Quercetin Attenuates Endoplasmic Reticulum Stress and Apoptosis in TNBS-Induced Colitis by Inhibiting the Glucose Regulatory Protein 78 Activation

Background

The inflammatory bowel diseases (IBD) are significantly influenced by apoptosis and endoplasmic reticulum (ER) stress.

Aims

To investigate the effects of quercetin on ER stress-mediated apoptosis in a trinitrobenzene sulfonic acid (TNBS) induced experimental IBD model.

Study Design

In vivo animal experimental study.

Methods

To demonstrate the effect of quercetin in an experimental colitis model, Control, TNBS, and TNBS+quercetin groups were created with 24 Wistar Albino rats. Colitis was induced by intrarectal administration of 25 mg TNBS. In the TNBS+quercetin group, intragastrically 100 mg/kg quercetin was given for 7 days, immediately after colitis induction. In the TNBS-induced experimental IBD model, we evaluated the effects of quercetin on colonic epithelial cell apoptosis, oxidative stress, ER stress, the mitogen-activated protein kinase c-Jun N-terminal kinase, and the nuclear factor kappa B immunoreactivities, the levels of myeloperoxidase and tumor necrosis factor-α, the disease activity index with colonic histopathologic changes.

Results

TNBS administration induced an elevated level of disease activity and oxidative stress indices, inflammation markers, and an increase in the immunoreactivities of nuclear factor kappa B and the mitogen-activated protein kinase c-Jun N-terminal kinase in the colon of the colitis group. Glucose regulatory protein 78, caspase-12 immunoreactivities, and epithelial cell apoptosis also were shown in the colon. However, quercetin improved TNBS-induced histopathological alterations, apoptosis, inflammation, oxidative stress, and ER stress.

Conclusion

This study suggests that quercetin has a regulatory effect on ER stress-mediated apoptosis, and thus may be beneficial in treating IBD.

Anti-Inflammatory and Antipruritic Effects of Remote Ischaemic Postconditioning in a Mouse Model of Experimental Allergic Contact Dermatitis

Background and Objectives: Allergic contact dermatitis is a common type IV hypersensitivity reaction characterised by redness, itching, oedema and thickening of the skin. It occurs in about 7% of the population and its incidence is increasing. It has been observed that the preconditioning of tissues by exposing them to transient ischemia increases resistance to subsequent permanent ischemia, and this phenomenon is called ischemic preconditioning. It has been shown that conditioning in one organ can also protect other organs. The protective effect of remote ischemic preconditioning is thought to be based on the induction of anti-inflammatory responses. The aim of this project was to investigate the anti-inflammatory and antipruritic effects of remote ischemic postconditioning in a mouse model of experimental allergic contact dermatitis. Methods: Experimental allergic contact dermatitis was induced with 1-fluoro-2,4-dinitrobenzene. Remote ischemic postconditioning was performed at 3 and 25 h after the challenge. Ear thickness and number of scratches 24 and 48 h after challenge, as well as cytokine levels and the infiltration of mast cells, neutrophils, CD4+ and CD8+ T lymphocytes in serum and ear tissue at 48 h were measured to determine the effect of RIPsC. Results: Remote ischemic postconditioning decreased ear thickness, one of the symptoms of allergic contact dermatitis (p < 0.0001). It had no significant effect on the number of scratches. It reduced serum IL-17 levels (p < 0.01). It alleviated local inflammation by suppressing CD8+ T lymphocyte and neutrophil infiltration. Conclusions: It was concluded that remote ischemic postconditioning may alleviate the symptoms of allergic contact dermatitis by suppressing CD8+ T lymphocyte and neutrophil infiltration and reducing IL-17 secretion.

The therapeutic effects of transferring remote ischemic preconditioning serum in rats with neuropathic pain symptoms

Background and objectives

Neuropathic pain is defined as pain caused by damage to the nerve as a result of a lesion or disease. It has been shown that ischemic preconditioning exerts a protective role in various tissue injuries; however, the effect of transplantation of remote ischemic preconditioning serum (RIPCs) on neuropathic pain symptoms has not been studied. The aim of this project is to investigate the effect of RIPCs transfusion by different routes of administration on neuropathic pain symptoms. Our secondary aim was to demonstrate the role of Schwann cells in the regeneration of sciatic nerve injury and to evaluate the change in the number of glial cells in the spinal cord dorsal horn.

