Effects of carbofuran and metsulfuron-methyl on the benthic macroinvertebrate community in flooded ricefields Efeito do carbofurano e metsulfuron-methyl sobre a comunidade de macroinvertebrados bentônicos de lavoura de arroz irrigado

AIM: This study evaluated the effect of the insecticide carbofuran and the herbicide metsulfuron-methyl on the abundance and diversity of benthic macroinvertebrates in a paddy ricefield. METHODS: To achieve this goal, two pesticide treatments [the insecticide carbofuran (IC) and the herbicide metsulfuron-methyl (HM)] and a control (Co) treatment with no added pesticide were established in an experimental area of the Plant Science Department of the Federal University of Santa Maria. Soil samples were collected in triplicate from each treatment 30 days before and 1, 10, and 51 days after the pesticide application, for macrofauna identification. RESULTS: Among the 21 taxa identified, Trichoceridae was present only in Co, Hydroptilidae was recorded only in IC, and Corixidae in HM. In Co, the most abundant group was Annelida, while in IC and HM Diptera (Chironomidae) was dominant. Significant differences were observed between Co and IC, in the density of Odontoceridae (Control>IC) and Hydrophilidae (Control<IC), and between Co and HM in the density of Odontoceridae (Control>HM) and Hirudinea (Control<HM). CONCLUSION: In spite of the possible negative effects of the pesticides on the benthic community, the assemblages recovered rapidly.<br>OBJETIVO: O objetivo desse estudo foi avaliar o efeito do inseticida carbofurano e do herbicida metsulfuron-methyl na abundância e diversidade de macroinvertebrados bentônicos em campo de arroz irrigado. MÉTODOS: Para isto, dois tratamentos com agrotóxicos [o inseticida carbofurano (IC) e o herbicida metsulfuron-methyl (HM)] e um controle (Co), tratamento sem pesticida, foram aplicados em uma área experimental no Departamento de Fitotecnia da Universidade Federal de Santa Maria. Amostras de solo foram coletadas em triplicatas em cada tratamento 30 dias antes (DBA) e 1, 10 e 51 dias após a aplicação dos pesticidas, posteriormente a macrofauna foi identificada. RESULTADOS: Vinte e um (21) taxa foram identificados, entre esses Trichoceridae esteve presente apenas em Co, enquanto que Hydroptilidae foi coletado apenas em IC, e Corixidae em HM. Em Co e IC, o grupo mais abundante foi Annelida, e em HM foi Diptera (Chironomidae) que prevaleceu. Diferenças significativas foram observadas entre Co e IC, na densidade de Odontoceridae (Co>IC) e Hydrophilidae (Co<IC), e entre Co e HM na densidade de Odontoceridae (Co>HM) e Hirudinea (Co<HM). CONCLUSÃO: Entretanto, apesar dos possíveis efeitos negativos dos pesticidas sobre a comunidade bentônica verificados nos primeiros dias após a aplicação, verificou-se que de forma geral a comunidade recuperou-se rapidamente

Erythropoietin Protects the Intestine Against Ischemia/ Reperfusion Injury in Rats

Previous studies have shown that erythropoietin (EPO) has protective effects against ischemia/reperfusion (I/R) injury in several tissues. The aim of this study was to determine whether EPO could prevent intestinal tissue injury induced by I/R. Wistar rats were subjected to intestinal ischemia (30 min) and reperfusion (60 min). A single dose of EPO (5000 U/kg) was administered intraperitoneally at two different time points: either at five minutes before the onset of ischemia or at the onset of reperfusion. At the end of the reperfusion period, jejunum was removed for examinations. Myeloperoxidase (MPO), malondialdehyde (MDA), and antioxidant defense system were assessed by biochemical analyses. Histological evaluation was performed according to the Chiu scoring method. Endothelial nitric oxide synthase (eNOS) was demonstrated by immunohistochemistry. Apoptotic cells were determined by TUNEL staining. Compared with the sham, I/R caused intestinal tissue injury (Chiu score, 3 ± 0.36 vs 0.4 ± 0.24, P < 0.01) and was accompanied by increases in MDA levels (0.747 ± 0.076 vs 0.492 ± 0.033, P < 0.05), MPO activity (10.51 ± 1.87 vs 4.3 ± 0.45, P < 0.05), intensity of eNOS immunolabelling (3 ± 0.4 vs 1.3 ± 0.33, P < 0.05), the number of TUNEL-positive cells (20.4 ± 2.6 vs 4.6 ± 1.2, P < 0.001), and a decrease in catalase activity (16.83 ± 2.6 vs 43.15 ± 4.7, P < 0.01). Compared with the vehicle-treated I/R, EPO improved tissue injury; decreased the intensity of eNOS immunolabelling (1.6 ± 0.24 vs 3 ± 0.4, P < 0.05), the number of TUNEL-positive cells (9.2 ± 2.7 vs 20.4 ± 2.6, P < 0.01), and the high histological scores (1 ± 0.51 vs 3 ± 0.36, P < 0.01), and increased catalase activity (42.85 ± 6 vs 16.83 ± 2.6, P < 0.01) when given before ischemia, while it was found to have decreased the levels of MDA (0.483 ± 0.025 vs 0.747 ± 0.076, P < 0.05) and MPO activity (3.86 ± 0.76 vs 10.51 ± 1.87, P < 0.05), intensity of eNOS immunolabelling (1.4 ± 0.24 vs 3 ± 0.4, P < 0.01), the number of TUNEL-positive cells (9.1 ± 3 vs 20.4 ± 2.6, P < 0.01), and the number of high histological scores (1.16 ± 0.4 vs 3 ± 0.36, P < 0.05) when given at the onset of reperfusion. These results demonstrate that EPO protects against intestinal I/R injury in rats by reducing oxidative stress and apoptosis. We attributed this beneficial effect to the antioxidative properties of EPO