Dallard B E, Ruffino V, Heffel S, Calvinho L F
Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Rvdo. Padre Kreder 2805, (3080) Esperanza, Santa Fe, Argentina.
J Dairy Sci. 2007 May;90(5):2229-40. doi: 10.3168/jds.2006-653.
Agents that increase natural protective mechanisms have been proposed for the prevention and treatment of intramammary infections. Staphylococcus aureus is a major pathogen causing primarily subclinical chronic mastitis that responds poorly to antibiotic therapy. The objectives of this study were to describe the effects of a single intramammary infusion of a lipopolysaccharide-based biological response modifier (BRM) on mammary epithelial cellular proliferation and expression of insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor (VEGF) in uninfected and Staph. aureus-infected bovine mammary glands during involution. Three groups of 12 cows, 6 Staph. aureus-infected and 6 uninfected, were infused with BRM or placebo in 2 mammary quarters and killed at 7, 14, and 21 d of involution. The proportion of infected quarters, mammary cell proliferation, and IGF-I and VEGF expression were evaluated. Biological response modifier treatment decreased the proportion of Staph. aureus-infected mammary quarters at 7 d of involution, but a similar number of isolations were observed at 14 and 21 d of involution in either treated or control quarters. The percentage of proliferating mammary epithelial cells was higher in infected than uninfected quarters at every observation period, irrespective of the treatment administered, whereas uninfected BRM-treated quarters showed increased cell proliferation at 7 d of involution. Insulin-like growth factor-I expression in uninfected quarters was not affected by treatment and showed a decrease at 21 d of involution. Expression of IGF-I was greater in infected than uninfected quarters at every observation period, irrespective of the treatment received. Expression of VEGF was greater in BRM-treated uninfected quarters at 7 d of involution compared with controls. In infected quarters, VEGF expression was lowest in BRM-treated quarters at 7 d of involution and increased throughout the observation period. Conversely, untreated infected quarters showed the highest VEGF expression at 7 d and decreased at 21 d of involution. Mammary cell proliferation and expression of IGF-I and VEGF were increased in Staph. aureus-infected quarters. Increased mammary cell proliferation and VEGF expression were observed in BRM-treated quarters during the first week of involution.
人们已经提出利用增强天然保护机制的制剂来预防和治疗乳房内感染。金黄色葡萄球菌是引起主要为亚临床慢性乳腺炎的主要病原体，对抗生素治疗反应不佳。本研究的目的是描述在奶牛干奶期，向未感染和感染金黄色葡萄球菌的乳腺单次乳房内注入基于脂多糖的生物反应调节剂（BRM）对乳腺上皮细胞增殖以及胰岛素样生长因子-I（IGF-I）和血管内皮生长因子（VEGF）表达的影响。三组，每组12头奶牛，其中6头感染金黄色葡萄球菌，6头未感染，在两个乳腺象限分别注入BRM或安慰剂，并在干奶期的第7、14和21天宰杀。评估感染象限的比例、乳腺细胞增殖以及IGF-I和VEGF的表达。生物反应调节剂治疗在干奶期第7天时降低了感染金黄色葡萄球菌的乳腺象限比例，但在干奶期第14天和21天时，治疗组和对照组的分离菌数量相似。在每个观察期，感染象限中增殖的乳腺上皮细胞百分比均高于未感染象限，与所给予的治疗无关，而未感染的BRM治疗象限在干奶期第7天时细胞增殖增加。未感染象限中IGF-I的表达不受治疗影响，且在干奶期第21天时下降。在每个观察期，无论接受何种治疗，感染象限中IGF-I的表达均高于未感染象限。与对照组相比，BRM治疗的未感染象限在干奶期第7天时VEGF的表达更高。在感染象限中，BRM治疗的象限在干奶期第7天时VEGF表达最低，并在整个观察期内增加。相反，未治疗的感染象限在干奶期第7天时VEGF表达最高，在干奶期第21天时下降。在感染金黄色葡萄球菌的象限中，乳腺细胞增殖以及IGF-I和VEGF的表达增加。在干奶期的第一周，BRM治疗的象限中观察到乳腺细胞增殖和VEGF表达增加。
