Inhibition of cytokine gene expression in mouse skin by subcutaneous injection of cyclosporine

Cyclosporine A - Induced gingival overgrowth and proliferating cell nuclear antigen expression in experimental periodontitis

The most important microscopic characteristic of Cyclosporine A-induced gingival overgrowth is fibroepithelial hyperplasia.

OBJECTIVE

The objective was to investigate the influence of previous exposure to Cyclosporine A over gingival epithelium in experimental periodontitis in rats.

METHODS

Twenty Wistar rats with 12 weeks-old were divided into four groups with 5 animals each: Control Group (CG); Cyclosporine Group (CsAG); Ligature group (LG) and Cyclosporine and Ligature Group (CsALG). Daily doses of CsA (10 mg/kg) were applied to CsAG and CsALG during 60 days since the beginning of the experiment and, a ligature was placed in LG and CsALG 30 days after the beginning of the experiment. After 60 days, animals were euthanized and gingival tissue was processed to histomorphometric analysis of epithelial thickness (mm²), immunohistochemical expression of PCNA (%) and inflammatory response. Data were analyzed by Kruskal-Wallis and Mann Whitney at 0.05 significance level.

RESULTS

Considering epithelial thickness, CG was thinner than all groups, CsALG was the largest and CsAG and LG were similar between each other. Regarding the PCNA expression CG (16.46 ± 9.26) was similar to CsAG (34.47 ± 19.75) and, LG (59.02 ± 10.33) was similar to CsALG (40.59 ± 18.25). Significant difference (p < 0.05) occurred only in inflammation presence comparing CG/LG and CsAG/CsALG. A weak positive correlation between the number of PCNA+ and inflammatory cells (p = 0.001; r = 0.611) was observed.

CONCLUSION

Based on these results it was concluded that the enlargement of gingival epithelium observed in experimental periodontitis can be increased by previous exposition to CsA and inflammatory conditions enhanced proliferative activity of the keratinocytes.

Ergocalciferol promotes in vivo differentiation of keratinocytes and reduces photodamage caused by ultraviolet irradiation in hairless mice

BACKGROUND

Ergocalciferol (VD(2)) is usually administered orally and it is metabolized to produce its biologically active metabolites in the liver and kidney. Active vitamin D is a well-known potent regulator of cell growth and differentiation.

PURPOSE

Active vitamin D such as 1,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) prevents photodamage, including wrinkles and morphologic alterations. However, its clinical and cosmetic use is limited because of its potent, associated effect on calcium metabolism. We examined the efficacy of vitamin D analogues with few adverse effects for preventing skin photodamage.

METHOD

Topical application of VD(2) to hairless mouse dorsal skin, and exposure to solar-simulating ultraviolet (UV) radiation at a dose of 10.8 J/cm(2) (UVA) were performed for 15 weeks, five times a week on weekdays. At the end of the final irradiation, histological and analytical studies were performed.

RESULTS

Topical application of VD(2) significantly prevented wrinkle formation and abnormal accumulation of extracellular matrix components. In addition, VD(2) suppressed excessive secretion of IL-6 induced by UV irradiation in cultured human normal keratinocytes, in a dose-dependent manner.

CONCLUSION

VD(2) promoted keratinocytes differentiation in the epidermis and showed diverse physiological effects, the same as the active form of VD(3). The results suggested that the suppression of skin photodamage involved the promotion of keratinocytes differentiation and suppression of IL-6 secretion induced by exposure to UV. Topical application of VD(2) may become an effective means to suppress solar UV-induced human skin damage.

Suppressive effects of cyclosporin A and FK-506 on superoxide generation in human polymorphonuclear leukocytes primed by tumor necrosis factor alpha

Most previous studies have found no effects of cyclosporin A and FK-506 on active oxygen generation in human polymorphonuclear leukocytes. Recently various differences in biologic properties have been reported between unprimed peripheral blood human polymorphonuclear leukocytes and tissue or primed human polymorphonuclear leukocytes. In this study, we investigated the effects of cyclosporin A and FK-506 on superoxide (O(2)(-)) generation induced by the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine in human peripheral blood polymorphonuclear leukocytes primed or unprimed with tumor necrosis factor alpha. Neither cyclosporin A nor FK-506 suppressed N-formyl-L-methionyl-L-leucyl-L-phenylalanine-induced O(2)(-) generation in unprimed human polymorphonuclear leukocytes at concentrations between 0.1 nM and 10 microM, as in previous studies. Only at 1 microM of cyclosporin A and 100 nM of FK-506 were marginal suppressive effects observed. On the other hand, cyclosporin A and FK-506 both suppressed N-formyl-L-methionyl-L-leucyl-L-phenylalanine-induced O(2)(-) generation in tumor-necrosis-factor-alpha-primed human polymorphonuclear leukocytes, strongly and dose dependently, at concentrations between 1 nM and 1 microM. Neither cyclosporin A nor FK-506 influenced tyrosyl phosphorylation of 115 kDa protein, which is inducible during the priming process, suggesting that neither cyclosporin A nor FK-506 influenced the tumor-necrosis-factor-alpha-induced priming process itself, and instead modified the biologic response of primed human polymorphonuclear leukocytes.

UVB-induced alterations in permeability barrier function: roles for epidermal hyperproliferation and thymocyte-mediated response

UV irradiation induces a variety of cutaneous responses, including disruption of epidermal permeability barrier function, the basis for which is not known. Herein, we investigated the separate roles of hyperproliferation and inflammation in the pathogenesis of UVB-induced barrier disruption. Adult hairless mice were exposed to increasing doses of UVB (1.5-7.5 MED), and transepidermal water loss (TEWL) was monitored daily for up to 7 d. The extent of TEWL increase was dependent on the UVB dose, but with all doses, the increase began after > or =48 h and peaked at 96 h, decreasing by 120 h. Epidermal [(3)H]thymidine incorporation increased at 24 h and peaked at 48 h (570%), preceding the maximal increase in TEWL. Cyclosporin A, methotrexate, 5-fluorouracil, or arabinosylcytosine significantly diminished the UVB-induced TEWL increase. Athymic nude mice also displayed a markedly diminished response to UVB, and DNA synthesis did not increased at 48 h. Transplantation of athymic mice with T-cell-enriched mixed immune cells significantly restored sensitivity to both the UVB-induced hyperproliferation and the barrier defect. Finally, although UVB exposure increased PGE2 levels in whole skin samples (2- to 3-fold within 1-3 h; p < 0.005), this increase was completely blocked by topical indomethacin, and neither topical indomethacin nor topical glucocorticoids blocked development of the barrier abnormality. These results show that (i) UVB produces delayed alteration in barrier function and (ii) both an epidermal proliferative response and thymocyte-mediated events (but not PGE2 production and nonspecific inflammation) appear to contribute to UVB-induced abrogation of the permeability barrier.