Evaluation of immunohistochemical markers of germ cells’ proliferation in the developing rat testis: A comparative study

Reprotoxic Effect of Tris(2,3-Dibromopropyl) Isocyanurate (TBC) on Spermatogenic Cells In Vitro

Tris(2,3-dibromopropyl) isocyanurate (TBC) belongs to the class of novel brominated flame retardants (NFBRs) that are widely used in industry. It has commonly been found in the environment, and its presence has been discovered in living organisms as well. TBC is also described as an endocrine disruptor that is able to affect male reproductive processes through the estrogen receptors (ERs) engaged in the male reproductive processes. With the worsening problem of male infertility in humans, a mechanism is being sought to explain such reproductive difficulties. However, so far, little is known about the mechanism of action of TBC in male reproductive models in vitro. Therefore, the aim of the study was to evaluate the effect of TBC alone and in cotreatment with BHPI (estrogen receptor antagonist), 17β-estradiol (E₂), and letrozole on the basic metabolic parameters in mouse spermatogenic cells (GC-1 spg) in vitro, as well as the effect of TBC on mRNA expression (Ki67, p53, Pparγ, Ahr, and Esr1). The presented results show the cytotoxic and apoptotic effects of high micromolar concentrations of TBC on mouse spermatogenic cells. Moreover, an increase in Pparγ mRNA levels and a decrease in Ahr and Esr1 gene expression were observed in GS-1spg cells cotreated with E₂. These results suggest the significant involvement of TBC in the dysregulation of the steroid-based pathway in the male reproductive cell models in vitro and may be the cause of the currently observed deterioration of male fertility. However, more research is needed to reveal the full mechanism of TBC engagement in this phenomenon.

Impact of chitosan administration on titanium dioxide nanoparticles induced testicular dysfunction

The potential reproductive toxic effects of oral TiO₂ NPs in adult male rats as well as the possible alleviation of chitosan administration was investigated. Animals were allocated to four groups; the first group received deionized water and was assigned as a control group. In the second group, rats received chitosan at a dose of 5 mg/kg BW/day. The third group was designed for administration of TiO₂ NPs at a dose of 150 mg/kg BW/day (1/80 LD₅₀). Rats in the fourth group received both TiO₂ NPs and chitosan. After 14 days, TiO₂ NPs induced testicular lipid peroxidation as well as oxidative stress. Nano-titanium significantly upregulated genes that encode apoptosis and inflammation in testicular tissue. Moreover, it induced histological alteration in the testicular structure with impairment in spermatogenesis via reduction of PCNA immune-staining. Chitosan administration significantly improved the activities of testicular GPx, SOD, and CAT enzymes. In addition, it significantly down-regulated the relative expressions of pro-apoptotic and pro-inflammatory testicular genes. Chitosan was able to improve the testicular architecture as well as spermatogenesis. The current study revealed the capability of chitosan to ameliorate nano-titanium induced testicular toxicity. Thus, attention should be given to the extensive consumption of nano-titanium particles.

Effect of Light-Dark Cycle Misalignment on the Hypothalamic-Pituitary-Gonadal Axis, Testicular Oxidative Stress, and Expression of Clock Genes in Adult Male Rats

This study investigated the influence of circadian misalignment on the male reproductive system. Adult Sprague-Dawley male rats were exposed to prolonged light (20 h light : 4 h dark) or prolonged darkness (4 h light : 20 h dark) for 12 consecutive weeks. The somatic index of seminal vesicles and prostates increased due to prolonged light exposure. Sperm count and motility were enhanced solely by prolonged light exposure, whereas the percentage of sperm abnormalities was reduced by both prolonged light and darkness. The serum levels of reproductive hormones (follicle-stimulating hormone, luteinizing hormone, testosterone, and prolactin) were elevated, and the estradiol level was reduced by long-term light and dark exposure. Testicular total antioxidant capacity and antioxidant enzyme activities were improved, and lipid peroxidation was inhibited following chronic exposure to light or dark. Chronic light exposure increased, but chronic darkness decreased, testicular nitric oxide production. The mRNA expression of the hypothalamic and testicular clock genes including PER1-2, CRY1-2, BMAL1, CLOCK, and Rev-Erbα was altered by circadian disruption. Prolonged light exposure decreased the levels of thyroid hormones and suppressed the mRNA expression of adiponectin receptors 1 and 2. The immunohistochemical expression of proliferating cell nuclear antigen was decreased only by chronic darkness. The present study thus provides new insights into the physiological changes associated with long-term exposure to light or darkness, in which the expression levels of various clock gene mRNAs are modulated, reproductive hormones are increased, and the antioxidant enzyme system is ameliorated as mechanisms of adaptation to chronic circadian disruption.

