To explore the immunological mechanisms underlying the effect of exogenous interleukin-34 (IL-34) on collagen-induced arthritis (CIA) in mouse. We established a CIA mouse model and injected exogenous recombination mouse IL-34 (rmIL-34) intraperitoneally. The articular index (AI) was measured according to the amount of erythema, swelling, or joint rigidity. The concentrations of TNF-α, IL-17, and IL-6 in CIA mice sera were measured by enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of TNF-α, IL-17, and IL-6 in CIA synovial tissue were detected by reverse transcription PCR. The CIA mice dosed with rmIL-34 exhibited increased AI. Neutralization of endogenous IL-17 with anti-IL-17 antibody reduced the effect of IL-34. TNF-α, IL-17, and IL-6 levels in serum in IL-34-treated CIA mice were increased compared to those in CIA mice. IL-34 increased the expression of TNF-α and IL-17 mRNA in synovial tissues of CIA mice, but the gene expression of IL-6 was not affected. The effects of IL-34 on TNF-α, IL-17, and IL-6 expression were abolished by anti-IL-17 antibody. In conclusion, IL-34 acts as a proinflammatory factor, aggravating the severity of arthritis in CIA mice by inducing the production of IL-17.

No abstract

Cadmium (Cd), a heavy metal, has harmful effects on animal and human health, and it can also obviously induce cell apoptosis. Quercetin (Que) is a flavonoid compound with antioxidant and other biological activities. To investigate the protective effect of Que on Cd-induced renal apoptosis in rats. 24 male SD rats were randomly divided into four groups. They were treated as follows: control group was administered orally with normal saline (10 ml/kg); Cd group was injected with 2 mg/kg CdCl2 intraperitoneally; Cd + Que group was injected with 2 mg/kg CdCl2 and intragastric administration of Que (100 mg/kg); Que group was administered orally with Que (100 mg/kg). The experimental results showed that the body weight of Cd-exposed rats significantly decreased and the kidney coefficient increased. In addition, Cd significantly increased the contents of Blood Urea Nitrogen, Creatinine and Uric acid. Cd also increased the glutathione and malondialdehyde contents in renal tissues. The pathological section showed that Cd can cause pathological damages such as narrow lumen and renal interstitial congestion. Cd-induced apoptosis of kidney, which could activate the mRNA and protein expression levels of Cyt-c, Caspase-9 and Caspase-3 were significantly increased. Conversely, Que significantly reduces kidney damage caused by Cd. Kidney pathological damage was alleviated by Que. Que inhibited Cd-induced apoptosis and decreased Cyt-c, Caspase-9 and Caspase-3 proteins and mRNA expression levels. To sum up, Cd can induce kidney injury and apoptosis of renal cells, while Que can reduce Cd-induced kidney damage by reducing oxidative stress and inhibiting apoptosis. These results provide a theoretical basis for the clinical application of Que in the prevention and treatment of cadmium poisoning.

Cadmium (Cd) is a toxic heavy metal extensively used in industrial and agricultural production. Among the main mechanisms of Cd-induced liver damage is oxidative stress. Quercetin (QE) is a natural antioxidant. Herein, the protective effect of QE on Cd-induced hepatocyte injury was investigated. BRL-3A cells were treated with 12.5 μmol/L CdCl2 and/or 5 μmol/L QE for 24 h. The cells and medium supernatant were collected, and the ALT, AST, and LDH contents of the medium supernatant were detected. The activities or contents of SOD, CAT, GSH, and MDA in cells were determined. Intracellular ROS levels were examined by flow cytometry. Apoptosis rate and mitochondrial-membrane potential (ΔΨm) were detected by Hoechst 33,258 and JC-1 methods, respectively. The mRNA and protein expression levels of Nrf2, NQO1, Keap1, CytC, caspase-9, caspase-3, Bax, and Bcl-2 were determined by real-time PCR (RT-PCR) and Western blot methods. Results showed that Cd exposure injured BRL-3A cells, the activity of antioxidant enzymes decreased and the cell ROS level increased, whereas the ΔΨm decreased, and the expression of apoptotic genes increased. Cd inhibited the Nrf2-Keap1 pathway, decreased Nrf2 and NQO1, or increased Keap1 mRNA and protein expression. Through the combined action of Cd and QE, QE activated the Nrf2-Keap1 pathway. Consequently, antioxidant-enzyme activity decreased, cellular ROS level decreased, ΔΨm increased, Cd-induced BRL-3A cell damage was alleviated, and cell apoptosis was inhibited. After the combined action of QE and Cd, Nrf2 and NQO1 mRNA and protein expression increased, Keap1 mRNA and protein expression decreased. Therefore, QE exerted an antioxidant effect by activating the Nrf2-Keap1 pathway in BRL-3A cells.

Background: Cadmium (Cd) is a widespread environmental toxic heavy metal. Naringin (Nar) is reported to have a protective effect on Cd-induced liver injury. This study aimed to explore the hepatic injury induced by Cd and the protective effects of Nar on Cd-induced oxidative stress and apoptosis in rat liver. Methods: In accordance with groups, male SD rats were injected intraperitoneally with Cd and orally with Nar every day. The treatment period was 3 weeks. Body weight, the morphological changes in liver, the activity of antioxidant indices and expression of the apoptotic genes caspase-3 and -9 were assessed. Result: Results showed that the body weight of Cd-exposed rats decreased, the superoxide dismutase and catalase activities in liver decreased, the glutathione content decreased and the malondialdehyde content increased. Further, Cd-induced hepatic structural damage and cell apoptosis were observed. However, Nar could alleviate liver damage caused by Cd. Therefore, Cd caused oxidative damage and cell apoptosis in rat liver, while Nar had preventive and ameliorative effects on these injuries.