Flávia Andressa Pidone Ribeiro

Polyphenols as a chemopreventive agent in oral carcinogenesis: putative mechanisms of action using in-vitro and in-vivo test systems.

Polyphenols are present in foods and beverages, being related to sensorial qualities such as color, bitterness, and astringency, which are relevant in products such as wine, tea, and grape juice. These compounds occur naturally in forms varying from simple phenolic acids to complex polymerized tannins. Oral cancer is the most common head and neck cancer, and it often has a poor prognosis owing to local tumor invasion and frequent lymph node metastasis. Nowadays, chemoprevention is considered as a promising approach for controlling cancer as a result of specific natural products or synthetic agents able to suppress, reverse, or even prevent premalignancy before transformation into invasive cancer. The use of polyphenols as a chemopreventive agent is a suitable tool for modulation of the oral carcinogenesis process. The aim of this article is to present data generated from the use of polyphenols as a chemopreventive agent in oral carcinogenesis using in-vivo and in-vitro test systems. These results have shown that polyphenols are able to exert some chemopreventive action as a result of inducing cellular death, apoptosis, inhibition of tumor growth, and antioxidative properties. Therefore, this area warrants further investigation as a new approach that would apply not only to polyphenols but also to other phytochemicals used as promising therapeutic agents against oral human diseases, especially cancer.

Anti-tumor activity of grape juice concentrate in the rat tongue two-stage initiation–promotion protocol induced by 4-nitroquinoline 1-oxide

Abstract The aim of this study was to evaluate the anti-tumor activity of grape juice concentrate following medium-term oral carcinogenesis assay induced by 4-nitroquinoline 1-oxide (4NQO). A total of 30 male Wistar rats were distributed into five groups, as follows (n = 6 per group): Group 1 – negative control group (non-treated group); Group 2 – received grape juice concentrate at 1% dose by gavage for eight consecutive weeks; Group 3 – received 4NQO for 8 weeks at 20 ppm dose in drinking water daily; Group 4 – received 4NQO at 20 ppm dose during 8 weeks in drinking water and treated with grape juice concentrate at 1% dose orally by gavage for first 4 weeks after 4-NQO administration; Group 5 – received 4NQO at 20 ppm dose for 8 weeks in drinking water and treated with grape juice concentrate at 1% dose orally by gavage between the 5th and 8th weeks daily. Histopathological analysis revealed a decrease in hyperplasic and dysplastic lesions in Group 4. Groups 4 and 5 showed decreased COX-2 and TNF-alpha and eNOS gene expression. Grape juice concentrate also increased SOD Cu/Zn and catalase expression. However, Ki-67 immunoexpression was reduced at the promotion step of oral carcinogenesis (G5). Taken together, our results demonstrate that grape juice concentrate modulates rat tongue carcinogenesis as a result of anti-inflammatory activity, antioxidant activity and down-regulation of oral cells proliferation.

The chemopreventive activity of apple against carcinogenesis: antioxidant activity and cell cycle control

Apples and their derivatives are rich in phytochemicals, including flavonoids (catechins, flavonols, quercetin) and phenolic acids (quercetin glycosides, catechin, epicatechin, procyanidins), vitamins, and fibers, that confer an important antioxidant property. Chemoprevention is defined by the use of natural or synthetic agents to interfere with the progression, reverse, or inhibit carcinogenesis, thereby reducing the risk of developing clinically invasive disease. The aim of this article is to present data generated from the use of apples as a chemopreventive agent in carcinogenesis using in-vivo and in-vitro test systems. Apple and its bioactive compounds can exert chemopreventive properties as a result of antioxidant activity and cell cycle control. However, future focus of research on apple such as identifying the specific phytochemical responsible for the anticarcinogenic effect, timing of consumption, and adequate amount of apples to achieve the best preventive effect using human large randomized-controlled trials is needed. Furthermore, animal studies are also relevant for better understanding the role of this fruit in human health as well as modulation of degenerative diseases such as cancer. Therefore, this area warrants further investigation as a new way of thinking, which would apply not only to apples but also to other fruit used as promising therapeutic agents against human diseases.

Chemopreventive activity of apple extract following medium-term oral carcinogenesis assay induced by 4-nitroquinoline-1-oxide

OBJECTIVE The aim of this study was to evaluate the chemopreventive activity of an apple extract following medium-term oral carcinogenesis assay induced by 4-nitroquinoline-1-oxide (4NQO). METHODS A total of 30 male Wistar rats were distributed into five groups as follows (n=6 per group): Group 1, negative control group (non-treated group); Group 2, received 4NQO during 8 weeks in drinking water and treated with apple extract at 1% by gavage between the first and fourth weeks daily (initiation phase); Group 3, received 4NQO for 8 weeks in drinking water and treated with apple extract by gavage at 1% between the fifth and eighth weeks daily (promotion phase); Group 4, received apple extract at 1% by gavage for 8 consecutive weeks only; and Group 5, received 4NQO for 8 weeks in drinking water daily. RESULTS Histopathological analysis revealed decreased hyperplasic lesions in Group 2 when compared with Group 5. Likewise, decreased dysplastic lesions in Group 3 were observed when compared with Group 5. In Groups 2 and 3, decreased COX-2 and TNF-alpha gene expressions were observed when compared with Group 5. Cytochrome c and caspase 3 levels increased in Groups 2 and 3 when compared with Group 5. CONCLUSION In conclusion, our results demonstrate that apple extract suppresses rat tongue carcinogenesis as a result of anti-inflammatory activity and apoptosis through the intrinsic mitochondrial pathway.

