Synergistic Antigenotoxic and Antioxidant Action of Gum Arabic and Eugenol in Rat Liver Following Induction of Colorectal Carcinogenesis.

OBJECTIVE: Much research has been conducted to identify natural antioxidant and antimutagenic compounds capable of preventing, reverting or treating conditions caused by oxidative stress and genotoxicity. In this study we evaluated the effects of 10% gum arabic (GA) and eugenol (EUG) on hepatic oxidative stress and genotoxicity induced by dimethylhydrazine (DMH) in rats. METHODS: The prevention arm of the study included 4 control groups and 4 experimental groups. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the same period and for an additional 9 weeks, the animals received either water, 10% GA , EUG or 10% GA + EUG  by gavage. The treatment arm of the study included 4 control groups and 4 experimental groups. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the subsequent 9 weeks, the animals received either water, 10% GA, EUG or 10% GA + EUG  by gavage. Finally, the livers were harvested for histopathological study with HE, measurement of genotoxicity and oxidative stress. RESULT: Genotoxicity and oxidative stress were found to be significantly lower in Group XII (animals treated concomitantly with GA and EUG). This is the first study to observe the synergistic action of GA and EUG administered concomitantly in this scenario. CONCLUSION: Indicating a synergistic antigenotoxic and antioxidant effect on liver cells in rats with DMH-induced colorectal carcinogenesis.

Effect of red propolis on hamster cheek pouch angiogenesis in a new sponge implant model.

PURPOSE: To evaluate the effects of red propolis on cheek pouch angiogenesis in a hamster new model sponge implant. METHODS: Forty eight animals divided into eight groups. (Groups I-IV), the animals were treated for 15 days before and 10 days after sponge implantation. (Groups V-VIII), the animals were treated for 10 days after sponge implantation (GI and GV: red propolis 100 mg/kg, GII and GVI: celecoxib 20 mg/kg, GIII and GVII: 1% gum arabic 5 mL/kg, GIV and GVIII: distilled water 5 mL/kg). On the 11th day of implantation, the animals were anesthetized for stereoscopic microscopic imaging and morphometric quantification of angiogenesis (SQAN), followed by histopathological evaluation (H&E). RESULTS: In the SQAN analysis, no significant difference was found between the groups. However, on histology, propolis was found reduce the population of mastocytes in the qualitative analyses (p = 0,013) in the quantitative analyses to reduce the number of blood vessels (p = 0,007), and increase the macrophage count (p = 0,001). CONCLUSION: Red propolis inhibited inflammatory angiogenesis when administered before andcontinuously after sponge implant, and was shown to have immunomodulating effects on inflammatory cells (mastocytes and macrophages) in a new sponge implant hamster model.

Effect of red propolis on hamster cheek pouch angiogenesis in a new sponge implant model

Abstract Purpose: To evaluate the effects of red propolis on cheek pouch angiogenesis in a hamster new model sponge implant. Methods: Forty eight animals divided into eight groups. (Groups I-IV), the animals were treated for 15 days before and 10 days after sponge implantation. (Groups V-VIII), the animals were treated for 10 days after sponge implantation (GI and GV: red propolis 100 mg/kg, GII and GVI: celecoxib 20 mg/kg, GIII and GVII: 1% gum arabic 5 mL/kg, GIV and GVIII: distilled water 5 mL/kg). On the 11th day of implantation, the animals were anesthetized for stereoscopic microscopic imaging and morphometric quantification of angiogenesis (SQAN), followed by histopathological evaluation (H&E). Results: In the SQAN analysis, no significant difference was found between the groups. However, on histology, propolis was found reduce the population of mastocytes in the qualitative analyses (p = 0,013) in the quantitative analyses to reduce the number of blood vessels (p = 0,007), and increase the macrophage count (p = 0,001). Conclusion: Red propolis inhibited inflammatory angiogenesis when administered before andcontinuously after sponge implant, and was shown to have immunomodulating effects on inflammatory cells (mastocytes and macrophages) in a new sponge implant hamster model.

Carcinogenesis in rats subjected to a new model ureterosigmoidostomy and treated with L-lysine

ABSTRACT PURPOSE: To evaluate the effects of L-lysine on the intestinal and urothelial epithelium of rats subjected to ureterosigmoidostomy (new model for surgical carcinogenesis). METHODS: Forty-two rats, 9 weeks of age, were divided into 6 groups. Animals in groups A, B, C were subjected to ureterosigmoidostomy (US) and treated with L-lysine, celecoxib and H2O, respectively. Groups D, E and F (non-operated controls) received L-lysine, celecoxib and H2O, respectively. The L-lysine dose was 150 mg/kg and that of celecoxib was 20 mg/kg. The colon was analyzed for the presence of aberrant crypt foci (ACF) under a stereomicroscope.The tissue was stained with hematoxylin and eosin and PAS alcian blue. RESULTS: There were rare ACF, and there was no statistically significant difference between the groups. Histopathologic study of the ureteral epithelium identified moderate to severe urothelial hyperplasia in rats with ureterosigmoidostomy. Transitional hyperplasia in the ureters of animals receiving L-lysine (A) showed an apparent difference compared to the control (C) (P=0.2424). There was no dysplasia or atypia CONCLUSION: L-lysine does not promote carcinogenesis of the intestinal and urethelial epithelium of rats subjected to ureterosigmoidostomy at the doses and times studied.

Carcinogenesis in rats subjected to a new model ureterosigmoidostomy and treated with L-lysine.

