Crotonaldehyde sub-chronic exposure-induced pulmonary pyroptosis in male rats / 中国职业医学

ABSTRACT

OBJECTIVE: To observe the effect and mechanism of crotonaldehyde sub-chronic exposure-induced pyroptosis in pulmonary inflammatory reaction in male rats. METHODS: Specific pathogen-free male Wistar rats were randomly divided into control group and low-, medium-and high-dose groups, with 10 rats in each group. Rats were treated with crotonaldehyde at concentrations of 0.0, 2.5, 4.5, and 8.5 mg/kg body weight by intra-gastric administration, once per day for 120 consecutive days. Rats′ body mass was recorded during exposure. After exposure, the rats were sacrificed, and the lung tissues were isolated. The relative expression of reactive oxygen species(ROS) in lung tissues was detected by fluorescent probes at the end of crotonaldehyde exposure. The fluorescent staining of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3(NLRP3) and Caspase-1 in lung tissues was observed by immunofluorescence microscope. The protein expression of NLRP3, apoptosis-associated spot-like protein(ASC), Caspase-1 precursor(pro-Caspase-1), Caspase-1, interleukin(IL)-1β and IL-18 in lung tissues was determined by Western blotting. RESULTS: At the end of exposure, the body weight gain of rats decreased with the increasing doses of crotonaldehyde(P<0.01). Among them, the body weight gain in the medium-and high-dose groups was lower than that of the control group(P<0.05). After exposure, the lung tissue of each group showed severe inflammatory change with the increasing doses of crotonaldehyde. Immunofluorescence staining showed that the expression of NLRP3 and Caspase-1 in the lung tissues of rats increased in a dose-dependent manner. The relative expression of ROS and the protein of NLRP3, ASC, pro-Caspase-1, Caspase-1, IL-1β and IL-18 in lung tissue of each group increased with the dose of crotonaldehyde(P<0.01). The above indexes of lung tissue in the medium-and high-dose groups were higher than that in the control group(P<0.05). CONCLUSION: Sub-chronic exposure to crotonaldehyde may cause pyroptosis by up-regulating ROS expression in the lung tissues of rats. The up-regulation of Caspase-1 classic dependent pathway leads to pyroptosis, thereby causing inflammatory responses in the lungs.