Gulnur Kizilay

Effects of curcumin on apoptosis and oxidoinflammatory regulation in a rat model of acetic acid-induced colitis: the roles of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase.

The present study evaluated the effects of curcumin on epithelial cell apoptosis, the immunoreactivity of the phospho-c-Jun N-terminal kinase (JNK) and phospho-p38 mitogen-activated protein kinases (MAPKs) in inflamed colon mucosa, and oxidative stress in a rat model of ulcerative colitis induced by acetic acid. Rats were randomly divided into three groups: control, acetic acid, and acetic acid+curcumin. Curcumin (100 mg/kg per day, intragastrically) was administered 10 days before the induction of colitis and was continued for two additional days. Acetic acid-induced colitis caused a significant increase in the macroscopic and microscopic tissue ranking scores as well as an elevation in colonic myeloperoxidase (MPO) activity, malondialdehyde (MDA) levels, and the number of apoptotic epithelial cells in colon tissue compared to controls. In the rat colon, immunoreactivity of phospho-p38 MAPK was increased, whereas the phospho-JNK activity was decreased following the induction of colitis. Curcumin treatment was associated with amelioration of macroscopic and microscopic colitis sores, decreased MPO activity, and decreased MDA levels in acetic acid-induced colitis. Furthermore, oral curcumin supplementation clearly prevented programmed cell death and restored immunreactivity of MAPKs in the colons of colitic rats. The results of this study suggest that oral curcumin treatment decreases colon injury and is associated with decreased inflammatory reactions, lipid peroxidation, apoptotic cell death, and modulating p38- and JNK-MAPK pathways.

Expression of Proliferative and Preapoptotic Molecules in Human Myometrium and Leiomyoma Throughout the Menstrual Cycle

The pathogenesis of leiomyoma may be related to an imbalance in the interaction of sex steroids with paracrine growth factors that may control the modulation of mitogenesis and local immunity. The authors investigate the temporal and spatial expression of proliferative and preapoptotic molecules that may participate in the modulation of myometrial function and leiomyoma pathogenesis. Immunohistochemistry and Western blot analysis are used to investigate Fas ligand (FasL), phosphatase and tensin homolog deletion on chromosome 10 (PTEN), and proliferating cell nuclear antigen (PCNA) expression in myometrium and leiomyoma. Western blot results show that in the secretory phase, FasL expression is 1.8-fold and 2.3-fold higher compared with the proliferative phase in the myometrium and leiomyoma, respectively (P = .022 and .047, respectively). A paired comparison between myometrium and leiomyoma reveals higher FasL expression in the leiomyoma (P = .003). On the contrary, when compared with the secretory phase, PCNA expression during the proliferative phase is 4.6-fold and 3.7-fold higher in the myometrium and leiomyoma, respectively (P = .041 and .034, respectively). A paired comparison between myometrium and leiomyoma reveals higher PCNA expression in the leiomyoma. Furthermore, lower PTEN expression is detected in the leiomyoma compared with the myometrium (P < .032). Immunohistochemistry results reveal that FasL, PTEN, and PCNA are expressed in the myometrium and leiomyoma, consistent with the results from the Western blot analysis. The results suggest that FasL, PTEN, and PCNA may be involved in the pathophysiology of leiomyoma. A higher FasL level in the leiomyoma is likely to correspond to suppression of local immunity by inducing apoptosis of immune cells, while a higher level of PCNA and a lower level of PTEN may be related to increased mitogenesis and decreased apoptosis in leiomyoma.

Protective effect of sildenafil on liver injury induced by intestinal ischemia/reperfusion.

BACKGROUND This study evaluated the protective effect of sildenafil on liver injury induced by intestinal ischemia-reperfusion. METHODS Forty female Sprague Dawley rats were divided into 4 groups: sham-control (SC), ischemia (I), ischemia-reperfusion (IR), and ischemia-reperfusion+sildenafil (SIL; sildenafil gavaged at 50mg/kg before operating). A 2-h ischemia-reperfusion was performed by clamping the superior mesenteric artery. Liver function, plasma alanine (ALT) and aspartate (AST) aminotransferase, and intestinal and liver malondialdehyde (MDA) were measured at the end of the experiment. Intestinal and liver tissue damage was examined by histology. Liver samples were immunologically stained for endothelial nitric oxide synthase (eNOS) and proliferating cell nuclear antigen (PCNA). RESULTS The ALT and AST levels were highest in the IR group and were lower in the SIL group (p<0.05). Intestinal MDA levels were statistically higher in the IR group than in the SC, I and SIL groups. Liver MDA levels were significantly higher in the IR group than in the I and SC groups (p<0.05) and higher than in the SIL group (p>0.05). Intestinal damage based on Chiu scoring was more severe in the IR than in the SIL group (p<0.05). Sildenafil reduced damage and also increased eNOS and PCNA immunoreactivity in liver tissue. CONCLUSIONS Sildenafil shows a protective effect on intestinal ischemia-reperfusion-induced liver injury, possibly by decreasing vascular resistance through increased nitric oxide levels.

