15-Deoxy-Δ12,14-prostaglandin J2 attenuates development of cyclophosphamide-induced cystitis in rats

Icariin attenuates cyclophosphamide-induced cystitis via down-regulation of NF-кB and up-regulation of Nrf-2/HO-1 signaling pathways in mice model

Cystitis is a chronic bladder pain associated with frequency and nocturia. In the present study, Icariin a prenylated flavonoid extracted from Epimedium koreanum, was investigated against cyclophosphamide (CYP)-induced cystitis pain in mice model. Preliminarily in an acute model, single dose of CYP (150 mg/kg; i.p) was administered followed by Icariin (5, 25 and 50 mg/kg, i.p.). The visceral sensitivity and nociceptive behaviors were significantly ameliorated by pretreatment with Icariin (25, 50 mg/kg) that were assessed by spontaneous pain scoring, von Frey test and clinical scoring. Further, in chronic model Icariin (25 mg/kg, i.p.) was administered for 10 consecutive days prior to CYP (75 mg/kg; i.p) challenged every 3rd day for the duration of 10 days. Icariin not only had a protective effect on edema including bladder wet weight and hemorrhage but also had a potential to reduce vascular permeability, mast cells infiltration and tissue fibrosis. Evidently, Icariin prevented the neutrophilia/lymphopenia caused by CYP, and markedly improved the antioxidant enzymes level including superoxide dismutase, glutathione sulfo-transferase, catalase, glutathione level and reduced Malondialdehyde level, myeloperoxidase activity and nitric oxide, and also decreased the production of tumor necrosis factor-α (TNF-α) and interleukin-1 beta (IL-1β) in bladder. Icariin markedly enhanced the Nrf-2, heme oxygenase (HO-1) and IкB-α expression, while attenuated the expression level of Keap1, TLR-4, NF-кB, i-NOS, COX-2 and TRPV1 as compared to negative group. This research illustrated the anti-inflammatory properties of Icariin and effectively improved CYP-induced cystitis pain.

15-Deoxy-Δ¹²,¹⁴-prostaglandin J₂, an electrophilic lipid mediator of anti-inflammatory and pro-resolving signaling

15-deoxy-Δ(12,14)-prostagandin J(2) (15d-PGJ2) is produced in the inflamed cells and tissues as a consequence of upregulation of cyclooxygenase-2 (COX-2). 15d-PGJ2 is known to be the endogenous ligand of peroxisome proliferator-activated receptor gamma (PPARγ) with multiple physiological properties. Though one of the terminal products of the COX-2-catalyzed reactions, this cyclopentenone prostaglandin exerts potent anti-inflammatory actions, in part, by antagonizing the activities of pro-inflammatory transcription factors, such as NF-κB, STAT3, and AP-1, while stimulating the anti-inflammatory transcription factor Nrf2. These effects are not necessarily dependent on its activation of PPARγ, but often involves direct interaction with the above signaling molecules and their regulators. The locally produced 15d-PGJ2 is also involved in the resolution of inflammatory responses. Thus, 15d-PGJ2, especially formed during the late phase of inflammation, might inhibit cytokine secretion and other events by antigen-presenting cells like dendritic cells or macrophages. 15d-PGJ2 can also affect the priming and effector functions of T lymphocytes and induce their apoptotic cell death. These represent a negative feedback explaining how once-initiated immunologic and inflammatory responses are switched off and terminated. In this context, 15d-PGJ2 and its synthetic derivatives have therapeutic potential for the treatment of inflammatory disorders.

Effects of the compounds MV8608 and MV8612 obtained from Mandevilla velutina in the model of hemorrhagic cystitis induced by cyclophosphamide in rats

