To observe the effect of acupoint injection on olfactory function, olfactory mucosa structure, olfactory mucosa apoptosis and apoptosis-related protein expression in rats with olfactory dysfunction of allergic rhinitis (AR), so as to explore its mechanisms underlying improvement of AR olfactory dysfunction.

Thirty-six SD rats were used in the present study. Nine of them were randomly selected to be used as the normal group, and the rest of the rats were used to prepare the AR olfactory dysfunction model by ovalbumin sensitization. After successful modeling, the AR model rats were allocated to the model, non-meridian non-acupoint injection, and acupoint injection groups, with 9 rats in each group. For rats of the acupoint injection group, an isotonic mixture (0.05 mL/point) of dexamethasone and lidocaine was injected into the bilateral ”Yingxiang” (LI20) once every 3 days, for a total of 4 times. For rats of the non-meridian non-acupoint injection group, the same mixture solution (0.05 mL/point) was injected into the midpoint of the line connecting “Houhai” (GV1) and “Huantiao” (GB30) on both sides. The frequency and course of treatment were the same as those of the acupoint injection group. The rats’ nasal symptoms were observed and scored, the olfactory function was evaluated by buried food pellet test (BFPT). The histopathological changes and ultrastructure of the olfactory mucosa were observed by H. E. staining and transmission electron microscopy. The contents of serum interleukin (IL) 4, IL-5, IL-13 and IL-17 were detected by ELISA. The expression of olfactory marker protein (OMP) in the olfactory mucosa was detected by immunofluorescence method, and apoptosis of olfactory mucosal cells was detected by TUNEL method. The expression levels of cysteine aspartate protease-3 (Caspase-3), B lymphoblastoma-2 related gene X protein (Bax), and B lymphoblastoma-2 gene (Bcl-2) proteins of the nasal mucosa were detected by Western blot.

The histopathological and ultrastructural observations showed that in the model group, the olfactory mucosal epithelium was severely shed, and the intrinsic layer cells were degenerated and necrotic with inflammatory infiltration; the outer mitochondrial membrane was blurred and broken, and the cristae structure dissolved and disappeared. But compared with the model group, the acupoint injection group had an apparent improvement in the structure of the olfactory mucosa, and a relatively complete and unambiguous structure in the outer mitochondrial membrane and cristae of the inner membrane. Compared with the normal group, the model group had a significant increase in the nasal symptom score, search time for food goblet, apoptosis rate of olfactory mucosal cells, contents of serum IL-4, IL-5, IL-13 and IL-17, and expression of Caspase-3 and Bax proteins in the nasal mucosa (P<0.01), and a notable decrease in the immunofluorescence density of OMP and expression of Bcl-2 in the olfactory mucosa tissue (P<0.01). After non-meridian non-acupoint injection and acupoint injection, both the increase and decrease of the indexes mentioned above were all reversed (P<0.05, P<0.01). Comparison between the two injection groups showed that the effects of the acupoint injection group were significantly superior to those of the non-meridian non-acupoint injection group in all indexes (P<0.01).

Acupoint injection can significantly improve olfactory function and olfactory mucosal damage in rats with AR olfactory dysfunction, which may be related to its functions in inhibiting the inflammatory damage and reducing cell apoptosis of the olfactory mucosa.

To observe the effect of “Yingxiang” (LI2) acupoint injection on T-helper 17 (Th17) cell, regulatory T (Treg) cell, and related cytokine expressions in allergic rhinitis (AR) rats, so as to explore its possible mechanism in improving AR.

Twenty-four SD rats were randomly divided into normal, model, and acupoint injection groups (n=8) . The AR model was established using ovalbumin sensitization. The rats of acupoint injection group received injection of a mixture solution of dexamethasone and lidocaine (0.05 mL/acupoint) at bilateral LI2, once every 3 d for a total of 4 times. Nasal allergy symptom scores were recorded; histopathological changes in the nasal mucosa were observed via HE staining; flow cytometry was used to detect the percentage of Th17 and Treg in peripheral blood; the levels of serum allergen-specific immunoglobulin E (sIgE) , interleukin (IL)-10 and IL-17A were detected by ELISA; the mRNA and protein expression levels of forkhead transcription factor p3 (Foxp3) and retinoic acid orphan receptor γt (RORγt) in nasal mucosa were detected by real-time fluorescence quantitative PCR and Western blot, respectively.

Following modeling, the symptom scores, Th17/CD4⁺ T cell ratio in peripheral blood, serum contents of sIgE and IL-17A, and RORγt mRNA and protein expression levels in nasal mucosa were significantly increased (P<0.01) , while the Treg/CD4⁺ T cell ratio, serum IL-10 content, and Foxp3 mRNA and protein expression levels in nasal mucosa were significantly decreased (P<0.01) . After acupoint injection intervention, the modeling induced increase and decrease of indexes mentioned above were completely reversed (P<0.01) . HE staining revealed thickened nasal mucosa, disordered epithelial arrangement, partial cilia loss, and massive inflammatory cell infiltration in the model group, which were markedly improved in the acupoint injection group.