The Broad-Spectrum Chemokine Inhibitor NR58-3.14.3 Suppresses the Implantation and Survival of Human Endometrial Implants in the Nude Mice Endometriosis Model

Many chemokines likely contribute to the pathogenesis of endometriosis. The authors hypothesize that the broad-spectrum chemokine inhibitor NR58-3.14.3 may prevent ectopic human endometrium implantation and growth. After placing human endometrium fragments into the peritoneal cavity, ovariectomized athymic nude mice (n = 31) receiving intramuscular estradiol valerate were randomly assigned to daily intraperitoneal injections of either phosphate-buffered saline or NR58-3.14.3. Fourteen days later, the implant number and volume, proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase (TdT)—mediated dUTP nick end-labeling (TUNEL) index, and MTT cell viability were assessed in the implants. NR58-3.14.3 reduced the total number (45%) and total volume (81%) of endometriotic lesions (P < .05) and revealed a lower PCNA and higher TUNEL index in ectopic implants compared with controls (P < .05). NR58-3.14.3 treatment did not affect endometrial cell proliferation in vitro. NR58-3.14.3, by possibly regulating cell survival, can reduce the number and size of ectopic implants in vivo, supporting the potential use of chemokine inhibitors in novel therapies for endometriosis.

Increased c-Jun N-terminal kinase activation in human endometriotic endothelial cells

Endometriosis is a common inflammatory gynecological disease characterized by the presence of endometrial tissue outside of the uterine cavity. The c-Jun N-terminal kinase (JNK) is a subfamily of the mitogen-activated protein kinases (MAPKs) involved in cellular processes ranging from cytokine expression to apoptosis, and is activated in response to inflammation and cellular stress. We hypothesized that inflammatory cytokines in the peritoneal microenvironment increase JNK MAPK activity in endometriotic endothelial cells, and that human endometrial endothelial cells (HEECs) may be involved in inflammatory pathogenesis of endometriosis. Thus, we evaluated the expression of the total- and phosphorylated-(phospho)-JNK in endometrial and endometriotic endothelial cells in vivo, and in HEECs treated with normal peritoneal fluid (NPF), endometriotic peritoneal fluid (EPF), and the inflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in vitro. Phospho-JNK immunoreactivity in HEECs in normal endometrium was significantly higher in the early proliferative and late secretory phases compared to other phases. Both eutopic and ectopic HEECs from the early secretory phase also revealed higher phospho-JNK immunoreactivity, compared to their respective cycle-matched normal HEECs. Moreover, HEECs treated with EPF showed significantly higher phospho-JNK levels compared to that in HEECs treated with NPF. In conclusion, our in vivo and in vitro findings suggest that increased phosphorylation of JNK in HEECs from women with endometriosis is likely due to high level of IL-1β and TNF-α in peritoneal fluid; this in turn may up-regulate inflammatory cytokine expression and thus play a role in the pathogenesis of endometriosis.

Evaluation of the Fas/FasL signaling pathway in diabetic rat testis

We investigated the role of the Fas/Fas ligand (FasL) signaling pathway in diabetic male infertility. Male rats were divided into two groups: a control group and a streptozotocin induced diabetic group. Thirty days after induction of diabetes, samples of testes were harvested and fixed in 10% formalin for light microscopy. Germ cell apoptosis was determined using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) and immunostaining of caspase 8 and active caspase 3. We also investigated the expressions of Fas and FasL using immunohistochemistry. Streptozotocin-induced diabetes caused severe histopathological damage and increased apoptotic tubule and apoptotic cell indices, caspase 8 and caspase 3 expressions, and Fas and FasL-immunopositive cells in the rat testes. We suggest that the Fas/FasL signaling pathway may play a role in male infertility caused by diabetes.

Vitamin E modulates apoptosis and c-jun N-terminal kinase activation in ovarian torsion–detorsion injury

The aim of this study was to evaluate the role of vitamin E in follicular degeneration and to assess histopathological and biochemical changes following ischemia-reperfusion (IR) injury in rat ovaries. Twenty-eight Wistar albino rats were randomly divided into four groups: sham, 4h torsion, 24h detorsion, and a vitamin E group. Thirty minutes before detorsion, a single dose of 200mg/kg vitamin E was administered intraperitoneally. The ovarian histology score was determined, serum levels of malondialdehyde (MDA) and myeloperoxidase (MPO) were measured. The apoptosis of granulosa cells and the phospho-c-jun N-terminal kinase (p-JNK) and phospho-p38 (p-p38) immunoreactivities of these cells were determined. MDA and MPO levels were significantly increased in the torsion and detorsion groups. Hemorrhage, edema, and congestion were also apparent in these groups. In addition, the apoptotic index and the immunoreactivity of p-JNK were highest in the detorsion group, which also showed marked follicular degeneration. However, p-p38 activity was not affected by torsion-detorsion (TD) induction. Vitamin E ameliorated TD-induced histological alterations. It also decreased serum levels of MDA and MPO, reduced the activity of p-JNK in the ovaries, and reduced numbers of apoptotic follicular cells. In conclusion, these data indicate that vitamin E attenuated ovarian follicular degeneration by inhibiting the immunoreactivity of p-JNK and reducing the apoptosis of granulosa cells.

