ABSTRACT
Objective To investigate the protective effect of recombinant adult serine protease inhibitor from Trichinella spiralis (TsadSPI) on sepsis-associated acute kidney injury in mice. Methods A total of 18 male BALB/c mice were randomly divided into the sham-operation group, the model group, and the TsadSPI treatment group, of 6 mice in each group. Sepsis-associated acute kidney injury was modeled in the model group and TsadSPI treatment group by cecal ligation puncture (CLP), while mice in the sham-operation group were only given exploratory laparotomy without ligation or perforation of the cecum. After 30 min of CLP, mice in the sham-operation group and the model group were intraperitoneally injected with PBS (100 μL), and mice in the TsadSPI treatment group were intraperitoneally injected with PBS (100 μL) containing TsadSPI (2 μg). At 12 h following modeling, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr) and urea nitrogen (BUN) were measured to assess the liver and kidney functions, and the changes of the mouse kidney structure were observed using HE staining. In addition, the serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and transforming growth factor (TGF)-β were measured using an enzyme-linked immunosorbent assay (ELISA), and the myeloid differentiation factor 88 (MyD88) and nuclear factor kappa-B (NF-κB) p65 expression was determined in kidney tissues using immunohistochemical staining. Results At 12 h following CLP, there were significant differences in the serum levels of ALT (F = 41.031, P < 0.001), AST (F = 54.757, P < 0.001), Cr (F = 24.142, P < 0.001) and BUN (F = 214.849, P < 0.001) among the three groups, and higher levels of ALT, AST, Cr and BUN were measured in model group than in the sham-operation group (P < 0.001), while lower ALT, AST, Cr and BUN levels were found in the TsadSPI treatment group than in the model group (P < 0.001). HE staining showed severe mouse kidney injuries following CLP, and TsadSPI treatment resulted in remarkable alleviation of the injury. ELISA measured significant differences in the TNF-α (F = 47.502, P < 0.001) and IL-6 levels (F = 222.061, P < 0.001) among the three groups, and showed a remarkable reduction in the TNF-α and IL-6 levels in the TsadSPI treatment group as compared to those in the model group (P < 0.001). In addition, there were significant differences in serum IL-10 (F = 16.227, P < 0.001) and TGF-β levels (F = 52.092, P < 0.001) among the three groups, and higher IL-10 and TGF-β levels were seen in the TsadSPI treatment group than in the model group (P < 0.001). Immunohistochemical staining showed greater MyD88 expression and a higher nuclear positive rate of NF-κB p65 in kidney tissues in the model group than in the TsadSPI treatment group. Conclusions TsadSPI may reduce the MyD88 expression and nuclear positive rate of NF-κB p65 in mouse kidney tissues to up-regulate the expression of immunomodulatory factors and down-regulate the expression of pro-inflammatory cytokines, thereby protecting sepsis-associated acute kidney injury.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the effect of Schistosoma japonicum cysteine protease inhibitor (rSjCystatin) for treatment of lipopolysaccharide (LPS)-induced sepsis in mice.</p><p><b>METHODS</b>After a week of adaptive feeding, 54 BALB/c mice were randomly divided into normal control group (group A), sepsis group (group B), and rSjCystatin intervention group (group C). The mice in group A received an intraperitoneal injection of PBS (100 µL), and those in groups B and C were injected with PBS (100 µL) containing LPS (10 mg/kg); the mice in group C were also intraperitoneally injected with 25 µg sjCystatin in 100 µL PBS 30 min after LPS injection. From each group, 10 mice were randomly selected 24 h after PBS or LPS injection for detecting serum levels of TNF-α, IL-6, and IL-10 using ELISA and the levels of ALT, AST, BUN, and Cr using automatic biochemical analyzer; the pathological changes in the liver, lung and kidney were observed with HE staining. The remaining 8 mice in each group were used for observing the changes in the general condition and the 72-h survival.</p><p><b>RESULTS</b>The 72-h survival rates of the mice was 100% in group A, 0 in group B, and 36% in group C, showing a significant difference among the 3 groups (P<0.05). Compared with those in group A, the mice in group B exhibited obvious liver, lung, and renal pathologies with increased levels of ALT, AST, BUN, Cr, IL-6, and TNF-α (P<0.05). Treatment with sjCystatin significantly lessened LPS-induced organ pathologies, lowered the levels of liver and renal functional indexes and the pro-inflammatory cytokines, and increased the serum level of IL-10 in the mice (P<0.05).</p><p><b>CONCLUSION</b>SjCystatin can produce a significant therapeutic effect on sepsis induced by LPS in mice.</p>