Figure 1.
Increase of the Treg population in splenocytes by PLA2.
Splenocytes from Foxp3EGFP mice were treated with various concentrations of PLA2 and PBS for three days. The flow cytometry data showed a population of Tregs in the groups of PBS-treated and PLA2 (10 µg/ml)-treated CD4+ T cells (A). The populations of CD25+Foxp3+ T cells treated with various concentrations of PLA2 are depicted as percentages of the total CD4+ T cells (B). The values shown indicate the means ± S.E.M. *P<0.05 vs. PBS, **P<0.01 vs. PBS, ***P<0.01 vs. PBS.
Figure 2.
Protective effects of PLA2 on acetaminophen-induced hepatotoxicity.
Mice were administered PLA2 (0.2 mg/kg) once a day for five days. The control group received the same volume of PBS. After the fifth administration of PLA2 or PBS, all of the mice received a single injection of acetaminophen (500 mg/kg). Blood samples were collected 0, 6 and at 24 h, and the mice were sacrificed under ether anesthesia 24 h after acetaminophen injection (n = 10). Hepatic dysfunction was confirmed based on the AST (B) and ALT levels (C) and H&E staining (A). The values shown indicate the means ± S.E.M. *P<0.05 vs. APAP, **P<0.01 vs. APAP, ***P<0.001 vs. APAP.
Figure 3.
Effect of PLA2 in CD25-depleted mice.
To deplete Tregs, an anti-CD25 antibody (0.1 mg/mouse) was injected i.p. each day before the PLA2 and acetaminophen injections. Blood was collected 6 and 24 h after the acetaminophen injection for the measurement of the AST (A) and ALT levels (B) (n = 6). There was no difference between the PBS-treated (APAP) and PLA2-treated (APAP + PLA2) CD25-depleted mice.
Figure 4.
Proinflammatory cytokines in the liver.
The proinflammatory cytokines and NO in the liver tissue from normal and CD25-depleted mice were measured by ELISA and the Griess method, respectively. The hepatic TNF (A), IL-6 (B) and NO levels (C) were decreased in the PLA2-treated group (APAP + PLA2) compared with the PBS-treated group (APAP). However, there was no difference between the PBS-treated and PLA2-treated mice in the anti-CD25 model. The values shown indicate the means ± S.E.M. *P<0.05 vs. APAP, **P<0.01 vs. APAP, ***P<0.001 vs. APAP, #P<0.05 vs. Con, ##P<0.01 vs. Con, ###P<0.001 vs. Con, NS; P>0.05 vs. APAP in anti-CD25 mice (n = 6–8).
Figure 5.
Hepatoprotective effects of PLA2 were mediated by IL-10 production.
Mice were injected with acetaminophen (500 mg/kg, i.p.) after PBS or PLA2 injection. Blood samples were collected 6 h after acetaminophen injection (n = 10). IL-10 production in the serum was measured by ELISA (A). IL-10-deficient mice were injected with acetaminophen (500 mg/kg, i.p.) after PBS or PLA2 injection. Blood samples were collected 24 h after acetaminophen injection (B∼D, n = 4). Hepatic dysfunction was reflected by the levels of AST (C) and ALT (D). There was no difference between the PBS-treated (APAP) and PLA2-treated (APAP + PLA2) IL-10−/− mice (B∼D).