This study revealed the modulatory role of transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) cation channels in the Aldara-induced (5% imiquimod) murine psoriasis model using selective antagonists and genetically altered animals. We have also developed a refined localized model to enable internal controls and reduce systemic effects. Skin pathology was quantified by measuring skin thickness, scaling, blood flow, and analyzing dermal cellular infiltrate, whereas nocifensive behaviors were also observed. Cytokine gene expression profiles were measured ex vivo. Psoriasiform dermatitis was significantly enhanced in TRPA1 knockout mice and with TRPA1 antagonist (A967079) treatment. By comparison, symptoms were decreased when TRPV1 function was inhibited. Imiquimod induced Ca influx in TRPA1-, but not in TRPV1-expressing cell lines. Immunohistochemical studies revealed that CD4+ T helper cells express TRPA1 but not TRPV1 ion channels in mice skin. Compared with the TRPV1 knockout animals, additional elimination of the TRPA1 channels in the TRPV1/TRPA1 double knockout mice did not modify the outcome of the imiquimod-induced reaction, further supporting the dominant role of TRPV1 in the process. Our results suggest that the protective effects in psoriasiform dermatitis can be mediated by the activation of neuronal and nonneuronal TRPA1 receptors.

Imiquimod (IMQ)-induced skin inflammation is currently the most widely accepted psoriasis animal model, however, it features several limitations. We have modified the IMQ-model to minimize its systemic effects towards effectively maintaining the characteristic skin reactions. The original protocol (OP) uses 62.5 mg Aldara cream (or vaseline) on the shaved back skin of mice for 4 days. In contrast, in our modified protocol (MP) 25 mg Aldara and vaseline are applied simultaneously in separate Finn chambers over the dorsal skin of mice. In both the OP and MP groups, histology showed unequivocal hallmarks of psoriasiform dermatitis. Additionally, skin scaling and blood perfusion values were similar. While Aldara elicited significantly increased skin thickness in the MP group, significant weight loss, spleen enlargement, increased inflammatory cytokine levels in plasma, and treatment related death were only observed in the OP group. Our new method reproduces psoriatic skin alterations highlighting considerably reduced systemic inflammatory reactions. Possessing psoriasiform and control skin areas on the same mouse also reduces inter-individual differences. Additionally, the new method permits prolonged IMQ treatment studies to mimic the chronic nature of psoriasis. Finally, our experimental approach may also be used in other mouse models, to prevent the undesired systemic effects of topically applied drugs.

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Psoriasis is a chronic inflammatory disease with unmet medical needs. To clarify potential therapeutic targets, different animal models have been developed. In the current study, imiquimod-induced psoriasiform dermatitis was used for monitoring the changes in skin thickness, transepidermal water loss, body weight, blood perfusion and drug permeability for a topical cream formulation of caffeine, both in wild type and in knock out mice. Morphological characterization of control and diseased tissues was performed by scanning electron microscopy and two-photon microscopy. The chemically induced psoriatic group showed increased skin permeability for the model drug during disease progression. In wild type and TRPA1 KO mice, however, enhanced skin thickness and hyperkeratosis blocked further increase of drug penetration at the late phase (96 h). These results indicate that topical drug therapy can be more effective in early phases of plaque development, when skin thickness is lower. Although paracellular connections (tight junctions) are looser in the advanced phase, hyperkeratosis blocks drug delivery through the transappendageal routes. Novel drug formulations may have the potency for effective drug delivery across the epidermal barrier even in the advanced phase. For development of more effective topical drugs, further research is proposed to explore drug penetration both in healthy and diseased conditions.

