Peritoneal Cavity Of Rats Research Articles

Leptospira interrogans encodes a canonical BamA and three novel noNterm Omp85 outer membrane protein paralogs

The Omp85 family of outer membrane proteins are ubiquitously distributed among diderm bacteria and play essential roles in outer membrane (OM) biogenesis. The majority of Omp85 orthologs are bipartite and consist of a conserved OM-embedded 16-stranded beta-barrel and variable periplasmic functional domains. Here, we demonstrate that Leptospira interrogans encodes four distinct Omp85 proteins. The presumptive leptospiral BamA, LIC11623, contains a noncanonical POTRA4 periplasmic domain that is conserved across Leptospiraceae. The remaining three leptospiral Omp85 proteins, LIC12252, LIC12254 and LIC12258, contain conserved beta-barrels but lack periplasmic domains. Two of the three ‘noNterm’ Omp85-like proteins were upregulated by leptospires in urine from infected mice compared to in vitro and/or following cultivation within rat peritoneal cavities. Mice infected with a L. interrogans lic11254 transposon mutant shed tenfold fewer leptospires in their urine compared to mice infected with the wild-type parent. Analyses of pathogenic and saprophytic Leptospira spp. identified five groups of noNterm Omp85 paralogs, including one pathogen- and two saprophyte-specific groups. Expanding our analysis beyond Leptospira spp., we identified additional noNterm Omp85 orthologs in bacteria isolated from diverse environments, suggesting a potential role for these previously unrecognized noNterm Omp85 proteins in physiological adaptation to harsh conditions.

Effect of Egyptian spitting cobra Naja nubiae crude venom on immunogenic activity of rats

Snakes show defensive activities, often counting visual or auditory displays against an aggressor. The study observed what happens to rats administered subcutaneously sub-lethal doses of crude venom Naja nubiae. The pro-inflammatory cytokines, such as tumor necrosis alpha (TNF-α) and interleukin-6 (IL-6), as well as the anti-inflammatory cytokines such as interleukin-10 (IL-10), and inflammatory mediator's prostaglandin E-2 (PG-E2), were evaluated. Vascular permeability (VP) was employed to assess how leaky or permeable blood vessels are in various tissues and organs, including the rat peritoneal cavity and lymphoid organs. Lymphoid organs' histological alterations brought on by Nubiae venom. The study found that the two venom doses—1/4 and 1/2 LD50—induced high levels of inflammatory activity as evidenced by the production of inflammatory cytokines. These findings demonstrated that venom enhanced innate immunity through specifically increased T helper cells, IL-6, TNF-α, IL-10, and PG-E2. The results reveal whether the venom has an immunomodulatory effect and promotes inflammation. The data have a substantial impact on the development of new drugs and treatments for inflammatory conditions.

Mesenchymal stem cells derived from CHIR99021 and TGF‑β induction remained on the colicomentum and improved cardiac function of a rat model of acute myocardium infarction.

Human induced pluripotent stem cells (hiPSCs) have been regarded as a potential stem cell source for cell therapy. However, the production of cells with mesenchymal potential from hiPSCs through spontaneous differentiation is time consuming and laborious. In the present study, the combined use of the GSK-3 inhibitor CHIR99021 and TGF-β was used to obtain mesenchymal stem cell (MSC)-like cells from hiPSCs. During the induction process, the transcription of epithelial-mesenchymal transition (EMT)-related genes N-cadherin and Vimentin in the transformed cells was upregulated, whereas the transcription of E-cadherin and pluripotency-related transcription factors SOX2, OCT4 and NANOG did not change significantly. This indicated that whilst cells were pluripotent, EMT was initiated by the upregulation of transcription of EMT promoting genes. Both SMAD-dependent and independent signalling pathways were significantly activated by the combined induction treatment compared with the single factor induction. The hiPSC-derived MSC-like cells (hiPSC-MSCs) expressed MSC-related markers and acquired osteogenic, chondrogenic and adipogenic differentiation potentials. After being injected into the peritoneal cavity of rats, the hiPSC-MSCs secreted angiogenic and immune-regulatory factors and remained on the colicomentum for 3 weeks. Within an 11-week period, four intraperitoneal hiPSC-MSC injections (1x107 cells/injection) into acute myocardial infarction (AMI) model rats significantly increased the left ventricular ejection fraction, left ventricular fractional shortening and angiogenesis and significantly reduced scar size and the extent of apoptosis in the infarcted area compared with that of the control PBS injection. Symptoms of hiPSC-MSC-induced immune reaction or tumour formation were not observed over the course of the experiment in the hiSPC-MSC treated rats. In conclusion, the CHIR99021 and TGF-β combined induction was a rapid and effective method to obtain MSC-like cells from hiPSCs and multiple high dose intraperitoneal injections of hiPSC-derived MSCs were safe and effective at restoring cardiac function in an AMI rat model.

