Intervention effect of Qingzao Runfei Huazhuo Xingxue decoction on PM2.5-induced pulmonary injury in mice

Abstract

To study the effects of Qingzao Runfei Huazhuo Xingxue decoction (QRHXD) on inflammatory reaction and histopathology in mice with PM2.5-induced pulmonary injury, and to approach the possible mechanism of prevention and treatment of traditional Chinese medicine on lung injury induced by haze. Fifty healthy male C57BL/6 mice were randomly divided into five groups (n = 10): namely control, PM2.5, PM2.5 + low-, moderate-, and high-dose groups. The PM2.5 suspensions at a dosage of 40 mg/kg was respectively given to mice by the nasal instillation for reproduction of mouse model of lung injury induced by PM2.5, and the mice in control group were given the same volume of normal saline. The mice in PM2.5 + low-, moderate-, and high-dose QRHXD groups were given 15, 25, 50 mL×kg-1×d-1 QRHXD by oral perfusion daily for consecutive 21 days at the next day of model reproduction (the QRHXD included: Pear 75 g, Bulbus Fritillariae Cirrhosae 10 g, Radix Stemonae 8 g, Rhizoma Pinelliae 8 g, Radix Platycodi 6 g, Aster 10 g, Almond 5 g, Lily 6 g, Rhodiola 4 g, Lotus 3 g, Fructrs Liquidambaris 6 g, Radix Paeoniae Rubra 5 g, Semen Cassiae 6 g). The mice in control and PM2.5 groups were given equivalent volume of normal saline respectively. After treatment for 21 days, the mice were sacrificed, and the left lung was harvested for bronchoalveolar lavage, and the bronchoalveolar lavage fluid (BALF) was collected for determination of levels of acid phosphatase (ACP), alkaline phosphatase (AKP), lactic dehydrogenase (LDH), and albumin (ALB). The right lung was harvested for histopathology observation under light microscope using hematoxylin and eosine (HE) staining. After intranasal instillation of PM2.5 suspension, the levels of ACP, AKP, LDH, and ALB in PM2.5 group were significantly higher than those in control group [ACP (U/L): 3.9±0.4 vs. 1.7±0.3, AKP (U/L): 9.0±1.5 vs. 4.8±0.3, LDH (U/L): 416.7±44.4 vs. 112.5±20.3, ALB (mg/L): 198.7±32.4 vs. 65.8±21.3, all P < 0.05]. Under light microscope, the PM2.5 particles were collected, the alveolar septa were thickened, and the inflammatory cells in the alveolar cavity and pulmonary interstitium were found. On the contrary, after administration of QRHXD, a significant reduction of biochemical indexes was found, which showed a dose-dependent manner. The parameters of PM2.5 + high-dose QRHXD group were significantly lower than those in PM2.5 group [ACP (U/L): 2.1±0.8 vs. 3.9±0.4, AKP (U/L): 5.3±1.4 vs. 9.0±1.5, LDH (U/L): 146.6±29.8 vs. 416.7±44.4, ALB (mg/L): 88.5±26.7 vs. 198.7±32.4, all P < 0.05]. At the same time, the pathological changes in lung tissue were better with the increase of the dose. QRHXD can reduce the pulmonary inflammatory response and tissue damage caused by PM2.5, with the increase concentration of Chinese medicine, and the effect is more obvious. This may be related to the immune response of the human body to regulate inflammatory mediators, which provide basis for the treatment of pulmonary injury induced by PM2.5.