[Effect and mechanism of acupoint injection on influenza A virus induced pneumonia in mice].

Objective: To investigate the effect and mechanism of acupoint injection with 0.1% vitamin C+vitamin B complex solution (V+VCo) at "Tiantu" (CV 22), "Quchi" (LI 11) and "Zusanli" (ST 36) in mouse model of pneumonia induced by influenza A virus (A/PR/8/34 [H1N1], PR8).

Methods: Sixty male ICR mice were randomized into 6 groups, i.e. control group, model group, acupoint injection group, intraperitoneal injection group, non-target point group and ribavirin group, 10 mice in each one. Except the control group, the pneumonia models were induced by slow nasal dripping PR8 virus in the other groups. On the 2nd day of experiment, V+VCo solution, 40 μL was injected at "Tiantu" (CV 22), "Quchi" (LI 11, left) and "Zusanli" (ST 36, left) in the acupoint injection group; V+VCo solution, 120 μL was injected intraperitoneally in the intraperitoneal injection group; V+VCo solution, 40 μL was injected at non-target acupoints (0.5 cm away from "Tiantu" [CV 22] to the left side, "Quchi" [LI 11, left] and "Zusanli" [ST 36, left]) in the non-target point group; and ribavirin solution, 120 μL was injected intraperitoneally in the ribavirin group. The intervention was delivered once daily, for consecutive 7 days. Three parallel experiments were undertaken. The mean death rate and survival time were assessed in each group, the body mass and lung index were compared among groups. Using HE staining, the morphology of lung tissue was observed; and with real-time fluorescence quantitative PCR, viral load in lung tissue was detected. The concentrations of inflammatory factors (tumor necrosis factor α [TNF-α], interleukin [IL]-1β, IL-10) were detected in lung tissue of each group using ELISA; and those of oxidative stress markers (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px], malondialdehyde [MDA]) were detected with chemiluminescence method.

Results: Compared with the control group, the body mass was decreased and lung index was increased in the model group (<0.01). In comparison with the model group, body mass was increased in the acupoint injection group (<0.05), lung index was reduced in the acupoint injection group the and ribavirin group (<0.05); the mean death rate was decreased and the mean survival time prolonged in the mice of the acupoint injection group (<0.01, <0.05); and the mean death rate was reduced in the mice of the ribavirin group (<0.05). In the model group, the alveolar structure was not integral, the alveolar septum was thickened, inflammatory cells were infiltrated and red blood cells exudated seriously (<0.01). Compared with the model group, in the acupoint injection group and the ribavirin group, the alveolar structure was integral, the thickened alveolar septum was alleviated; and the infiltration of inflammatory cells and the exudation of red blood cells were reduced remarkably. The viral load was reduced in the mice of the ribavirin group when compared with the model group (<0.01). Compared with the control group, the concentrations of TNF-α, IL-1β and MDA in lung tissue were increased and those of IL-10, SOD and GSH-Px were reduced in the model group (<0.01). In the acupoint injection group and the ribavirin group, the concentrations of TNF-α, IL-1β and MDA were reduced in lung tissue and those of IL-10, SOD and GSH-Px were increased (<0.05, <0.01) when compared with the model group.

Conclusion: Acupoint injection with V+VCo solution may alleviate inflammatory responses and oxidative stress in lung tissue of the PR8-induced pneumonia mice, improve survival rate and prolong the survival time in the case of no effect of the viral load.