“Yingxiang” acupoint injection can effectively alleviate nasal allergy symptoms in AR rats, which may be related to its function in regulating Treg/Th17 immune balance and suppressing inflammatory responses.

To observe the effects of electroacupuncture (EA) on olfactory function, olfactory epithelial cell apoptosis, olfactory marker protein (OMP), cysteinyl aspartate-specific protease-3 (Caspase-3), and the expression of inflammatory factors in rats with allergic rhinitis (AR)-induced olfactory dysfunction, so as to explore the underlying mechanism by which EA improves olfactory function in AR-induced olfactory dysfunction.

SD rats were randomly divided into control, model and EA groups, with 8 rats in each group. AR-induced olfactory dysfunction rats model was established using ovalbumin sensitization. Bilateral "Yingxiang" (LI20) acupoints were stimulated with EA (2 Hz/15 Hz, 1 mA) for 10 min, once daily for 14 days. After the intervention, AR symptom scores of each group of rats were evaluated. Olfactory function was assessed using the buried food pellet test. HE staining was performed to observe the morphological changes in olfactory mucosa tissue. ELISA was used to detect plasma IgE, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) contents in plasma and nasal lavage fluid. Immunofluorescence staining was used to detect OMP and Caspase-3 positive expressions in olfactory mucosa. TUNEL staining was performed to detect olfactory epithelial cell apoptosis condition.

Compared with the control group, rats in the model group showed significantly thinner olfactory mucosal epithelium, reduced number and disorganized arrangement of olfactory receptor neurons (ORNs), increased inflammatory cell infiltration, significantly decreased olfactory function, significantly decreased OMP expression in olfactory mucosa (P<0.01), significantly increased nasal symptom scores, plasma IgE contents, IL-1β and TNF-α contents in plasma and nasal lavage fluid, significantly increased Caspase-3 expression in olfactory mucosa (P<0.01), and significantly increased occurrence of olfactory epithelial cell apoptosis (P<0.01). Compared with the model group, rats in the EA group showed significantly thicker olfactory mucosal epithelium, increased number and more orderly arrangement of ORNs, reduced inflammatory cell infiltration, significantly improved olfactory function, significantly increased OMP expression in olfactory mucosa (P<0.01, P<0.05), significantly decreased nasal symptom scores, plasma IgE contents, IL-1β and TNF-α contents in plasma and nasal lavage fluid (P<0.05, P<0.01), significantly decreased Caspase-3 expression in olfactory mucosa (P<0.01), and significantly decreased occurrences of olfactory epithelial cell apoptosis (P<0.01).

EA therapy can improve olfactory function of olfactory-malfunctioned AR rat. The mechanism could be inhibition of the AR-induced damage of inflammatory cytokines to olfactory epithelium and neurons.

To observe the effects of acupoint injection on the expression of p38 mitogen-activated protein kinase (MAPK), phosphorylated (p)-p38 MAPK, mucin 5 subtype AC (MUC5AC) in the nasal mucosa, and serum inflammatory factors of rats with allergic rhinitis, so as to explore the mechanism of acupoint injection in improving inflammatory reactions in the nasal mucosa of rats with allergic rhinitis.

SD rats were randomly divided into the normal group, model group, acupoint injection group, and non-acupoint group, with 7 rats in each group. The allergic rhinitis rat model was established using ovalbumin sensitization. Intervention was performed by injecting dexamethasone and 1% lidocaine mixture (0.05 mL) into the bilateral "Yingxiang" (LI20) and "Yintang" (GV24⁺) acupoints, with injection at non-acupoints for non-acupoint group as the control, once every 3 days for a total of 4 times. Allergic symptoms in the rat nose were evaluated using a cumulative scoring method; histopathological changes in the nasal mucosa were observed after HE staining; serum histamine (HA), interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha (TNF-α) contents were detected using ELISA; real-time fluorescent quantitative PCR was used to detect the expression of MUC5AC mRNA in the nasal mucosa; Western blot was used to detect the expression of p38 MAPK, p-p38 MAPK, and MUC5AC protein in the nasal mucosa.

Compared with the normal group, nasal allergic symptom score, serum HA, IL-6, IL-8, and TNF-α contents, nasal mucosal p38 MAPK, p-p38 MAPK proteins expression, MUC5AC mRNA and protein expression were significantly increased (P < 0.01) in the model group. Compared with the model group and non-acupoint group, nasal allergic symptom score, serum HA, IL-6, IL-8, and TNF-α contents, nasal mucosal p38 MAPK and p-p38 MAPK proteins expression, MUC5AC mRNA and protein expression were significantly reduced (P < 0.01, P < 0.05) in the acupoint injection group.

Acupoint injection can reduce nasal allergic symptom, and MUC5AC secretion in rats with allergic rhinitis, alleviate nasal mucosal inflammatory reactions, and its mechanism of action may be related to the inhibition of p38 MAPK phosphorylation, thereby reducing the release of inflammatory factors.