Protective role of irbesartan against cyclophosphamide-induced testicular damage in rats via up-regulating PPAR-γ signaling and ameliorating NF-κB/NLRP3/IL-18 inflammatory axis

BACKGROUND

Cancer and its therapies can impact fertility in various ways, and therefore a growing number of cancer survivors face fertility as a significant concern. The cytotoxic alkylating agent cyclophosphamide (CP) is commonly used as an antineoplastic agent; unfortunately, its use is significantly associated with male infertility and damage to the reproductive system.

AIM

The present study aimed to assess the possible beneficial effects of Irbesartan (IRB) in a rat model of CP-induced testicular toxicity.

MAIN METHODS

The effects of treatment were assessed by measuring peroxisome proliferator-activated receptor gamma (PPAR-γ) expression via qRT-PCR, the immunohistochemical (IHC) assessment of apoptotic markers, NOD-like receptor protein 3 (NLRP3), and nuclear factor-κB (NF-κB), determination of the count and viability of epididymal sperm, oxidative stress markers via biochemical analysis, serum testosterone, caspase-1, and interleukin-18 (IL-18) levels via ELISA, histopathological assessment, and fibrosis by Masson's trichrome (MT) stain.

KEY FINDINGS

There was a significant increase in malondialdehyde (MDA), caspase-1, and IL-18 contents, NF-κB, NLRP3, Bcl-2-associated X protein (Bax), caspase-3, and MT staining in testicular tissue after CP administration compared to the normal control group. Whereas reduced glutathione (GSH), superoxide dismutase (SOD), PPAR-γ expression, B-cell lymphoma-2 (Bcl-2) staining, serum testosterone, and the count and viability of epididymal sperm were decreased compared to the normal control group. The IRB treatment has reversed CP-induced testicular toxicity.

SIGNIFICANCE

It is possible to conclude that IRB revealed a significant testicular protective effect against CP via antioxidant, anti-apoptotic, and anti-inflammatory effects.

Phenolics from Caesalpinia ferrea Mart.: antioxidant, cytotoxic and hypolipidemic activity

Nine phenolics were isolated from the aqueous ethanol extract of the leaves of Caesalpinia ferrea. The isolates were characterized for the first time from that plant. The structures of all isolates (1-9) were elucidated by conventional methods, spectroscopic analysis, including 1 D and 2D NMR, and by HR-ESIMS as well. The antioxidant capacities using the ORAC method and the cytotoxic activity using the neutral red assay (NRU) for that extract and three major isolates have been evaluated. In addition, the hypolipidemic activity (in vitro and in vivo) of the extract has been assessed.

Stimulation of contraction of pregnant rat uterus in vitro by non-dechlorinated and microbially dechlorinated mixtures of polychlorinated biphenyls

A previous study of six polychlorinated biphenyl (PCB) congeners showed that PCBs with four or fewer chlorines and ortho substitution stimulate uterine contraction frequency in vitro, whereas congeners with a greater number of chlorines or non-ortho substitution are inactive in vitro. We tested the hypothesis that PCB mixtures stimulate uterine contractions in a manner inversely related to the degree of chlorination and the presence of chlorines in the ortho- position of the biphenyl constituents of the mixtures. Uterine strips from pregnant rats were suspended in standard muscle baths and analyzed for changes in isometric contractions in response to in vitro exposure to commercial PCB mixtures (Aroclors) and their dechlorinated products after microbial degradation. The PCB mixtures Aroclor 1242, 1248, and 1254 significantly stimulated uterine contraction frequency, and the least chlorinated mixture, Aroclor 1242, was the most potent stimulant. Microbes from Hudson River sediment dechlorinated Aroclor 1242 and Aroclor 1254 under reducing conditions to produce mixtures with an increased proportion of ortho-substituted congeners with one or two chlorine substitutions. The PCB mixtures that had undergone microbial reductive dechlorination stimulated uterine contraction frequency to a significantly greater extent than the parent mixtures. These results show that increased uterotonic activity was associated with decreased chlorination and increased ortho substitution of the biphenyl constituents of the mixtures.

