3-nitrotyrosine and cloricromen

Retinal microvascular cells play a crucial role in the pathogenesis of diabetic retinopathy. The endothelial effects of cloricromene, a novel coumarin derivative, on diabetic retinopathy induced by streptozotocin (STZ) in the rat were investigated.. Cloricromene (10 mg/kg intraperitoneally) was administered daily in diabetic rats, and 60 days later eyes were enucleated for localization of nitrotyrosine, ICAM-1, VEGF, ZO-1, occludin, claudin-5, and VE-cadherin by immunohistochemical analysis. The effect of treatment was also evaluated by TNFalpha, ICAM-1, VEGF, and eNOS protein levels measurement in the retina with the respective ELISA kits. Blood-retinal barrier (BRB) integrity was also evaluated by Evans blue.. Increased amounts of cytokines, adhesion molecule, and nitric oxide synthase were observed in retina. Cloricromene treatment significantly lowered retinal TNFalpha, ICAM-1, VEGF, and eNOS. Furthermore, immunohistochemical analysis for VEGF, ICAM-1, nitrotyrosine (a marker of peroxynitrite), and tight junctions revealed positive staining in the retina from STZ-treated rats. The degree of staining for VEGF, ICAM-1, nitrotyrosine, and tight junctions was markedly reduced in tissue sections obtained from diabetic rats treated with cloricromene. Treatment with cloricromene suppressed diabetes-related BRB breakdown by 45%.. This study provides the first evidence that the new coumarin derivative cloricromene attenuates the degree of inflammation preserving the BRB in diabetic rats.

Topics: Animals; Antigens, CD; Blood-Retinal Barrier; Blotting, Western; Cadherins; Chromonar; Claudin-5; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Immunohistochemistry; Injections, Intraperitoneal; Intercellular Adhesion Molecule-1; Male; Membrane Proteins; Nitric Oxide Synthase Type III; Occludin; Phosphoproteins; Platelet Aggregation Inhibitors; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha; Tyrosine; Vascular Endothelial Growth Factor A; Zonula Occludens-1 Protein

Recent studies have demonstrated that cloricromene, a coumarin derivative, exerts protective effects in models of inflammation and shock. Tumour necrosis factor plays a pivotal role in the induction of genes involved in physiological processes, as well as in the response to inflammation. We investigated the effect of cloricromene in a rat model of periodontitis. Periodontitis was induced in rats by placing a 2/0 braided silk ligature around the lower left first molar. At day 8 the gingivomucosal tissue encircling the mandibular first molar was removed for evaluation of tumour necrosis factor production, neutrophil infiltration, tissue permeability, nitrotyrosine formation, poly (ADP-ribose) polymerase activation, radiography and histology. Ligation significantly induced an increased tumour necrosis factor production, neutrophil infiltration and a positive staining for nitrotyrosine formation and poly (ADP-ribose) polymerase activation. Ligation significantly increased Evans blue extravasation in gingivomucosal tissue and alveolar bone erosion as evaluated by radiography analysis. Intraperitonal injection of cloricromene (10 mg/kg daily for 8 days) significantly decreased all of the parameters of inflammation as described above. This suggests that cloricromene treatment, which reduced tumour necrosis factor production, may be of benefit in the treatment of periodontitis.

Topics: Animals; Capillary Permeability; Chromonar; Male; Neutrophil Infiltration; Periodontitis; Poly(ADP-ribose) Polymerases; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha; Tyrosine