91-OR: AdoShell Islet, a New Biomaterial for Allogenic Islet Encapsulation Shows Six Months Insulin Secretion in Diabetic Immunocompetent Rats

Islet transplantation is an effective cure for T1D but the requirement for immunosuppression makes its application limited. AdoShell® is an implantable and fully retrievable scaffold for islet transplantation without immunosuppression. It is based on a permselective hydrogel film that allows the diffusion of insulin and prevents immune cell invasion. AdoShell® is a soft biomaterial with 95% water, synthetized from non-degradable polymers cross-linked by bio-orthogonal click chemistry. Encapsulated human islets displayed a gluco-responsive insulin secretion comparable to naked islets in perifusion experiments after 7 days and 1 month (N=3 donors 7 days / N=2 donors 1 month). Wistar rat allogenic islets encapsulated in AdoShell® were implanted in immunocompetent STZ-induced diabetic rats. Insulin levels in vivo were on average 121pM/day over 41 days (n=22 rats), a significant increase versus negative control (45pM/day, n=9 rats) (M.W. t-test, p<0.0001). AdoShell® Islets led to physiological weight gain, reduction of fasting hyperglycemia, and sustained C-peptide and insulin secretion for over 6 months in diabetic rats. It was well tolerated and did not trigger inflammatory reaction nor fibrosis after the 6-month implantation period in rat peritoneal cavity. Neither biodegradation, nor immune cell penetration were observed. Disclosure A.Geissler: Employee; Adocia, Stock/Shareholder; Adocia. O.Jouannot: Employee; ADOCIA, Stock/Shareholder; ADOCIA. A.Gaffuri: Employee; ADOCIA, Stock/Shareholder; ADOCIA. C.Gautier: Employee; Centre européen d'étude du diabète, Biomeostasis, Charles Rivers Laboratories, Institut de recherche contre les cancers de l'appareil digestif, GenOway, NAMSA. Y.P.Courbebaisse: None. K.Bouzakri: Consultant; Adocia, Stock/Shareholder; ILONOV. R.Eloy: Stock/Shareholder; Adocia. O.Soula: Employee; Adocia, Stock/Shareholder; Adocia.

Monocytic Ontogeny of Regenerated Macrophages Characterizes the Mesotheliomagenic Responses to Carbon Nanotubes.

Macrophages are not only derived from circulating blood monocytes or embryonic precursors but also expand by proliferation. The origin determines macrophage fate and functions in steady state and pathological conditions. Macrophages predominantly infiltrate fibre-induced mesothelioma tumors and contribute to cancer development. Here, we revealed their ontogeny by comparing the response to needle-like mesotheliomagenic carbon nanotubes (CNT-7) with tangled-like non-mesotheliomagenic CNT-T. In a rat peritoneal cavity model of mesothelioma, both CNT induced a rapid macrophage disappearance reaction (MDR) of MHCIIlow resident macrophages generating an empty niche available for macrophage repopulation. Macrophage depletion after mesotheliomagenic CNT-7 was followed by a substantial inflammatory reaction, and macrophage replenishment completed after 7 days. Thirty days after non-mesotheliomagenic CNT-T, macrophage repopulation was still incomplete and accompanied by a limited inflammatory reaction. Cell depletion experiments, flow cytometry and RNA-seq analysis demonstrated that, after mesotheliomagenic CNT-7 exposure, resident macrophages were mainly replaced by an influx of monocytes, which differentiated locally into MHCIIhigh inflammatory macrophages. In contrast, the low inflammatory response induced by CNT-T was associated by the accumulation of self-renewing MHCIIlow macrophages that initially derive from monocytes. In conclusion, the mesotheliomagenic response to CNT specifically relies on macrophage niche recolonization by monocyte-derived inflammatory macrophages. In contrast, the apparent homeostasis after non-mesotheliomagenic CNT treatment involves a macrophage regeneration by proliferation. Macrophage depletion and repopulation are thus decisive events characterizing the carcinogenic activity of particles and fibres.