Implication of somatolactin in the regulation of sexual maturation and spawning of Mugil cephalus

Specific antibody for chum salmon somatolactin (SL) was used for immunocytochemical investigation of SL cell activity of Mugil cephalus during the gonadal cycle in both natural habitat and captivity. The SL-immunoreactive cells showed strong and specific immunoreactivity to antichum salmon SL. The number of SL-immunoreactive cells increased, as did the secretory and synthetic activity during sexual maturation and spawning in the natural habitat. The SL cells were rather small and moderately immunoreactive in immature fish; they were enlarged, their numbers increased, and they frequently showed more SL immunoreactivity during gonadal development. In addition, during late stages of maturation, small cell size with more or less SL immunoreactive cells were noted, indicating an active release of SL granules. Prespawning females tended to have more enlarged SL cells with stronger immunoreactivity than equivalent males. The SL cells showed an increase in the secretory activity during spawning as indicated by small size and weak immunoreactivity. The SL cells of M. cephalus reared in captivity showed high activity. This may be due to the low concentration of calcium in fresh water. The gradual stimulation of SL synthesis and release during sexual maturation and spawning of M. cephalus suggest that SL may be involved in the control of some steps of reproductive processes, such as steroidogenesis, calcium metabolism, and energy mobilization.

Immunocytochemical and histological studies on the hypophyseal-gonadal system in the freshwater nile tilapia, oreochromis niloticus (L.), during sexual maturation and spawning in different habitats

The activities of the hypophyseal-gonadal system of O. niloticus in different habitats were investigated using immunocytochemical and histological techniques. The observed physico-chemical results indicated that Lake Nasser water characteristics are within the allowed and desired safety baseline levels. In contrast, Lake Manzalah exhibited high levels of Ca(2+), Mg(2+), SO(4)(2-) and heavy metals (Zn, Pb, and Cd). These water conditions affected the activity of the hypophyseal-gonadal axis of tilapia. The secretory and the synthetic activities of GTH and SL cells in the pituitary gland, in general, underwent obvious normal changes during gonad maturation and spawning of O. niloticus in Lake Nasser. In Lake Manzalah, the secretory activity of GTH and SL cells declined. This may be due to the effect of the high levels of heavy metals which interfere with the release of hormones and disturb the feedback mechanisms. In addition, the activity of both PRL and GH cells in Lake Nasser was higher than that of Lake Manzalah, but the synthetic activity of the ACTH and MSH cells was higher in Lake Manzalah. This may be related to the increased stress on fishes and the dark polluted water in Lake Manzalah. Both the environmental and the endocrine impacts in Lake Manzalah caused a decline in the gonadal activity as reflected by the decrease of sperm amount in the ripe testis, the appearance of oocytes in the testis and the degeneration of ripe oocytes (atresia) during the spawning season. J. Exp. Zool. 284:343-354, 1999. Copyright 1999 Wiley-Liss, Inc.

Immunocytochemical study on the localization and distribution of the somatolactin cells in the pituitary gland and the brain of Oreochromis niloticus (Teleostei, cichlidae)

Using specific antibody for chum salmon somatolactin (SL), immunocytochemical studies were employed to determine the distribution of this hormone in the pituitary gland and the brain of Orechromis niloticus. The results indicated that the SL-immunoreactive (ir) cells are found in the pars intermedia (PI) of the pituitary gland. The SL-ir cells showed strong and specific immunoreactivity to anti-chum salmon SL. Moreover, SL-ir cells were found to be widely distributed in most brain regions. Most of the SL-ir cell bodies were scattered along a nearly continuous line extending posteriorly from the olfactory bulb to the medulla oblongata through the nucleus preopticus periventricularis, habenula, and midbrain tegmentum and ventral to the nucleus lateralis tuberis pars posterior through the nucleus preopticus basalis lateralis and organum vasculosum luminae terminalis. Also SL-ir cells were observed in the cerebellum. The synthetic and secretory activity of the SL-ir cells, in the pituitary and the brain, showed an increase during sexual maturation and spawning. The highly organized SL-containing system and the gradual stimulation of SL synthesis and release during sexual maturation and spawning of O. nilotcus suggest that SL may be involved in the control of some steps of reproductive processes.