To investigate the effects of cloricromene, a coumarin derivative, in rats subjected to endotoxin-induced uveitis (EIU).. Endotoxin uveitis was induced in male Lewis rats by a single footpad injection of 200 microg lipopolysaccharide (LPS). Cloricromene was topically applied to the rat eye twice at 1 hour before and 7 hours after injection of LPS. A separate group of animals was treated with vehicle. Rats were killed 16 hours after injection and the eyes enucleated for histologic examination and immunohistochemical analysis. The effect of treatment was also evaluated by slit lamp examination, by the number of intraocular inflammatory cells on histologic sections, and by measuring the protein and TNFalpha levels in the aqueous humor. Nitrite and nitrate production was also measured in the aqueous humor.. The histopathology of the iris-ciliary body included inflammatory cell infiltration and nuclear modification of vessel endothelial cells. Cloricromene treatment reduced the inflammatory cell infiltration and improved histologic status of the ocular tissue. Immunohistochemical analysis for P-selectin, intracellular adhesion molecule (ICAM)-1, nitrotyrosine, and poly(ADP-ribose) synthetase (PARS) revealed a positive staining in inflammatory cell infiltration from LPS-treated rats. The degree of staining for P-selectin, ICAM-1, nitrotyrosine, and PARS was markedly reduced in tissue sections obtained from LPS-recipient rats that had received cloricromene. Cloricromene strongly inhibited cell infiltration, protein exudation, TNFalpha production, and nitrite-nitrate formation.. This study provides the first evidence that cloricromene, a coumarin derivative, attenuates the degree of inflammation and tissue damage associated with EIU in rats.

Topics: Administration, Topical; Animals; Aqueous Humor; Chromonar; Ciliary Body; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique, Indirect; Intercellular Adhesion Molecule-1; Iris; Lipopolysaccharides; Male; Nitrates; Nitrites; Ophthalmic Solutions; P-Selectin; Platelet Aggregation Inhibitors; Poly(ADP-ribose) Polymerases; Rats; Rats, Inbred Lew; Salmonella; Tumor Necrosis Factor-alpha; Tyrosine; Uveitis, Anterior

1. The aim of the present study was to investigate the effects of cloricromene, a coumarine derivative, in rats subjected to collagen-induced arthritis. 2. Collagen-induced arthritis (CIA) was induced in Lewis rats by an intradermal injection of 100 microl of the emulsion (containing 100 microg of bovine type II collagen) (CII) and complete Freund's adjuvant (CFA) at the base of the tail. On day 21, a second injection of CII in CFA was administered. 3. Lewis rats developed an erosive hind paw arthritis when immunized with CII in CFA. Macroscopic clinical evidence of CIA first appeared as peri-articular erythema and oedema in the hind paws. The incidence of CIA was 100% by day 27 in the CII challenged rats and the severity of CIA progressed over a 35-day period with radiographic evaluation revealing focal resorption of bone together with osteophyte formation in the tibiotarsal joint and soft tissue swelling. 4. The histopathology of CIA included erosion of the cartilage at the joint margins. Treatment of rats with cloricromene (10 mg kg(-1) i.p. daily) starting at the onset of arthritis (day 23), delayed the development of the clinical signs at days 24 - 35 and improved histological status in the knee and paw. 5. Immunohistochemical analysis for iNOS, COX-2, nitrotyrosine and for poly (ADP-ribose) synthetase (PARS) revealed a positive staining in inflamed joints from collagen-treated rats. The degree of staining for iNOS, COX-2, nitrotyrosine and PARS were markedly reduced in tissue sections obtained from collagen-treated rats, which had received cloricromene. 6. Radiographic signs of protection against bone resorption and osteophyte formation were present in the joints of cloricromene-treated rat. 7. This study provides the first evidence that cloricromene, a coumarine derivative, attenuates the degree of chronic inflammation and tissue damage associated with collagen-induced arthritis in the rat.

Topics: Animals; Arthritis; Body Weight; Cattle; Chromonar; Collagen; Cyclooxygenase 2; Disease Progression; Enzyme Activation; Hindlimb; Interleukin-1; Isoenzymes; Male; Malondialdehyde; Nitric Oxide; Poly(ADP-ribose) Polymerases; Prostaglandin-Endoperoxide Synthases; Radiography; Rats; Rats, Inbred Lew; Severity of Illness Index; Time Factors; Tumor Necrosis Factor-alpha; Tyrosine