Treatment with milk thistle extract (Silybum marianum), ursodeoxycholic acid, or their combination attenuates cholestatic liver injury in rats: Role of the hepatic stem cells.

BACKGROUND/AIMS: Cholestasis, which results in hepatic cell death, fibrosis, cirrhosis, and eventually liver failure, is associated with oxidative stress. The aim of this study was to evaluate the effects of milk thistle (MT, Silybum marianum) and ursodeoxycholic acid (UDCA) or their combination on the activation of hepatic stem cells and on the severity of cholestasis liver injury in rats. MATERIALS AND METHODS: Under anesthesia, bile ducts of female Sprague Dawley rats were ligated (BDL) or had sham operation. BDL rats were administered saline, UDCA (15 mg/kg/d), MT (600 mg/kg/d), or UDCA+MT by gavage for 10 days. On the 11th day, rats were sacrificed and blood and liver samples were obtained. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatic malondialdehyde (MDA) levels, and myeloperoxidase (MPO) activity were measured. Hepatic injury, a-smooth muscle actin expression, and stem cell markers c-kit, c-Myc, Oct3/4, and SSEA-1 were histologically determined. RESULTS: Histological scores, serum ALT, and hepatic MDA levels were higher in BDL group than in the sham rats, while all treatments significantly reduced these levels. The reduction in ALT was significantly greater in UCDA+MT-treated group than in other treatment groups. c-Kit, c-Myc, Oct3/4, and SSEA-1 were increased in saline-treated BDL group with respect to sham-operated control group, and these markers were significantly reduced in all treatment groups. CONCLUSION: In addition to a modulatory effect on the stem cell-induced regenerative response of the liver, UDCA, MT, and their combination demonstrated similar anti-inflammatory and antiproliferative effects on cholestasis-induced hepatic injury.

Stem cell and extracellular matrix-related molecules increase following melatonin treatment in the skin of postmenopausal rats.

The menopause has a negative effect in the skin. Melatonin affects skin functions and structures through actions mediated by cell-surface and putative-nuclear receptors expressed in skin cell. We have therefore determined the effects of melatonin treatment on stem cell in the epidermis and extracellular matrix related molecules in the dermis the skin of postmenopausal rats. A total of 45 female rats were divided into 5 groups: control group, group A [ovariectomy (OVX)], group B (OVX +10 mg/kg/day melatonin), group C (OVX +30 mg/kg/day melatonin), group S (sham operated + 10 mg/kg/day melatonin). Ventral skin samples were excised at 12th week after ovariectomy. Hematoxylin-eosin, periodic acid- methylamine silver, elastic van Gieson staining techniques were used to measure histomorphometrically the thickness of elastic fibers and basement membrane, depths of the epidermis, dermis, and subcutaneous fat layer. Immunohistochemical staining methods were used for fibroblast growth factor ß (FGF ß), collagen type I, fibronectin, ß-catenin, c-kit, c-Myc evaluation. Epidermal thickness, subcutaneous fat layer, and elastic fibers were significantly decreased in group C, and there was a significant increase after melatonin treatment. Although there was no difference in dermal thickness of group C, melatonin also significantly increased the dermal thickness. High FGF ß, type I collagen, fibronectin, ß-catenin, c-Myc immunoreactivity developed following melatonin in all groups. Thus melatonin treatment of postmenopausal rats was mostly due to the decrease of stem cell and extracellular matrix-related molecules in the skin.

Enteral resveratrol supplementation attenuates intestinal epithelial inducible nitric oxide synthase activity and mucosal damage in experimental necrotizing enterocolitis.

BACKGROUND/PURPOSE: The release of various enzymes including inducible nitric oxide synthase (iNOS) leads to enterocyte apoptosis through free nitrogen radicals, which in turn leads to impaired mucosal barrier and bacterial translocation with resultant sepsis in necrotizing enterocolitis (NEC). Resveratrol, a polyphenol compound from phytoalexins with antioxidant and scavenger properties, also play a critical role in modulating key enzymes in cell cycle including iNOS. We therefore hypothesized that resveratrol would prevent mucosal damage in experimental NEC in rats. METHODS: Newborn rats were randomized into 3 groups: group 1 was left to breast-feed (BF), whereas group 2 (NEC) was induced by enteral formula feedings twice daily and by being subjected to hypoxia thrice. The third group (R) received the same treatment as the NEC group but the enteral feeds were supplemented with resveratrol. Rats were killed on day 4, and their terminal ileal samples were harvested for histopathologic analysis. Expression of iNOS was assessed by sodium dodecyl sulfate polyacrylamide-gel electrophoresis analysis and immunohistochemistry. Band densities were quantified by using the software NIH image. RESULTS: The epithelial structure in group BF was normal. In the NEC group, there were marked loss of the brush border, vacuolization, and necrosis. The epithelial structure was found to be preserved in group R. Western blot analysis revealed marked elevation in the expression of iNOS protein at 130 kD molecular weight (band densities in groups BF, NEC, and R were 0.3 +/- 3.5, 3.7 +/- 2.9, and 0.6 +/- 5.1, respectively; P < .01). Immunohistochemical analysis revealed that iNOS staining was significantly increased in the NEC group, whereas it remained minimal for the BF and R groups. Ileal tissue nitrate/nitrite levels for groups BF, NEC, and R were 178.3 +/- 7, 191.4 +/- 4.1, and 181 +/- 3.6 micromol/(L x g), respectively (P < .01). CONCLUSIONS: These findings may provide insights for the beneficial effect of enteral resveratrol supplementation on inflammatory conditions of the bowel including NEC through attenuating the release of iNOS and preservation of mucosal integrity.