Morin ameliorates the testicular apoptosis, oxidative stress, and impact on blood-testis barrier induced by photo-extracellularly synthesized silver nanoparticles

Silver nanoparticles (AgNPs) have been widely produced for different industrial purposes. Recently, biogenic synthesis of AgNPs has emerged although the extent of effects from exposure, oral exposure in particular, to nanomaterials synthesized in such a manner remains elusive. The main objective of this study was to evaluate the effects of oral administration of a dose of 50 mg/Kg body weight AgNPs biosynthesized in baker's yeast (Saccharomyces cerevisiae) over a period of eight weeks on the reproductive performance and the possibility of a protective effect through co-administration of morin. Forty-eight male Sprague-Dawley rats were used in four experimental groups (control, morin-treated group, AgNP-treated, and AgNP + morin co-treatment). AgNPs produced no significant alteration in daily food intake or body weight. Both the absolute and relative testicular weights were significantly reduced but not the epididymal weight. Also, serum levels of urea, creatinine, uric acid, and liver enzymes were significantly elevated. Furthermore, AgNPs significantly downregulated the hypothalamic-pituitary-gonadal axis. This corresponds to lower motility and viability percent, reduced sperm concentration, and a higher abnormality ratio as well as a prominent alteration in the blood-testis barrier (BTB) and testicular histology and induction of testicular apoptosis and oxidative stress. The supplementation of morin evidently restored most of the reproductive characters to its physiological range. We can conclude that exposure to the biologically synthesized AgNPs for an extended period of time has proven to be a health risk that can be ameliorated via oral administration of some bioactive agents including morin.

Positive PCNA and Ki-67 Expression in the Testis Correlates with Spermatogenesis Dysfunction in Fluoride-Treated Rats

The present study aimed to evaluate the effect of fluoride (F) on spermatogenesis in male rats. F^- at 50 and 100 mg/L was administered for 70 days, after which the testicular and epididymis tissues were collected to observe the histopathological structure under a light microscope. The ultrastructure of the testis and sperm was also examined via transmission electron microscopy. The apoptosis of spermatogenic cells was measured through terminal deoxynucleotidyl transferase dUTP nick end labeling staining. The expression of proliferation factors, namely, proliferating cell nuclear antigen (PCNA) and Ki-67, in the testicular and epididymis tissues, were assayed through immunohistochemistry. F^- at 50 and 100 mg/L significantly damaged the structure of the testis and epididymis, and the testis and sperm ultrastructure exhibited various changes, including mitochondrial swelling and vacuolization, and apsilated and raised sperm membrane. F treatment significantly increased spermatogenic cell apoptosis in the testis. PCNA (P < 0.01) and Ki-67 (P < 0.01) also presented positive expression in the testis. By comparison, no significant changes occurred in the epididymis. In summary, excessive F intake results in spermatogenesis dysfunction by damaging the testicular structure and inducing spermatogenic cell apoptosis in male rats. The positive expression level of PCNA and Ki-67 was a good response to spermatogenesis dysfunction.

