[Study on anisodamine hydrobromide improves Th17/Treg imbalance in resuscitated pigs]

To investigate whether anisodamine can regulate the ratio of helper T helper cells/regulatory T cells (Th17/Treg) and its protective effect on animals after resuscitation.

Twenty-four Beijing white minipigs were randomly divided into sham operation group (Sham group), resuscitation and normal saline group (SA group), and resuscitation and anisodamine hydrobromide group (AH group), with 8 pigs in each group. In SA group and AH group, ventricular fibrillation was induced by continuous stimulation with intraventricular electrodes for 8 minutes and then resuscitated to establish ischemia/reperfusion (I/R) model. In SA group, after cardiopulmonary resuscitation (CPR), only normal saline was intravenously infused, while in AH group, normal saline and anisodamine hydrobromide were given intravenously at the same time point. Hemodynamic indexes, arterial blood gas analysis indexes, interleukins (IL-17, IL-10) levels in venous blood and IL-17/IL-10 ratio were recorded at 6 different time points: baseline, immediately after return of spontaneous circulation (ROSC), 1 hour, 2 hours, 4 hours and 6 hours after ROSC. The animals were sacrificed at 6 hours after ROSC, and intestinal lymphatic tissues were taken to observe pathological changes under light microscope. At the same time, the levels of IL-17 and IL-10 in intestinal lymphatic tissue were measured (the ratio of IL-17/IL-10 represents the ratio of Th17/Treg cytokines) to evaluate the immune status of the resuscitated animals. The bacterial translocations of different groups were evaluated by culturing intestinal lymphoid tissue.

With the extension of ROSC time, the levels of IL-17 in venous blood and the IL-17/IL-10 ratio in pig blood samples continued to decrease, while the levels of IL-10 continued to increase. From 2 hours after ROSC, the IL-17/IL-10 ratio in AH group was significantly higher than that in SA group continued until at 6 hours after ROSC (0.79±0.05 vs. 0.49±0.08, P < 0.05). Light microscopy showed that the number and size of lymph nodules in the cortex of intestinal lymphatic tissue were less in AH group, compared with SA group. Compared with Sham group, the levels of IL-17 and IL-17/IL-10 ratio also decreased in intestinal lymphatic tissue at 6 hours after ROSC [IL-17 (ng/L): 155.23±0.92, 178.76±7.25 vs. 209.21±19.82, IL-17/IL-10 ratio: 1.43±0.13, 1.92±0.18 vs. 3.30±0.31, all P < 0.05], and IL-10 increased significantly (ng/L: 109.85±11.60, 93.55±81.83 vs. 63.45±0.62, all P < 0.05); IL-17/IL-10 ratio in AH group was significantly higher than that in SA group (1.92±0.18 vs. 1.43±0.13, P < 0.05). Tissue culture indicated the intestinal bacterial translocation after resuscitation, suggesting that the animals had immunosuppression and the increased risk of intestinal secondary infection after resuscitation. Compared with SA group, the risk of bacterial translocation was lower than that in AH group [62.5% (5/8) vs. 87.5% (7/8), P < 0.05].

Anisodamine plays an immunomodulatory role by affecting the balance of Th17/Treg cytokines in resuscitated animals, so as to reduce the risk of intestinal secondary infection and has an organ protective effect.