Acute renal failure related to ischemic episodes pro foundly impairs the renal epithelium. Following ischemia reperfusion injury, cytoskeletal disruption and loss of epithelial cell polarity contribute to back leak of ized to the periphery. TNF IFN treatment produces a marked elevation of claudin 1 cytoplasmic staining. the addition of U0126 restores claudin selleck Pazopanib 1 locali zation to the periphery. Claudin 2 staining is localized to the periphery, the TNF IFN exposure produced a significant decrease in junctional intensity, U0126 produced little restoration of claudin 2 staining in the presence of TNF IFN. In contrast, claudin 3 staining and J/I analysis glomerular filtrate into the blood. In a recent study following kidney transplant, decreased ZO 1 staining was reported in response to postischemic injury.

Impor tantly, leukocyte infiltration is likely to occur in chronic renal conditions such as diabetes, hypertension, autoim mune disorders leading to production of proinflamma tory cytokines. In this study, we employ an important renal cell model, to examine the effects of proinflammatory cytokines on barrier function. Initially, we were interested in determining whether the proinflammatory treatment regiment was altering MDCK barrier function as a cytotoxic effect. TNF is a known acti vator of NFB, a transcription factor that promotes sur vival. in a recent report NFB activity was inhibited by exogenous expression of Smad7 resulting in elevated apoptosis in MDCK cells. However, it was recently reported that TNF initiated caspase 8 cleaved PARP that induced apoptosis in serum starved MDCK cells.

In the present study, MDCK cells were treated in media containing five percent FBS to minimize serum withdrawal responses, we report that the combination of cytokines used in this study did not significantly induce apoptosis. At the highest doses of cytokine treatment there was a moderate elevation in Cilengitide LDH release, however this was less than a ten percent elevation in LDH levels compared to control. Impor tantly, we report that paracellular flux increased in a graded fashion with increasing dose of TNF IFN. When are serum and energy starved ionic permeability decreased in response to TNF IFN. These data suggest that the MDCK cell response to TNF IFN is distinct from a cyto toxic insult. In support of this concept a recent study using the intestinal epithelial T84 cell line demonstrated that the combination of TNF IFN increases paracellular per meability in an apoptosis independent manner.