Methods

The sciatic nerve partial ligation method was used to induce neuropathic pain. Changes in neuropathic pain symptoms were assessed by measuring thermal hyperalgesia and mechanical allodynia. To determine the possible therapeutic site, alterations in the number of spinal cord lumbar posterior horn microglia and astrocytes were evaluated by ionized calcium-binding adapter molecule 1 (iba1) and glial fibrillary acidic protein (GFAP) immunostaining. Myelin basic protein immunohistochemistry was also used to assess Schwann cell immunoreactivity in the sciatic nerve.

Results

In rats that underwent partial sciatic nerve ligation, neuropathic pain symptoms developed on average on day 12 and persisted up to day 21 (p < 0.0001). RIPCs administered intravenously for five days reduced thermal hyperalgesia more than intraperitoneal and subcutaneous administration (p < 0.05). Both central glial cells appear to play a role in the effect of RIPCs. RIPCs treatment increases Schwann cell remyelination.

Conclusions

Our results showed that intravenously administered RIPCs remarkably improved the neuropathic pain symptoms, thermal hyperalgesia and mechanical allodynia. Further studies are needed to evaluate the role of RIPCs transfusion on glial cells.

Role of JNK, TGF-β1, Akt, IL-1β and INSL-3 in proanthocyanidin protection against apoptosis in diabetic rat testis

We investigated how proanthocyanidin treatment altered c-Jun N-terminal kinases, transforming growth factor beta 1, serine/threonine-specific protein kinase, interleukin 1 beta and insulin-like 3 expression in the testis of diabetic rats. We used 24 Wistar albino male rats divided into four groups. Group 1 was untreated control. Group 2 was treated with 40 mg/kg streptozotocin (STZ) for 5 days. Group 3 was treated with 40 mg/kg STZ + 250 mg/kg proanthocyanidin once daily for six weeks. Group 4 was treated with 40 mg/kg STZ + 250 mg/kg proanthocyanidin. Superoxide dismutase activity was reduced in groups 3 and 4 compared to group 2. Glutathione peroxidase activity was increased significantly in groups 3 and 4 compared to groups 1 and 2. Catalase activity was decreased in group 4 compared to group 2. We found that proanthocyanidin increased cell proliferation in diabetic testis. Phospho-JNK and TGF-β1 immunostaining was decreased groups 3 and 4 compared to group 2, while p-Akt immunostaining was increased in groups 3 and 4. The number of IL-1β immunostained cells in groups 3 and 4 was decreased compared to group 2. INSL-3 immunostaining was increased significantly in group 3 compared to group 2. Our findings indicate that proanthocyanidin ameliorated diabetes related testicular dysfunction. Proanthocyanidin contributes to a balanced oxidant-antioxidant status, and balanced proliferation and apoptosis activity in the germinal cells.

The effects of epidermal growth factor on early burn-wound progression in rats

After burns, protecting tissues by medicines in the zone of stasis reduces the width and depth of injury. This study's goal was to reduce burned tissue damage in the zone of stasis using epidermal growth factor (EGF). Forty-eight Wistar rats were separated into three groups. In all groups, the burn procedure was applied following the comb burn model. In Group 1, no postburn treatment was administered. In Group 2, physiological saline solution (0.3 cc) was injected intradermally and in Group 3, EGF (0.3 cc) was injected intradermally into stasis zone tissues after the burn procedure. Surviving tissue rates were 24.0% in Group 1, 25.3% in Group 2, and 70.2% in Group 3. The average numbers of cells stained with Nrf2, HO-1, and the number of apoptotic cells were 230, 150, and 17.5 in Group 1, 230, 145, and 15.0 in Group 2, and 370, 230, and 0 in Group 3, respectively. Values in Group 3 were found to be statistically significantly different than those of Groups 1 and 2; there was no difference between Groups 1 and 2. This study shows that EGF protects zone of stasis tissue from burn damage.

