Objective: To observe whether the transient receptor potential vanilloid 1(TRPV 1) plays a role in moxibustion (Moxi)-induced regulation of local immune inflammatory response.
Methods: Fifteen C 57 BL/6 J and 15 TRPV 1-/- mice were randomly and respectively divided into blank control, Moxi-30 min and Moxi-72 h groups (5 mice/group). The Moxi intervention ([46±1] ℃) was applied to the left "Zusanli" (ST 36) for 30 min. The local tissue of the left ST 36 region was collected for observing the histological changes after H．E. staining, and for counting the number of tumor necrosis factor-α (TNF-α) immune-reaction (IR)-positive cells after immunofluorescence staining.
Results: In both C 57 BL/6 J and TRPV 1-/- mice, following Moxi, the local epidermis tissue was incomplete, with vague layers and arrangement of the stratum corneum (being thicker than control mice), and visible scar tissue. The corium layer was relatively looser in the structure, and the collagenous and elastic fibers were loosened in the arrangement or absence, with an abundant inflammatory cell infiltration, vascular dilation and congestion of blood vessels, and abnormal hyperplasia of hair follicles and sebaceous glands (but without marked structural changes of the subcutaneous tissue). In C 57 BL/6 J mice, compared with the control group, the numbers of TNF-α IR-positive cells were significantly increased in the epidermis of the Moxi-30 min group (P<0.05), and in the dermis of the Moxi-30 min and -72 h groups (P<0.01). In TRPV 1-/- mice, compared with the control group, the numbers of TNF-α IR-positive cells were also considerably increased in the epidermis of the Moxi-30 min group, and in the dermis of both Moxi-30 min and -72 h groups (P<0.01). Comparison between the two Moxi groups showed that the number of TNF-α positive cells was significantly lower in the dermis of the Moxi-72 h group than in that of the Moxi-30 min group in C 57 BL/6 J mice (P<0.01), and significantly lower in both the epidermis and dermis of the Moxi-72 h group than in those of the Moxi-30 min group in TRPV 1-/- mice (P<0.01)．.
Conclusion: Moxibustion stimulation of ST 36 can induce structural changes of the regional epidermis and dermis of the skin and up-regulate the number of TNF-α IR-positive cells in both C 57 BL/6 J and TRPV 1-/- mice, which may contribute to its therapeutic effect via local TRPV 1-independent immunoregulation.
Keywords: Moxibustion; Skin structural changes; Transient receptor potential vanilloid 1(TRPV 1); Tumor necrosis factor-α; Zusanli (ST 36).