Objective: To investigate the effect of Schistosoma japonicum infection on lipid status in mouse serum.
Methods: Twenty-four ICR mice were randomly divided into two groups, fed a high fat diet (HFD) or a normal diet (ND). On the 28th day, 6 mice from each group were infected with double sex cercariae of S. japonicum via abdominal skin (150 cercariae/mouse). At 42 days post-infection, the mice were sacrificed and the sera were collected. Other 36 ICR mice were randomly divided into three groups fed on normal diet. Mice in the first group were infected with S. japonicum single-sex cercariae via abdominal skin (150 cercariae/mouse) and sacrificed on Day 42. Mice in the second group were intraperitoneally injected with 10,000 S. japonicum eggs and serum samples were collected at Day 4 and Day 7. Mice in the third group were intraperitoneally injected with soluble egg antigen (SEA) every day for 6 days [1 mg/(mice x d)] and serum was collected at Day 7. Mice from control group were fed a high fat diet or a normal diet without infection. Serum levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), and low density lipoprotein (LDL) were measured.
Results: Compared with the uninfected controls, the serum levels of TC, TG, HDL, and LDL decreased significantly in double-sex cercariae infected-mice fed on a high fat diet or a normal diet (P < 0.05). In HFD group, serum TC[(1.45 +/- 0.31) mmol/L], TG [(0.17 +/- 0.06)mmol/L], HDL [(1.11 +/- 0.26) mmol/L] and LDL [(0.44 +/- 0.15)mmol/L] levels in mice infected with double-sex cercariae were lower than that of uninfected mice [(7.86 +/- 0.07)mmol/L, (0.23 +/- 0.07) mmol/L, (4.96 +/- 0.81) mmol/L, (3.93 +/- 0.29) mmol/L] (P < 0.05) . In ND group, serum TC [(1.03 +/- 0.08) mmol/L] , TG [(0.17 +/- 0.03) mmol/L], HDL [(0.84 +/- 0.02) mmol/L], and LDL [(0.09 +/- 0.02) mmol/L] levels in mice infected with double-sex cercariae were lower than that of uninfected mice [(1.85 +/- 0.05) mmol/L, (0.90 +/- 0.14) mmol/L (1.38 +/- 0.18) mmol/L, (0.15 +/- 0.01) mmol/L, respectively] (P < 0.05) . The mice serum lipid indices had no obvious change after single-sex cercariae or egg injection (P > 0.05). Serum TC [(1.07 +/- 0.15) mmol/L], TG [(1.06 +/- 0.15) mmol/L], HDL [(0.71 +/- 0.14) mmol/L], and LDL [(0.05 +/- 0.04) mmol/L] levels in SEA injected mice were lower than that of the control group [(1.81 +/- 0.06) mmol/L, (2.15 +/- 0.13) mmol/L, (1.160.15) mmol/L, (0.16 +/- 0.03) mmol/L] (P < 0.05).
Conclusion: Schistosoma japonicum infection can decrease serum lipid concentrations in the mouse host.