Previous work by others has shown that culture activation of HSCs into myofibroblasts only partially reproduced the gene expression changes observed during BDL- and CCl4-induced activation [44]. Conclusion Although 4A3COOHmethyl AZD8931 molecular weight potently inhibited HSC trans-differentiation to pro-fibrogenic myofibroblasts in vitro without activating the PXR, it failed to inhibit liver fibrosis in an in vivo rat model. The cause of the disparity between in vitro and in vivo responses to 4A3COOHmethyl was most likely associated with a lack of expression

of the PGRMC1 target in liver myofibroblasts in vivo in contrast to in vitro activated myofibroblasts. This underscores the importance of animal models for testing potential anti-fibrogenics and suggests that confirming the presence of drug targets in vivo (including human diseased liver tissue) may assist in the development of effective anti-fibrotic drugs for clinical use. These data also demonstrate that the anti-fibrogenic effects of PCN in vivo are likely mediated entirely via the PXR. Methods Reagents All compounds in Additional files 1 and 2 were

purchased from Steraloids (Rhode Island, USA) except dexamethasone, betamethasone, progesterone, androstenedione and testosterone which were purchased from the Sigma Chemical Company (Poole, UK). All other reagents were from local commercial sources and were of the highest purity available. Isolation and culture of GW3965 HSCs HSCs were isolated from rats (250–300 g body weight, Harlan, UK) by sequential pronase/collagenase perfusion of the liver followed by density gradient centrifugation and elutriation as previously outlined [45]. Human HSCs were isolated by an essentially similar procedure [46] using discarded tissue from patients undergoing a hepatectomy with patient consent and ethical approval by the Grampian Regional Ethical Committee. HSCs were seeded onto plastic culture dishes and cultured in Dulbecco’s modified Eagle Medium (DMEM) containing 4.5 g/l of glucose mafosfamide and supplemented with 5% or 16% (v/v) fetal calf serum (for rat or human respectively), 80

μ/ml penicillin, 80 μg/ml streptomycin and 32 μg/ml gentamycin. Additional treatments were made by addition of compounds in an ethanol vehicle (stock solutions at 1000× final concentration). Ethanol at 0.1% (v/v) acted as control. Frequency of treatment (3 treatments per week/2 medium changes per week), as previously Ro 61-8048 described [8]. Isolation and culture of hepatocytes Rat hepatocytes were prepared by collagenase perfusion, essentially as previously described [46, 47], and cultured in William’s Medium E supplemented with 1 μg/ml bovine insulin, 10% foetal calf serum (FCS), 80 μ/ml penicillin and 80 μg/ml streptomycin on collagen type-I coated 6 well plates (BD Biosciences). After 2 hours, the medium was renewed without FCS and insulin supplementation and thereafter changed daily with renewed media additions where indicated.