The aim of this study was to determine the effect of the supplementation of an organic acid (citric acid), antibiotic growth promoter (avilamycin), a

Renal fibrosis is regarded as the common final pathway leading to chronic kidney diseases; macrophages and myofibroblasts play important roles in the development of fibrosis. F344 rats were injected once with cisplatin (CDDP; 6 mg/kg BW) for renal lesions. Here, immunophenotypical characteristics of macrophages and lymphocytes in CDDP-induced rat renal lesions were investigated histopathologically; the CDDP-induced renal lesions consisted of tissue damage at the early-stage, worsen the damage and commencement of interstitial fibrosis at the mid-stage, and progressive fibrosis at the late stage; the KIM-1 expression and α-SMA⁺ myofibroblast area reflected renal tubular damage/abnormal regeneration and renal interstitial fibrosis, respectively. CD68⁺ M1 macrophages began to increase at the mid-stage, with increased mRNA expressions of M1-related cytokines (INF-γ, TNF-α and IL-6), and then slightly decreased at the late-stage. CD163⁺ M2 macrophages showed a gradually increased number at the mid- and late-stages, accompanied by increased TGF-β1 mRNA expression (a fibrogenic factor). Double immunofluorescence using fibrotic samples at the late-stage revealed that 62.0–78.0% of CD68⁺ M1 macrophages co-expressed CD163, indicating that M1/M2 macrophages may contribute to progressive renal fibrosis in cooperation; further, MHC class II-expressing macrophages had a tendency towards M1 polarization, whereas CD204-expressing macrophages towards M2 polarization. In addition, CD4⁺ and CD8⁺ T cells were increased at the late-stage. Collectively, progressive renal interstitial fibrosis may be developed by complicated mechanisms that arose via interaction of M1/M2 macrophages (inflammatory for M1 and anti-inflammatory for M2) and T cells reacting to CD4 (for helper) and CD8 (for cytotoxicity). This study would provide some information on the pathogenesis of renal fibrosis based on inflammatory cells.

The goal of this research was to investigate the effect of citric acid (CA), the antibiotic growth promoter flavomycin (FL) and their combination on the growth performance, tibia ash and immune status of broilers. One hundred and sixty straight run day-old broiler chicks (Hubbard Classic) were randomly distributed into four dietary groups, with four replicate cages having 10 birds in each. Standard corn-soybean-based basal starter diet was given to control birds. Diets for other groups were further fortified by 0.5% CA, 0.001% FL and their combination (0.5% CA plus 0.001% FL). On day 35, CA and its combination (CA + FL) group had 17 and 12% increase in live weight compared with control, respectively (P < 0.05). Total live weight on day 35 was 1141, 1337, 1169, and 1275 g bird^-1 in different groups, respectively (P < 0.05). Cumulative feed intake was higher (P < 0.05) in CA and its combination (CA + FL) compared with the control and FL groups on day 28. Supplementation with CA improved (P > 0.05) feed conversion ratio [FCR; feed intake (kg):weight gain (kg)] compared with FL and its combination (CA + FL). Carcass yield was increased (P > 0.05) due to the addition of CA and its combination (CA + FL). Tibia ash content in the CA group (59.0) was higher (P < 0.05) than in the control (53.6%), FL (53.1%) and their combination (57.1%). The lymphocyte cells associated with immunity in the lymphoid organs (caecal tonsil, bursa Fabricius and ileum) were more densely populated, suggesting an increased level of innate immunity in the CA group. Overall mortality was low (1.25%), and there were no treatment-related effects on mortality. Citric acid reduced the pH of formulated feeds, but mild reduction was found in the pH of the faeces. Dietary supplementation of 0.5% CA increase weight gain, feed intake, tibia ash deposition and non-specific immunity (P < 0.05) as well as feed efficiency and carcass yield (P > 0.05) of broilers. Citric acid has potential as a growth promoter to replace the antibiotic growth promoter FL.Key words: Citric acid, flavomycin, growth performance, immunity, tibia ash, broiler

