Ana Paula Ribeiro Paiotti

Immunoexpression of cyclooxygenase-1 and -2 in ulcerative colitis.

Ulcerative colitis (UC) is a disease of the colon and rectum characterized by a nonspecific chronic inflammation mediated by the concerted response of cellular and humoral events. Prostaglandins are synthesized by cyclooxygenase (COX)-1 and -2 and exhibit both pro- and anti-inflammatory activity. To evaluate COX-1 and COX-2 immunoexpression in 42 cases of UC and to correlate it with clinicopathological parameters, COX-1 and COX-2 expression was investigated by the immunohistochemistry method. Only patients with all pertinent clinical and evolutive data as well as with adequate biopsy material were included in the study. Fifteen samples of colorectal adenocarcinoma and 14 of large bowel with no histological changes were used for positive and negative controls, respectively. UC patients showed COX-1 immunoreactivity in epithelial cells in 29% of the cases and in inflammatory cells in 43%. COX-2 positivity in epithelial and inflammatory cells was found in 69% of the samples. The comparison between UC and the control groups revealed that the UC group had significantly more positive cases for COX-1 and COX-2 in inflammatory cells. Immunohistochemistry allowed the identification of COX-1 and COX-2 expression in epithelial and inflammatory cells in UC biopsies. No significant difference between COX-1 and COX-2 immunoreactivity in epithelial and inflammatory cells was observed regarding the clinicopathological parameters. COX-2 presented low expression in normal colon and high expression in colorectal adenocarcinoma. COX-2 might play a role in the pathophysiologic processes of inflammatory bowel disease and the development of neoplasia. Treatment with selective COX-2 inhibitors might be an additional option for therapy.

The anti-inflammatory potential of phenolic compounds in grape juice concentrate (G8000™) on 2,4,6-trinitrobenzene sulphonic acid-induced colitis.

Chronic inflammatory bowel disease is characterised by an up-regulation of the synthesis and release of a variety of pro-inflammatory mediators leading to excessive tissue injury. Flavonoids are able to inhibit enzymes and/or due to their antioxidant properties regulate the immune response. The goal of the present study was to evaluate the mechanisms of action of phenolic compounds present in grape juice on 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. A total of forty-one male Wistar rats were randomised into seven groups: negative control group; TNBS non-treated induced colitis; 2% grape juice control group; 1% grape juice 24 h after TNBS colitis induction; 1% grape juice on day 7 after colitis induction; 2% grape juice 24 h after colitis induction; 2% grape juice on day 7 after colitis induction. The 1% grape juice-treated induced colitis group showed marked clinical improvement when compared with the TNBS-induced colitis group. Rats that received 1% grape juice, on day 7 after colitis induction, presented reduced intensity of macroscopic and histological scores. Statistically significant differences (P,0·05) of TNF-a and inducible NO synthase mRNA expression were detected in the groups treated with grape juice at the 1% dose after inducing experimental colitis when compared with the TNBS group. Grape juice reduced the noxious effects induced by colitis caused by TNBS, especially at the 1% dose.

Effect of COX-2 inhibitor lumiracoxib and the TNF-α antagonist etanercept on TNBS-induced colitis in Wistar rats

Crohn’s disease (CD) is associated with gut barrier dysfunction. Besides the baseline barrier defect, a subgroup of patients also expresses an intestinal barrier hyperresponsiveness to nonsteroidal anti-inflammatory drugs. On the other hand, the anti-tumour necrosis factor alpha (TNF-α) treatment has brought benefits to these patients. Thus, this study aimed to evaluate the effect of lumiracoxib, a selective-cyclooxygenase-2 (COX-2) inhibitor, and Etanercept (ETC), a TNF-α antagonist on the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis. A total of 47 Wistar rats were randomized into seven groups, as follows: (1) Sham: sham induced-colitis; (2) TNBS: nontreated induced-colitis; (3) Lumiracoxib control; (4) Lumiracoxib-treated induced-colitis; (5) ETC control; (6) ETC-treated induced-colitis; (7) Lumiracoxib-ETC-treated induced-colitis. Rats from groups 6 and 7 presented significant improvement of macroscopic and histopathological damages in the distal colon. The gene expression of COX-2 mRNA, as well of TNF-α mRNA, decreased significantly in groups 6 and 7 compared to the TNBS nontreated and lumiracoxib-treated groups. The treatment only with lumiracoxib did not reduce the inflammation on TNBS-induced experimental colitis. ETC attenuated the damage seen in the colon and reduced the inflammation caused by TNBS. Our results suggest that down-regulation of TNF-α and COX-2 resulted in a decrease in inflammation caused by TNBS and thus provided some protection from the colonic damage caused by TNBS.

