Efeito de infusões intravenosas e intramamárias de lipopolissacarídeo (LPS) sobre parâmetros inflamatórios, reprodutivos e metabólicos em novilhas e vacas da raça holandesa

Abstract

The aim of the study was to evaluate the effects of the inflammatory response over endometrial gene expression and energy metabolism in heifers and cows. Initially, a protocol to induce a systemic pro-inflammatory profile was established based on multiple LPS infusions. Subsequently, 22 heifers were synchronized, inseminated (D0) and divided into control group (Saline sol.) and LPS, infusions started on D2. LPS group received intravenous infusions (IV) with saline solution + LPS (0.1; 0.25; 0.5; 0.75; 1.0; 1.25 mg / kg). Were analyzed the rectal temperature, plasma concentrations of TNF-α, haptoglobin (Hp), progesterone, AGNE and BHB, beside leucometrics analysis. On D15, the endometrial biopsies were performed, and subsequent analysis by qRT-PCR of genes related to cell adhesion, immune system and embryonic development. LPS infusions established a pro-inflammatory profile characterized by increase of temperature (P<0.05), TNF-α (P=0.05) and Hp (P<0.01), and effects on the differential leukocyte count. There was no change in metabolic parameters. The LPS group showed lower expression of IDO (P=0.04; fold=0.48) and PTX3 (P=0.01; fold=0.38), and high expression of MX1 (P=0.02; fold=2.85). Was concluded that the induced pro-inflammatory profile showed a strong but limited effect on gene expression related to immune system, suggesting a possible explanation for sub-fertility related pathophysiological changes in dairy cows. In the second study, to evaluate the influence of the inflammatory response on the energy metabolism of dairy cows, 20 cows were divided into control group (10 mL saline sol.) and LPS (25 ug LPS/10ml saline sol.). Was evaluated the somatic cell count, milk production, reticular temperature, as well the serum levels of Hp, TNF-α, AGNE and BHB. In LPS group was observed increased SCC (P<0.0001), decrease of production (P<0.05), and increased reticular temperature (P<0.005), as well an increase of Hp concentration (P<0,0001). Was observed increase on AGNE on day nine and BHB on day nine (P<0.005) and ten (P=0,05). Was concluded that the induced pro-inflammatory profile showed a strong but limited effect on gene expression related to immune system, suggesting a possible explanation for sub-fertility related pathophysiological changes in dairy cows. Aditonally, considering the inflammatory response induced by LPS intramammary infusions, were observed evidences of the relationship of the inflammatory response with the energy metabolism of dairy cows, and reaffirmed the participation of inflammatory mediators in the pathogenesis of metabolic diseases in dairy cows.