Effects of electroacupuncture pretreatment on NLRP3 inflammasome in mice with ventilator-induced lung injury

Abstract

To observe the effect of electroacupuncture (EA) pretreatment on inflammatory response in ven-tilator-induced lung injury (VILI) mice, so as to explore the underlying mechanism of EA pretreatment on prevention of VILI. C57BL/6 mice were randomly divided into sham-operation group, model group, EA group and sham-acupoint group，with 8 mice in each group. The VILI model was established by ventilation with high tidal volume. Mice in the EA group and sham-acupoint group were given EA at "Zusanli" (ST36)and "Feishu"(BL13) or non-acupoints (located at 1-2 cm on both sides of the tail root of the proximal trunk) before mechanical ventilation, 30 min each time, once a day for 5 days. Arterial blood was collec-ted for blood gas analysis, the total protein content in bronchoalveolar lavage fluid (BALF) was detected by BCA method. The contents of interleukin-1β (IL-1β) and interleukin-18 (IL-18) in BALF were detected by ELISA. Lung injury score was determined after HE staining. The protein expression levels of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and Caspase-1 in lung tissue was detected by Western blot. Compared with the sham-operation group, the arterial partial pressure of oxygen and oxygenation index were decreased(P<0.05), the levels of total protein, IL-1β and IL-18 in BALF, the W/D value and the pathological injury score of lung tissue and the protein expression levels of NLRP3, Caspase-1 and ASC were increased(P<0.05)in the model group. Following the interventions, the above mentioned increased or decreased indicators were reversed(P<0.05) in the EA group rather than in the sham-acupoint group. EA pretreatment of ST36 and BL13 can reduce the damage of lung tissue caused by mechanical ventilation, which may be related to its effect in reducing the expression of NLPR3 inflammasome related proteins, reducing the activation of inflammasome, and thereby reducing the inflammatory response.