Oral Concentrated Grape Juice Suppresses Expression of NF-kappa B, TNF-α and iNOS in Experimentally Induced Colorectal Carcinogenesis in Wistar Rats

UNLABELLED The aim of this study was to evaluate the effects of grape juice on colon carcinogenesis induced by azoxymethane (AOM) and expression of NF-kB, iNOS and TNF- α. METHODS Forty male Wistar rats were divided into 7 groups: G1, control; G2, 15 mg/kg AOM; G3, 1% grape juice 2 weeks before AOM; G4, 2% grape juice 2 weeks before AOM; G5, 1% grape juice 4 weeks after AOM; G6, 2% grape juice 4 weeks after AOM; G7, 2% grape juice without AOM. Histological changes and aberrant crypt foci (ACF) were studied, while RNA expression of NF- kB, TNF- and iNOS was evaluated by qPCR. RESULTS The number of ACF was higher in G2, and G4 presented a smaller number of crypts per focus than G5 (p=0.009) and G6. Small ACF (1-3) were more frequent in G4 compared to G2, G5 and G6 (p=0.009, p=0.009 and p=0.041, respectively). RNA expression of NF-kB was lower in G3 and G4 compared to G2 (p=0.004 and p=0.002, respectively). A positive correlation was observed between TNF- α and NF-kB gene expression (p=0.002). In conclusion, the administration of 2% grape juice before AOM reduced the crypt multiplicity, attenuating carcinogenesis. Lower expression of NF-kB was observed in animals exposed to grape juice for a longer period of time, regardless of concentration.

Etanercept attenuates TNBS-induced experimental colitis: role of TNF-α expression

Crohn′s disease (CD) is associated with gut barrier dysfunction. Tumour necrosis factor-α (TNF-α) plays an important role into the pathogenesis of several inflammatory diseases because its expression is increased in inflamed mucosa of CD patients. Anti-TNF therapy improves significantly mucosal inflammation. Thus, this study aimed to evaluate the effect of Etanercept (ETC), a tumour necrosis factor alpha (TNF-α) antagonist on the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis. A total of 18 Wistar rats were randomized into four groups, as follows: (1) Sham: sham induced-colitis; (2) TNBS: non-treated induced-colitis; (3) ETC control; (4) ETC-treated induced-colitis. Rats from group 4 presented significant improvement either of macroscopic or of histopathological damage in the distal colon. The gene expression of TNF-α mRNA, decreased significantly in this group compared to the TNBS non-treated group. The treatment with etanercept attenuated the colonic damages and reduced the inflammation caused by TNBS. Taken together, our results suggest that ETC attenuates intestinal colitis induced by TNBS in Wistar rats by TNF-α downregulation.

Chemopreventive activity of grape juice concentrate (G8000TM) on rat colon carcinogenesis induced by azoxymethane.

Colorectal cancer is the third most common cancer worldwide in both sexes, with similar geographic patterns between genders. This neoplasm has good prognosis if the disease is diagnosed at early stages. The aim of this study was to evaluate the effect of red grape juice on the expression of COX-2 and Ki-67 expression following colon carcinogenesis induced by azoxymethane (AOM). Thirty-five rats were randomly distributed into seven groups (n=5 per group): G1: SHAM or negative control received only saline; G2 (positive control): animals received 15 mg/kg AOM; G3: animals received 1% red grape juice 2 weeks before the administration of AOM; G4: animals received 2% red grape juice 2 weeks before the administration of AOM; G5: animals received 1% red grape juice 4 weeks after the last administration of AOM; G6: animals received 2% red grape juice 4 weeks after the last administration of AOM; G7: animals received only 2% red grape juice. COX-2 mRNA expression was reduced in animals treated with 1% red grape juice before AOM induction or 2% red grape juice after AOM induction. COX-2 immunoexpression was also reduced to groups treated with red grape juice at 1% before and after AOM induction or 2% red grape juice after AOM induction. Decreased immunoexpression of Ki-67 positive cells was observed in animals treated with 1% grape juice before AOM-treated animals. Taken together, grape juice concentrate is able to exert some chemopreventive activity on rat colon carcinogenesis.

Dual role of cyclooxygenase-2 during tissue repair induced by low level laser therapy: An intriguing issue

Abstract Tissue repair is an excellent example of pathophysiological model for studying the role of cyclooxygenase-2 (COX-2) on eukaryotic cells. It has been established that two COX isoforms are expressed in human tissues: constitutive or induced. COX-1 activity is constitutive, present in nearly all cell types at a constant level; COX-2 activity is normally absent from cells, and when induced, the protein levels increase and decrease in a matter of hours after a single stimulus. Thus, the purpose of this review was to describe the role of COX-2 during tissue repair induced by low level laser therapy (LLLT) in humans and experimental models. COX-2 expression has been implicated in the onset or the exacerbation of inflammation during tissue repair induced by LLLT in a number of studies, Many studies are conducted to investigate the role of COX-2 during tissue repair induced by LLLT using different experimental protocols and dosages. Therefore, this is an area that warrants investigation, since the estimation of COX-2 expression from using such important techniques in therapeutics with respect to tissue repair will be added to those already established in the literature as a way to improve health status and prevention of side effects.