Thymol regulates the functions of immune cells in the rat peritoneal cavity after l-arginine-induced pancreatitis

AimsThe present study aimed to evaluate the protective action of thymol towards l-arginine-induced acute pancreatitis (AP) by studying the function of rat peritoneal immune cells. Main methodsRat peritoneal exudate cells (PECs), obtained 24 h after the injection of l-arginine (350 mg/100 g of b.w.), were evaluated for mitochondrial activity (MTT assay), adherence capacity (methylene-blue assay), and phagocyte enzyme activity (myeloperoxidase, MPO, assay). The activity of α-amylase and free MPO, as well as the concentration of reactive oxygen species (ROS, i.e. O2−), were determined in the peritoneal exudate fluid. Also, serum α-amylase activity determination and pancreatic tissue pathohistological analysis were performed. Key findingThe administered thymol (50 and 100 mg/kg, per os) caused a significant decrease in the PEC mitochondrial activity and adherence capacity when compared with these functions of PECs isolated from rats with AP. A decrease in cellular MPO activity, as well as in the levels of ROS, α-amylase, and free MPO in peritoneal exudates was found in animals treated with thymol compared to the control animals with AP. Additionally, thymol administration prevented an increase in serum α-amylase activity, accompanied by the decrease in pancreatic tissue damage that follows l-arginine application. SignificanceThe present results showed that thymol exerts significant immunomodulatory properties and a potential to silence PEC functions in inflammatory conditions such as the AP induced by l-arginine.

Implantable platinum nanotree microelectrode with a battery-free electrochemical patch for peritoneal carcinomatosis monitoring

As a severe stage of cancers, peritoneal carcinomatosis should be frequently monitored by means of ascites analysis. Nevertheless, the analysis process is traumatic and time-consuming in clinical practice. In this study, an implantable platinum nanotree microelectrode with a wireless, battery-free and flexible electrochemical patch was developed for in vivo and real-time peritoneal glucose detection to monitor peritoneal carcinomatosis. As the core of implantable microelectrode, platinum trees were synthesized by one-step electrodeposition method and highly sensitive to glucose detection. The platinum nanotree microelectrode was implantable in peritoneal cavity in minimally invasive way. A flexible circuit patch could execute electrochemical test and realize wireless power harvesting and data interaction with a near field communication (NFC)-enabled smartphone. The whole system could detect glucose dynamics in vivo in rat peritoneal cavity. Furthermore, the accuracy of this system was validated in ascites of patients. In this way, the system could offer hassle-free, rapid and minimally invasive opportunities toward peritoneal carcinomatosis monitoring.

Mannan activates tissue native and IgE-sensitized mast cells to proinflammatory response and chemotaxis in TLR4-dependent manner.

Mast cells take part in host defense against microorganisms as they are numerous at the portal of infection, exert several essential mechanisms of pathogen destruction, and they express pattern recognition receptors. Accumulating evidence indicates that these cells are involved in the control and clearance of bacterial, viral, or parasitic infections, but much less is known about their contribution in defense against fungi. The study was aimed to establish whether mannan, which comprises an outermost layer and major structural constituent of the fungal cell wall, may directly stimulate tissue mast cells to the antifungal response. Our findings indicate that mannan activates mast cells isolated from the rat peritoneal cavity to initiate the proinflammatory response. We found that mannan stimulates mast cells to release histamine and to generate cysteinyl leukotrienes, cytokines (IFN-γ, GM-CSF, TNF), and chemokines (CCL2, CCL3). It also increased the mRNA expression of various cytokines/chemokines. We also documented that mannan strongly activates mast cells to generate reactive oxygen species and serves as a potent chemoattractant for these cells. Furthermore, we established that mannan-induced activity of mast cells is mediated via TLR4 with the involvement of the spleen tyrosine kinase molecule. Taking together, our results clearly support the idea that mast cells act as sentinel cells and crucially determine the course of the immune response during fungal infection. Additionally, presented data on IgE-coated mast cells suggest that exposure to fungal mannan could influence the severity of IgE-dependent diseases, including allergic ones.

