[Effect of acupuncture combined with bloodletting therapy on mast cell degranulation in urticaria rats].

Objective: To observe the effects of acupuncture combined with bloodletting on the expression of inflammatory factors in serum, the morphology of sensitized skin tissue and the mast cell degranulation in urticaria rats, and to explore the potential mechanism of this therapy for urticaria.

Methods: Among 42 SD rats of SPF grade, 6 rats were randomly collected for the preparation of sensitized antiserum; and the rest 36 rats were randomized into a blank group, a model group, a positive drug group, an acupuncture group, a bloodletting group and a combined treatment group (acupuncture + bloodletting), 6 rats in each one. The rat model of urticaria was established by passive cutaneous anaphylaxis. In the positive drug group, loratadine (1 mg•kg) by gavage was administered once a day. In the acupuncture group, 1 h after gavage with 0.9% NaCl (1 mL), acupuncture was delivered at "Baihui" (GV 20), "Zhongwan" (CV 12), and bilateral "Quchi" (LI 11) and "Xuehai" (SP 10) for 15 min, once daily . In the bloodletting group, 1 h after gavage with 0.9% NaCl (1 mL), bloodletting was operated at "Dazhui" (GV 14) and bilateral "Geshu" (BL 17), around 0.1 mL of bleeding volume at each point, once daily. In the combined treatment group, 1 h after gavage with 0.9% NaCl (1 mL), the interventions as the acupuncture group and the bloodletting group were adopted, once daily. All the interventions started on day 6 of modeling, lasting 2 weeks. After intervention completion, antigenic stimulation was performed in the rats of each group. Using ELISA, the levels of serum immunoglobulin E (IgE), tryptase (TPS), interleukin-4 (IL-4), interleukin-5 (IL-5), tumor necrosis factor-α (TNF-α) were detected. The diameter of the blue spots of the sensitized skin on the back was measured with ruler in each rat. The morphology of sensitized skin tissue was observed using HE staining, and the degranulation of mast cells was observed using Toluidine blue staining.

Results: Compared with the blank group, in the model group, the levels of serum IgE, TPS, IL-4, IL-5 and TNF-α increased (<0.01), the diameter of blue spot on the sensitized part of the rat back was larger (<0.01), the degranulation rate of mast cells was elevated (<0.01), and there were obvious inflammatory cell infiltration and edema in the dermis of sensitized skin tissue on the rat back. Compared with the model group, the serum levels of IgE, TPS, IL-4, IL-5 and TNF-α were reduced in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group (<0.01, <0.05); skin blue spot diameter was smaller in the positive drug group and the combined treatment group (<0.05); the degranulation rate of mast cells decreased in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group (<0.01); and the dermal edema, inflammatory infiltration were attenuated in the positive drug group, the acupuncture group, the bloodletting group and the combined treatment group. Compared with the acupuncture group and the bloodletting group, the serum levels of IgE, TPS, IL-4, IL-5 and TNF-α, as well as the degranulation rate of mast cells in the sensitized tissue were lower in the positive drug group and the combined treatment group (<0.05).

Conclusion: Acupuncture combined with bloodletting effectively suppress mast cell degranulation in the sensitized skin tissue on the back of urticaria rats, and ameliorate the histopathological morphology. Its effect mechanism may be related to inhibiting the differentiation and proliferation of helper T cells 2 and regulating the humoral immune response.