Enzymatic Activities of Bovine Peripheral Blood Leukocytes and Milk Polymorphonuclear Neutrophils during Intramammary Inflammation Caused by Lipopolysaccharide (original) (raw)
Related papers
Veterinary Research, 2001
The local and systemic effects of intramammary lipopolysaccharide (LPS) injection on the chemiluminescence (CL) of milk and blood polymorphonuclear leukocytes (PMN) were investigated in six healthy early lactation cows. Clinical signs of acute mastitis such as fever, increased heart rate and a decreased milk production were observed in all cows. Before LPS challenge, the CL activity of milk PMN was significantly lower than that of blood PMN (P < 0.01). A significant negative correlation was found between pre-challenge milk and blood PMN CL and, the decreased milk production in unchallenged quarters. The CL activity of milk PMN from LPS-injected quarters increased following LPS challenge, whereas it remained unchanged in control quarters. The CL activity of blood PMN showed a biphasic increase, with two peaks and a valley below pre-challenge CL activity (P < 0.01). At post-challenge hours (PCH) 6 and 12, the CL activity of milk PMN from LPS-injected quarters exceeded that of blood PMN (P < 0.05 and P < 0.001, respectively). The decreased CL activity of blood PMN and the enhanced CL activity of milk PMN during endotoxin-induced mastitis was reflected by changes in the shape of the CL curve. In blood PMN, a decrease of the second peak of the CL curve suggests that the myeloperoxidase (MPO)-H 2 O 2 system is impaired during endotoxin-induced mastitis. In contrast, the MPO-H 2 O 2 system was enhanced in milk PMN from challenged quarters. The highest duration and intensity of reactive oxygen intermediate (ROI) production was observed in milk PMN from LPS-injected quarters at PCH 12. The increased viability of PMN in LPS-injected quarters and to a lesser extent in control quarters suggests possible effects of both facilitated diapedesis and inflammatory mediators on milk PMN survival. In conclusion, our results suggest that a combination of local and systemic action of E. coli endotoxin is involved in the priming of milk PMN during mastitis.
Proteases involved in mammary tissue damage during endotoxin-induced mastitis in dairy cows
Journal of dairy science, 2005
During and after diapedesis, milk polymorphonu-clear neutrophils (PMN) release many proteases that have the potential of degrading extracellular matrix proteins and milk proteins. However, the kinetics of milk proteolysis during inflammation and the underlying mechanisms are poorly defined. The enzymes involved in bovine mammary tissue destruction were investigated in this study using an endotoxin-induced mastitis model. Using zymography techniques, the proteolytic activity of milk and mammary tissue during mastitis was examined. Mastitic milk produced 6 caseolysis bands, 4 of which differed from the ones produced by plasmin. Peak proteolytic activity, bovine serum albumin contents, and mammary tissue damage occurred between 6 and 12 h postchallenge. Mastitic milk proteases hydrolyzed casein, gelatin, collagen, hemoglobin, mammary gland membrane proteins, and lactoferrin. These results confirm that mastitic milk proteases have a broad spectrum of activity. The hydrolytic activity of...
Mobilization of neutrophils and defense of the bovine mammary gland
Reproduction Nutrition Development, 2003
The leucocytes present in normal milk are not very efficient in preventing infection, because very small numbers of bacteria are able to induce infection experimentally. The mobilization of phagocytes from the blood to milk appears crucial in coping with the expansion of the bacterial population in the mammary gland. Important parameters for the outcome of mammary infections are the bactericidal efficiency of neutrophils and the antiphagocytic and cytotoxic properties of the invading bacteria, but several studies have shown that the promptness and the magnitude of the initial recruitment of neutrophils by the infected mammary gland have a profound influence on the severity and the outcome of mastitis. This is an incentive for studying the mechanisms behind the mobilization of neutrophils to the mammary gland. Although milk macrophages may play a role in the triggering of the inflammatory response, studies on several responses to infections at various epithelium sites strongly suggest that epithelial cells are capable of responding to bacterial intrusion and play a major part in the initiation of inflammation. A better knowledge of the effector cells and of the mediators involved in the mobilization of neutrophils could help in devising strategies to modulate this important determinant of milk quality and udder defense.
Frontiers in Veterinary Science, 2021
Milk somatic cell counts (SCCs) have been used as a gold standard to monitor mammary health as well as an indicator of raw milk quality. The present work was undertaken to compare the changes in the milk SCC, milk differential leukocyte counts (DLCs), phagocytic activity (PA) of milk neutrophils and macrophages (by nitroblue tetrazolium assay), extracellular trap formation (PicoGreen assay) and mRNA expression of various genes in milk neutrophils and macrophages (reverse transcription-polymerase chain reaction), and milk plasma cortisol concentration (enzyme-linked immunosorbent assay) in healthy, subclinical mastitis (SCM), and clinical mastitis (CM) cows. Milk was collected from healthy, SCM, and CM cows grouped based on their SCCs and California mastitis test with eight cows in each group. Milk SCC was estimated by SCC counter, and DLC was done after staining the milk slide under a microscope at 100×. Total SCCs in healthy, SCM, and CM cows were on an average of 128.30, 300.3, and 694.40 × 10 3 cells/mL, respectively. Milk DLCs indicated a lower percentage of macrophage and lymphocytes and a higher (p < 0.05) percentage of neutrophils in SCM and CM compared to healthy milk. The percentage of mature segmented neutrophils was lower, whereas immature band neutrophils were higher (p < 0.05) in the SCM and CM groups as compared to healthy cows. The viability, in vitro PA, and extracellular trap formation of neutrophils were lower (p < 0.05) in SCM and CM milk samples as compared to healthy samples. However, the PA of macrophage remained unchanged in all the studied groups. The relative mRNA expression of Toll-like receptors (TLR2, TLR4), myeloperoxidase, and interleukin 2α (IL-2α) receptor (CD25) were minimum in healthy samples and increased (p < 0.05) with the progress of mammary inflammation. However, CD44 decreased (p < 0.05), and CD62L remained unchanged in mastitis as compared to healthy cows. Plasma cortisol concentrations were higher (p < 0.05) in mastitis as compared to healthy cows and were negatively correlated with the number of milk macrophages and the functions of milk phagocytes. Estimation of total SCC, milk DLC, and activity of milk phagocytes is essential for effective control and prevention of incidence of mastitis in dairy cows.