Immunophenotypical aspects of lung and spleen macrophages derived animals with the model of alloxan diabetes (type I) and their correction by sodium aminodigydrophtalazindione in vitro

Macrophages are found in all tissues and organs and display functional plasticity, which is necessary to maintain homeostasis, tissue regeneration and immunity. The macrophage phenotype is determined by microenvironment signals. Macrophages are traditionally classified into subsets- such as classically (M1) or alternatively (M2) activated macrophages. In the pathogenesis of diabetes mellitus (T1DM), M1 macrophages contribute to damage to the islets of Langerhans, loss of β-cells, causing autophagy, which can result in development of persistent infection increasing the risk of death from influenza or pneumonia in patients with type 1 diabetes. Therefore, it seems Important to study functional response of resident macrophages in organs and tissues not targeted in development of diabetes mellitus, as well as in response to ADPH stimulation that showed modulatory effect on immunocompetent cells. In this study morphological and functional characteristics of macrophage cell cultures obtained from different sites in intact animal (IA) and modeled type 1 diabetes mellitus (DM1) were investigated. For this, we examined macrophage cell cultures isolated from rat liver and peritoneal cavity to be stimulated in vitro for 24 and 72 hours with a sodium aminodigydrophtalazindione. Cells, nucleus, cytoplasm area were measured and nuclear cytoplasmic ratio (NCR) were calculated. The phenotype was determined by surface expression of CD163 (M2-macrophages) and CD80 (M1-macrophages) receptors. Macrophage cytokine activity was determined by measuring IL-1α, IL-10 и TNFα level. ADPH effects on animal macrophages with DM1 after 24 h of exposure also led to a changedmorphometric parameters (decreased size of the nucleus and cells of the spleen macrophages, increased size of the nucleus of the alveolar macrophages, increased NCR in spleen macrophages) and production activity of the cells (increased levels of IL-1α and TNF α in almost all cell populations). After 72 h of cultivation, the levels of IL-1α and TNFα decreased in alveolar macrophages, splenic macrophages, whereas TNFα level was decreased, but IL-1α asmount was increased. The expression of surface cell markers for M1 and M2 phenotypes was also affected by ADPH so that CD163 expression was increased in stimulated alveolar macrophages isolated from animals with type 1 diabetes.

The Response of Tissue Mast Cells to TLR3 Ligand Poly(I:C) Treatment.

Mast cells (MCs) are found mainly at the anatomical sites exposed to the external environment; thus, they are localized close to blood vessels, lymphatic vessels, and a multitude of immune cells. Moreover, those cells can recognize invading pathogens through a range of surface molecules known as pathogen recognition receptors (PRRs), mainly Toll-like receptors (TLRs). MCs are extensively engaged in the control and clearance of bacterial infections, but much less is known about their contribution to antiviral host response as well as pathomechanisms of virus-induced diseases. In the study, we employed in vivo differentiated mature tissue mast cells freshly isolated from rat peritoneal cavity. Here, we demonstrated that rat peritoneal mast cells (rPMCs) express viral dsRNA-specific TLR3 molecule (intracellularly and on the cell surface) as well as other proteins associated with cellular antiviral response: IRF3, type I and II IFN receptors, and MHC I. We found that exposure of rPMCs to viral dsRNA mimic, i.e., poly(I:C), induced transient upregulation of surface TLR3 (while temporarily decreased TLR3 intracellular expression), type II IFN receptor, and MHC I. TLR3 ligand-stimulated rPMCs did not degranulate but generated and/or released type I IFNs (IFN-α and IFNβ) as well as proinflammatory lipid mediators (cysLTs), cytokines (TNF, IL-1β), and chemokines (CCL3, CXCL8). We documented that rPMC priming with poly(I:C) did not affect FcεRI-dependent degranulation. However, their costimulation with TLR3 agonist and anti-IgE led to a significant increase in cysLT and TNF secretion. Our findings confirm that MCs may serve as active participants in the antiviral immune response. Presented data on modulated FcεRI-mediated MC secretion of mediators upon poly(I:C) treatment suggests that dsRNA-type virus infection could influence the severity of allergic reactions.

