Dose dependent changes in inflammatory parameters in the milk of dairy cows after intramammary infusion of lipopolysaccharide

Abstract

The goal of this study was to evaluate the dose dependent changes in common milk and blood parameters for udder health after an intramammary (IM) infusion of five different doses of lipopolysaccharide (LPS, 100, 50, 25, 12.5 and 6.25 μg, respectively). Ten Holstein Friesian cows randomly divided into five groups of 2 cows each were IM infused into one quarter with one LPS dose dissolved in 10 ml of saline. The contralateral quarter was infused with 10 ml saline (9 g/l). Milk samples were taken immediately before and 12, 24, 36, 48 and 60 hours after the treatment. All milk samples were analysed for somatic cell counts (SCC), lactose, sodium (Na), chloride (Cl) and electrical conductivity (EC). Two blood samples were taken immediately after milking for analysing leukocytes (WBC), polymorphonuclear neutrophils (PMN), Na and Cl. The SCC increased maximal at 12 hours after the LPS challenge and differed among LPS doses, as well as the area under curve from 0 to 36 hours (AUC 0−36 h). There were no significant differences among LPS doses in lactose levels for the regression at 12 hours and AUC 0−36 h. Lactose levels in milk from quarters receiving the lowest dose of LPS were lowest after 24 hours, whereas in all other groups lactose levels decreased maximal within the first 12 hours. The regression at 12 hours as well as the AUC 0−36 h showed significant changes for Cl levels but not for Na and EC, respectively. Amongst all groups EC increased maximal within 12 hours and peak EC showed dose dependent differences with highest values at the highest LPS dose. There were no dose differences in WBC. Blood electrolytes showed only tendentially dose dependent differences for blood Na in AUC 0−36 h. The results were possibly due to a great individual variance amongst all cows. In conclusion there are dose dependent differences in the response to LPS especially in milk parameters, which are likely caused by a greater tight junction damage by higher LPS doses. 100 μg LPS seems to be a threshold between low and high doses of LPS. All doses used in this study induced signs of mastitis but there might be a low dose of LPS with only an enhancing effect on mammary gland immune status without inducing mastitis symptoms. This needs to be investigated for developing new ways of mastitis prophylaxis.

Effects of prepartal oronasal administration of lipopolysaccharide on milk composition and productivity of transition Holstein dairy cows

“…A number of studies have shown decreased milk lactose and casein during LPS-induced inflammation [36], by interfering with cellular secretion of specific milk components [37][38][39]. Our data are in line with those of Werner-Misof et al [40] who reported decreased milk lactose content when LPS was infused intramammary between 12.5 to 100 μg. It was demonstrated that LPS damaged the tight junctions leading to increased permeability of the mammary gland epithelium and leakage of milk lactose in dairy cows.…”

Retinoic acid attenuates lipopolysaccharide-induced inflammatory responses by suppressing TLR4/NF-κB expression in rat mammary tissue

“…Within the dairy industry, approximately 40-50% of clinical mastitis cases are caused by coliform bacteria, and nearly 25% of these cases result in death and the culling of the animals [8,22]. LPS, an outer bacterial cell wall component, is responsible for the acute clinical symptoms associated with coliform mastitis [8,9]. So, LPS-induced inflammatory models are recognized as valuable tools with which to study the effects of mastitis [23,24].…”

“…Lipopolysaccharide (LPS), which is a component of the outer membrane of Gram-negative bacteria, is responsible for acute clinical symptoms associated with coliform mastitis [8,9]. LPS transfers signals via toll-like receptor 4 (TLR4), which initiates systemic inflammation by producing inflammatory mediators such as inflammatory cytokines, adhesion molecules, chemokines, growth factors and cyclooxygenase [10,11].…”

The Innate Immunity in Bovine Mastitis: The Role of Pattern-Recognition Receptors

“…So, LPS upon activation of TLR4 present a central role in the pathogenesis of clinical mastitis caused by this pathogen (Gonen et al, 2007) in a dose-dependent manner (Baumert et al, 2009). The inflammation caused by LPS also leads to alteration in milk parameters, as lactose and chloride levels, in dose dependent manners which are likely caused by greater tight junction damage by higher LPS doses (Werner-Misof et al, 2007). These parameters are also used to evaluated the indicators of inflammation in bovine mastitis and consequently in their diagnosis (Pyorala et al, 2003).…”