Effect of hypoxia on ECM protein synthesis and secretion of PSCs in vitro and quantification of secreted VEGF and endostatin in PCC and PSC SNs by ELISA: Sister clones of PSCs were kept under normoxic (N) and hypoxic (H) conditions for 1 (A) and 3 days (B) in serum-free medium. Matching CLs and SNs (SN) were analyzed by immunoblot analysis to evaluate the synthetic and secretory responses, respectively. All experiments were performed at least three times, and the results of densitometric analyses are presented as percent change (mean ± SEM) compared with the matching normoxic control (100%). Immunoblots were consecutively probed with α-SMA, periostin, type I collagen, fibronectin, and γ-tubulin antibodies. Sister clones of PCCs and PSCs were kept under normoxic and hypoxic conditions for 24 hours in serum-free medium. The amounts of VEGF (C) and endostatin (D) secreted in the SNs were quantified by ELISA. The values are expressed normalized to 100,000 cells. The experiments were performed at least three times using different PSC clones. *P = .037, **P = .0286.