For quantification of staining, 800 μL of 10% acetic acid (Merck, Darmstadt, Germany) was added to each well, and the plate was incubated at room temperature for 30 min with shaking. The monolayer, now loosely attached to the plate, was then scraped from the plate with a cell scraper (Corning Incorporated, NY, USA) and transferred to a 1.5 mL microcentrifuge tube with a wide-mouth pipette. After vortexing

for 30 s, the slurry was overlaid with 500 μL of mineral oil (Sigma–Aldrich, St. Louis, MO, USA), heated to exactly 85 °C Bleomycin for 10 min, and transferred to ice for 5 min. The slurry was then centrifuged at 20,000 × g for 15 min and 500 μL of the supernatant was removed to a new 1.5 mL

microcentrifuge tube. Then 200 μL of 10% ammonium hydroxide (Sigma–Aldrich, St. Louis, MO, USA) was added to neutralize the acid. Aliquots (150 μL) of the supernatant were read in duplicate in 96-wells format at 405 nm by software VersaMax in an ELISA reader. Cells cultured without OSI-906 purchase osteogenic medium were used as staining negative control. Reverse transcription followed by qPR was utilized in order to evaluate the effect of PTH administration on the expression of ALP, COL1, MMP-2, BGN and DSPP genes in MDPC-23 cells. The total RNA was harvested from cells in 6-well plates (n = 3) and extracted using the TRIzol® reagent (Invitrogen, Carlsbad, CA, USA), following the manufacturer’s recommendation. The RNA quantification and purity were measured by photometric measurement using a Nanodrop 2000 Spectrophotometer

(Thermo Fisher Scientific, Wilmington, DE, USA), and the RNA quality was assessed by electrophoresis on a denaturing 2% agarosis gel. One microgram of total highly purified RNA was treated with DNase (Invitrogen, Carlsbad, CA, USA) and 500 ng was used for cDNA synthesis. The reaction was carried out using the SuperScript III First-strand Synthesis of the Oligo (dT) primer (Invitrogen, Carlsbad, CA, DNA ligase USA), following the manufacturer’s recommendations. Real-time PCR was conducted in the LightCycler® 480 II (Roche Diagnostics GmbH, Indianapolis, IN, USA) using the Jump Start SYBR Green Taq Ready Mix™ (Sigma–Aldrich, St. Louis, MO, USA). In the amplification it was used the TaqMan® Hydrolysis Probe (Applied Biosystems, Life Technologies, Carlsbad, CA, USA) for ALP (Assay ID: Mm00475834_m1) and DSPP (Assay ID: Mm00515666_m1) and primers sequences (IDT®, Integrated DNA Technologies, Coralville, IA, USA) for COL1, MMP-2 and BGN, designed with Primer3 software (http://biotools.umassmed.edu/bioapps/primer3_www.cgi). The sequences of the primers used were: COL1 (Col1a1, Gene ID: 12842) (forward 5′-GTCAGCAGATTGAGAACATCC-3′; reverse 5′-TGAGTAGGGAACACACAGGTC-3′, amplicon: 196 pb, GenBank NM_007742.