From in vitro evaluation to human postmortem pre-validation of a radiopaque and resorbable internal biliary stent for liver transplantation applications

The implantation of an internal biliary stent (IBS) during liver transplantation has recently been shown to reduce biliary complications. To avoid a potentially morbid ablation procedure, we developed a resorbable and radiopaque internal biliary stent (RIBS). We studied the mechanical and radiological properties of RIBS upon in vivo implantation in rats and we evaluated RIBS implantability in human anatomical specimens.For this purpose, a blend of PLA50-PEG-PLA50 triblock copolymer, used as a polymer matrix, and of X-ray-visible triiodobenzoate-poly(ε-caprolactone) copolymer (PCL-TIB), as a radiopaque additive, was used to design X-ray-visible RIBS. Samples were implanted in the peritoneal cavity of rats. The radiological, chemical, and biomechanical properties were evaluated during degradation. Further histological studies were carried out to evaluate the degradation and compatibility of the RIBS. A human cadaver implantability study was also performed.The in vivo results revealed a decline in the RIBS mechanical properties within 3 months, whereas clear and stable X-ray visualization of the RIBS was possible for up to 6 months. Histological analyses confirmed compatibility and resorption of the RIBS, with a limited inflammatory response. The RIBS could be successfully implanted in human anatomic specimens. The results reported in this study will allow the development of trackable and degradable IBS to reduce biliary complications after liver transplantation. Statement of SignificanceBiliary reconstruction during liver transplantation is an important source of postoperative morbidity and mortality although it is generally considered as an easy step of a difficult surgery. In this frame, internal biliary stent (IBS) implantation is beneficial to reduce biliary anastomosis complications (leakage, stricture). However, current IBS are made of non-degradable silicone elastomeric materials, which leads to an additional ablation procedure involving potential complications and additional costs. The present study provides in vitro and human postmortem implantation data related to the development and evaluation of a resorbable and radiopaque internal biliary stent (RIBS) that could tackle these drawbacks.

Cultivation of Leptospira interrogans Within Rat Peritoneal Dialysis Membrane Chambers.

In order to sustain its zoonotic lifecycle, leptospires must adapt to growth within the host milieu. Signals encountered within the mammal also trigger regulatory programs required by Leptospira for the expression of virulence-related gene products. The complex transcriptional, antigenic, and physiological changes leptospires undergo within the mammal are collectively referred to as "host adaptation." In this chapter, we describe the procedures for the generation of host-adapted Leptospira spp. by cultivation within dialysis membrane chambers (DMCs) implanted in rat peritoneal cavities. In this model, Leptospira spp. diluted in EMJH medium are sequestered within sterile dialysis membrane tubing closed at both ends. The chamber then is surgically implanted within the peritoneal cavity of a rat and incubated for 7-10days. During this period, leptospires are exposed to many, if not all, of the physiological and nutritional cues required for host adaptation while at the same time protected from clearance by host innate and adaptive immune defenses.

Design and characterization of a porous pouch to prevent peritoneal adhesions during in vivo vascular graft maturation

Vein grafts for coronary artery bypass are not available in more than 30% of patients due to prior use or systemic vascular diseases. Tissue engineered vascular grafts (TEVGs) have shown promise, but intimal hyperplasia and graft thrombosis are still concerns when grafted in small-diameter arteries. In this study, we utilized the peritoneal cavity as an “in vivo” bioreactor to recruit autologous cells to electrospun conduits enclosed within porous pouches to improve the response after grafting. Specifically, we designed a new poly (ethylene glycol)-based pouch to avoid adhesion to the peritoneal wall and still allow the necessary peritoneal fluid to reach the enclosed conduit. The pouch mechanics in compression and bending were determined through experiments and finite element simulations to optimize the pouch design. This included poly (ethylene glycol) concentration, pore density, and pouch size. We demonstrated that the optimized pouch was able to withstand the estimated forces applied in the rat peritoneal cavity and it allowed maturation of the enclosed electrospun conduit. This pouch significantly reduced peritoneal adhesion formation compared to polytetrafluoroethylene pouches that have been used previously, which overcomes this potential limitation to clinical translation. After aortic grafting of pre-conditioned conduits, patent grafts with limited intimal hyperplasia were observed. Overall, this study demonstrated a new pouch design that allows the in vivo bioreactor strategy to be used for vascular tissue engineering without the potential side effect of peritoneal adhesion formation.

