BACKGROUNDPrevention of osteonecrosis (ON) has seldom been addressed. The purpose of this study was to evaluate the effect of resveratrol on preventing steroid-induced ON in rabbits.

METHODSSeventy-two rabbits were divided into four groups: (1) NEC (ON) group: thirty rabbits were treated with lipopolysaccharide (LPS) once, then with methylprednisolone (MPS) daily for 3 days; (2) PRE (prevention) group: thirty rabbits were given one dose of LPS, then MPS daily for 3 days, and resveratrol on day 0 and daily for 2 weeks; (3) RES (resveratrol) group: six rabbits were given resveratrol for 2 weeks but without LPS/MPS; (4) CON (control) group: six rabbits were given alcohol for 2 weeks but without LPS/MPS. Levels of plasma tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), thrombomodulin (TM), vascular endothelial growth factor (VEGF), maximum enhancement (ME) by magnetic resonance imaging, and ON incidence were evaluated.

RESULTSThe PRE group had a lower ON incidence than the NEC group, but with no significant differences at 2 weeks and 12 weeks. The RES and CON groups did not develop ON. TM and VEGF were significantly higher in the NEC group compared with the PRE group at weeks 1, 2, and 4 (TM: 1 week, P = 0.029; 2 weeks, P = 0.005; and 4 weeks, P = 0.047; VEGF: 1 week, P = 0.039; 2 weeks, P = 0.021; 4 weeks, P = 0.014), but the difference disappeared at 12 weeks. The levels of t-PA and PAI-1 were not significantly different between the NEC and PRE groups. The TM, t-PA, PAI-1, and VEGF concentrations in the RES and CON groups did not change over time. Compared to the baseline, ME in the NEC group decreased significantly (P = 0.025) at week 1, increased significantly (P = 0.021) at week 2, and was decreased at week 12. The variance was insignificant in the PRE group.

CONCLUSIONSResveratrol may improve blood supply to bone in a rabbit model of ON of the femoral head via anti-inflammatory effects to protect the vascular endothelium and reduce thrombosis.

Animals ; Disease Models, Animal ; Femur Head Necrosis ; chemically induced ; prevention & control ; Lipopolysaccharides ; toxicity ; Magnetic Resonance Imaging ; Methylprednisolone ; toxicity ; Plasminogen Activator Inhibitor 1 ; blood ; Rabbits ; Stilbenes ; pharmacology ; therapeutic use ; Thrombomodulin ; blood ; Tissue Plasminogen Activator ; blood ; Vascular Endothelial Growth Factor A ; blood

Intravitreal fibrin clots were produced by intravitreal injection of 0.2 ml of autologous plasma in 62 rabbit eyes. The intravitreal injection of 0.25 micrograms or more of tissue plasminogen activator(tPA) resulted in a total clearing of intravitreal fibrin within one day in all treated eyes. This was significantly faster than in the control eyes, in which complete clearing was not seen until 8 days later. This represents the plateau on the dose-response curve in doses ranging from 0.25 to 200 micrograms. With light microscopy and transmission electron microscopy, retinal toxicity was demonstrated in eyes enucleated seven days after injection of 25 micrograms or more of tPA. This study demonstrates that tPA was effective and safe at 12.5 micrograms or less in clearing intravitreal fibrin in an experimental model. These results suggest that low dosages of tPA, probably of 3 micrograms or less, may be useful in the treatment of severe postvitrectomy fibrin formation seen clinically.
Animals ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Fibrinolysis/*drug effects ; Rabbits ; Retina/drug effects/pathology ; Tissue Plasminogen Activator/*toxicity ; *Vitreous Body