Hemorrhagic cystitis (HC) is a common side effect observed in patients under chemotherapy with cyclophosphamide (CYP). The urotoxic side effects of CYP are attributed to the metabolic compound acrolein, and can be partially prevented by the uroprotector agent 2-mercaptoethene sulfate (Mesna). The present study analyzed the anti-inflammatory and the antinociceptive effects of compounds MV8608 and MV8612 obtained from Mandevilla velutina in the rat model of CYP-induced HC. Male Wistar rats were used (six to eight per group, 220-250 g). HC was induced by a single administration of CYP (100 mg/kg, ip). Three behavioral parameters--breathing rate, closing of the eyes, and specific posture--were used as nociception indexes, and scored at different time intervals (15-180 min) after cystitis induction. As inflammatory parameters, hemorrhage presence, edema formation, and bladder weight were determined at 24 h after CYP administration. The neutrophil migration was assessed by means of myeloperoxidase (MPO activity), 4 h after cystitis induction. As expected, Mesna treatment was able to reduce in a significant manner all the inflammatory and the nociceptive parameters induced by CYP. Of note, the administration of MV8608 significantly inhibited the hemorrhage formation and the neutrophil recruitment, while the MV8612 treatment markedly reduced the bladder weight, without interfering with neutrophil influx. Interestingly, the treatment with either MV8608 or MV8612 markedly reduced the nociceptive responses. The present results clearly indicate that MV8608 and MV8612 might represent important alternatives to prevent side effects, especially the nociception, following chemotherapy with CYP.

Albumin-binding and tumor vasculature determine the antitumor effect of 15-deoxy-Delta-(12,14)-prostaglandin-J(2) in vivo

15-Deoxy-Delta(12,14)-prostaglandin-J(2) (15d-PGJ(2)), a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, induces cell death in tumor cells in vitro; however, no study showed its in vivo effect on tumors. Here, we report that 15d-PGJ(2) shows antitumor effects in vivo in mice. However, its effects correlate with tumor uptake of albumin, to which it reversibly binds. 15d-PGJ(2) induces cell death in B16F10 melanoma and C26 colon carcinoma cells in vitro. These effects were not elicited through PPARgamma-dependent pathways because an irreversible PPARgamma antagonist GW9662 did not inhibit these effects. Caspase- and nuclear factor kappaB- (NF-kappaB) dependent pathways were found to be involved as determined with caspase-3/7 fluorescent assay and NF-kappaB containing plasmid transfection assay, respectively. Noticeably, 15d-PGJ(2) had significantly stronger effects in C26 cells compared with B16 cells in all assays. However, in vivo, there was no effect on C26 tumors, yet it significantly inhibited the B16 tumor growth in mice by 75%. We found that 15d-PGJ(2) rapidly bound to albumin and in vivo albumin greatly distributed to B16 tumors compared with C26 tumors, shown with gamma-camera imaging and immunohistochemical staining. Albumin accumulation can be attributed to the large blood vessel diameter in B16 tumors and an enhanced permeability and retention effect. These findings suggest that 15d-PGJ(2) can be an effective therapeutic agent for cancer, although its effects seem to be limited to the tumors allowing albumin penetration.

Involvement of orexin-A on micturition reflex in normal and cyclophosphamide-induced cystitis bladder in rat

The purpose of the present study was to investigate the effect of orexin-A in the spinal cord on bladder function in normal rats and cyclophosphamide (CYP)-induced cystitis rat models. The effects of intrathecal (i.t.) injection of orexin-A (0.01, 0.1 and 1.0 nmol) on bladder function were examined during continuous infusion cystometrogram (CMG) in urethane anesthetized normal and CYP-induced cystitis rats. The effects of i.t. injection of selective orexin-1 receptor (OXR1) antagonist SB334867 (10 nmol) on orexin-A-induced bladder overactivity in normal rats and SB334867 (10 and 30 nmol) on changes in bladder function in normal and CYP-induced cystitis rats were investigated. The effects of intravenous (i.v.) injection of orexin-A (0.3 and 1.0 nmol) on micturition reflex were also investigated in normal rats. I.t. injection of orexin-A (0.1 and 1.0 nmol) significantly decreased the intercontraction intervals (ICI) in normal and CYP-induced cystitis rats. I.t. injection of SB334867 (10 nmol) significantly increased the ICI of orexin-A induced overactive bladder in normal rats and i.t. injection of SB334867 (30 nmol) also increased the ICI in normal rat bladder. However, in CYP-injected cystitis rat models, i.t. injection of SB334867 did not change the bladder function. I.v. injection of orexin-A failed to affect the bladder function in normal rats. Orexin mRNA levels in the lateral hypothalamus were significantly decreased in CYP-induced cystitis rats. These results indicate that orexin-A in the spinal cord activates micturition reflex via OXR1 in normal rats. In addition, OXR1 antagonist did not have any effect on micturition reflex in CYP-induced cystitis rats.

