Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression

In the present study, we have shown for the first time that a plant steroid, diosgenin, causes an inhibition of the growth of fibroblast-like synoviocytes from human rheumatoid arthritis, with apoptosis induction associated with cyclooxygenase-2 (COX-2) up-regulation. Celecoxib, a selective COX-2 inhibitor, provoked a large decrease in diosgenin-induced apoptosis even in the presence of exogenous prostaglandin E(2), whereas interleukin-1β, a COX-2 inducer, strongly increased diosgenin-induced apoptosis of these synoviocytes. These findings suggest that the proapoptotic effect of diosgenin is associated with overexpression of COX-2 correlated with overproduction of endogenous prostaglandin E(2). We also observed a loss of mitochondrial membrane potential, caspase-3 activation, and DNA fragmentation after diosgenin treatment

Effect of diosgenin on DNA fragmentation after incubation with celecoxib (an inhibitor of cyclooxygenase-2 COX-2) or exogenous prostaglandin E(PGE)

<p><b>Copyright information:</b></p><p>Taken from "Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression"</p><p>Arthritis Research & Therapy 2004;6(4):R373-R383.</p><p>Published online 17 Jun 2004</p><p>PMCID:PMC464911.</p><p>Copyright © 2004 Liagre et al.; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> (a) Human rheumatoid arthritis fibroblast-like synoviocytes (FLS) were preincubated with or without celecoxib (1 μM) for 4 hours and then 40 μM diosgenin was added for 24 or 48 hours. Measurements were made on FLS from four different patients. Data are expressed as mean ± SD of four experiments. *A value of less than 0.05 (Fisher's protected-least-significant-difference test [PLSD]) was considered to indicate significance in comparison with diosgenin alone. (b) Cells were preincubated with or without celecoxib (1 μM) in the absence or presence of PGE(10 nM) for 4 hours, followed by incubation with 40 μM diosgenin for an additional 24 hours. Measurements were made on FLS from four different patients. Data are expressed as mean ± SD of four experiments. *A -value of less than 0.05 (Fisher's PLSD test) was considered to indicate significance in comparison with diosgenin alone. OD, optical density

Effect of diosgenin on DNA fragmentation after stimulation with IL-1β (an inducer of cyclooxygenase-2 COX-2)

<p><b>Copyright information:</b></p><p>Taken from "Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression"</p><p>Arthritis Research & Therapy 2004;6(4):R373-R383.</p><p>Published online 17 Jun 2004</p><p>PMCID:PMC464911.</p><p>Copyright © 2004 Liagre et al.; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> Human rheumatoid arthritis fibroblast-like synoviocytes (FLS) were preincubated with or without IL-1β (1 ng/ml) for 4 hours and then 40 μM diosgenin was added for 24 or 48 hours. Measurements were made on FLS from four different patients. Data are expressed as mean ± SD of four experiments. *A value of less than 0.05 (Fisher's protected-least-significant-difference test) was considered to indicate significance in comparison with diosgenin alone. OD, optical density

Analysis of mitochondrial membrane potential (Δψm) after diosgenin treatment

<p><b>Copyright information:</b></p><p>Taken from "Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression"</p><p>Arthritis Research & Therapy 2004;6(4):R373-R383.</p><p>Published online 17 Jun 2004</p><p>PMCID:PMC464911.</p><p>Copyright © 2004 Liagre et al.; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> Human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) were cultured in 10% FCS medium for 48 hours and then treated or not with 40 μM diosgenin. Δψm was analyzed in adherent RA FLS after 24 hours of treatment, using the potential-dependent aggregate-forming lipophilic cation JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazole carbocyanide iodide). Red fluorescence (a) represents mitochondria with intact membrane potential whereas green fluorescence (b) represents de-energized mitochondria. Staining with DAPI (4',6-diamidino-2-phenylindole), showed that diosgenin treatment of cells altered the extracellular and nuclear membrane permeability, as is shown by the nuclear localization of the DAPI (b, white arrows) in comparison with untreated cells (a). Pictures were taken with a Nikon microscope ECLIPSE E800 (original magnification ×400). One of three representative experiments from three different patients is shown