Characterization of cis-platinum-induced Sertoli cell dysfunction in rodents

Cell-Cell Interaction-Mediated Signaling in the Testis Induces Reproductive Dysfunction—Lesson from the Toxicant/Pharmaceutical Models

Emerging evidence has shown that cell-cell interactions between testicular cells, in particular at the Sertoli cell-cell and Sertoli-germ cell interface, are crucial to support spermatogenesis. The unique ultrastructures that support cell-cell interactions in the testis are the basal ES (ectoplasmic specialization) and the apical ES. The basal ES is found between adjacent Sertoli cells near the basement membrane that also constitute the blood-testis barrier (BTB). The apical ES is restrictively expressed at the Sertoli-spermatid contact site in the apical (adluminal) compartment of the seminiferous epithelium. These ultrastructures are present in both rodent and human testes, but the majority of studies found in the literature were done in rodent testes. As such, our discussion herein, unless otherwise specified, is focused on studies in testes of adult rats. Studies have shown that the testicular cell-cell interactions crucial to support spermatogenesis are mediated through distinctive signaling proteins and pathways, most notably involving FAK, Akt1/2 and Cdc42 GTPase. Thus, manipulation of some of these signaling proteins, such as FAK, through the use of phosphomimetic mutants for overexpression in Sertoli cell epithelium in vitro or in the testis in vivo, making FAK either constitutively active or inactive, we can modify the outcome of spermatogenesis. For instance, using the toxicant-induced Sertoli cell or testis injury in rats as study models, we can either block or rescue toxicant-induced infertility through overexpression of p-FAK-Y397 or p-FAK-Y407 (and their mutants), including the use of specific activator(s) of the involved signaling proteins against pAkt1/2. These findings thus illustrate that a potential therapeutic approach can be developed to manage toxicant-induced male reproductive dysfunction. In this review, we critically evaluate these recent findings, highlighting the direction for future investigations by bringing the laboratory-based research through a translation path to clinical investigations.

Mice with a Sertoli cell-specific knockout of the Ctr1 gene exhibit a reduced sensitivity to cisplatin-induced testicular germ cell apoptosis

Exposure to the chemotherapeutic agent cis-diamminedichloroplatinum(ii) (cDDP) is well known to instigate acute and prolonged testicular injury in male patients.

Exposure to the chemotherapeutic agent cis-diamminedichloroplatinum(ii) (cDDP) is well known to instigate acute and prolonged testicular injury in male patients. Many investigators have hypothesized that cDDP-induced dysfunction of Sertoli cells (SCs) may, in part, account for the cDDP-induced lasting testicular injury. Nevertheless, the relative contribution of cDDP-induced SC injury versus direct effects on germ cells (GCs) to the pathogenesis of GC loss remains to be elucidated. The expression of the copper transporter 1 (CTR1) protein in cells directly corresponds with cDDP uptake and its cellular toxicity. Therefore, to discern the role of SCs in the pathogenic mechanism, mice were developed with a SC-specific disruption of the Ctr1 gene (SC^ΔCtr1) as a strategy to prevent their exposure to cDDP. Adult mice at postnatal day (PND) 60 were treated with 5 mg kg^–1 cDDP and then testis collected at 48 hours. A two-fold increase in GC-apoptosis occurred in the testis of cDDP-treated wildtype (WT) mice as compared to saline-treated WT mice. In contrast, cDDP-treated SC^ΔCtr1 mice exhibited only a half-fold increase in GC-apoptosis as compared to the saline-treated SC^ΔCtr1 mice. This reduced incidence of GC apoptosis in the SC^ΔCtr1 mice corresponded to a significantly lower level of platinum within the testis. Taken together, these findings reveal that the uptake of cDDP by CTR1 in SCs accounts for the accumulation of cDDP in the testis and plays a pivotal role in the pathogenic sequence of events leading to the loss of germ cells via apoptosis.