Mobile phone radiation during pubertal development has no effect on testicular histology in rats

Mobile phones are extensively used throughout the world. There is a growing concern about the possible public health hazards posed by electromagnetic radiation emitted from mobile phones. Potential health risk applies particularly to the most intensive mobile phone users—typically, young people. The aim of this study was to investigate the effects of mobile phone exposure to the testes, by assessing the histopathological and biochemical changes in the testicular germ cells of rats during pubertal development. A total of 12 male Sprague Dawley rats were used. The study group ( n = 6) was exposed to a mobile phone for 1 h a day for 45 days, while the control group ( n = 6) remained unexposed. The testes were processed with routine paraffin histology and sectioned. They were stained with hematoxylin–eosin, caspase 3, and Ki-67 and then photographed. No changes were observed between the groups ( p > 0.05). The interstitial connective tissue and cells of the exposed group were of normal morphology. No abnormalities in the histological appearance of the seminiferous tubules, including the spermatogenic cycle stage, were observed. Our study demonstrated that mobile phones with a low specific absorption rate have no harmful effects on pubertal rat testicles.

Germ cell differentiation and proliferation in the developing testis of the South American plains viscacha, Lagostomus maximus (Mammalia, Rodentia)

Cell proliferation and cell death are essential processes in the physiology of the developing testis that strongly influence the normal adult spermatogenesis. We analysed in this study the morphometry, the expression of the proliferation cell nuclear antigen (PCNA), cell pluripotency marker OCT-4, germ cell marker VASA and apoptosis in the developing testes of Lagostomus maximus, a rodent in which female germ line develops through abolished apoptosis and unrestricted proliferation. Morphometry revealed an increment in the size of the seminiferous cords with increasing developmental age, arising from a significant increase of PCNA-positive germ cells and a stable proportion of PCNA-positive Sertoli cells. VASA showed a widespread cytoplasmic distribution in a great proportion of proliferating gonocytes that increased significantly at late development. In the somatic compartment, Leydig cells increased at mid-development, whereas peritubular cells showed a stable rate of proliferation. In contrast to other mammals, OCT-4 positive gonocytes increased throughout development reaching 90% of germ cells in late-developing testis, associated with a conspicuous increase in circulating FSH from mid- to late-gestation. TUNEL analysis was remarkable negative, and only a few positive cells were detected in the somatic compartment. These results show that the South American plains viscacha displays a distinctive pattern of testis development characterized by a sustained proliferation of germ cells throughout development, with no signs of apoptosis cell demise, in a peculiar endocrine in utero ambiance that seems to promote the increase of spermatogonial number as a primary direct effect of FSH.

PBK/TOPK in the differential diagnosis of cholangiocarcinoma from hepatocellular carcinoma and its involvement in prognosis of human cholangiocarcinoma

The increased expression of PDZ binding kinase/lymphokine-activated killer T-cell-originated protein kinase (PBK/TOPK) is associated with some human malignant tumors. In this study, we analyzed PBK/TOPK expression in hepatic primary tumor and explored its role in cholangiocarcinoma biology. Seventy-four cholangiocarcinomas, 33 hepatocellular carcinomas, and 10 normal liver tissues were prepared from paraffin-embedded specimens. PBK/TOPK protein was assessed by immunohistochemical staining, and the survival time was analyzed with the Kaplan-Meier method. The protein, mRNA of PBK/TOPK, and cell cycle of cholangiocarcinoma cell line after PBK/TOPK suppression with small interfere RNA were studied by Western blot, semiquantitative reverse transcriptase-polymerase chain reaction, and flow cytometry, respectively. PBK/TOPK was usually expressed in normal bile duct epithelial cells and much more frequently expressed in cholangiocarcinoma (68/74) but never expressed in hepatocytes and hepatocellular carcinomas (0/33). PBK/TOPK down-regulation was related to the poor prognosis of patients with cholangiocarcinoma (P = .013). Epidermal growth factor can enhance PBK/TOPK expression in cholangiocarcinoma QBC 939 cells, but suppression of PBK/TOPK in the cells did not affect their proliferation. PBK/TOPK protein could serve as a useful indicator for histopathologic differentiation between cholangiocarcinoma and hepatocellular carcinomas and the low expression of PBK/TOPK is predicative of poor survival in cholangiocarcinoma patients.