Expression of tumor necrosis factor-alpha in cultured human endothelial cells stimulated with lipopolysaccharide or interleukin-1alpha.

Tumor-necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine with a wide variety of biological effects. The most important source of this cytokine is monocytes/macrophages. It is a potent agonist in the activation of endothelial cells; however, the precise role of endothelial cells as a source of TNF-alpha is not known. In the present study, we addressed the possibility that TNF-alpha is produced by cultured human umbilical vein endothelial cells (HUVEC) stimulated with factors such as lipopolysaccharide (LPS) or interleukin-1alpha (IL-1alpha). LPS and IL-1alpha induced expression of TNF-alpha mRNA in HUVEC. IL-1alpha induced expression and secretion of TNF-alpha protein, but LPS did not induce production of TNF-alpha protein. Most of the TNF-alpha protein in cell lysate was found in the membrane fraction. The mRNA for TNF-alpha-converting enzyme (TACE) was expressed in unstimulated HUVEC, and its level was not altered by treatment with LPS or IL-1alpha. Transfection of HUVEC with full-length cDNA encoding the precursor TNF-alpha enhanced secretion of TNF-alpha protein by these cells, and treatment of the cells with a TACE inhibitor reduced the secretion. These results suggest that HUVEC produce TNF-alpha and have TACE activity. Secreted TNF-alpha may be involved in autocrine activation of endothelial cells, and TNF-alpha retained in cell membrane may serve as a juxtacrine system to activate target cells on the endothelial surface.

[Croton oil-induced hemorrhoid model in rat: comparison of anti-inflammatory activity of diflucortolone valerate with other glucocorticoids].

A hemorrhoid model was prepared by means of application of croton oil onto the recto-anus of rats. Cotton swab soaked with the inducer, which consisted of water, pyridine, diethylether and 6% croton oil in diethylether, was inserted into the anus. The following conditions were found to be optimal for preparing the model: cotton swab containing 0.16 ml of the inducer solution was applied to the anus of a 6 week-old rat (body wt. about 140 g) for 10 sec. The edema developed linearly until 7-8 hr after application, and the severity of the edema was sustained almost constantly for more than 24 hr. Macroscopic observations at 6 hr p. a. revealed homogeneous and consistent inflammation in the recto-anus applied region. Histological observation showed appearance of edema, infiltration of fibrin, inflammatory cells, vasodilation, blood congestion and medium to high degrees of necrosis in the mucosal epithelium. Thus this model was useful for evaluating the effect of anti-hemorrhoidal drugs on intumescence and vasodilatation. The efficacy of diflucortolone valerate, hydrocortisone caproate and hydrocortisone was evaluated in this model. Wet weight and vasopermeability increased by the inducer was suppressed strongly by simultaneous application of the corticoids, and the degree of suppression was parallel with the potency of the glucocorticoid activity. Compared to Scheriproct, Posterisan forte, Posterisan and Borraginol N, Neriproct showed the strongest effects in the protection against and treatment of the experimental hemorrhoid. Scheriproct, which was less active than Neriproct, was also found to have higher efficacy than the others.

[Neriproct: its anti-inflammatory effect on an experimentally induced hemorrhoid model in the rat].

Several glucocorticoids as a cream formulation were applied to the recto-anus of the croton-oil-induced hemorrhoid rat. Among the steroids tested, i.e. diflucortolone valerate (DFV), prednisolone (PS), hydrocortisone caproate (HC), and hydrocortisone (H), DFV was found to suppress inflammation most effectively. The effect of DFV was not affected by combination with lidocaine. In this model, the analgesic effect of lidocaine was apparently prolonged by an increase of the threshold for pain by the anti-inflammatory effect of DFV. This additive effect is regarded as a merit of the combination in Neriproct. Therapeutic effects of Neriproct and several anti-hemorrhoid drugs were also examined by using a hemorrhoid model with abrasive irritation compared to those obtained by the croton-oil model. In both models, efficacy of Neriproct was superior to that of the other drugs such as Scheriproct, Proctosedyl, Posterisan forte, Borraginol N, Posterisan and Borraza G. Microscopic observation showed that destruction of the mucus epithelium, necrosis of the mucus layer, infiltration of inflammatory cells and vasodilatation in the croton-oil model were also suppressed markedly by Neriproct application. No difference was observed in the efficacy between the cream and suppository formulation of Neriproct. Suppression of wound healing was found with a dosage of DFV lower than those of PS, HC and H. However, the efficacy ratio of the wound-healing suppression and anti-inflammation of DFV was the largest among the steroids tested.