[The roles of IL-17 and CXCR4 in chronic allograft nephropathy in rat models].

Objective: To investigate the role and mechanism of IL-17 and CXCR4 in chronic graft nephropathy (CAN) in rat models. Methods: CAN rat models were established using Fisher 344 to Lewis rats. In the control group(n=10), Lewis rats were performed isotransplantation. CAN rat models were established in experimental group(n=10). All the rats were havested 6 weeks after transplantation. Kidneys were examined by pathology to evaluate the injury of the renal allograft. SDF-1/CXCR4, IL-17 and α-SMA expression level in serum and renal graft were detected by immunohistochemical staining and Enzyme-linked immunosorbent assays(ELISA). The percent and the absolute amount of CD4(+) cells、CXCR4(+) cells and IL-17(+) cells were detected by flow cytometry. Results: The graft of the experiment group showed obvious pathological features of CAN. The protein expression levels of SDF-1/CXCR4 and IL-17 in the experiment group are significantly higher than in the control group. We could also observe the number of Th17 cells has a significant increase in the experiment group[blood (0.19±0.05)% vs (0.12±0.03)%; kidney (0.52±0.21)% vs (0.17±0.12)%]. The IL-17 level also showed the same differences between the experiment[blood (243.12±17.63) pg/ml, kidney (521.54±21.76) pg/ml]and the control group[blood (35.78±7.3) pg/ml, kidney (77.34±11.1) pg/ml]. Conclusions: The Th17 cells increase in the CAN rats model, maybe the SDF-1/CXCR4 has a chemotaxis to collect Th17 cells to the injured kidney. And its expression of IL-17 may promote the renal cells to transform into fibroblasts.

Identification and characterization of Laodelphax striatellus (Insecta: Hemiptera: Delphacidae) neutral sphingomyelinase.

The neutral sphingomyelinase (nSMase) 1 homologue gene LsSMase was cloned from Laodelphax striatellus, a direct sap-sucker and virus vector of gramineous plants, and expressed via a Bac to Bac baculovirus expression system. The LsSMase-enhanced green fluorescent protein fusion protein was located in the endoplasmic reticulum in a similar manner to mammalian nSMase 1. The biochemical properties of LsSMase were determined in detail. The optimal pH and temperature for recombinant LsSMase were 8 and 37 °C, respectively. LsSMase was an Mg2+ or Mn2+ dependent enzyme, but different concentration of each were needed. The activity of LsSMase was significantly stimulated by Ethylene glycol bis(2-aminoethyl ether)tetraacetic acid (EGTA), whereas it was inhibited by ethylenediaminetetraacetic acid. Millimolar concentrations of Zn2+ completely inhibited LsSMase. The reducing agents dithiothreitol and ß-mercaptoethanol varied in their effects on activity. Phospholipids were not found to stimulate LsSMase.