Candesartan Mediated Amelioration of Cisplatin-Induced Testicular Damage Is Associated with Alterations in Expression Patterns of Nephrin and Podocin

Nephrin and podocin are known to be closely related to the pharmacological effects of angiotensin-II receptor blocker (ARB). The objectives of this study were to investigate the role of nephrin and podocin using cisplatin-induced testicular damage and to evaluate the effect of ARB. At first, we evaluated the effects of cisplatin either alone or in combination with ARB candesartan on changes in expression patterns of nephrin and podocin in the rat testes. We then conducted in vitro studies to investigate the effects of angiotensin using cultured Sertoli cells, line TM4. As a result, the expression of nephrin and podocin was shown to localize around the basal membrane of seminiferous tubules. Treatment with cisplatin resulted in a marked decrease in the expression of nephrin and podocin and induced a shift of both proteins from linear to granular expression patterns, accompanying the increased apoptotic index in the testes; these changes were partially restored by the additional administration of candesartan. In vitro studies with TM4 revealed the angiotensin-II mediated expression changes of nephrin and podocin. These findings suggest that candesartan can prevent cisplatin-induced testicular damage by regulating expression patterns of the nephrin-podocin complex in the testes.

Simvastatin protects Sertoli cells against cisplatin cytotoxicity through enhanced gap junction intercellular communication

Cisplatin, an important chemotherapeutic agent against testicular germ cell cancer, induces testicular toxicity on Leydig and Sertoli cells, leading to serious side-effects such as azoospermia and infertility. In a previous study, it was found that simvastatin enhanced the sensitivity of Leydig tumor cells to chemotherapeutic toxicity through the enhancement of gap junction functions. In the present study, the effect of simvastatin on the sensitivity of normal Sertoli cells to cisplatin and the role of gap junctions in such effects was investigated. The results showed that, simvastatin attenuated cisplatin toxicity only when cells exhibited high-density culture where gap junctional formation was possible. When gap junction function was decreased by the gap junction inhibitor or by siRNA targeting connexin 43, the protective effect of simvastatin to cisplatin toxicity was substantially attenuated. Simvastatin also enhanced gap junction functions between Sertoli cells. This effect was mediated by the reduction of PKC-mediated connexin phosphorylation, thereby increasing connexin 43 membrane localization. Thus, simvastatin-induced enhancement of gap junction‑mediated intercellular communication attenuated cisplatin toxicity on Sertoli cells. This result indicated that enhancement of gap junction function by simvastatin may have bilateral beneficial effects on cisplatin‑based chemotherapy, enhancing cisplatin killing on cancer while ameliorating the reproduction toxicity.

Ghrelin partially protects against cisplatin-induced male murine gonadal toxicity in a GHSR-1a-dependent manner

The chemotherapeutic drug cisplatin causes a number of dose-dependent side effects, including cachexia and testicular damage. Patients receiving a high cumulative dose of cisplatin may develop permanent azoospermia and subsequent infertility. Thus, the development of chemotherapeutic regimens with the optimal postsurvival quality of life (fertility) is of high importance. This study tested the hypothesis that ghrelin administration can prevent or minimize cisplatin-induced testicular damage and cachexia. Ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR-1a), are expressed and function in the testis. Targeted deletion of ghrelin, or its receptor, significantly increases the rate of cell death in the testis, suggesting a protective role. Intraperitoneal administration of vehicle, ghrelin, or cisplatin alone or in combination with ghrelin, in cycles of 9 or 18 days, to adult male C57Bl/6 mice was performed. Body weight was measured daily and testicular and epididymal weight, sperm density and motility, testicular histology, and testicular cell death were analyzed at the time of euthanization. Ghrelin coadministration decreased the severity of cisplatin-induced cachexia and gonadal toxicity. Body, testicular, and epididymal weights significantly increased as testicular cell death decreased with ghrelin coadministration. The widespread damage to the seminiferous epithelium induced by cisplatin administration was less severe in mice simultaneously treated with ghrelin. Furthermore, ghrelin diminished the deleterious effects of cisplatin on testis and body weight homeostasis in wild-type but not Ghsr(-/-) mice, showing that ghrelin's actions are mediated via GHSR. Ghrelin or more stable GHSR agonists potentially offer a novel therapeutic approach to minimize the testicular damage that occurs after gonadotoxin exposure.

