Figure 4.

XBP1S stimulates chondrocyte hypertrophy, mineralization and endochondral bone growth. (A and B) Safranin O/Fast Green staining of metatarsal bones. Metatarsals from 15-day-old mouse embryos were cultured in the absence of (CTR) or presence of Ad-XBP1S (MOI 20) for 5 days and stained with Safranin O/Fast Green, shown in low-power (A) and high-power (B) microphotographs. (C) Alizarin red/Alcian blue staining of metatarsals. Explants were fixed and processed for staining. A representative photograph of an explanted metatarsal is presented. (D) Percentage changes in total (T) and mineralization (M) length of metatarsal bones. Percentage changes in bone length were calculated as (length at d5 − length at d0)/length at d0. *P < 0.05 versus control; scale bar = 100 μm.