Combination of inductive effect of lipopolysaccharide and in situ mechanical conditioning for forming an autologous vascular graft in vivo

Autologous vascular grafts have the advantages of better biocompatibility and prognosis. However, previous studies that implanted bare polymer tubes in animals to grow autologous tubular tissues were limited by their poor yield rates and stability. To enhance the yield rate of the tubular tissue, we employed a design with the addition of overlaid autologous whole blood scaffold containing lipopolysaccharides (LPS). Furthermore, we applied in vivo dynamic mechanical stimuli through cyclically inflatable silicone tube to improve the mechanical properties of the harvested tissues. The effectiveness of the modification was examined by implanting the tubes in the peritoneal cavity of rats. A group without mechanical stimuli served as the controls. After 24 days of culture including 16 days of cyclic mechanical stimuli, we harvested the tubular tissue forming on the silicone tube for analysis or further autologous interposition vascular grafting. In comparison with those without cyclic dynamic stimuli, tubular tissues with this treatment during in vivo culture had stronger mechanical properties, better smooth muscle differentiation, and more collagen and elastin expression by the end of incubation period in the peritoneal cavity. The grafts remained patent after 4 months of implantation and showed the presence of endothelial and smooth muscle cells. This model shows a new prospect for vascular tissue engineering.

Adipocytokines leptin and adiponectin function as mast cell activity modulators.

A growing body of data indicates that adipocytokines, including leptin and adiponectin, are critical components not only of metabolic regulation but also of the immune system, mainly by influencing the activity of cells participating in immunological and inflammatory processes. As mast cells (MCs) are the key players in the course of those mechanisms, this study aimed to evaluate the impact of leptin and adiponectin on some aspects of MC activity. We documented that in vivo differentiated mature tissue MCs from the rat peritoneal cavity express a receptor for leptin (OB-R), as well as receptors for adiponectin (AdipoR1 and AdipoR2). We established that leptin, but not adiponectin, stimulates MCs to release of histamine as well as to generation of cysteinyl leukotrienes (cysLTs) and chemokine CCL2. We also found that both adipocytokines affect mRNA expression of various cytokines/chemokines. Leptin and adiponectin also activate MCs to produce reactive oxygen species. Moreover, we documented that leptin significantly augments the surface expression of receptors for cysLTs, i.e. CYSLTR1, CYSLTR2, and GPR17 on MCs, while adiponectin increases only GPR17 expression, and decreases CYSLTR2. Finally, we showed that both adipocytokines serve as potent chemoattractants for MCs. In intracellular signaling in MCs activated by leptin Janus-activated kinase 2, phospholipase C, phosphatidylinositol 3-kinase (PI3K), extracellular signal-regulated kinase (ERK1/2), and p38 molecules play a part whereas the adiponectin-induced activity of MCs is mediated through PI3K, p38, and ERK1/2 pathways. Our observations that leptin and adiponectin regulate MC activity might indicate that adipocytokines modulate the different processes in which MCs are involved.

Evidence for novel tubular-bundle structures entangled in the fascia of the inner abdominal wall of a rat

