Inhibiting prolactin by cabergoline accelerates mammary gland remodeling during the early dry period in dairy cows

Abstract

The inhibition of prolactin release using cabergoline, a dopamine agonist, is an effective strategy to accelerate the changes in mammary secretion composition after drying-off. The objective of this study was to determine how cabergoline may affect mammary tissue remodeling during early involution. Holstein dairy cows were treated with either a single i.m. administration of 5.6 mg of cabergoline (Velactis, Ceva Santé Animale, Libourne, France, n = 7) or placebo (n = 7) at the time of drying-off. Mammary biopsy samples were collected 1 wk before drying-off (d −6), after 30 h of milk accumulation (d 1), and again 8 d following drying-off (d 8) to determine changes in gene expression, lactoferrin content, and cell turnover. Blood and mammary secretion samples were collected at d −6 and again at d 1, 2, 3, 4, 8, and 14 following the abrupt cessation of lactation to evaluate indicators of blood-milk barrier integrity and other markers of mammary tissue remodeling. Cabergoline induced less SLC2A1, BAX, CAPN2, and IGFBP5 mRNA expression. In contrast, cabergoline did not modify changes in cell proliferation and apoptosis. Following the cessation of lactation, changes in mammary secretion composition (Na + and K + ) and blood lactose concentrations were indicative of a loss in the blood-milk barrier function in both treatment groups. Cabergoline treatment affected only Na + and K + concentrations at d 1, suggesting a moderate increase in tight junction permeability. The increase in the activity of MMP9 and in mammary epithelial cell concentration in mammary secretions was greater in cabergoline-treated cows than in control cows, suggesting more mammary tissue remodeling. The increase in lactoferrin immunostaining in the mammary tissue occurred earlier for cabergoline-treated cows than for control cows, and was essentially localized in the stroma. Changes in some key markers of mammary involution suggest that cabergoline accelerates mammary gland remodeling. Thus, a single injection of cabergoline after the last milking would facilitate drying-off by enhancing mammary gland involution.

In vivo inhibition followed by exogenous supplementation demonstrates galactopoietic effects of prolactin on mammary tissue and milk production in dairy cows

“…Interestingly, QN increased the number of living and dead MEC exfoliated into the milk, whereas PRL reduced the number of dead MEC exfoliated into milk. A similar effect was observed during mammary gland involution, where an injection of cabergoline, another dopamine agonist, in dairy cows induced an increase in the MEC concentration in mammary secretions and a reduction in their viability (Boutinaud et al, 2013). In another recent experiment, more MEC were exfoliated into milk when the PRL concentration was reduced by a short-day photoperiod (Boutinaud et al, 2014).…”

Sütçü İneklerde Mastitis Yönünden Kuru ve Geçiş Dönemlerinin Önemi

“…Laktasyon sonu süt üretimi fazla (25-30 kg/gün) olan ineklerde aniden sütten kesme ile kuruya alındığında, memeden süt sızıntısı artarak keratin plak oluşumunun geciktiği (25), patojen girişinin kolaylaştığı ve meme içi lökositlerinin fonksiyonunun azalttığı tespit edilmiştir (26). Bununla birlikte KD'ye girişte 12.5 kg'dan fazla süt üretiminde, her 5 kg süt için doğumda yeni meme içi enfeksiyon insidansının %77'ye kadar arttığı tespit edilmiştir (19).…”

Involução da glândula mamária durante o final da lactação e período seco de cabras Saanen: respostas de sobrevivência celular ao estresse agudo e relações com a temperatura por infravermelho

“…A diminuição na expressão das integrinas correlaciona-se com a distensão dos alvéolos mamários . Contudo, no plasma sanguíneo há um aumento da concentração de lactose BOUTINAUD et al, 2017). Outra característica de regressão do tecido mamário é o aumento da concentração de Na² + e declínio de K + no leite, os quais são importantes marcadores da ruptura das junções tight e das células epiteliais mamárias (BOUTINAUD et al, 2017).…”

“…Contudo, no plasma sanguíneo há um aumento da concentração de lactose BOUTINAUD et al, 2017). Outra característica de regressão do tecido mamário é o aumento da concentração de Na² + e declínio de K + no leite, os quais são importantes marcadores da ruptura das junções tight e das células epiteliais mamárias (BOUTINAUD et al, 2017). Essa diferença de concentração correlaciona-se concomitante com o aumento da lactose no plasma sanguíneo (STELWAGEN et al, 1997;BEM CHEDLY et al, 2009;BOUTINAUD et al, 2017).…”

“…Além disso, observa-se uma migração de células imunes no tecido mamário (SINH et al, 2005;, a qual é caracterizada pelo aumento na contagem de células somáticas nas secreções mamárias . BOUTINAUD et al, 2017). Enquanto que os níveis de Bcl-2 parecem não ser alterados até 36 horas .…”