PURPOSE: The effects of amiloride on cellular toxicity caused by tissue plasminogen activator (tPA) in mouse primary retinal cells were investigated. METHODS: Primary retinal cell cultures were maintained using glial conditioned medium. Commercial tPA and L-arginine were added, and the level of cyclic guanosine monophosphate (cyclic-GMP) in the culture supernatant was assessed using an ELISA assay. We measured the cell viability of cultured retinal cells pretreated with three different concentrations of amiloride (1, 10, and 100 microm) in addition to commercial tPA or L-arginine treatment. RESULTS: After exposing the cultured mouse retinal cells to tPA plus L-arginine or L-arginine alone, cyclic-GMP concentrations were 61.9 +/- 5.1 pmole/mL and 63.1 +/- 6.1 pmole/mL, respectively. However, the control group had a significantly lower concentration of cyclic-GMP (37.2 +/- 3.4 pmole/mL, p < 0.01). The cyclic GMP-dissolved solution did not cause retinal cell death. In the control group and the group treated with 1 microm amiloride and tPA containing L-arginine, the cell viability was 43.7% and 44.5%, respectively. However, cell viability increased to 70.6% with 10 microm amiloride and 78.4% with 100 microm amiloride (p = 0.015). CONCLUSIONS: L-arginine increases intracellular cyclic-GMP and may give rise to retinal cells through this mechanism. In addition, amiloride in concentrations greater than 10 microm protects against L-arginine-induced retinal cell death.
Amiloride/*pharmacology ; Analysis of Variance ; Animals ; Arginine/toxicity ; Cell Death/drug effects ; Cells, Cultured ; Cyclic GMP/pharmacology ; Enzyme-Linked Immunosorbent Assay ; Mice ; Retina/cytology/*drug effects ; Tissue Plasminogen Activator/*toxicity

OBJECTIVETo evaluate whether the medicinal serum of Yi-shen Ruan-jian san can antagonize the fibrogenic effect of human proximal tubular epithelial cell line (HKC) activated by aristolochic acid (AA) in vitro.

METHODThe HKC was incubated in the media containing 40 mg x L(-1) aristolochic acid sodium salt (AA-Na) with or without 10% concentration of Yi-shen Ruan-jian san medicinal serum. Then the cell proliferation and cytotoxicity of HKC were determined by MTF and lactate dehydrogenase (LDH) release assay respectively, the antigen expression of cytokeratin and alpha-smooth muscle actin on HKC was detected by immunocytochemistry, the mRNA expression of transforming growth factor-beta1 (TGF-beta1), connective tissue growth factor (CTGF), plasminogen activator inhibitor-1 (PAI-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and type I Collagen (Col I) of HKC was measured by RT-PCR, and their protein expression was measured by ELISA or Western blot.

RESULTNo cytotoxic effect was found in HKC after stimulation of AA-Na with or without the medicinal serum of Yi-shen Ruan-jian san (P > 0.05). No epithelial-myofibroblast transdifferentiation was found in HKC after AA-Na stimulation. The mRNA and protein expression of TGF-beta1, CTGF, PAI-1 and TIMP-1 of HKC was significantly upregulated by AA-Na (P < 0.05). The above-mentioned enhanced mRNA and protein expression, except for PAI-1, was significantly downregulated by the medicinal serum of Yi-shen Ruan-jian san, compared with the control (normal rat serum in the same concentration) (P < 0.05).

CONCLUSIONThe fibrogenic effects of HKC activated by AA are antagonized by Yi-shen Ruan-jian san, through downregulating the expression of promoting excellular matrix (ECM) synthesis factors (TGF-beta1, CTGF) and inhibiting ECM degradation factor (TIMP-1).

Animals ; Aristolochic Acids ; antagonists & inhibitors ; toxicity ; Cell Line ; Cell Proliferation ; drug effects ; Connective Tissue Growth Factor ; Drug Combinations ; Drugs, Chinese Herbal ; pharmacokinetics ; pharmacology ; toxicity ; Epithelial Cells ; drug effects ; metabolism ; Immediate-Early Proteins ; biosynthesis ; genetics ; Intercellular Signaling Peptides and Proteins ; biosynthesis ; genetics ; Kidney Tubules, Proximal ; cytology ; L-Lactate Dehydrogenase ; metabolism ; Male ; Materia Medica ; pharmacology ; Plants, Medicinal ; chemistry ; Plasminogen Activator Inhibitor 1 ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Serum ; Tissue Inhibitor of Metalloproteinase-1 ; biosynthesis ; genetics ; Transforming Growth Factor beta ; biosynthesis ; genetics ; Transforming Growth Factor beta1