Modulation TNF-alpha-induzierter Entzündung durch den p53-Inhibitor Pifithrin-alpha

Abstract

Inflammation of traumatized tissue still represents a challenge in surgical practice, causing discomfort of patients, remarkable costs by delay of wound healing and follow-up surgery. Both disturbance of the microcirculation and apoptotic cell death may take part in this process. The aim of the presented study was to evaluate the role of p53 in TNF-α-induced inflammation by temporary inhibition with pifithrin-α. Dorsal skinfold chambers of hairless mice (6–8 weeks, 25 – 30 g bw) were locally exposed to 2000 U of murine TNF-α 4 days after preparation. Arteriolar diameters, arteriolar red blood cell velocity (RBV), arteriolar volumetric blood flow (VBF), functional capillary density (FCD), number of permanent adherent leukocytes and the amount of apoptotic cell death were evaluated before pretreatment and 30, 60, 90 min as well as 2, 3, 8, 24 and 48 h after exposure to TNF-a by means of intravital fluorescence microscopy. Animals were either pre-treated with 2.2 mg/kg bw PFT-α ip 15 min before TNF-α-exposure (PFT-α n = 6) or with the vehicle DMSO ip (1 ml/kg bw; DMSO; n = 6). Saline-treated animals served as controls (control; n = 9). ANOVA and Student’s t-test. In controls, arteriolar diameters were almost unchanged 8 h after TNF-α-exposure while RBV and VBF were significantly reduced, resulting in a significant restriction of FCD. As a sign of inflammation, the number of adherent leukocytes and the amount of apoptotic cell death significantly increased. Pretreatment with DMSO elicted no changes in arteriolar diameters while RBV and VBF were markedly, and FCD even significantly increased compared to controls. The number of adherent leukocytes and the amount of apoptotic cell death were increased comparable to that in controls. Pre-treatment with PFT-α resulted in a significant reduction of apoptotic cell death compared to DMSO and a moderate reduction of leukocyte adherence while there was no effect on microcirculatory dysfunction and perfusion failure. In summary, we could prove a significant reduction of TNF-α-induced apoptotic cell death by pifithrin-α while the accompanying improvement of microvascular perfusion was, at least in this model, presumably caused by the vehicle DMSO. The temporary inhibition of p53 may thus contribute to the reduction of TNF-α-induced damage following soft tissue trauma.