The effect of mirtazapine on cisplatin-induced oxidative damage and infertility in rat ovaries

Cisplatin causes infertility due to ovarian toxicity. The toxicity mechanism is unknown, but evidence suggests oxidative stress. In this study, the effect of mirtazapine on cisplatin-induced infertility and oxidative stress in rats was investigated. 64 female rats were divided into 4 groups of 16. Except for the controls that received physiologic saline only, all were administered with cisplatin (5 mg/kg i.p.) and mirtazapine (15 mg/kg p.o.) or mirtazapine (30 mg/kg p.o.) for 10 days. After this period, six rats from each group were randomly selected, and malondialdehyde (MDA), myeloperoxidase (MPO), nitric oxide (NO), total gluthatione (tGSH), gluthatione peroxidase (GPx), superoxide dismutase (SOD), and 8-hydroxy-2 deoxyguanine (8-OH Gua) levels were measured in their ovarian tissues. Reproductive functions of the remaining rats were examined for 6 months. The MDA, MPO, NO groups and 8-OH Gua levels were higher in the cisplatin-treated groups than the controls, which was not observed in the mirtazapine and cisplatin groups. GSH, GPx, and SOD levels were reduced by cisplatin, which was prevented by mirtazapine. Cisplatin caused infertility by 70%. The infertility rates were, respectively, 40% and 10% for the 15 and 30 mg/kg mirtazapine administered groups. In conclusion, oxidative stress induced by cisplatin in the rat ovary tissue causes infertility in the female rats. Mirtazapine reverses this in a dose-dependent manner.

Amifostine protective effect on cisplatin-treated rat testis

Cisplatin is a potent drug used in clinical oncology but causes spermatogenesis damage. Amifostine is a drug used against toxicity caused by ionizing irradiation and chemotherapeutic drugs. Since cisplatin provokes fertility and induces germ cell apoptosis and necrosis, we proposed to evaluate the amifostine cytoprotective action on testes of cisplatin-treated rats. Thirty-day-old prepubertal Wistar rats received a single cisplatin dose of 5 mg/kg and were killed after 3, 6, and 12 hr. The hematoxylin-eosin stained testicular sections were submitted to histological, morphometric, and stereological analysis. The terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) method was used to label apoptotic cells. TUNEL-positive and TUNEL-negative germ cells with abnormal nuclear morphology (ANM) were scored. Significant alterations of greater part of the parameters occurred in the cisplatin-treated group (CE) compared to the group that received amifostine before the cisplatin-treatment (ACE); however, testicular weight and volume did not vary between these groups. Tubular diameter was reduced in CE in comparison to ACE rats, while interstitial tissue and lymphatic space volume and volume density were significantly higher in CE rats; interstitial testicular edema probably occurred in cisplatin-treated rats. CE rats showed important histological alterations, which were more accentuated than in ACE rats. The numerical densities of apoptotic germ cells and TUNEL-negative cells with ANM were lower in ACE than in CE rats. In conclusion, the amifostine previously administered to prepubertal rats reduced the testicular damage caused by cisplatin. We conclude that amifostine partially protected the rat seminiferous epithelium against cisplatin toxicity.

Differential effects of ionizing radiation and platinum-derivative chemotherapy on apoptotic pathways in testicular germ cells

PURPOSE

The purpose here was to identify whether ionizing radiation and oxaliplatin triggered testicular germ cells apoptosis through different executionary pathways.

MATERIALS AND METHODS

Adult male mice are treated with oxaliplatin (0.5 mg/kg, Ox) 4 h before being locally irradiated (0.5 Gy, IR, considered as time 0 h).

