte chemoattractant protein and leukotriene-4 and in comet assays. CP treatments were associated with deleterious histopathological, biochemical and genetic changes in rat testicles, and these were ameliorated by IP6 supplements in drinking water.

Immunosuppressants and Male Reproduction

Prolonged use of immunosuppressant medications is occasionally seen in infertile men with chronic inflammatory conditions; autoimmune disorders; or an organ or hematopoietic stem cell transplant. Chronic inflammation impacts negatively on male reproductive endpoints, so immunosuppressant therapy can produce improvements. Corticosteroids have been used to treat antisperm antibodies and even as an empirical treatment for male infertility in general. Trials of these methods have provided mixed results on semen quality and fertility, with improvement, no change and negative effects reported by different investigators. In a substantial number of observational studies, patients on long-term therapy with prednisone for chronic inflammatory disease, testosterone levels were lower compared to untreated controls, though randomized controlled trials have not been conducted. Similarly decreases in testosterone have been reported in men receiving corticosteroids to minimize transplant rejection; however, most were treated with multiple immunosuppressive medications that may have contributed to this effect. A large number of trials of healthy men treated with corticosteroids have shown some disruption in reproductive hormone levels, but other studies reported no effect. Studies in monkeys, rats (at human equivalent dose), cattle, sheep, and horses have shown endocrine disruption, including low testosterone with dexamethasone treatment. Of the cytostatic immunosuppressives, which have high potential for cellular damage, cyclophosphamide has received the most attention, sometimes lowering sperm counts significantly. Methotrexate may decrease sperm numbers in humans and has significant negative impacts in rodents. Other chemotherapeutic drugs used as immunosuppressants are likely to impact negatively on male fertility endpoints, but few data have been collected. The TNF-α Inhibitors have also received little experimental attention. There is some evidence that the immunophilin modulators: cyclosporine, sirolimus, and everolimus cause endocrine disruption and semen quality impairment. As we review in this chapter, results in experimental species are concerning, and well-designed studies are lacking for the effects of these medications on reproductive endpoints in men.

Trigonellae Semen Enhances Sperm Motility and the Expression of the Cation Sperm Channel Proteins in Mouse Testes

Genetic defects during spermatogenesis can lead to a reduction in sperm motility and cause male infertility. The cation channels of sperm (CatSper) play a role in the regulation of hyperactivated sperm motility in mouse testes. The effect of Trigonellae Semen (TS) on the male reproductive system and CatSper protein in mouse testes during spermatogenesis was examined. C57BL/c mice were divided into the following five groups: normal, cyclophosphamide- (CP-) only treated (control group), and three groups treated with varying concentrations of TS with CP (100, 500, and 1000 mg/kg TS and 100 mg/kg CP). Real-time PCR, western blot analysis, and a testosterone immunoassay were performed to assess CatSper protein levels in the five groups. Additionally, sperm cell counts and motility were examined. Results indicate that sperm motility and sperm counts increased in the TS treated groups in a dose-dependent manner (p < 0.01). CatSper levels were also significantly higher in the TS treated groups compared to that of the control group (p < 0.001). Therefore, TS treatment could enhance sperm function by promoting spermatogenesis and the expression of CatSper proteins in mouse testes.

Effects of tadalafil on hemorrhagic cystitis and testicular dysfunction induced by cyclophosphamide in rats

INTRODUCTION

The protective and/or therapeutic potential of tadalafil (TDL) on cyclophosphamide (CP)-induced hemorrhagic cystitis (HC) and testicular dysfunction in rats was evaluated.

MATERIALS AND METHODS

The animals except from the control group were divided into four groups and treated with saline, or 1, 5 or 10 mg/kg TDL orally (CP, TDL1, TDL5 and TDL10 groups, respectively) before and after CP injection. Body and organ weights, sperm count, cGMP, nitric oxide (NO), IL-6 and IL-10 levels in serum and bladder tissue, and serum testosterone (T), LH and FSH levels were determined. The histological analysis of bladder and testis was performed and the number of apoptotic cells was determined.

RESULTS AND CONCLUSION

The CP group had decreased cGMP and NO levels in the bladder, serum T level (p < 0.05) and sperm count (p < 0.001) and higher IL-6 levels in serum and bladder (p < 0.01). Treatment with TDL resulted in increased cGMP (p < 0.001), NO (p < 0.05) and serum T (p < 0.05) levels. Histological analysis of the CP group showed severe HC in bladder and testicular damage. TDL-treated animals showed a dose-dependent improvement in all of these histological impairments. In conclusion, a selective inhibitor of phosphodiesterase-5 enzyme, TDL, showed a protective and/or therapeutic effect on CP-induced HC and testicular dysfunction in rats.

Chemoprotective effect of lipoic acid against cyclophosphamide-induced changes in the rat sperm

