Mechanism of catechin regulating MAPK pathway in improving allergic airway inflammation in young rats

Objective To explore the mechanism of catechin regulating mitogen-activated protein kinase (MAPK) pathway in improving allergic airway inflammation in young rats. Methods There were 50 SPF-class BALB/c mice randomly divided into model group, normal group, positive control group, low dose catechin group and high dose catechin group each group.In addition to the normal group, all other groups of mice prepared an allergic asthma model.After successful modeling, the positive control group mice were given a dose of 0.5 mg/kg of dexamethasone solution, a low dose of catechin and catechin.The high-dose group was intragastrically dosed with 1 mg/kg and 2 mg/kg catechin solution.The model group and the normal group were intragastrically administered with normal saline once daily.The cells, total cell count, interleukin-13 (IL-13), IL-5 and IL-4 levels in bronchoalveolar lavage fluid (BALF) of mice were observed, p-p38MAPK, ERK, p-ERK, p38MAPK protein expression and p38MAPK, ERK mRNA expression in lung tissue of mice were detected. Results Compared with the normal group, the levels of IL-13, IL-5 and IL-4 in BALF of the model group were increased.Compared with the model group, the positive control group, the low dose group of catechin and the high dose group of catechin were small.The levels of IL-13, IL-5 and IL-4 in BALF were decreased, and the difference was statistically significant (all P<0.05). Compared with normal group, p-p38MAPK and p-ERK in lung tissue of model group mice.The protein expression was increased.Compared with the model group, the expression of p-p38MAPK and p-ERK protein in the lung tissue of the positive control group, the low-dose catechin group and the high-dose catechin group were decreased, and the difference was statistically significant (all P<0.05); Compared with the normal group, the expression of p38MAPK and ERK mRNA in the lung tissue of the model group increased; Compared group, positive control group, the lung tissue catechins catechin low dose group and high dose group mice p38MAPK, ERK mRNA was decreased, there was significant difference (all P<0.05). Conclusions Catechin can effectively improve the airway inflammation in allergic asthma mice, and its mechanism may be related to the inhibition of ERK/MAPK signal pathway activation. Key words: Allergic asthma; Airway inflammation; Catechin