Mimosa (Mimosa caesalpiniifolia) prevents oxidative DNA damage induced by cadmium exposure in Wistar rats

Abstract The Mimosa (Mimosa caesalpiniifolia) is a plant native from South America; it is used in the traditional medicine systems for treating bacterial, fungal, parasitic and inflammatory conditions. The aim of this study was to evaluate the antigenotoxic and antioxidant activities induced by mimosa (M. caesalpiniifolia) in multiple rodent organs subjected to intoxication with cadmium chloride. A total of 40 Wistar rats (8 weeks old, 250 g) were distributed into eight groups (n = 5), as follows: Control group (non-treated group, CTRL); Cadmium exposed group (Cd); cadmium exposure and treated with extract at 62.5 mg/kg/day; cadmium exposure and treated with extract at 125 mg/kg/day; cadmium exposure and treated with extract at 250 mg/kg/day; cadmium exposure and treated with ethyl acetate fraction at 62.5 mg/kg/day. For evaluating the toxicogenetic potential of mimosa, two groups were included in the study being treated with extract at 250 mg/kg/day and acetate fraction of mimosa at 62 mg/kg/day, only. Extract of mimosa at concentrations of 62.5 and 125 mg decreased DNA damage in animals intoxicated with cadmium when compared to cadmium group. In a similar manner, treatment with ethyl acetate fraction of mimosa at 62.5 mg concentration in animals previously exposed to cadmium reduced genetic damage in peripheral blood cells. In a similar manner, the treatment with ethyl acetate fraction reduced DNA damage in liver cells. Oxidative DNA damage was reduced to animals exposed to cadmium and treated with 125 mg of extract as well as those intoxicated to cadmium and treated with 62.5 of acetate fraction of mimosa. Taken together, our results indicate that mimosa prevents genotoxicity induced by cadmium exposure in liver and peripheral blood cells of rats as a result of antioxidant activity.

Burn injury induces histopathological changes and cell proliferation in liver of rats

AIM To investigate effects of severe burn injury (BI) in rat liver through the histopathological and inflammatory markers analysis. METHODS Forty-two male Wistar rats were distributed into two groups, control (C) and subjected to scald BI (SBI). The animals were euthanized one, four and 14 d post sham or 45% of the total body surface BI. Liver fragments were submitted to histopathological, morphoquantitative (hepatocyte area and cell density), ciclooxigenase-2 (COX-2) immunoexpression, and gene expression [real-time polymerase chain reaction for tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS) and caspase-3] methods. RESULTS Histopathological findings showed inflammatory process in all periods investigated and hepatocyte degeneration added to increased amount of connective tissue 14 d post injury. Hepatocyte area, the density of binucleated hepatocytes and density of sinusoidal cells of SBI groups were increased when compared with control. COX-2 immunoexpression was stronger in SBI groups. No differences were found in TNF-α, iNOS and caspase-3 gene expression. CONCLUSION BI induces histopathological changes, upregulation of COX-2 immunoexpression, and cell proliferation in liver of rats.

Apple juice attenuates genotoxicity and oxidative stress induced by cadmium exposure in multiple organs of rats.

The aim of this study was to evaluate the health benefits associated with apple consumption following cadmium exposure. A total of 15 Wistar rats were distributed into three groups (n=5), as follows: control group (non-treated group, CTRL); cadmium group (Cd) and apple juice group (Cd+AJ). The results showed a decrease in the frequency micronucleated cells in bone marrow and hepatocytes in the group exposed to cadmium and treated with apple juice. Apple juice was also able to reduce the 8OHdG levels and to decrease genetic damage in liver and peripheral blood cells. Catalase (CAT) was decreased following apple juice intake. Taken together, our results demonstrate that apple juice seems to be able to prevent genotoxicity and oxidative stress induced by cadmium exposure in multiple organs of Wistar rats.

Antioxidant activity of apple extract protects against rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide.