International Dairy Journal, 2006
An Escherichia coli mastitis model was used to characterize enzymes involved in bovine mammary tissue damage and proteolysis in milk. One-quarter each of four cows were inoculated with a suspension (10 4 cfu mL À1) of E. coli P4:O32. Blood and milk were collected before inoculation and for 216 h afterwards. Intracellular elastase, collagenase and cathepsin activities were measured by flow cytometry of peripheral blood leukocytes and milk polymorphonuclear neutrophils (PMNs). Leukopenia occurred in peripheral blood 9 h after infection, concomitant with an increase in somatic cell count in milk. Milk PMNs had lower activity of cathepsins and collagenase than peripheral blood PMNs. In parallel, milk samples were studied by zymography, and several proteases were detected in mastitic milk. These activities increased after infection, to reach a peak in 6 h. However, total protease profiles and plasmin activities differed. It was concluded that proteases released by PMNs and E. coli contribute to proteolysis of casein during mastitis, as well as plasmin.
Leukocytes--second line of defense against invading mastitis pathogens
Journal of dairy science, 1979
In mammals, neutrophile polymorphonuclear leukocytes constitute one of the essential body defenses against disease. In a large mammal, such as the dairy cow, billions of neutrophils are mobilized to fight infection. For example, over 50 million neutrophils per milliliter milk are commonly in a mammary quarter inflicted with clinical mastitis. However, in spite of these numerous leukocytes, pathogenic organisms remain viable. Recent evidence indicates that bacteria are not eliminated from a diseased quarter because the phagocytic capacity of the neutrophils is reduced in the mammary gland. The morphology and physiology of the leukocyte is examined in this review in an attempt to explain why the phagocytic capacity of the neutrophil is reduced in the mammary gland of the bovine.
Journal of King Saud University - Science, 2020
Mastitis an inflammation of mammary gland in dairy herds is a key concern of economic losses worldwide caused by bacteria and its toxins. In this study, we investigated pro-inflammatory and anti-inflammatory cytokines (IL-2, IL-1b, IL-6, TGF-b, IL-10, TNF-a), lactoferrin and albumin, and milk composition in normal dairy cows and lactating cows with symptoms of sub-clinical and clinical mastitis. Lactating cows with clinical mastitis showed marked increase in IL-2, IL-6, IL-1b, TNF-a and a decrease in anti-inflammatory levels of TGF-b, IL-10, milk parameters fat, protein, SNF, lactose and increase in pH compared to normal lactating cows. Subclinical lactating cows showed significant alteration in TNF-a, IL-1b when compared to normal lactating cows. There was no significant difference between IL and 2 and IL-6 in normal and subclinical lactating cows. The subclinical cows also did not exhibit significant difference in TGF-b, albumin, milk fat, protein and pH when compared with normal lactating cows. Findings in the present study indicate that cytokines together with proteins lactoferrin and albumin can be considered as prospective markers in early detection of subclinical and clinical mastitis.
Research in veterinary science
The accumulation of leucocytes in milk and in teat cistern tissues, and the presence of the cytokines interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma) in milk was studied during inflammation in the lactating ovine udder induced by Staphylococcus aureus and Escherichia coli. Milk and/or teat tissue samples were taken before and four, eight and 24 hours after inoculation. Both S aureus and E coli induced a significant accumulation of leucocytes in milk, S aureus from eight hours with a peak after 24 hours, and E coli from four hours, with a peak after eight hours. After the inoculation of S aureus the numbers of subepithelial neutrophils in the teat cistern tissues were increased after four hours and had increased further by eight hours. After the inoculation of E coli, tissue neutrophil numbers peaked at four hours and were still high at eight hour...
Defense of the bovine mammary gland by polymorphonuclear neutrophil leukocytes
Journal of mammary gland biology and neoplasia, 2002
The primary phagocytic cells of the bovine mammary gland, polymorphonuclear neutrophil leukocytes (PMN), and macrophages, comprise the first line of defense against invading pathogens. In the normal healthy mammary gland, macrophages predominate and act as sentinels to invading mastitis-causing pathogens. Once invaders are detected, macrophages, and possibly mammary epithelial cells, release chemoattractants that direct migration of PMN into the area. In the mammary gland, protection is only effective if rapid influx of PMN from the circulation and subsequent phagocytosis and killing of bacteria occur. The second line of defense against infection consists of a network of memory cells and immunoglobulins that interact with the first line of defense. To minimize mammary tissue damage caused by bacterial toxins and oxidative products released by PMN, elimination of invading bacteria must proceed quickly. Therefore, the inflammatory response needs to be regulated. Hormones, metabolites,...