RESULTS

The number of apoptotic germ cells was significantly higher for IR (p < 0.008), Ox (p < 0.0001) and Ox + IR (p < 0.0001) groups compared to the untreated mice group. Similarly, the different treatments induced an increase of p53 expression. Downstream p53, IR and Ox used different pathways. Indeed, IR increased effector caspase-3 expression in terms of mRNA (p < 0.002), pro-enzyme p < 0.0001) and active (3.7-fold, p < 0.003) protein levels but not the inhibitors of apoptosis proteins (IAP) including cIAP1, cIAP2 and XIAP. In contrast, while oxaliplatin treatment had no apparent effect on caspase-3 expression, it significantly decreased the cIAP1 (p < 0.005), cIAP2 (p < 0.008) and XIAP (p < 0.02) proteins levels. Finally, the combination of both treatments decreased IAP expression but did not modify caspase-3 levels while it increased the AIF (apoptosis-inducing factor) protein levels (5.5-fold, p < 0.003). No modification of AIF levels was observed with OX or IR alone.

CONCLUSIONS

Together, these results indicate that the platinum analogue oxaliplatin and the ionizing radiations trigger apoptosis in the testicular germ cells, probably through different pathways.

A postulated role of testosterone for prevention of cisplatin gonadal toxicity

Testicular cancer is the most common solid tumor in young men. It has become one of the most curable solid neoplasms by applying multidisciplinary treatment approaches and new chemotherapeutic drugs. Cisplatin based chemotherapy as the most efficient chemotherapy of germ cell tumors has severe deleterious effects on all stages of spermatogenesis by various direct and indirect mechanisms. By marked improvement in oncologic control, prognosis and survival of patients with testicular cancer, their fertility, as one of the essential aspects of quality of life, is a matter of great concern. Since the probability and severity of spermatogenesis impairment is quite unpredictable during a course of cisplatin based chemotherapy, protecting the spermatogenesis during that phase by administration of exogenous testosterone in order to reduce the proliferation rate of germ cells would seem to be beneficial.

Sertoli cell function in albino rats treated with etoposide during prepubertal phase

Sertoli cell plays a key role in spermatogenesis. Many studies refer that this cell is not harmed by the majority of anticancer treatments known to cause damage to the testis. However, in the previous study we observed that etoposide, an efficient chemotherapeutic drug, provokes an increase in numerical density of the Sertoli cells. This phenomenon suggests that this cell was harmed by etoposide. Thus, we decided to investigate a possible direct action of etoposide on Sertoli cells analyzing the function of this cell and relating it with the integrity and damage of the seminiferous epithelium. Prepubertal albino rats received 5 mg/kg of etoposide for eight consecutive days and were sacrificed in different ages. The control groups received 0.9% saline solution. The testes were fixed in Bouin's liquid for transferrin immunolabeling and testicular labeled tissue volume density measurement. Except for the younger rats, all the etoposide-treated rats showed diminution of transferrin immunolabeling in the seminiferous epithelium, and consequently, of total labeled testicular tissue volume density. We concluded that the diminution of transferrin labeling in the seminiferous epithelium was not associated with germ cell absence such as commonly reported. The results suggest etoposide impairs Sertoli cell function.

Cytokines and junction restructuring during spermatogenesis—a lesson to learn from the testis

In the mammalian testis, preleptotene and leptotene spermatocytes residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier (BTB) at late stage VIII through early stage IX of the epithelial cycle during spermatogenesis, entering the adluminal compartment for further development. However, until recently the regulatory mechanisms that regulate BTB dynamics remained largely unknown. We provide a critical review regarding the significance of cytokines in regulating the 'opening' and 'closing' of the BTB. We also discuss how cytokines may be working in concert with adaptors that selectively govern the downstream signaling pathways. This process, in turn, regulates the dynamics of either Sertoli-Sertoli tight junction (TJ), Sertoli-germ cell adherens junction (AJ), or both junction types in the epithelium, thereby permitting TJ opening without compromising AJs, and vice versa. We also discuss how adaptors alter their protein-protein association with the integral membrane proteins at the cell-cell interface via changes in their phosphorylation status, thereby altering adhesion function at AJ. These findings illustrate that the testis is a novel in vivo model to study the biology of junction restructuring. Furthermore, a molecular model is presented regarding how cytokines selectively regulate TJ/AJ restructuring in the epithelium during spermatogenesis.

