Hypochlorite-induced porcine model of peritoneal fibrosis through the activation of IL1β-CX3CL1-TGFβ1 signal axis

Abstract

Patients with kidney failure rely on life-saving peritoneal dialysis to facilitate waste exchange and maintain homeostasis of physical conditions. However, peritoneal dialysis often results in peritoneal fibrosis and organ adhesion that subsequently compromise the efficiency of peritoneal dialysis and normal functions of visceral organs. Despite rodent models provide clues on the pathogenesis of peritoneal fibrosis, no current large animal model which shares high degree of physiological and anatomical similarities to human is available, limiting their applications on the evaluation of pre-clinical therapeutic efficacy. Here we established for the first time, hypochlorite-induced porcine model of peritoneal fibrosis in 5-week-old piglets. We showed that administration 15–30 mM hypochlorite, a dose- and time-dependent severity of peritoneal fibrosis characterized by mesothelium fragmentation, αSMA + myofibroblasts accumulation, organ surface thickening and type I collagen deposition were observed. We also demonstrated in vitro using human mesothelial cells that hypochlorite-induced fibrosis was likely due to necrosis, but not programmed apoptosis; besides, overexpression of IL1β, CX3CL1 and TGFβ on the peritoneal mesothelium in current model was detected, similar to observations from peritoneal dialysis-induced peritoneal fibrosis in human patients and earlier reported mouse model. Moreover, our novel antemortem evaluation using laparoscopy provided instant feedback on the progression of organ fibrosis/adhesion which allows immediate adjustments on treatment protocols and strategies in alive individuals that can not and never be performed in other animal models.

Sulodexide Prevents Peritoneal Fibrosis by Downregulating the Expression of TGF-β1 and Its Signaling Pathway Molecules

“…Clinical studies have shown that transforming growth factor- β 1 (TGF- β 1), related cytokines, and inflammatory factors are closely related to peritoneal fibrosis. TGF- β 1 is considered to be the most critical cytokine in the pathogenesis of peritoneal fibrosis, which can regulate cell proliferation and differentiation, promote the formation of an extracellular matrix, participate in the regulation of embryonic development, etc., mainly through the activation of its downstream signal protein Smads [ 7 – 11 ]. Other studies have shown that in various acute and chronic inflammatory states, peritoneal mesothelial cells are damaged, and macrophages are activated to participate in the formation of peritoneal fibrosis by secreting a large number of inflammatory cytokines, growth factors, matrix proteins, etc.…”

Oxidative Stress-Induced Alterations of Cellular Localization and Expression of Aquaporin 1 Lead to Defected Water Transport upon Peritoneal Fibrosis

“…Nine five-week-old LYD (mixed breed of Landrace-Yorkshire-Duroc) male piglets free from porcine epidemic diarrhea virus, porcine reproductive and respiratory syndrome virus, and porcine circovirus (tested with PCR, data not shown) were purchased from Tung-Ying Agriculture Inc., Taiwan, and housed in groups in a certified animal facility for one week prior to the experiment. NaClO-induced peritoneal fibrosis was established as earlier described [24]. Pigs were randomly divided into three groups (n = 3 in each experimental group) as control, 0.1% NaClO and 0.1% NaClO*2 group.…”

“…Histological and Quantitative Assessments on Mesothelium Integrity, Tissue Thickening and the Amount of αSMA After pigs were sacrificed, both parietal and visceral peritoneum were collected and fixed overnight (O/N) in 10% neutral formalin before being processed for paraffin embedding. Ten-µm tissue sections were de-paraffinized and stained with hematoxylin and eosin (H&E) for general morphological and histological evaluations as described earlier [24,25]. For tissue fibrosis analysis, Masson's trichrome stained sections were quantitatively assessed using CellSens software (Olympus, Tokyo, Japan).…”

“…For tissue fibrosis analysis, Masson's trichrome stained sections were quantitatively assessed using CellSens software (Olympus, Tokyo, Japan). To quantify the changes in the peritoneum under NaClO injury, an objective multipoint measurement of the surface thick-ness was carried out as described earlier [24]. In short, CK was used for mesothelium integrity evaluation.…”

“…Previously, we established a novel porcine model of peritoneal fibrosis using sodium hypochlorite (NaClO) [24]. In this study, we further establish PET in pigs to allow instant evaluation of the transportability of the peritoneum.…”