D-galactosamine (d-GalN) is a well-known hepatotoxic agent that causes liver injury. Conversely, hepatic macrophages play a crucial role in maintaining liver tissue integrity. Macrophage functions were investigated in hepatic lesions induced by a single intraperitoneal injection of d-GalN (800 mg/kg body weight [BW]) in 6-week-old F344 rats. Blood and liver samples were examined at 8 hr and on 1, 2, 3, and 5 days postsingle injection (PSI). Hepatic lesions consisting of degeneration/sporadic foci of coagulation necrosis, inflammatory cell reaction, and reparative fibrosis were seen on PSI days 1 and 2, reflected by significantly increased serum levels of aspartate transaminase and alanine transaminase and upregulation of CD68 M1 (tumor necrosis factor-α, interleukin [IL]-6, and interferon-γ) and CD163 M2 (transforming growth factor-β1, IL-10, monocyte chemoattractant protein-1, and IL-4) macrophage-related factors. Double immunofluorescence staining on PSI day 2 demonstrated that 82% of hepatic macrophages expressed of CD163/CD68 simultaneously; 65–75% of MHC class II macrophages showed co-expression of CD163 or CD68 and 95% CD204-expressing macrophages reacted to CD163 or CD68. These findings showed that both M1- and M2-macrophages contributed to the development of hepatic lesions induced by d-GalN and provided information about macrophage activation, indicating the importance of analysis of macrophage phenotypes for hepatotoxicity based on M1/M2-polarization.

To investigate the significance of the appearance of hepatic macrophages and expression of inflammatory factors in normal and macrophage-depleted livers, hepatic macrophages were depleted with liposome (Lipo)-encapsulated clodronate (CLD; 50 mg/kg, i.v.) followed by lipopolysaccharide (LPS) administration (0.1 mg/kg, i.p.) in F344 rats (CLD + LPS). Vehicle control rats (Lipo + LPS) received empty-Lipo before LPS. The low dose of LPS did not result in microscopic changes in the liver in either treatment group but did modulate M1 and M2 macrophage activity in Lipo + LPS rats without altering repopulating hepatic macrophages in CLD + LPS rats. LPS treatment in Lipo + LPS rats dramatically increased the M1 (IL-1β, IL-6, TNF-α, and MCP-1) but not M2 macrophage-related factors (IL-4 and CSF-1) compared to CLD + LPS rats. In the CLD + LPS rats, the M2 macrophage-related factors IL-4 and CSF-1 were elevated. In conclusion, low-dose LPS activated hepatic macrophages in rat livers without causing liver injury or stimulating repopulating hepatic macrophages. These data suggest that LPS may alter the liver microenvironment by modulating M1 or M2 macrophage-related inflammatory mediators and macrophage-based hepatotoxicity.

Beta-catenin, E-cadherin and N-cadherin are adhesion molecules that play important roles in organogenesis, tissue homeostasis, renal epithelial integrity and polarity. The present study demonstrated their immunolocalization in adult and neonate rat kidney. Membranous or cytoplasmic expression of beta-catenin, E-cadherin and N-cadherin were seen in adult and developing renal tubular epithelial cells. Particularly, in adult kidney, E-cadherin and beta-catenin were intensively expressed in distal renal tubules, whereas N-cadherin was expressed in proximal renal tubules. In neonate rat kidney on 1 and 4 days old, developing renal tubular epithelial cells were mainly reacted with E-cadherin and very weakly expressed N-cadherin; beta-catenin was expressed in developing renal tubules and mesenchymal blastemal cells. Interestingly, beta-cateninpositive renal tubular epithelial cells simultaneously expressed E-cadherin in the kidney of adult and developing rats. Collectively, the adhesion molecules were differentially distributed in the renal tubules of adult rats and beta-catenin and E-cadherin are predominant adhesion molecules in developing kidney. The present findings would provide the basic information of evaluating renal tubular toxicity using rats, in addition to renal genesis, in terms of adhesion molecules.