cis-diamminedichloroplatinum (II) (cisplatin) alters microtubule assembly dynamics

Cisplatin is an highly effective chemotherapeutic agent which produces a cumulative dose-limiting peripheral neuropathy. In this study, a possible role for microtubule abnormalities in cisplatin-induced toxicity was explored. CD rats (300 g) were injected daily ip with five doses of cisplatin (2 mg/kg) or every other day ip with two doses of cisplatin (10 mg/kg). The day after the last dose, the rats were killed and tubulin was purified from their testes. The maximal rate of cold-induced microtubule disassembly was consistently slower for testis tubulin purified from cisplatin-treated rats compared with control rats. Overnight in vitro coincubation of polymerized bovine brain tubulin with cisplatin followed by a purifying cycle of assembly and disassembly yielded tubulin capable of forming morphologically normal but short microtubules (average length: cisplatin-treated, 2.5 microns; control, 3.7 microns). Cisplatin coincubation markedly reduced the rate of cold-induced microtubule disassembly, producing a half-maximal effect at approximately 0.3 mM. The cold stability of cisplatin-treated microtubules could be partially reversed by diethyldithiocarbamate. Carboplatin, a cisplatin analog which does not cause clinical peripheral neuropathy, was less capable of producing microtubule disassembly abnormalities. These findings demonstrate the ability of cisplatin to alter microtubule disassembly by direct tubulin modification, an abnormality which may contribute to cisplatin-induced peripheral neuropathy.

Effects of carboplatin on the testis. A histological study

In the present study, the influence of carboplatin [diammine(cyclobutane-1,1-dicarboxylato)platinum(II)], the main and most active representative of second-generation antitumour platinum complexes, on the morphology of the testes of male CF1 mice was investigated histologically by examining semithick sections. Carboplatin was administered in doses of 30, 60, or 120 mg/kg and applied as a single intraperitoneal injection. For comparison purposes, the parent compound cisplatin [cis-diamminedichloroplatinum(II)] was administered at equitoxic doses (3, 6 or 12 mg/kg). At various intervals between days 1 and 28 after treatment, the testes were removed and embedded in Epon. Both compounds effected severe structural alterations of Sertoli cells, disrupted the blood/testis barrier, and impaired the processes both of spermatogenesis and spermiohistogenesis. The structural damage in the testes following treatment with carboplatin was at least as pronounced as that occurring under the influence of equitoxic doses of cisplatin. Within a few days, the intercellular spaces around Sertoli cells widened, the tight contacts with neighbouring cells were disrupted, the cytoplasm of Sertoli cells disintegrated and their nuclei shrank. Numerous necroses, abnormal mitotic figures of spermatogenic cells and malformed spermatozoa appeared. Severe damage was evident on days 10-21 after treatment with carboplatin, the strength of the symptoms being clearly dependent on the dose applied. The first indications of ongoing recovery processes were detected on day 21 in the case of the low dose (30 mg/kg) or on day 28 following treatment with 60 mg/kg or 120 mg/kg. These results confirm that carboplatin is at least as toxic to the testes as cisplatin and that its substitution for cisplatin in clinical therapy does not diminish the problem of drug-induced infertility following platinum-based chemotherapy.

Short-term morphological response of the rat testis to administration of five chemotherapeutic agents