Altered biologic activities of commercial polychlorinated biphenyl mixtures after microbial reductive dechlorination

The reductive dechlorination of polychlorinated biphenyls (PCBs) by anaerobic bacteria has recently been established as an important environmental fate of these compounds. This process removes chlorines directly from the biphenyl ring with replacement by hydrogen, resulting in a product mixture in which the average number of chlorines per biphenyl is reduced. In this study, dechlorination of commercial PCB mixtures (Aroclors 1242 and 1254) by microorganisms eluted from PCB-contaminated sediments of the River Raisin (Michigan) and Silver Lake (Massachusetts) caused a depletion in the proportion of highly chlorinated PCB congeners and an accumulation of lesser-chlorinated congeners. Dechlorination occurred primarily at the meta and, to a much lesser extent, para positions of biphenyl. The concentrations of the coplanar congeners including 3,3',4,4',5-pentachlorobiphenyl, the most potent dioxinlike congener, were significantly lowered by reductive dechlorination. Microbial reductive dechlorination of commercial PCB mixtures caused a substantial reduction in biologic activities in several instances. It significantly lowered or eliminated the inhibitory effects of Aroclors on fertilization of mouse gametes in vitro. Similarly, the dechlorinated product mixtures had substantially lower ethoxyresorufin-O-deethylase induction potencies and showed less ability to induce activating protein 1 transcription factor activity as compared to the unaltered Aroclors. In other assays the same dechlorinated product mixtures demonstrated biologic activities similar to the nondechlorinated Aroclors, including the ability of PCB mixtures to stimulate insulin secretion and cause neutrophil activation. The data presented here establish that the biologic activities of commercial PCB mixtures are altered by microbial reductive dechlorination and that an assessment of their toxic potential requires an array of tests that include the different mechanisms associated with PCBs.

Inhibition of L-aromatic amino acid decarboxylase by polychlorinated biphenyls

PC12 cells were used to examine the mechanisms by which polychlorinated biphenyls (PCBs) reduce cellular levels of dopamine (DA). In cells treated 3 days with Aroclor 1254, 2,2',5,5'-tetrachlorobiphenyl (2,2',5,5'-TCB), or 2,2',3,3',4,4'-hexachlorobiphenyl (2,2',3,3',4,4'-HCB), the PCB-mediated reduction in 3H-tyrosine uptake was observed only at high PCB concentrations that produced a reduction in DNA levels. The PCB congener, 2,2',4,4',5,5'-hexachlorobiphenyl (2,2',4,4',5,5'-HCB) did not produce a reduction in 3H-tyrosine uptake at any concentration tested. Thus, there were PCB concentrations at which a reduction in DA levels did not coincide with a decrease in 3H-tyrosine uptake, suggesting that inhibition of tyrosine uptake was not the primary mechanism by which PCBs reduce DA levels. Aroclor 1254-treated cells also exhibited elevated levels of DOPA, further supporting the conclusion that tyrosine levels were not limiting. Incubation of Aroclor 1254-pretreated cells with 3H-tyrosine resulted in a dose-dependent increase in cellular levels of 3H-DOPA and decrease in cellular levels of 3H-DA, suggesting a PCB-mediated inhibition of the conversion of 3H-DOPA to 3H-DA. When the media was supplemented with DOPA, Aroclor 1254-treated cells still exhibited reduced levels of DA, compared to control cells, even though the control and PCB-treated cells had similar cellular levels of DOPA. Thus, one mechanism by which PCBs may reduce cellular levels of DA is by inhibiting L-aromatic amino acid decarboxylase-mediated conversion of DOPA to DA. The PCB congeners, 2,2',4,4'-TCB, 2,2',5,5'-TCB, and 2,2',4,4',5,5'-HCB, also produced dose-dependent increases in DOPA levels. The congener 2,2',3,3',4,4'-HCB did not produce an increase in DOPA levels, although it did mediate reductions in cellular DA levels. However, when PC12 cells were supplemented with DOPA, all four PCB congeners produced a similar reduction in DA levels, suggesting that the conversion of DOPA to DA was inhibited by the PCBs.

Study of HLA class I/IL and T lymphocyte subsets in Kuwaiti vitiligo patients

HLA polymorphisms of class I and class II MHC were investigated in 40 Kuwaiti vitiligo patients and in 40 controls using microcytotoxicity assay. HLA-B21, Cw6 and DR53 were increased significantly in patients compared to controls (P = 0.00001, 0.00001 and P = 0.0053 respectively) while HLA-A19, DR52, were significantly decreased (P = 0.00236, 0.05, respectively). Total T-cells, T4 and T8 were measured as CD2, CD4 and CD8 respectively by flow cytometry. Vitiligo patients showed significant increase in CD4 compared to controls (P = 0.03). Our findings suggest that HLA-B21 and Cw6 and DR53, are susceptible genes of vitiligo, while A19 and DR52 are protective genes in the Kuwaiti population.