After incubation with Janus Green B in the peritoneal cavities of rats, lymph-vessel-like structures (LSs) were noticed under a stereomicroscope to run parallel to each other with rectangular branches on the inner abdominal wall; rarely were these LSs seen to connect with peritoneal LSs. These LSs were identified by using fluorescence microscopy (FM) at a magnification of 1,000X and confocal laser scanning microscopy (CLSM) to be lymph-vessel-like bundle structures (LBSs). Serial cross-sections of these LBSs were microscopically examined by using hematoxylin and eosin staining, Mattson trichrome staining, terminal deoxynucleotidyl transferase dUTP nick end labeling, and immunohistochemistry (IHC) with Lyve 1 and CD 31. The histology data from these LBSs revealed such novel characteristics as parallel clusters of live cells wrapped by collagen fibers of the fascia and an IHC different from those of lymphatic and blood vessels, being the novel bundle structures (NBSs). Under FM and CLSM with optical sections, some of the NBSs were observed to be able to swell like tiny balloons, implying that the bundle structures were hollow. Moreover, transmission electron microscopy images of two different cross-sections of an NBS showed it to be composed of four parallel tubules involving three kinds of sinuses with neither axons nor Schwann cells in the outermost wall, thus being a novel tubular-bundle structure (NTBS). The results of this research make evident with high repeatability (10/11) that beyond the orthodoxy of a single-tube system of blood and lymph vessels, a system of NTBSs is widely entangled in the fascia of the inner abdominal wall of a rat. Thus, the author suggests that NTBS-related functions and the entire NTBS network should be explored.

The pharmacokinetics of porcine C-peptide after intraperitoneal injection.

Previously, we have demonstrated that there were very low C-Peptide concentrations and normal blood glucose levels when we transplanted encapsulated islets in the abdominal cavity of diabetic nude mice. In addition, the C-peptide concentration in the ascites fluid of the peritoneal cavity was 40 times higher than in the peripheral blood. In this study, we investigated the pharmacokinetics of intraperitoneal porcine C-peptide. To assess the pharmacokinetics of porcine C-peptide, a synthesized porcine C-peptide solution was injected into the peripheral circulation through the tail vein or into the peritoneal cavity in rats at low or high doses of either 200 or 2000pmol/kg, respectively. Arterial blood samples were collected at time intervals of 1-120minutes after injection to calculate the terminal elimination half-life (t1/2 ) and area under the time-concentration curve (AUC0-t ). After intraperitoneal C-peptide injection, the highest porcine C-peptide concentration in peripheral blood was only one-fortieth compared to after intravenous injection. The AUC0-t for the intraperitoneal injection was 78% at the low dose and only 39% at the high dose compared to the intravenous injection. This finding indicates that C-peptide remains in the abdominal cavity when intraperitoneally transplanted islets release C-peptide via high glucose stimulation. Porcine C-peptide injected into a peritoneal cavity slowly and incompletely entered peripheral circulation, which resulted in very low concentration in peripheral blood.

Antiadhesion effect of the C17 glycerin ester of isoprenoid-type lipid forming a nonlamellar liquid crystal

Postoperative adhesion is a relevant clinical problem that causes a variety of clinical complications after abdominal surgery. The objective of this study is to develop a liquid-type antiadhesion agent and evaluate its efficacy in preventing tissue adhesion in a rat peritoneal adhesion model. The liquid-type agent was prepared by submicron-sized emulsification of C17 glycerin ester (C17GE), squalene, pluronic F127, ethanol, and water with a high-pressure homogenizer. The primary component was C17GE, which is an amphiphilic lipid of one isoprenoid-type hydrophobic chain and can form two phases of self-assembly nonlamellar liquid crystals. The C17GE agent consisted of nanoparticles with an internal inverted hexagonal phase when evaluated by small-angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (cryo-TEM). Upon contact with the biological tissue, this agent formed a thin membrane with a bioadhesive property. After this agent was applied to a sidewall injury of rats, it showed a percentage average of adhesion significantly less than that obtained with the Seprafilm® antiadhesion membrane in a rat model. Additionally, the retention of the agent prolonged at the applied site in the peritoneal cavity of rats. In conclusion, the C17GE agent is promising as an antiadhesion material. Statement of SignificancePostoperative adhesion remains a common adverse effect. Although various materials have been investigated, there are few products commercially available to prevent adhesion. For the sheet-type agent, it is inconvenient to be applied through small laparotomy, especially in laparoscopic surgery. Additionally, the liquid-type agent currently used requires a complicated procedure to spray at the targeted site.Our liquid-type antiadhesion agent can form liquid crystals and act as a thin membrane-like physical barrier between the peritoneum and tissues to prevent adhesion. Indeed, the antiadhesion agent used in our present study significantly prevents adhesion compared with the antiadhesion membrane most used clinically. Moreover, our agent is highly stable by itself and easy to use in laparoscopic surgery, thus leading to a promising new candidate as an antiadhesion material.