As cancer survival rates improve, there is increasing concern about the adverse effects of chemotherapeutic agents on male fertility. Five chemotherapeutic agents (amethopterin, AP or methotrexate; doxorubicin, DX; cytoxan or cyclophosphamide, CP; cisplatinum, CDDP; and 5-fluorouracil, 5-FU) which belong to three different categories of chemotherapeutic agents (antimetabolite, antibiotic, alkylating agent, alkylating agent, antimetabolite, respectively) were given systemically to adult rats to determine the short-term morphological patterns of response in the testis, and the testes were examined by light microscopy. Morphological patterns of response were found to be highly characteristic for each agent, and some shared morphological responses were evident. All except one chemotherapeutic agent (5-FU) caused spermatogonial damage. Among the defects seen were probable degenerating meiotic spermatocytes (CDDP), presence of micronuclei (DX), "arrested" spermatid development (5-FU), and abnormally shaped step 15 spermatids (5-FU). Damage that could be due to the effect of an agent on the Sertoli cell was failure of sperm release (5-FU, CDDP, DX, and AP), increase in the Sertoli cell lipid (5-FU), and malorientation of step 8 spermatids (5-FU, DX). The varied patterns of damage observed are a possible explanation of why the reproductive recovery potential in cancer patients undergoing chemotherapy is variable and drug-specific.

Ultrastructural observations in testicular tissue of chromium-treated rats

The administration of hexavalent chromium (2 mg/kg, ip as potassium dichromate) in adult rats daily for 15 days produced significant increases in the blood and testicular chromium levels. Although no light microscopic pathologic changes or alterations in epididymal sperm counts and motility were observed, lanthanum perfusion in treated rats revealed leakage of Sertoli-cell tight junctions under EM. A few tubules showed marked ultracellular alterations in the form of vacuolization of cytoplasm and degeneration of mitochondria in the epithelial cells. Late stage spermatids were the most affected germ cells. The mitochondrial sheath of the midpiece was vacuolated, incomplete, swollen, or broken in places. The observed alterations may result in the disruption of normal testicular physiology leading to reproductive impairment after chromium exposure.

Toxicity of cis-diamminedichloroplatinum (II) (cisplatin) in the frog, Rana pipiens

The toxicity of the anti-cancer drug cis-diamminedichloroplatinum (II) (cisplatin), at 2 to 40 mg per kg, was studied in the frog, Rana pipiens. The LD50 for the drug was approximately 17 mg per kg. Major non-nervous system toxicity occurred in the kidney. Renal failure was manifested as anasarca and increasing blood urea nitrogen (BUN). Histopathological changes included acute tubular necrosis and tubular dilatation, which were more severe at higher doses. Interstitial fibrosis occurred after prolonged survival after a single dose. Ultrastructurally, there was increased electron-dense material in tubular cells, but no specific changes in mitochondria or nuclear structures were seen. Gastro-intestinal toxicity was less severe than in other species and was more prominent at higher doses. Pathological changes consisted of epithelial nuclear atypia and apoptosis. By electron microscopy, there was increased separation of cell borders, depletion of chylomicrons and mucin granules and increases in electron-dense material. Again no specific mitochondrial or nuclear changes were seen. Relatively slight changes were seen in the liver, consisting of altered distribution of rough endoplasmic reticulum and dispersion of nuclear chromatin. Minimal pathology was demonstrated in the haematopoietic system or in the gonads. Thus toxicity of cisplatin in the frog is similar to that seen in mammals, including rodents and man.

Effect of cis-platinum on heme, drug, and steroid metabolism pathways: possible involvement in nephrotoxicity and infertility

cis-Platinum, a coordination complex of platinum, is highly effective against a number of human tumors, including steroid-dependent tumors such as testicular and prostatic cancers. It is generally assumed that DNA is the cellular target responsible for the antitumor activity of the drug. Much evidence, however, has been gathered in recent years suggesting that cis-platinum has major effects on the endocrine system, particularly the hypothalamic-pituitary-testis steroidogenesis axis, and severely disrupts the normal production of testosterone. In the axis, testis is the prime target, where the LH receptor-binding capacity of Leydig cells is decreased by nearly 80%. Within the testis, the mitochondrial cytochrome P-450scc and side-chain cleavage activity are markedly depressed and the microsomal 17 alpha-hydroxylase activity and cytochrome P-450 concentration are decreased; side-chain cleavage activity is rate-limiting in testosterone production. The effects are not limited to the testis cytochrome P-450, but extend to other organs including the liver and the kidney cytochromes. In the liver, a feminization of the cytochromes P-450 profile is produced, and hence the biotransformation of endogenous steroids as well as that of exogenous chemicals is affected. In the kidney, cis-platinum appears to be the most effective inducer of cytochrome P-450, whereby the biotransformation of the prostaglandins and fatty acids could be altered. The spectrum of the effects of cis-platinum on cytochrome P-450-dependent drug metabolism and steroid hydroxylation activity mimic those produced by hypophysectomy and are for the most part reversed by the anterior pituitary hormones. These findings suggest the possibility that general feminization of steroidogenesis caused by cis-platinum may significantly contribute to the activity of cis-platinum against hormone-dependent tumors.