A morphological study of uterine alterations in mice due to exposure to cadmium

We investigated the morphologic and molecular effects of exposure to cadmium (Cd) for 30 and 60 days on the uteri of mice. We assessed uterine morphometric measurements, eosinophilia, mast cell numbers, endometrial apoptosis, proliferation and estrogen receptor alpha (ERα) immunoreactivity. We examined vaginal smears that reflected the hormonal alterations in the female reproductive tract. Because the female reproductive tract exhibits different morphology at each stage of the estrous cycle, we sacrificed all animals at estrus to make appropriate comparisons. Female BALB/c mice were exposed to 200 ppm Cd in their drinking water for either 30 or 60 days. Cd exposure caused significant decreases in endometrial thickness and number of glands in estrus phase uteri. The endometrial eosinophilia in the groups exposed to Cd also decreased compared to controls. Cd exposure increased the number of mast cells. Luminal and glandular epithelia were examined using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and by immunostaining proliferating cell nuclear antigen (PCNA) and estrogen receptor α (ERα). Compared to controls, the apoptotic index increased with time in both Cd exposed groups, while the proliferation index decreased. ERα immunoreactivity was decreased in both Cd exposed groups compared to controls; the decrease was most apparent in the 30 day Cd group. We found that 60 day Cd exposure increased apoptosis in the endometrium, which may affect the receptivity of the uterus for implantation.

The role of ionizing radiaton on ovulation rate and oocyte morphology in mouse

We investigated the effects of ionizing radiation on maturation ability and radiosensitivity of oocytes enclosed in preantral and antral follicles. Balb/c female mice received total body single dose gamma radiation (7.2 Gy) at the diestrous to proestrous transition period. In the first experiment, spontaneously ovulated oocytes were collected from irradiated animals. In the second experiment, irradiated animals were allowed to superovulate to assess the ovarian function. The spontaneous ovulation rate of the follicles exposed at antral stage was significantly lower than the sham-irradiated mice (p < 0.01), and most of the oocytes were found at the metaphase I stage. Oocyte morphology and the ovulation rate of the follicles exposed at preantral stage were similar to the sham-irradiated group. Minimal morphological abnormalities were observed in the oocytes and the polar body as well. The superovulation response of all the irradiated animals was lower than the respective control animals. The superovulation rate was significantly lower in the first ovulation after irradiation (p < 0.01). In conclusion, our findings indicate that total body gamma irradiation, on a basis of estrous cycle stages, leads to ovulation failure in the antral stage while causes abnormal oocyte morphology in the preantral stage follicles in mice.

N-Acetylcysteine counteracts oxidative stress and protects alveolar epithelial cells from lung contusion-induced apoptosis in rats with blunt chest trauma

The aim of this study was to investigate the protective effects of N-acetylcysteine (NAC) on peroxidative and apoptotic changes in the contused lungs of rats following blunt chest trauma. The rats were randomly divided into three groups: control, contusion, and contusion + NAC. All the rats, apart from those in the control group, performed moderate lung contusion. A daily intramuscular NAC injection (150 mg/kg) was given immediately following the blunt chest trauma and was continued for two additional days following cessation of the trauma. Samples of lung tissue were taken in order to evaluate the tissue malondialdehyde (MDA) level, histopathology, and epithelial cell apoptosis using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and active caspase-3 immunostaining. In addition, we immunohistochemically evaluated the expression of surfactant protein D (SP-D) in the lung tissue. The blunt chest trauma-induced lung contusion resulted in severe histopathological injury, as well as an increase in the MDA level and in the number of cells identified on TUNEL assay together with active caspase-3 positive epithelial cells, but a decrease in the number of SP-D positive alveolar type 2 (AT-2) cells. NAC treatment effectively attenuated histopathologic, peroxidative, and apoptotic changes, as well as reducing alterations in SP-D expression in the lung tissue. These findings indicate that the beneficial effects of NAC administrated following blunt chest trauma is related to the regulation of oxidative stress and apoptosis.

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.