Expression of HMGB1 in lung tissues of silicotic fibrosis rats and effectiveness of TCM lumbricus medicine intervention

Objective To observe the expression of high mobility group protein B1 (HMGB1) in the lung tissues of silicotic fibrosis rats, and explore the effectiveness of TCM Lumbricus medicine intervention. Methods A total of 45 rats were randomly divided into control group, model group and Lumbricus group with 15 rats in each group. The rats in model group and Lumbricus group received silica exposure to develop a silicotic fibrosis rat model, while the control group received intratracheal instillation of saline. The Lumbricus group received earthworm decoction 4 ml/kg by gavage, while the control group and model group received the same volume of normal saline. Five rats in each group were sacrificed on 7th, 14th and 28th days at a time. The lung coefficient was measured. The development of alveolitis and pulmonary fibrosis were compared among the three groups. The expression of HMGB1 was observed by immunohistochemistry. Results The lung coefficient of model group on the 7th, 14th and 28th days was 6.48±0.19, 6.71±0.14, 7.01±0.33, respectively, which were increased as compared with the control group (4.36±0.13, 4.52±0.33, 4.56±0.10), respectively, all P<0.01; The lung coefficient of Lumbricus group on the 7th, 14th and 28th days was 5.07±0.17, 5.38±0.05, 5.53±0.08, respectively, which was decreased as compared with model group, P< 0.01; The optical density of HMGB1 of model group on the 7th, 14th and 28th days was 0.31±0.03, 0.35 ±0.03, 0.38 ±0.02, respectively, which was increased as compared with control group (0.20±0.02, 0.21±0.04, 0.20±0.03), P< 0.01; The optical density of HMGB1 of the Lumbricus group on the 7th, 14th and 28th days was 0.30±0.02, 0.29±0.02, 0.27±0.03, respectively, the difference on the 7th days was not significant as compared with the model group (P=0.507), but decreased obviously on the 14th and 28th days (P<0.05). Conclusion The pulmonary fibrosis and progressive elevated HMGB1 can be observed in rats after exposure to dust, which can be improved by TCM Lumbricus medicine intervention, the mechanism may associate with inhibition of TCM Lumbricus on the expression of HMGB1.