Expressão gênica de TLR-2, TLR-4, HMGB1 E VEGF em úlceras abomasais em bovinos de corte
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Data
2016-01-05
Autores
Bentin, Leonardo Aparecido Teixeira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As úlceras abomasais atingem bovinos de todas as idades e raças em todos os sistemas de produção, gerando perdas econômicas. A úlcera resulta da isquemia, atraindo leucócitos e macrófagos, estimulando fibroblastos, células endoteliais e epiteliais. A proteína do grupo de alta mobilidade 1 (HMGB1) liga-se a diferentes receptores de superfície celular, incluindo Toll-like-2 (TLR-2) e -4 (TLR-4), produzindo citocinas. A presença da HMGB1 causa aumento dos níveis do fator de crescimento endotelial vascular (VEGF), um regulador fundamental da angiogênese. Assim, investigou-se a participação da HMGB1, TLR-2, TLR-4 e VEGF em úlceras abomasais em bovinos de corte. Um total de 150 abomasos de bovinos de corte foi examinado em um abatedouro; 17 amostras da região cárdica foram colhidas. Os tecidos extraídos foram classificados em grupo normal (sem ulceração de mucosa); ulceração de grau 1 (erosões não perfuradas com lesões mínimas da mucosa) e ulceração de grau 2 (erosões não perfuradas combinadas com sangramento moderado da mucosa) e confirmado pela histopatologia. A expressão dos genes nas amostras normais ou ulceradas no abomaso foi avaliada pela RT qPCR. Os dados foram submetidos à ANOVA seguido por teste de Bonferroni ao nível de p<0,05. Não houve diferença de expressão de HMGB1, de TLR-4 e de VEGF entre os dois tipos de úlceras em relação aos abomasos normais. Úlceras de grau 2 tiveram expressão de TLR-2 superior a úlceras de grau 1. O aumento da expressão de TLR-2 pode estar associado à manutenção da cicatrização, promovendo a resposta inflamatória, evidenciado pela presença de infiltrado inflamatório mononuclear e neutrófilos.
Abomasal ulcers affect cattle of all ages and breeds in all production systems, leading to economic losses. The ulcer resulting from tissue ischemia, attracting leukocytes and macrophages, stimulates fibroblasts, endothelial and epithelial cells. The protein of high mobility group 1 (HMGB1) binds to different cell surface receptors, including Toll-like-2 (TLR-2) and 4 (TLR-4) resulting in cytokine production. The presence of HMGB1 causes increased levels of vascular endothelial growth factor (VEGF), a key regulator of angiogenesis. Thus, it was investigated whether HMGB1, TLR-2, TLR-4 and VEGF play a role in abomasal ulcers in beef cattle. A total of 150 abomasums from beef cattle were examined in a slaughterhouse; 17 samples were collected from the cardiac region. The extracted tissues were divided into normal group (without ulceration of the mucosa); type 1 ulcers (unperforated erosions with minimal mucosal injury) and type 2 ulcers (unperforated erosions combined with moderate bleeding of the mucosa) and confirmed by histopathology. Gene expression was evaluated by RT qPCR in samples of normal or ulcerated abomasums. Data were analyzed by ANOVA followed by Bonferroni test at p <0.05. No difference in expression of HMGB1, TLR-4 and VEGF was detected between the two types of ulcers when compared to normal abomasums. TLR-2 expression was higher in type 2 ulcers than in type 1 ulcers. Increased TLR-2 expression might be associated with the maintenance of abomasal healing, promoting the inflammatory response, as evidenced by the presence of mononuclear cell infiltration and neutrophils.
Abomasal ulcers affect cattle of all ages and breeds in all production systems, leading to economic losses. The ulcer resulting from tissue ischemia, attracting leukocytes and macrophages, stimulates fibroblasts, endothelial and epithelial cells. The protein of high mobility group 1 (HMGB1) binds to different cell surface receptors, including Toll-like-2 (TLR-2) and 4 (TLR-4) resulting in cytokine production. The presence of HMGB1 causes increased levels of vascular endothelial growth factor (VEGF), a key regulator of angiogenesis. Thus, it was investigated whether HMGB1, TLR-2, TLR-4 and VEGF play a role in abomasal ulcers in beef cattle. A total of 150 abomasums from beef cattle were examined in a slaughterhouse; 17 samples were collected from the cardiac region. The extracted tissues were divided into normal group (without ulceration of the mucosa); type 1 ulcers (unperforated erosions with minimal mucosal injury) and type 2 ulcers (unperforated erosions combined with moderate bleeding of the mucosa) and confirmed by histopathology. Gene expression was evaluated by RT qPCR in samples of normal or ulcerated abomasums. Data were analyzed by ANOVA followed by Bonferroni test at p <0.05. No difference in expression of HMGB1, TLR-4 and VEGF was detected between the two types of ulcers when compared to normal abomasums. TLR-2 expression was higher in type 2 ulcers than in type 1 ulcers. Increased TLR-2 expression might be associated with the maintenance of abomasal healing, promoting the inflammatory response, as evidenced by the presence of mononuclear cell infiltration and neutrophils.
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Palavras-chave
HMGB1 protein, Abomasum, Cattle deseases, Healing, Ulcers, Abomaso, Cicatrização, Doenças de bovinos, Proteína HMGB1, Úlceras