Effects of Green Tea Polyphenols on Allergic Rhinitis in Rats through p38 MAPK Signaling Pathway

Wang Yujie; Xu Dingyuan; Wang Bin

doi:10.3969/j.issn.1004-5775.2026.02.009

Abstract：Objective:To investigate the improvement effect and its mechanism of green tea polyphenols on allergic rhinitis in rats.Methods:Forty rats were randomly divided into normal group,model group,green tea polyphenol group and loratadine group,with 10 rats in each group.Except for normal group,allergic rhinitis rats in other groups were infected by obumin+aluminum hydroxide powder.After successful model creation,green tea polyphenol group rats were intragastatically injected with green tea polyphenol suspension 300 mg/kg,loratadine group rats were intragastatically injected with loratadine 0.9 mg/kg,normal group and model group were intragastatically injected with the same amount of normal saline.Behavioral symptom scores,serum immunoglobulin E(IgE),histamine(HIS),interleukin(IL)-10 and IL-17 were compared among all groups,and pathological injury of nasal mucosa was observed by HE staining.qRT-PCR and western blot were used to detect mRNA and protein expression levels of retinoic acid receptor-related orphan receptor gamma-t(RORγt),forkhead box P3(Foxp3)and p38 mitogen-activated protein kinase(MAPK).Results:In normal group,there was no obvious abnormality in nasal mucosa,and the epithelium structure was intact and arranged neatly.In the model group,the nasal mucosal epithelium was disorganized,some epithelial cells were shed,glands were hyperplastic and swollen,and inflammatory cells were infiltrated.In the green tea polyphenol group and loratadine group,the pathological damage of nasal mucosa was reduced,the epithelial structure was slightly normal,and the inflammatory cells were reduced.Compared with the normal group,behavioral symptomatology scores,IgE,IL-17 and HIS levels,ROR γt mRNA and protein expression,p38 MAPK mRNA expression and p-p38 MAPK protein expression of rats in the model group were increased;while IL-10 level,the mRNA and protein expressions of Foxp3 were decreased,with statistically significant differences(P＜0.05).Compared with the model group,the behavioral symptomatology scores,IgE,IL-17 and HIS levels,ROR γt mRNA and protein expression levels,p38 MAPK mRNA expression levels and p-p38 MAPK protein expression levels of green tea polyphenol group and loratadine group were decreased,while IL-10 levels,mRNA and protein expressions of Foxp3 were increased,with statistically significant differences(P＜0.05).Green tea polyphenols significantly reduced behavioral scores in rats and decreased serum levels of IgE,HIS,IL-17,and IL-10,with statistically significant differences(P＜0.05).Histopathological examination of nasal mucosal tissue revealed that green tea polyphenols mitigated disruption of the nasal epithelial structure and inflammatory cell infiltration.Furthermore,tea polyphenols significantly downregulated RORγt and p38 MAPK mRNA and protein expression while simultaneously upregulating Foxp3 mRNA and protein expression,with statistically significant differences(P＜0.05).Conclusion:Green tea polyphenols can improve the nasal allergic symptoms of rats with allergic rhinitis,which may play a role in regulating the immune balance of Treg/Th17 cells by inhibiting p38 MAPK pathway.