Rolipram, a specific type-4 phosphodiesterase inhibitor, inhibits cyclophosphamide-induced haemorrhagic cystitis in rats

OBJECTIVE

To investigate the protective roles of type 4 phosphodiesterase (PDE4) inhibitor in cyclophosphamide (CYP)-induced haemorrhagic cystitis, as the PDE4 inhibitor has anti-inflammatory effects but its characterization is still unknown in urinary tract diseases.

MATERIALS AND METHODS

In female Sprague-Dawley rats, CYP was administered intraperitoneally and bladders were harvested 24 h after CYP injection. In another group, rolipram as a PDE4 inhibitor was administered before CYP treatment. The effects and mechanisms of CYP with/without rolipram pretreatment were evaluated by microscopic features, bladder wet weight, myeloperoxidase (MPO) activity, nitric oxide (NO)-metabolite production and expression levels of inflammation-related genes.

RESULTS

CYP injection resulted in severe cystitis. Pretreatment with rolipram significantly reduced the increase in bladder wet weight and MPO activity, and ameliorated histological inflammatory changes caused by CYP. The levels of inflammation-related transcripts including inducible NO synthase (iNOS), interleukin-1beta and tumour necrosis factor-alpha, induced by CYP, were down-regulated significantly by pretreatment with rolipram. Also, rolipram reduced the NO-metabolite production and iNOS protein expression in the immunohistochemical examination.

CONCLUSION

These results indicate that rolipram can attenuate the development of CYP-induced cystitis in rats by suppressing cytokine production and iNOS induction. Thus, treatment with PDE4 inhibitor has potential clinical implications of the prevention of bladder inflammatory diseases.

Protective effects of bilirubin against cyclophosphamide induced hemorrhagic cystitis in rats

PURPOSE

The end product of the heme oxygenase pathway, bilirubin, is the most abundant endogenous antioxidant in mammals. We report the heme oxygenase-1 mediated production of bilirubin and its cytoprotective roles in cyclophosphamide induced hemorrhagic cystitis in rats.

MATERIALS AND METHODS

Female Sprague-Dawley rats received intraperitoneal administration of cyclophosphamide. In the first experiment hemin (an inducer of heme oxygenase-1) with or without zinc protoporphyrin IX (an inhibitor of heme oxygenase activity) was given before cyclophosphamide injection. Endogenous bilirubin production was analyzed in bladder tissues immunohistochemically. In another experiment bilirubin solution was administered before the cyclophosphamide injection. Changes in bladder weight, microscopic feature and expression levels of inducible nitric oxide synthase, proinflammatory cytokines and heme oxygenase were evaluated using polymerase chain reaction and immunostaining.

RESULTS

Bilirubin was generated in bladders with cyclophosphamide induced cystitis, especially in the urothelium and suburothelium. Hemin pretreatment provided increased production of endogenous bilirubin, which was decreased by zinc protoporphyrin IX. In an evaluation of the roles of bilirubin exogenous bilirubin administration ameliorated cyclophosphamide induced inflammatory changes and reduced the increase in bladder weight. The elevated expression of inducible nitric oxide synthase and interleukin-1beta in cyclophosphamide induced cystitis was significantly down-regulated by exogenously applied bilirubin. The expression of heme oxygenase-1 and 2 was not modified by bilirubin administration.

CONCLUSIONS

Cyclophosphamide induced hemorrhagic cystitis is accompanied by endogenous bilirubin production through heme oxygenase-1 induction in the bladder. Bilirubin has cytoprotective roles in association with the down-regulation of inducible nitric oxide synthase expression. Our results suggest that bilirubin may have therapeutic potential against bladder inflammatory insults such as cyclophosphamide induced cystitis.

Glucocorticoid receptors modulate auditory sensitivity to acoustic trauma

Glucocorticoids are widely used to treat different hearing disorders yet the exact mechanisms of glucocorticoid action on the inner ear are not known. The inner ear of both humans and experimental animals demonstrate an abundance of glucocorticoid receptors (GRs) in both neuronal and non-neuronal tissues. In this review, we discuss how activation of the hypothalamic-pituitary-adrenal axis can directly modulate hearing sensitivity. Recent findings indicate that several factors define the responsiveness of the peripheral auditory system to glucocorticoids including the concentration of agonist, availability of the GR, and the activation of GR and NF-kappaB. These findings will further our understanding of individual glucocorticoid responsiveness to steroid treatment, and will help improve the development of pharmaceuticals to selectively target GR in the inner ear for individuals with increased sensitivity to acoustic trauma.