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Effects of vitamin E on urokinase-plasminogen activator receptor expression by bovine neutrophils

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  • 1 Department of Animal Production, Agricultural University of Athens, 75 Iera Odos, Athens, Greece 11855.
  • | 2 Nutrition Research Division, 22 Ross Ave, Health Canada, Ottawa, ON, Canada KIA OL2.
  • | 3 Department of Veterinary Science and Technology for Food Safety, University of Milan, 10 Via Celoria, Milan, Italy 20133.
  • | 4 Department of Veterinary Science and Technology for Food Safety, University of Milan, 10 Via Celoria, Milan, Italy 20133.

Abstract

Objective—To determine the effect of vitamin E supplementation on urokinase-plasminogen activator (u-PA) receptor (u-PAR) expression by neutrophils of dairy cows.

Animals—16 healthy Holstein dairy cows.

Procedure—16 cows were assigned to 1 of 2 experimental groups: control (no vitamin E supplementation) and vitamin E supplementation. Supplementation of vitamin E started 4 weeks prior to and continued up to 4 weeks after parturition and included oral administration of vitamin E at 3,000 U/cow per day; these cows also received 1 injection of vitamin E (5,000 units), 1 week prior to the expected date of parturition. Blood samples were collected, and neutrophils were isolated weekly throughout the experimental period. The following variables were measured: u-PA (mRNA), total cell-associated u-PA activity, membrane-bound u-PA activity, and free unoccupied u-PA binding sites on the cell membrane of neutrophils.

Results—Stimulated neutrophils isolated from cows that received vitamin E supplementation had significantly higher u-PA mRNA and total cell-associated and membrane-bound u-PA activity at postpartum week 1, compared with those of stimulated neutrophils isolated from control cows. There were no differences between groups throughout the whole experimental period in u-PA binding sites of neutrophils.

Conclusions and Clinical Relevance—The increased total cell-associated and membrane-bound u-PA activity in neutrophils isolated from cows that received vitamin E may facilitate the ability of neutrophils to extravasate and reach the mammary gland at postpartum week 1. Rapid recruitment of neutrophils is critical for proper defense of the gland.(Am J Vet Res 2001;62:1934–1938)

Abstract

Objective—To determine the effect of vitamin E supplementation on urokinase-plasminogen activator (u-PA) receptor (u-PAR) expression by neutrophils of dairy cows.

Animals—16 healthy Holstein dairy cows.

Procedure—16 cows were assigned to 1 of 2 experimental groups: control (no vitamin E supplementation) and vitamin E supplementation. Supplementation of vitamin E started 4 weeks prior to and continued up to 4 weeks after parturition and included oral administration of vitamin E at 3,000 U/cow per day; these cows also received 1 injection of vitamin E (5,000 units), 1 week prior to the expected date of parturition. Blood samples were collected, and neutrophils were isolated weekly throughout the experimental period. The following variables were measured: u-PA (mRNA), total cell-associated u-PA activity, membrane-bound u-PA activity, and free unoccupied u-PA binding sites on the cell membrane of neutrophils.

Results—Stimulated neutrophils isolated from cows that received vitamin E supplementation had significantly higher u-PA mRNA and total cell-associated and membrane-bound u-PA activity at postpartum week 1, compared with those of stimulated neutrophils isolated from control cows. There were no differences between groups throughout the whole experimental period in u-PA binding sites of neutrophils.

Conclusions and Clinical Relevance—The increased total cell-associated and membrane-bound u-PA activity in neutrophils isolated from cows that received vitamin E may facilitate the ability of neutrophils to extravasate and reach the mammary gland at postpartum week 1. Rapid recruitment of neutrophils is critical for proper defense of the gland.(Am J Vet Res 2001;62:1934–1938)