The effects of soybean isoflavones and 17β-estradiol in uterus and mammary glands of diabetic rat models

Abstract The objective of this study was to evaluate the action of soy isoflavones and 17 beta estradiol on the extracellular matrix in the uterus and mammary gland of diabetic rats. Sixty adult female rats underwent ovariectomy, then randomized into seven groups of ten animals each: Non-diabetic: GI Sham control animals ovariectomized; and GII control ovariectomized that received propylene glycol vehicle. Diabetic: GIII Sham control diabetic animals ovariectomized; GIV ovariectomized diabetic animals receiving propylene glycol vehicle; GV diabetic ovariectomized animals treated with soy isoflavones (150 mg/kg by gavage); GVI ovariectomized diabetic rats treated with estrogen (17b-estradiol, 10 mg/kg, subcutaneously); GVII diabetic ovariectomized animals treated with soy isoflavones (150 mg/kg by gavage), and with estrogen (17b-estradiol, 10 mg/kg combination therapy). Treatments occurred during 30 consecutive days. After animals euthanasia, a portion of the uterus was immersed in liquid nitrogen for molecular biology analysis, the other portion of uterus and mammary glands were removed and processed for paraffin embedding. Soy isoflavones (GV) and 17b estradiol improved the production of compounds of extracellular matrix, such as small leucine-rich proteoglycans (SLRPs). The combination of both therapies had an additive effect in SLRPs expression. Soy isoflavones contribute to the uterine integrity of SLRPs of diabetic rats.

Grape juice concentrate (G8000™) modulates apoptosis but not oxidative stress following rat colon carcinogenesis induced by azoxymethane

Abstract Objectives: The aim of this study was to evaluate if grape juice concentrate is able to protect against experimental colon carcinogenesis. Material and methods: For this purpose, a total of 35 male Wistar rats were randomly distributed into seven groups: G1: SHAM animals receiving only saline; G2: animals receiving 15 mg/kg azoxymethane (AOM); G3: animals receiving 1% grape juice concentrate 2 weeks before the administration of AOM; G4: animals receiving 2% grape juice concentrate 2 weeks before the administration of AOM; G5: animals receiving 1% grape juice concentrate 4 weeks after the last administration of AOM; G6: animals receiving 2% grape juice concentrate 4 weeks after the last administration of AOM; G7: animals receiving only 2% grape juice concentrate. Results: The group that received 2% grape juice concentrate before induction with AOM showed the decreased expression of Bcl-2 compared to those animals that were induced by AOM (positive control). Regarding Bax, animals that received grape juice at 2% decreased Bax immunoexpression when compared to AOM group. Furthermore, animals that intake grape juice at 1% after induced by AOM decreased Bax immunoexpression as well. 8-OHdGLI did not show significant statistically differences (p > 0.05) among groups. Conclusion: In summary, our results demonstrate that grape juice is able to modulate rat colon carcinogenesis as a result of induction of apoptosis.

Effects of Grape Juice in Superoxide Dismutase and Catalase in Colorectal Cancer Carcinogenesis Induced by Azoxymethane

Background: The intestinal mucosa is commonly exposed to oxidant nutrients and carcinogens, which can lead to the generation of free radicals. The antioxidants present in the diet assume great importance as possible protective agents, reducing the oxidative damage. In this way, we evaluated the antioxidant action of grape juice on preneoplastic lesions induced by azoxymethane (AOM) in Wistar rats. Methods: The colorectal carcinogenesis was induced by two intraperitoneal injections of 15mg/kg of AOM in Wistar rats. The animals were divided in 7 groups and treated with 1 and 2% concentrations of grape juice before and after carcinogen administration. After euthanasia, the expression of antioxidant enzymes catalase (CAT), copper-zinc superoxide dismutase (Cu/Zn-SOD) and manganese superoxide dismutase (Mn-SOD) CAT, SOD1 and SOD2 were evaluated by immunohistochemistry. Results: AOM decreased the expression of CAT and Mn-SOD enzymes, but not for Cu/Zn-SOD. We observed an increase expression of CAT and Mn-SOD after grape juice administration in some concentrations according to the time of administration of the grape juice before the carcinogen or just after the carcinogen. Conclusion: Our results suggest an independent action of each enzyme and a possible antioxidant action of the grape juice components in the diet being able to balance the body to neutralize the superoxide radicals and not leave them in the cell-damaging form.