Abstract Several studies have shown that apple (Malus sp.) has many components able to exert chemopreventive activity. The aim of this study was to evaluate the chemopreventive potential of apple extract following medium-term oral carcinogenesis assay induced by 4-nitroquinoline 1-oxide (4NQO) by means of histopathological analysis and gene expression of antioxidant enzymes, such as CuZnSOD, MnSOD and catalase. A total of 30 male Wistar rats were distributed into five groups, as follows (n = 6 per group): Group 1 – negative control group (non-treated group); Group 2 – received 4NQO during 8 weeks in drinking water and treated with apple extract by gavage between the 1st and 4th weeks daily (initiation phase); Group 3 – received 4NQO for 8 weeks in drinking water and treated with apple extract by gavage between the 5th and 8th weeks daily (promotion phase); Group 4 – received apple extract by gavage for eight consecutive weeks only; and Group 5 – received 4NQO for 8 weeks in drinking water daily. Histopathological analysis revealed that apple extract protect oral lesions induced by 4NQO at initiation or promotion phase. Higher gene expression of CuZnSOD and MnSOD enzymes were noticed in groups treated with apple extract as well. Taken together, our results demonstrate that the apple extract is able to modulate medium-term oral carcinogenesis assay as a result of antioxidant activity.

Therapeutical effects of vaccine from Trypanosoma cruzi amastigote surface protein 2 by simultaneous inoculation with live parasites: RIBEIRO et al.

The aim of this study was to evaluate the efficacy of vaccine using replication‐deficient human recombinant Type 5 replication‐defective adenoviruses (AdHu5) carrying sequences of the amastigote surface protein 2 (ASP2) (AdASP2) in mice infected with the Trypanosoma cruzi ( T cruzi) Y strain. A total of 16 A/Sn mice female were distributed into four groups, as follows (n = 4 per group): Group 1 – Control Group (CTRL); Group 2 – Infected Group (TC): animals were infected by subcutaneous route with 150 bloodstream trypomastigotes of T cruzi Y strain; Group 3 – Immunized Group (AdASP‐2): animals were immunized by intramuscular injection (im) route with 50 µL of AdSP‐2 (2 × 10 8 plaque forming units [pfu]/cam) at day 0; Group 4‐Immunized and Infected Group (AdASP‐2+TC): animals were immunized by im route with 50 µL of ASP‐2 (2 × 10 8 pfu/cam) and infected by T cruzi at the same day (day 0). It was observed a significant decrease of nests in the group that was immunized with AdASP‐2 and infected on the same day. Tumor necrosis factor alpha (TNF‐α) and inducible nitric oxide synthase (iNOS) gene expressions showed a significant increase in the AdASP‐2+TC group when compared to TC group, but it was noted that Cyclooxygenase‐2 (Cox‐2) was increased in TC group when compared to AdASP‐2+TC group. Increase of matrix metalloproteinases‐2 (MMP‐2) and decrease of MMP‐9 immunoexpression in the AdASP‐2+TC group was noticed as well. Oxidative DNA damage was present in myocardium for AdASP‐2+TC group as a result of 8‐hydroxydeoxyguanosine immunoexpression. Taken together, our results highlighted an increased oxidative stress, MMP‐2 activity and inflammatory host response promoted by AdASP‐2 against T cruzi infection.

Therapeutic effects of vaccine derived from amastigote surface protein-2 (ASP-2) against Chagas disease in mouse liver

&NA; This study investigated the efficacy of the vaccine in liver of mice infected with the Trypanosoma cruzi (T. cruzi) and immunized with AdASP‐2. For this purpose, histopathological analysis and gene expression of COX‐2, TNF‐alpha, TNFR, iNOS, cytochrome C, caspase‐3, TLR4, IL‐6 and IL10 were evaluated. The following groups were used in this study: Group 1 ‐ Control Group (CTRL) animals received Ad&bgr;Gal vehicle; Group 2 ‐ Infected Group (TC) animals were infected with T. cruzi; Group 3 ‐ Immunized Group (AdASP‐2): animals were immunized by AdASP‐2 vaccine; Group 4 ‐ Immunized and Infected Group (AdASP‐2+TC) animals were infected with T. cruzi and immunized by AdSP‐2 vaccine. A significant decrease of amastigote nests was noticed in the group of animals that were immunized with AdASP‐2 and infected on the same day. COX‐2 and TNF‐alpha gene expressions increased in TC group, whereas TNF‐alpha decreased in the TC+AdASP‐2 group. TNFR expression was high in AdASP‐2+TC group. iNOS expression was high for all experimental groups whereas cytochrome C decreased for all experimental groups. Caspase 3 increased in TC and TC+AdASP‐2 groups. The gene expression of TLR4 and IL‐10 showed an increase in AdASP‐2+TC group. Finally, hepatic fibrosis was noticed to TC and AdASP‐2 + TC groups. Taken together, our results demonstrated that vaccination with AdASP‐2 was effective against the acute phase of experimental Chagas disease as a result of a more powerful and rapid immune response closely related to expression of some inflammatory genes, such as iNOS, TNF‐alpha, TLR 4, and IL‐10.