Quantification of kidney fibrosis was carried out by measurement of renal hydroxyproline concentration by a calorimetric selleck chemical method. In brief, at least 50 mg of frozen kidney tissue was homogenized in 6 N of HCl and hydrolyzed overnight at 110°C. After 16 hours, hydrolysates were filtered, neutralized with NaOH, and oxidized with chloramine-T. This was followed by a reaction with perchloric acid and p-dimethylaminobenzaldehyde, resulting in the formation of a chromophore
quantified photometrically at 565-nm wavelengths. Protein was isolated by sonication of kidney tissue in a homogenization buffer (0.25 mol/L of sucrose, 10 mmol/L of HEPES [pH 7.5], and 1 mmol/L of EDTA [pH 8.0], containing the protease inhibitors, phenylmethylsulfonyl fluoride, aprotinin, leupeptin, and pepstatin). Protein (30 µg) was run on a 10% sodium dodecyl sulphate/polyacrylamide gel, transferred to nitrocellulose, and blotted with respective Abs (mouse VCAM-1/CD106 Ab; catalog no.: AF643; dilution, 1:1,500; R&D Systems, Minneapolis, MN; monoclonal anti-β-actin Ab; catalog no.: A5441; dilution, selleckchem 1:5,000; Sigma-Aldrich).
Binding was detected by using peroxidase-conjugated respective immunoglobulins (Dako), and peroxidase activity was visualized by using the enhanced chemiluminescence method western blotting detection system.[23, 24] RNA was extracted and reverse transcribed into complementary DNA (cDNA). Polymerase chain reaction reaction (20 μL) contained 12.5 learn more ng of cDNA, 330 nM of each primer, and 10.5 μL of SYBR Green Master mix (Applied Biosystems, Foster City, CA). Expression
levels of all transcripts were normalized to the housekeeping gene, 36b4. Primers used are summarized in Supporting Table 1. Data are reported as arithmetic means ± standard deviation (SD) of 5-10 animals in each group. Statistical analysis included the Student t test, when appropriate, Mann-Whitney’s nonparametric U test, or analysis of variance with Bonferroni’s post-testing when three or more groups were compared, using SPSS statistics (SSPS, Inc., Chicago, IL) with the generous help of Prof. Dr. Andrea Berghold (Institute for Medical Informatics, Statistics and Documentation; Medical University Graz, Graz, Austria). A P value <0.05 was considered significant. To mimic chronic cholestasis, CBDL was performed for a duration of up to 8 weeks, leading to significantly elevated serum parameters for liver injury (ALT) and cholestasis (ALP and BA; Supporting Table 2), together with histological evidence for biliary fibrosis demonstrating chronic cholestatic liver injury (not shown). At the time of harvesting, 8-week CBDL mice frequently showed an impressively dilated common bile duct and obvious loss of abdominal and, especially, epididymal fat, but no signs of bile leakage or peritonitis (Fig. 1A).