Zinc acetate pretreatment ameliorates cisplatin-induced Sertoli cell dysfunction in Sprague-Dawley rats

The present study was undertaken to determine if prior administration of zinc acetate (ZnAc) or copper sulfate (CuSO4) could prevent pituitary, Leydig, or Sertoli cell dysfunction subsequent to cisplatin administration in adult Sprague-Dawley rats. Animals were given cisplatin at a dose of 2 mg/kg daily for 5 days, with or without the i.p. administration of ZnAc (6 mg/kg per day) or CuSO4 (5 mg/kg per day), beginning 5 days prior to and continuing through the administration of cisplatin. Control animals were given vehicle, ZnAc1, or CuSO4. Animals were sacrificed 1 week after the initial cisplatin injection. Cisplatin administration resulted in suppressed serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels as well as a 77% reduction in serum testosterone and an 82% reduction in testicular testosterone. The concomitant administration of either ZnAc or CuSO4 did not result in a significant difference relative to animals receiving cisplatin alone, although administration of both cations alone significantly reduced testicular testosterone content. Serum androgen-binding protein (ABP) was not significantly lowered in any treatment group. There was a marked reduction of 57% in testicular ABP content relative to control values subsequent to cisplatin administration. This reduction was partially prevented by ZnAc treatment: the testicular ABP concentration was only 15% lower than that in controls (not significant). Since the cisplatin-induced reduction in serum FSH was not altered by ZnAc pretreatment, we conclude that the near normalization of testicular ABP content may be evidence of improved Sertoli cell function. In contrast, cisplatin-induced decreases in the serum gonadotropins and testicular androgens were not lessened by pretreatment with either cation. Further studies may be warranted to determine whether ZnAc pretreatment has a beneficial effect on spermatogenesis during cisplatin treatment.

The ultrastructure and reversibility of testicular atrophy induced by ethylene glycol monomethyl ether (EGME) in the rat

Inhalation exposure to 300 ppm ethylene glycol monomethyl ether (EGME) for 3 days produced degenerative changes in spermatocytes of pachytene and meiotic division at spermatogenic stage XIV in rats. However, a wide range of germ cell types including spermatogonia was affected and the stage-specific damage was not discernible after 2 weeks exposure to 300 ppm EGME. The stage-specific damage was related to exposure concentration-time course. In early stages, degenerating spermatocytes showed nuclear chromatin clumping around synaptonemal complexes, cytoplasmic vesiculation with electron-dense material deposition, and disruption of the plasma membrane. Chromosomal microtubules in the meiotic division of spermatocytes were discontinued with deposition of electron-dense chromatin material. Sertoli cells showed cytoplasmic vacuolization, contact loss to germ cells, and cytoplasmic processes fragmentation with disrupted microtubules. Degenerative pachytene or meiotic spermatocytes were associated with disrupted Sertoli-germ cell relationship, chromosomal microtubules, and synaptonemal complexes. Spermatid degeneration and giant cell formation were observed after spermatocyte degeneration. Spermatid degeneration appeared to be a secondary change resulting from disrupted Sertoli-to-germ cell association. After 14 days post-exposure (PE) following 2 weeks exposure, some tubules were lined with regenerating spermatocytes with or without round spermatids. By 42 days PE, many tubules regained normal germinal epithelium, but some tubules were still atrophic even after 84 days PE. Reversibility of testicular atrophy was inversely proportional to severity of damaged stem cells.