Milk Thistle Extract and Silymarin Inhibit Lipopolysaccharide Induced Lamellar Separation of Hoof Explants in Vitro

Abstract

The pathogenesis of laminitis is not completely identified and the role of endotoxins (lipopolysaccharides, LPS) in this process remains unclear. Phytogenic substances, like milk thistle (MT) and silymarin, are known for their anti-inflammatory and antioxidant properties and might therefore have the potential to counteract endotoxin induced effects on the hoof lamellar tissue. The aim of our study was to investigate the influence of endotoxins on lamellar tissue integrity and to test if MT and silymarin are capable of inhibiting LPS-induced effects in an in vitro/ex vivo model. In preliminary tests, LPS neutralization efficiency of these phytogenics was determined in an in vitro neutralization assay. Furthermore, tissue explants gained from hooves of slaughter horses were tested for lamellar separation after incubation with different concentrations of LPS. By combined incubation of explants with LPS and either Polymyxin B (PMB; positive control), MT or silymarin, the influence of these substances on LPS-induced effects was assessed. In the in vitro neutralization assay, MT and silymarin reduced LPS concentrations by 64% and 75%, respectively, in comparison PMB reduced 98% of the LPS concentration. In hoof explants, LPS led to a concentration dependent separation. Accordantly, separation force was significantly decreased by 10 µg/mL LPS. PMB, MT and silymarin could significantly improve tissue integrity of explants incubated with 10 µg/mL LPS. This study showed that LPS had a negative influence on the structure of hoof explants in vitro. MT and silymarin reduced endotoxin activity and inhibited LPS-induced effects on the lamellar tissue. Hence, MT and silymarin might be used to support the prevention of laminitis and should be further evaluated for this application.

Polyphenols from Silybum marianum inhibit in vitro the oxidant response of equine neutrophils and myeloperoxidase activity

“…A recent study showed that silymarin might be used to support the prevention of laminitis through neutralization of endotoxins and inhibition of LPS induced effects on the lamellar tissue (Reisinger et al ., ). De la Rebière de Pouyade et al .…”

“…In accordance with Reisinger et al . () the multipronged anti‐inflammatory activity of silymarin, together with its relatively low cost and low toxicity would make it an attractive solution for the management of complex inflammatory conditions such as laminitis, provided sufficiently high tissue concentrations can be reached. A bioavailability study of oral silybin–phosphatidylcholine in horse has shown that plasma concentrations in the order of 1 μ m can be reached with a 26 mg/kg dose (Hackett, ; Hackett et al ., ), although the authors also noted a nonlinear relationship between plasma‐silybin concentration and dose.…”

“…Our group has shown that neutrophils and some of their degranulation products such as elastase and MPO infiltrate the tissue in experimental models of the disease (Riggs et al, 2007;De la Rebi ere de Pouyade et al, 2010). In relation to this, a recent study showed that silymarin, a standardized extract of Silybum marianum, might be used as a dietary supplement to support the prevention of laminitis in horse (Reisinger et al, 2014).…”

Silymarin attenuates paraquat‐induced lung injury via Nrf2‐mediated pathway in vivo and in vitro

“…10,11 Silymarin, an active component extracted from the seeds of the plant Silybum marianum (which is also known as milk thistle), 12 possesses anti-inflammatory, antioxidant, immunomodulatory, antifibrotic, antiproliferative and antiviral properties. 13,14 A previous study has found that silymarin has a marked therapeutic effect on Parkinsonism due to maneb or PQ. 15 This effect may be through elevating the dopamine content, increasing tyrosine hydroxylase-positive neuron number and regulating oxidative stress and the anti-apoptotic pathway.…”

“…Silymarin, an active component extracted from the seeds of the plant Silybum marianum (which is also known as milk thistle), possesses anti‐inflammatory, antioxidant, immunomodulatory, antifibrotic, antiproliferative and antiviral properties . A previous study has found that silymarin has a marked therapeutic effect on Parkinsonism due to maneb or PQ .…”