Increased intra-abdominal pressure during laparoscopy leads to hypoxia due to reduced blood flow. Aim of our study was to investigate whether preconditioning can reduce this negative effect of the pneumoperitoneum. Fifty female Wistar rats were used, divided into 5 groups. I: Sham operation (Sham), II: conventional pneumoperitoneum (PP), III: transvaginal pneumoperitoneum (TV), IV: preconditioning for 2.5 minutes in two cycles (Pre 2.5), V: preconditioning for 5 minutes (Pre 5). Malondialdehyde (MDA), reduced glutathione (GSH), sulfhydrylgroup (SH-) concentrations, superoxide-dismutase (SOD) and mieloperoxidase (MPO) activity, and anti-apoptotic pathway marker p-AKT level and inflammatory cytokine TNF-α were measured. SOD activity and GSH concentration were decreased in PP and TV groups comparing to Sham and preconditioning groups. MPO activity was decreased also in PP and TV groups comparing to the Sham group but in the preconditioning groups it has remained high. MDA concentration in plasma was increased in PP and TV groups comparing to Sham and preconditioning groups. There was no difference in the case of blood MDA and SH-concentrations between groups. Anti-apoptotic pathway marker p-AKT level was decreased in the TV group comparing to the sham and preconditioning groups. TNF-α level was increased in TV and preconditioning groups compared to the sham group. According to the results preconditioning can reduce negative effects of pneumoperitoneum.

After revascularization of an acute arterial occlusion the development of a serious ischaemic-reperfusion injury is a menacing challenge and a hard task in peripheral vascular surgery. A whale of evidences point to oxidative stress, as an important trigger, in the complex chain of events leading to reperfusion injury. In the present study authors aimed to examine oxidative stress parameters, antioxidant-prooxidant state and leukocyte adhesion molecules (CD11a and CD18) expression following acute revascularization surgery of lower limb.10 patients were examined in the prospective randomized study. Peripheral blood sample was collected in ischaemic period, and after reperfusion in the 2nd and 24th hours, and on 7th day. Superoxide-dismutase activity, reduced glutathion concentration and leukocytes free radical production were measured. The degree of lipidperoxidation was marked with the quantity of malondialdehyde. The expressions of adhesion molecules were measured with flowcytometry.The speed and rate of free radical production significantly increased in the early reperfusion (p < 0.05). The level of antioxidant enzymes decreased after revascularization. The CD11a and CD18 expression of the granulocytes significantly (p < 0.05) decreased right after the revascularization, but with a gradual elevation until the 7th day they exceed the ischaemic value.Our results showed a time specific turnover of the sensitive antioxidant-prooxidant balance after revascularization operation.

Objective: We studied the protective effects of ischaemic postconditioning (PS) on ischemia-reperfusion injury of the lower extremities in a rat model of abdominal aortic intervention. We aimed to examine the evoked oxidative stress, cytokine expression and leukocyte activation after revascularisation surgery.Methods: Anesthetized animals (48 Whistar rats) underwent a 60 min infrarenal aorta cross-clamping. After the ischaemic period, an intermittent 4 times 15 s reperfusion -15 seconds ischaemic episodes -were applied (ischaemic postconditioning: group PS). Then we started a 120 min reperfusion in the aorta. In untreated group animals underwent a long ischaemia (60 min) and the following reperfusion (group IR). Peripherial blood samples were collected before operation, and in early (5, 10, 15, 30, 60 and 120 min) reperfusion periods. Serum peroxide level, TNF-alpha concentration, myeloperoxidase (MPO) activity and PMA-induced leukocyte ROS production were measured.Results: In PS group, plasma peroxide level elevation was significantly lower in very early reperfusion (5-30 min) comparing to non-conditioned IR group (10.04 ± 1.9 µM/l vs. 16.91 ± 3.67 µM/l, p < 0.05). PS also reduced serum TNF-alpha concentration (167.41 ± 31.26 µg/ml vs. 116.55 ± 12.04 µg/ml, p < 0.05), MPO activity (1.759 ± 0.239 µM/ml vs. 1.22 ± 0.126 µM/ml, p < 0.05) and leukocyte activation detected by PMA-induced leukocyte ROS production (5.7 ± 0.96 AU/10 3 cells vs. 4.63 ± 0.69 AU/10 3 cells).Conclusions: Ischaemic postconditioning could reduce ROI production after IR in early reperfusion period, thus limiting ROI mediated tissue lesion, cytokine-leukocyte activation and inflammatory responses. PS seems to be an effective tool in vascular surgery to reduce reperfusion injuries after revascularization interventions.