| Objectives To investige the effect of VEGFR-3 on the early pulmonary lympha-ngiogenesis and the mechanism of VEGFR-3 regulating pulmonary lymphangiogen-esis in silicosis rats.At the same time,further to elucidate the important role of pulmonary lymph circulation by detecting the changes of inflammatory factors and fibrotic factors during the development of silicosis,is d,which may provide a ne w theoretical basis for effective prevention and treatment of silicosis.Methods 96 SPF adult male rats weighing 250-300 g were randomly divided int o control group,mobile dust exposure group,drug-promoted lymphangiogenesis gr oup and operation-blocked lymphangiogenesis group.Rats in each group were sacr ificed at 7,14,28 and 56 days respectively to obtain biological specimens,6 rats in each subgroup.Rats exposed to dusts(2000 mg/m~3)for 3 hours daily in HOP E-MED8050 series of dynamic poisoning control device.Rats in the control group stayed in the device for the same time without exposed to dusts.Rats in the dru g-treated group were given intraperitoneal injection of sodium tanshinone II A sulf onate(15 mg/(kg.d))after exposed to dusts every day;rats in the surgical treatme nt group exposed to dusts for 3 hours every day after thoracic duct ligated.The right lower lung of rats was embedded in paraffin,and the inflammatory lesions of lung tissue were observed by hematoxylin-eosin(HE)staining;collagen depositi on in lung tissue was observed by Masson and Sirius red staining;lymphatic vess el proliferation in lung tissue was detected by immunohistochemistry;total protein was extracted by homogenizer from other lung tissues.Expressions of smooth m uscle actin(?-SMA),phosphoinositol kinase(PI3K),phosphoserine/threonine protei n kinase(P-AKT),vascular endothelial growth factor receptor-3(VEGFR-3),transf orming growth factor-beta(TGF-?),nuclear transcription factor(NF-?Bp65)and ot her factors in tissues were quantitatively detected by Western blot.Thymic duct ly mph fluid of rats in each group was collected and the expression of tumor necros is factor-alpha(TNF-?)in lymph was detected by enzyme-linked immunosorbent a ssay(ELISA).Results 1 HE,Masson and Sirius red staining results showed that the rat silicosi s model was successfully established by using HOPE-MED8050 mobile dust-cleani ng device.2 Immunohistochemical results showed that compared with the control group,there were different degrees of lymphatic hyperplasia in the lung tissue of rats in the dynamic dust-exposed group,the drug-promoted lymphatic hyperplasia group and the operation-blocked lymphatic hyperplasia group.Compared with the mobile dust group(4.16±0.28),the density of lymphatic vessels in lung tissue incre ased in the drug-induced lymphangiosis group(5.83±0.76),and decreased in the op eration-blocked lymphangiosis group compared with the mobile dust group(2.66±0.76).3 Western blot was used to quantitatively determine the expression of regulat ory lymphangiogenic factor(VEGFR-3)in lung tissue of rats in each group.Com pared with the control group,the content of vascular endothelial growth factor(V EGFR-3)in lung tissue of rats in the three groups increased.However,compared with the model dust group(0.97±0.03),the content of vascular endothelial growth factor R-3 in lung tissue of the drug-treated rats increased significantly(1.54±0.03),while the content of vascular endothelial growth factor R-3 in lung tissue of the operation-treated rats decreased(0.87±0.01).Quantitative analysis of PI3K and P-AKT proteins in signal pathways related to lymphangiogenesis showed that the res ults were the same as the changes of the content of VEGFR-3 in lung tissue of e ach group.5.The degree of pulmonary fibrosis in four groups of rats was evaluat ed.The results showed that the expression of fibrogenic factors TGF-?and?-SM A increased in varying degrees except for the normal control group,and the chan ge trend was the same.The protein content increased with the prolongation of du st exposure.Compared with each time point in the dust-exposed group(3.09±0.06and 3.10±0.05),the contents of TGF-?(2.61±0.09)and?-SMA(2.63±0.01)in lun g tissue of rats in the drug-stimulated Lymphangiosis group decreased,while the c ontents of TGF-?(3.99±0.01)and?-SMA(4.01±0.04)in lung tissue of rats in th e operation-blocked Lymphangiosis group increased.6 Quantitative analysis of infl ammatory factor NF-?Bp65 in lung tissue of rats in each group showed that the c ontent of NF-?Bp65 in lung tissue of rats in drug-promoted lymphangioplasia grou p was lower than that in dynamic dust-exposed group at each time point.The co ntent of NF-?Bp65 in lung of rats in operation group was higher than that in dus t-exposed group and normal control group.7 ELISA kit was used to detect the e xpression of inflammatory factor TNF-?in rat thoracic duct lymph.The results sh owed that the expression of NF-?Bp65 in rat lung tissue was consistent with that in each group at different time points.Conclusions 1 Drugs could promote the proliferation of pulmonary lymphatic ves sels in early silicosis rats and alleviate the pathogenesis of silicosis.2 VEGFR-3plays an important role in the lymphatic circulation of the silicosis and can regula te lymphangiogenesis.3 VEGFR-3 regulates the formation of pulmonary lymphatic-s in early silicosis mainly through activating PI3K/AKT signaling pathway.Figure12;Table 13;Reference 152... |
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