Experimental study on application of polypropylene hernia of fat stem cells in rats.

An inguinal hernia is the most common type of external abdominal hernia. Normal surgery utilized polypropylene mesh to fix a hernia, but often leads to adverse effects including pain and foreign body sensation. Adipose-derived stem cells are pluripotent stem cells that can be differentiated into adipocytes, chondrocytes, skeletal myoblast and osteoblast. The compatibility of stem cells with absorbent material mesh or cellular biology mesh has been studied. This study investigated the application of adipose-derived stem cells coated polypropylene mesh in treating an inguinal hernia. Adipose-derived stem cells were separated and cultured from adipose tissues of SD rats. Flow cytometry was utilized to determine antigen subtype including CD90, CD34, CD44, and CD45 on the cell surface. Those cells were then induced to be differentiated into adipocytes, osteocytes and chondrocytes. Adipose-derived stem cells coated polypropylene mesh was then prepared and implanted under a muscular layer of rat peritoneal cavity. The occurrence of hematoma and routine blood indexes were examined. Adipose-derived stem cells showed attached growth with satisfactory proliferation ability. Flow cytometry results showed positive rates for CD90, CD44, CD34, and CD45 at 98.2% ± 1.4%, 97.6% ± 2.3%, 54.3% ± 6.3%, and 13.4% ± 4.2%, respectively. Adipose-derived stem cells had the potency of differentiation. The application of novel mesh decreased macrophage number and lymphocytes (p < 0.01) but not leukocytes or neutrophils (p > 0.05). Adipose-derived stem cells coated polypropylene mesh can decrease the inflammation post inguinal hernia and can be used as one novel biomaterial in treating an inguinal hernia.

Lipopolysaccharide up-regulates IP-10 expression through the activation of NF-κB in rat peritoneal mesothelial cells

Objective To observe the expression of interferon induced protein (IP) -10 and the role of nuclear factor-kappaB (NF-κB) signaling pathway in rat peritoneal mesothelial cells (RPMCs) under the action of lipopolysaccharide (LPS). Methods RPMCs were harvested from Sprague-Dawley rat peritoneal cavity and cultured under defined in vitro conditions. The cells were exposed respectively to different concentrations of LPS (0, 10, 100, 1 000, 10 000 ng/ml) for 3 h or treated with LPS (100 ng/ml) for different time points (0, 1, 3, 6, 12, 24, 48 h). For observing the effect of LPS on the expression of p-p65 and p65, the RPMCs were treated with LPS (100 ng/ml) for different time points (0, 15, 30, 60, 120 min). For observing the effect of BAY11-7085 on the expression of IP-10 mRNA, the RPMCs were treated by LPS or pretreated with BAY11-7085 (5 μmol/L) for 2 h, then treated with LPS for another 3 h, respectively. Expression of IP-10 mRNA was examined by reverse transcription-polymerase chain reaction (RT-PCR). Expression of NF-κB and p-NF-κB protein was detected by Western blot. The secretion of IP-10 was determined by enzyme-linked immunosorbent assay (ELISA). Results Compared with the control group, stimulation of RPMCs with 10 ng/ml LPS resulted in a significant increase in the expression of IP-10 mRNA (P<0.05). 1 000 ng/ml LPS has the strongest effect on IP-10 expression compared with that of 10 ng/ml and 100 ng/ml LPS. Treatment with 100 ng/ml LPS resulted in time-dependent increase in the gene level of IP-10, with the peak at 3 h. However, after that time point, the gene level of them was gradually attenuated. Following treatment with LPS (100 ng/ml), the level of p-NF-κB began to increase at 15 min, gradually reached the peak at 1 hour, and then decreased. But the level of which at 2 h is still significant higher than that of medium control. 5 μmol/L BAY11-7085 significantly decreased the up-regulation of IP-10 induced by LPS. Conclusions LPS enhanced the expression of IP-10 on RPMCs in a concentration-dependent and a time-dependent manner. LPS induced expression of IP-10 depended on the NF-κB signal transduction pathway. Key words: Lipopolysaccharides/PD; Peritoneum/CY; Epithelium/DE; Chemokine CXCL10/ME; NF-kappa B; Rats