MAPK immunoreactivity in streptozotocin-induced diabetic rat testis

PURPOSE To evaluate the alterations of two mitogen-activated protein kinases (MAPK)s, extracellular signal regulated kinase (ERK) and c-Jun NH2 terminal kinase (JNK), in the testes of male rats with experimental diabetes. METHODS Twenty males Sprague-Dawley rats were randomly divided into a control group (n=8) and a diabetes group (administration of 40 mg/kg/day streptozotocin (STZ) for five sequential days, n=12). After six weeks, testicular biopsy samples were obtained for light microscopy and immunohistochemical methods. RESULTS The PCNA (proliferating cell nuclear antigen) index was significantly decreased in the diabetes group (p=0.004) when compared to the control group. Both total (t)-ERK and phosphor (p)-ERK immunoreactivities were significantly decreased in the diabetes group (p=0.004, p<0.001, respectively). The t-JNK immunoreactivity was unchanged in both groups (p=0.125), while p-JNK immunoreactivity was significantly increased in the diabetic group (p=0.002). CONCLUSIONS The decrease of androgen levels in the course of diabetes may contribute to the decrease of the immunoreactivities of t-ERK and p-ERK. JNK may be activated due to the changes in various cytokines and chemochines that participate in the oxidative stress process of diabetes. Therefore, testicular apoptosis may occur and lead to infertility associated with diabetes.

In vivo effects of curcumin and deferoxamine in experimental endometriosis

BACKGROUND Endometriosis is one of the most common chronic gynecological diseases. OBJECTIVES The aim of the study was to examine the effects of curcumin and/or deferoxamine on cell proliferation in a rat model of endometriosis. MATERIAL AND METHODS Thirty female 12-week-old albino Wistar rats, weighing 200-250 g, were used in this study. All the rats underwent ovariectomy and 0.1-mg β-estradiol 17-valerate pellets were placed intraperitoneally. An experimental model of endometriosis was created in all the animals. To create the experimental model, an approximately 1-cm long section of the uterus was taken, primarily from the right horn of the uterus. Autologous fragments were then placed between the peritoneum and muscle. The animals were divided into 3 groups: Group A, treated only with the vehicle used for curcumin and deferoxamine; group B, treated with curcumin (100 mg/kg body weight); and group C, treated with deferoxamine + curcumin (100 mg/kg body weight). After biopsy samples were obtained, the sections were stained with hematoxylin and eosin. Immunostaining for cytokeratin-7 and proliferating cell nuclear antigen (PCNA) was performed. Blood iron levels were measured using a Perkin Elmer AAnalyst 800 Atomic Absorption Spectrophotometer. RESULTS The endometrial implant size increased in Group A, but treatment with curcumin (p = 0.01) and deferoxamine + curcumin (p = 0.007) reduced the implant size. In ectopic endometrial epithelial cells, there were significant decreases in PCNA immunoreactivity between groups A and B (p = 0.044) and between groups A and C (p = 0.033). CONCLUSIONS Treatment with curcumin alone and/or in combination with deferoxamine contributed to a reduction in implant size and cell proliferation in a rat endometriosis model. Iron-chelating agents may act in the same manner when used in women with endometriosis; however, further studies from different perspectives are still needed.

Changes in nociceptin/orphanin FQ levels in rat brain regions after acute and chronic cannabinoid treatment in conjunction with the development of antinociceptive tolerance

It has been indicated that acute and chronic morphine administrations enhance nociceptin/orphanin FQ (N/OFQ) levels in the brain, which might play role in the development of tolerance to the antinociceptive effect of morphine. Accordingly, N/OFQ receptor (NOP) antagonists have been shown to prevent the development of antinociceptive tolerance to morphine. Our aim is to observe whether cannabinoids, similarly to opioids, enhance N/OFQ levels in pain‐related brain regions and whether antagonism of NOP receptors attenuates the development of tolerance to the antinociceptive effect of cannabinoids. Hot plate and Tail flick tests are used to assess the antinociceptive response in Sprague‐Dawley rats. N/OFQ levels are measured in cortex, amygdala, hypothalamus, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains using Western blotting and immunohistochemistry. Within 9 days, animals became completely tolerant to the antinociceptive effect of the cannabinoid agonist WIN 55,212‐2 (2, 4, 6 mg/kg, i.p.). Chronic administration of JTC‐801, a NOP receptor antagonist, at a dose that exerted no effect on its own (1 mg/kg, i.p.), attenuated development of tolerance to the antinociceptive effect of WIN 55,212‐2 (4 mg/kg, i.p.). Western blotting and immunohistochemistry results showed that N/OFQ levels significantly increased in amygdala, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains when WIN 55,212‐2 was combined with JTC‐801. We hypothesize that, similar to opioids, chronic cannabinoid + NOP antagonist administration may enhance N/OFQ levels and NOP receptor antagonism prevents development of tolerance to cannabinoid antinociception.