To explore the mechanism of action of tanthine in the treatment of allergic rhinitis (AR) complicated with asthma in rats by regulating microRNA-27a-3p (miR-27a-3p) targeting thymic stromal lymphopoietin (TSLP).

The AR-asthma rat model was established using ovalbumin (OVA) sensitization and nasal drip attack method. Fifty rats were divided into control group (equal volume 0.9% NaCl), model group (AR-asthma model+equal volume 0.9% NaCl), experimental group (AR-asthma model+100 mg·kg^-1 xanthortin) and miR-27a-3p inhibitor group (caudal vein injection of 0.5 nmol·μL^-1 miR-27a-3p inhibitor 10 μL on the basis of the experimental group), si-TSLP group (0.5 nmol·μL^-1 si-TSLP 10 μL intravenously injected on the basis of miR-27a-3p inhibitor group), 10 rats in each group. Serum immunoglobulin E (IgE), interleukin-2 (IL-2), IL-13 and tumor necrosis factor-α (TNF-α) levels of rats were detected by enzyme-linked immunosorbent assay. The level of superoxide dismutase (SOD) was detected by xanthoxine oxidase method. The level of malonaldehyde (MDA) was detected by thiobarbituric acid method (TBA).

The levels of IgE in control group, model group, experimental group, miR-27a-3p inhibitor group and si-TSLP group were (18.33±3.53), (89.95±17.62), (55.70±10.08), (78.43±15.30) and (47.87±9.44) ng·mL^-1, respectively; IL-2 levels were (8.01±1.36), (19.61±3.94), (14.12±2.51), (17.33±3.18) and (11.89±2.03) pg·mL^-1, respectively; IL-13 levels were (6.79±1.33), (34.15±7.02), (24.70±5.13), (35.97±7.24) and (20.53±4.26) pg·mL^-1, respectively; TNF-α levels were (94.08±19.07), (312.47±58.61), (209.78±41.49), (296.42±55.99) and (187.45±37.28) pg·mL^-1, respectively; SOD levels were (29.14±5.04), (13.25±2.63), (24.19±4.89), (17.28±3.16) and (33.94±5.87) U·mg prot^-1, respectively; MDA levels were (2.26±0.51), (4.43±0.72), (3.17±0.58), (3.94±0.69) and (2.62±0.45) nmol·m gprot^-1, respectively. The above indicators were compared between control group and model group, model group and experimental group, experimental group and miR-27a-3p inhibitor group, miR-27a-3p inhibitor group and si-TSLP group. The differences were statistically significant (all P<0.05).

Xanthine can improve oxidative stress and reduce inflammation of AR complicated with asthma in rats, and its mechanism may be related to the regulation of miR-27a-3p targeting TSLP.