PURPOSE:: To evaluate the effects of L-lysine on the intestinal and urothelial epithelium of rats subjected to ureterosigmoidostomy (new model for surgical carcinogenesis). METHODS:: Forty-two rats, 9 weeks of age, were divided into 6 groups. Animals in groups A, B, C were subjected to ureterosigmoidostomy (US) and treated with L-lysine, celecoxib and H2O, respectively. Groups D, E and F (non-operated controls) received L-lysine, celecoxib and H2O, respectively. The L-lysine dose was 150 mg/kg and that of celecoxib was 20 mg/kg. The colon was analyzed for the presence of aberrant crypt foci (ACF) under a stereomicroscope.The tissue was stained with hematoxylin and eosin and PAS alcian blue. RESULTS:: There were rare ACF, and there was no statistically significant difference between the groups. Histopathologic study of the ureteral epithelium identified moderate to severe urothelial hyperplasia in rats with ureterosigmoidostomy. Transitional hyperplasia in the ureters of animals receiving L-lysine (A) showed an apparent difference compared to the control (C) (P=0.2424). There was no dysplasia or atypia. CONCLUSION:: L-lysine does not promote carcinogenesis of the intestinal and urethelial epithelium of rats subjected to ureterosigmoidostomy at the doses and times studied.

Potential chemoprotective effects of green propolis, L-lysine and celecoxib on bone marrow cells and peripheral blood lymphocytes of Wistar rats subjected to bladder chemical carcinogenesis.

PURPOSE: To evaluate the genotoxicity of propolis and L-lysine, as well as their effects on the possible cellular damage in erythroblasts (bone marrow) and leukocytes (peripheral blood) caused by the carcinogen BBN (n - butyl - n {4 - hydroxybutyl} nitrosamine) in rats subjected to bladder carcinogenesis and treated with green propolis and L-lysine. METHODS: One hundred and twenty five rats were distributed into the following groups: I, IIA, IIB, III, K, L M N, X, XI, XII and XIII. Groups I to X received BBN in drinking water for 14 weeks (wks). Group I was treated with intragastric (ig) propolis at 150 mg/kg body weight, for 44 wks, beginning 30 days before start of BBN. Groups IIA and III were treated with propolis (150 mg/kg), for 40 wks, subcutaneous (sc) and ig, respectively, beginning simultaneously with BBN. On the 32nd wk, the animals of groups L, M and N were treated ig with L-lysine (300 mg/kg), celecoxib (30 mg/kg) and propolis (300 mg/kg), respectively, up to the 40th wk. The groups that received only BBN (IIB and K) were treated with water, sc and orally, respectively, for 40 wks. Groups XI, XII and XIII received respectively propolis (150 mg/kg), L-lysine (150 mg/kg) and water ig for 40 wks. After 40 wks, the surviving animals were anesthetized and subjected to femoral bone marrow aspiration and blood collection from the aorta, for CA and MNT, respectively, for investigation of genotoxicity. RESULTS: Groups IIB and K, which received only BBN and water, showed the greatest DNA damage in peripheral leukocytes (CA) and largest number of micronuclei in bone marrow erythrocytes (MNT) in relation to all other groups that received BBN and lysine and/or propolis (p<0.001). CONCLUSIONS: Both propolis and L-lysine are effective in protecting against genotoxicity, as well not being genotoxic themselves toward the cells evaluated, at the doses and times administered and according to the two tests utilized.

Potential chemoprotective effects of green propolis, L-lysine and celecoxib on bone marrow cells and peripheral blood lymphocytes of Wistar rats subjected to bladder chemical carcinogenesis

PURPOSE: To evaluate the genotoxicity of propolis and L-lysine, as well as their effects on the possible cellular damage in erythroblasts (bone marrow) and leukocytes (peripheral blood) caused by the carcinogen BBN (n - butyl - n {4 - hydroxybutyl} nitrosamine) in rats subjected to bladder carcinogenesis and treated with green propolis and L-lysine. METHODS: One hundred and twenty five rats were distributed into the following groups: I, IIA, IIB, III, K, L M N, X, XI, XII and XIII. Groups I to X received BBN in drinking water for 14 weeks (wks). Group I was treated with intragastric (ig) propolis at 150 mg/kg body weight, for 44 wks, beginning 30 days before start of BBN. Groups IIA and III were treated with propolis (150 mg/kg), for 40 wks, subcutaneous (sc) and ig, respectively, beginning simultaneously with BBN. On the 32nd wk, the animals of groups L, M and N were treated ig with L-lysine (300 mg/kg), celecoxib (30 mg/kg) and propolis (300 mg/kg), respectively, up to the 40th wk. The groups that received only BBN (IIB and K) were treated with water, sc and orally, respectively, for 40 wks. Groups XI, XII and XIII received respectively propolis (150 mg/kg), L-lysine (150 mg/kg) and water ig for 40 wks. After 40 wks, the surviving animals were anesthetized and subjected to femoral bone marrow aspiration and blood collection from the aorta, for CA and MNT, respectively, for investigation of genotoxicity. RESULTS: Groups IIB and K, which received only BBN and water, showed the greatest DNA damage in peripheral leukocytes (CA) and largest number of micronuclei in bone marrow erythrocytes (MNT) in relation to all other groups that received BBN and lysine and/or propolis (p<0.001). CONCLUSIONS: Both propolis and L-lysine are effective in protecting against genotoxicity, as well not being genotoxic themselves toward the cells evaluated, at the doses and times administered and according to the two tests utilized. .