Polyguanylic acid intervenes silicosis fibrosis in rats through endoplasmic reticulum stress / 中国职业医学

ABSTRACT

OBJECTIVE: To investigate the role and mechanism of the endoplasmic reticulum stress(ERS) pathway of apoptosis mediated by inositol-requiring enzyme-1(IRE1) in the intervention of silicosis fibrosis in rats using polyguanylic acid(PolyG).METHODS: The specific pathogen free adult male SD rats were randomly divided into control group(24rats),silicosis model group(24 rats),PolyG intervention group(16 rats) and PolyG treatment group(16 rats).The silicosis fibrosis rat model was constructed using the single inhalable intratracheal instillation method.The rats in the control group were injected with 1 mL of 0.9% sodium chloride solution.The other 3 groups were given 1 mL of silica suspension at 50.0 g/L mass concentration.The rats in PolyG intervention group on the day of model construction and rats in PolyG treatment group on the 28 th day after model construction were all given PolyG with 2.5 mg/kg body weight by one time tail vein intravenous injection.Eight rats in the PolyG intervention group and PolyG treatment group were sacrificed respectively on day 28 and day 56 after injection.The pathological changes of lung tissue in each group were observed.The expression of glucose regulated protein-78(GRP78),IRE1,CCAAT/enhancer-binding protein homologous protein(CHOP),Casepase-3,Casepase-12,type Ⅰ collagen and type Ⅲ collagen in lung tissue was detected by the Western blot.RESULTS: The histopathology examination results showed that the structure of lung tissue in control group was normal.The alveolar structure of the lung tissue of the silicosis model group was severe,and the fibrous nodules and a large amount of collagen deposition appeared.The silicosis nodules and collagen deposition in PolyG intervention group and PolyG treatment group were less than those in silicosis model group.The expression of GRP78,IRE1,CHOP,Casepase-3,Casepase-12,type Ⅰ collagen and type Ⅲ collagen in silicosis model group was higher than that of control group(P <0.05).The expression of the above 7 proteins in the PolyG intervention group and PolyG treatment group was lower than that of silicosis model group(P<0.05),higher than that of control group(P<0.05),except IRE1 and CHOP in PolyG intervention group.On day 56 after model construction,the expression of GRP78,IRE1,Casepase-3,Casepase-12,typeⅠ collagen and type Ⅲ collagen in PolyG intervention group were lower than that of PolyG treatment group(P<0.05).CONCLUSION: The unfolded protein response of ERS mediated by IRE1 may participate in the process of PolyG the intervention on silicosis fibrosis in rats.PolyG can effectively prevent and treat silicosis fibrosis.Prophylactic administration is recommended.