[Experimental study of the influence of Sini decoction on the inflammatory response and the immune function in septic...

To observe the effect of Sini decoction on inflammatory response and immune function in septic rats and to discuss its possible mechanism.

66 Sprague-Dawley (SD) rats were randomly divided into normal control group (n=6), model group (n=30), and Sini decoction group (n=30). Septic model was reproduced by intraperitoneal injection of lipopolysaccharide (LPS, 5 mg/kg). After the reproduction of sepsis, rats in Sini decoction group received Sini decoction (5 g/kg) by gavage, while those in model group were given equal dose of normal saline in the same way. Rats in normal control group did not receive any treatment. Blood was collected via eye sockets at 2, 12, 24, 48, 72 hours after LPS administration, then the rats were sacrificed. The concentrations of inflammatory mediators, such as interleukin (IL-1, IL-6, IL-10), tumor necrosis factor-α (TNF-α), and the expression level of monocyte human leukocyte antigen-DR (HLA-DR) were determined with enzyme linked immunosorbent assay (ELISA), and the pathological changes in intestinal mucosa were observed under electron microscope.

The concentration of IL-1 at 2 hours in model group was gradually increased and peaked at 48 hours (4.07±0.10 ng/L), and then gradually decreased, while the IL-1 level in Sini decoction group peaked at 12 hours (2.98±0.12 ng/L) followed by a gradual decrease. IL-6 in model and Sini decoction groups peaked twice at 12 hours (91.39±1.55 ng/L, 73.00±2.38 ng/L) and 48 hours (82.51±1.49 ng/L, 64.68±1.68 ng/L) respectively. IL-10 in model group gradually decreased after peaking at 2 hours (86.66±6.12 ng/L), and that in Sini decoction decreased at 12 hours (71.61±2.35 ng/L) followed by an increasing tendency, and approached normal level at 48 hours (109.09±4.77 ng/L vs. 124.01±7.89 ng/L, P>0.05). TNF-α in model group was gradually increased and peaked at 48 hours (83.37±3.79 ng/L), and that in Sini decoction peaked at 12 hours (48.52±1.21 ng/L), and decreased to normal level at 72 hours (18.59±1.97 ng/L vs. 15.50±2.68 ng/L, P>0.05). During the course of the experiment, as compared with those of the model group, level of IL-1, IL-6, and TNF-α were significantly lower at all time points in Sini decoction group, and IL-10 was significantly higher. The expression level of HLA-DR in model and Sini decoction groups peaked at 2 hours (4.86±0.15 μg/L, 4.85±0.17 μg/L), and then gradually lowered. HLA-DR expression at 48 hours and 72 hours in Sini decoction group was significantly lower than that in model group (48 hours: 4.21±0.12 μg/L vs. 2.74±0.16 μg/L, 72 hours: 3.80±0.09 μg/L vs. 2.27±0.12 μg/L, both P<0.01). Pathological study of intestinal mucosa showed that the intestinal mucosa were infiltrated significantly by inflammatory cells, and villi were damaged severely in both model group and Sini decoction group at 2 hours after LPS challenge. Infiltration of inflammatory cells in Sini decoction group was less intense after 12 hours, and the intestine villi repair was more obvious compared with model group.

Sini decoction could regulate systemic inflammatory response, and promote the repair of intestinal mucosa, the intestinal function and the immune status of septic rats.