Treatment with cyclophosphamide (CP), a commonly used anticancer and immunosuppressive agent, may result in oligospermia and azoospermia. CP administration induces oxidative stress and is cytotoxic to normal cells. In this context, we have studied the effect of an established antioxidant, lipoic acid on its influence on CP-induced oxidative injury in rat sperm. In this study, we have assessed the possible protective efficacy of lipoic acid on the sperm characteristics, peroxidative damages and abnormal antioxidant levels in the epididymal sperm of CP-administered rats. Male Wistar rats of 140+/-20 g were categorized into four groups. Two groups of rats were administered CP (15 mg/kg body weight once a week for 10 weeks by oral gavage) to induce testicular toxicity; one of these groups received lipoic acid treatment (35 mg/kg body weight intraperitoneally once a week for 10 weeks; 24 h prior to CP administration). A vehicle treated control group and a lipoic acid drug control group were also included. CP-treated rats showed a significant decrease in sperm count and motility with an increase in dead and abnormal sperms. The epididymal sperm of untreated CP-exposed rats showed 1.9-fold increase in lipid peroxidation, along with a significant increase in protein carbonyl level. These changes were associated with significant increase in DNA damage in the sperm as evidenced by increased single strand breaks in fluorimetric analysis of DNA unwinding (FADU). In rats treated with CP, abnormal changes in the activities/levels of enzymic (superoxide dismutase, catalase and glutathione peroxidase) and non-enzymic (reduced glutathione, ascorbate and alpha-tocopherol) antioxidants, were also observed. Pretreatment with lipoic acid improved the semen quality and reduced the oxidative stress and DNA damage induced by CP, thereby demonstrating the protection rendered by lipoic acid.

A TIME-COURSE CHARACTERIZATION OF MALE REPRODUCTIVE TOXICITY IN RATS TREATED WITH METHYL METHANESULPHONATE (MMS)

Methyl methanesulphonate (MMS), a potent alkylating agent and testicular toxicant, was orally administered to rats for 5 days at doses of 20, 30, and 40 mg/kg. During the recovery period of 5 weeks, males were evaluated for multiple endpoints such as organ weights, fertility, and sperm parameters. The 5-week recovery periods are designated as follows: Day 1 (1 day after final treatment); Week 1, Week 2, Week 3, Week 4, and Week 5 (first, second, third, fourth, and fifth week after final treatment). A clear time-course of dominant lethals was observed. The peak severities of the dominant lethals were observed in Week 2. It was judged that the most sensitive cellular targets for the dominant lethals are late spermatids. Sperm examination revealed a clear time-course and dose-dependent changes in the frequency of sperm morphological abnormalities. The peak severities of the sperm morphological alterations in cauda epididymis were observed in Week 4. Sensitive cellular stages for the induction of sperm morphological abnormalities were judged to be late spermatocytes and early spermatids. The most frequently observed type of morphologically abnormal spermatozoa was tailless sperm, followed by no-hook head sperm. Although the initial cause for both sperm morphological alterations and dominant lethals was suggested to be genetic insult to the germ cells, there were no obvious relationships observed between these two findings.

Computer assisted semen analyzers in andrology research and veterinary practice

The evaluation of sperm cell motility and morphology is an essential parameter in the examination of sperm quality and in the establishment of correlations between sperm quality and fertility. Computer-assisted sperm analysis (CASA) allows an objective assessment of different cell characteristics: motion, velocity, and morphology. The development and problems related to this technology are raised in this review, paying particular attention to the biases and standardization requirements absolutely needed to obtain useful results. Although some interesting results, mainly in humans, have already been obtained, many questions remain, which have to be answered to allow for further development of this technology in veterinary medicine, clinical fertility settings, physiological, and toxicology research activities. The main problem is related to the standardization and optimization of the equipment and procedures. The different CASA instruments have all demonstrated high levels of precision and reliability using different sperm classification methodology. Their availability gives us a great tool to objectively compare sperm motility and morphology and to improve our knowledge and ability to manipulate spermatozoa.

Overview of studies on rat sperm motion analysis using a Hamilton-Thorne Sperm Analyzer--collaborative working study

This collaborative study was conducted to determine the utility and sensitivity of nine sperm motion parameters generated by a Hamilton-Thorne Sperm Analyzer (HTM-IVOS) for detecting adverse effects of chemicals on sperm motion in rats. The efficacy of sperm motion parameters was investigated using nine reproductive toxicants: adriamycin, alpha-chlorohydrin (3 different studies were carried out), dinoseb, ethylene glycol monoethyl ether, 2,5-hexanedione, sulfasalazine, trimethyl phosphate, and ornidazole. The percentage of motile sperm (% motile sperm), the only parameter expressing the status of semen containing non-motile sperm, detected adverse effects on sperm motion in 9 out of 10 studies. However, weak effects on sperm motion were not detected by this parameter in 4 out of 7 studies in which sperm motion disorders were noted at medium or low dosages. The percentage of progressively motile sperm (% progressive sperm) and the sperm velocity parameters (average path velocity, straight line velocity, and curvilinear velocity) detected adverse effects on sperm motion in all studies. In 7 studies which noted sperm motion disorders at medium or low dosages, weak effects on sperm motion were detected by the % progressive sperm in 5 studies and by the sperm velocity parameters in 6 studies. In 10 studies, amplitude of lateral head displacement (ALH) did not detect adverse effects on sperm motion in 4 studies, and beat cross frequency (BCF) failed to detect adverse effects on sperm motion in 3 studies. Because ALH and BCF show the swimming pattern of spermatozoa as head movement, the characteristics of these parameters are different from the % progressive sperm and the sperm velocity parameters. Straightness (STR) and linearity (LIN), which are secondary parameters calculated from sperm velocity parameters, could not detect adverse effects on sperm motion when the sperm velocity parameters did not detect adverse effects. On the basis of these results, we concluded that the % progressive sperm and sperm velocity parameters are useful and sensitive indicators for detecting adverse effects on sperm motion. However, in the % progressive sperm, setting up a suitable threshold of VAP and/or STR is important to gain further sensitivity for detecting adverse effects on sperm motion. The % motile sperm is useful for assessment of sperm motion disorder, and ALH and BCF are useful for evaluating the swimming pattern of sperm. STR and LIN are not very useful for detecting adverse effects on sperm motion.