Cytokines Network Of Silica-induced Pulmonary Fibrosis In Rats Serum

The silicosis is a systemic disease of the lung caused by continued inhalation of the dust of silicon dioxide and characterized by lung fibroblast.It is one of the most common and detrimental occupational diseases with high mortality. Experts estimate that the incidence number of pneumoconiosis is little less than 1,000,000 example.Silicosis causes astonishing economic loss, the direct economy loss in one year is roughly RMB 9,000,000,000,the indirectly loss is larger.The mechanism of it is complicated and hard to explain,the pathogenesis is still not clear now.Non-specificity anti-inflammatory and immunologic suppression are main therapic method to silicosis in Clinical therapy,but Silicosis are deficiency of specific and effective therapy.On the basis of the previous studies,the occurrence and development of pneumoconisos is a mutli-stage process with participation and intreration of many cytokines.Helper T(Th) lymphocytes, important immune regulating cells of organism, could be divided into four functional subsets,Th0,Thl,Th2,Th3,on the basis of the immunoregulatory cytokines that these clones produced.The cross-gulatory properties of Thl and Th2 subset cells and relevant cytokines network are very important to maintain normal immunity of organisms.The imbalance of pro-inflammatory Th₁ and anti-inflammatory Th₂ cytokine production play an important role in Silica-induced pulmonary fibrosis.Therefore it is necessary to investigate the efficacy of Silica in disorder of cytokines network rats of pulmonary fibrosis.The aim of this paper is to study changes of cytokines in pulmonary fibrosis of rat model.Part 1 Meta–analysis on the change of cytokines in pulmonary fibrosisObjective:The aim of this paper is to study changes of cytokines including TGF-β₁,IFN-γ,NF-κB,IL-4 and IL-6 levels in pulmonary fibrosis of rat model.Methods:Reported research data about pulmonary fibrosis caused by silica or bleomycin were analyzed with a meta–analysis software,Review Manager.Data libraries about studies on pulmonary fibrosis were collected mainly from the MEDLINE, CNKI,and Vipo.Literature references were checked at the same time.Silicosis related magazines were searched manually.Languages were restricted to Chinese and English. Standard criteria were made for collecting and evaluating with the inclusion and exclusion.Data were extracted for the experiment and the control group respectively and selecting fixed and random model were used in analyzing the heterogeneity.The publication biases were also evaluated by funnel plot and fail-safe number.Results:1 The cytokines in bleomycin-induced pulmonary fibrosis1.1 There were increases trend of TGF-β₁,TNF-αin the lung tissue and BALF respectively in all time points.The SMD of TGF-β₁ was statistically significant increased in the 3,7,14,28days(P<0.01);The SMD of TNF-αwas statistically significant increased in the lung tissue and BALF in the 1,14,28 days(P<0.01),and 1,3,7,14,28 days(P<0.01),respectively. 1.2 The increase of IFN-γin the BALF started from 7 day in the experimental group compared with the normal group and decreased from 14 and 28 days.However,no obvious statistically significant could be got in each time point(P>0.05).1.3 The BALF NF-κB level increased on the 7 and 14 with a climax in the 7 day then deceases along with the time,the SMD was statistically significant increased in the 7day(P<0.01),On 28 day,this index lowered its level in experimental group than the control. 1.4 There were increases of IL-4 in the lung tissue with obvious statistically significant in each time points (P<0.01,P<0.05) which reached it climax on the 3 day;IL-6 level in the lung alveolus macrophage was increased also,the SMD was statistically significant increased in the 3,21 days(P<0.01). 2 The cytokines in silica-induced pulmonary fibrosis The levels of TNF-αand TGF-β₁ in the fibroblast were increased in each time points,with the maximum on the 14 and 60 days,respectively.The SMD of TGF-β₁ was statistically significant increased in the 1,3,7,14,60 days(P<0.01,P<0.05); The SMD of TGF-β₁ was statistically significant increased in the 7,14,28 days(P<0.01,P<0.05).Conclusion:1 In bleomycin model, compared with the control group,the levels of TGF-β₁,TNF-α,IL-6,IL-4 were increased in all time points of pulmonary fibrosis caused by bleomycin. The changes of IFN-γand NF-ΚB were increased in early time then deceased laterly. 2 Markedly elevated TGF-β₁ levels were observed in SiO2 when compared with bleomycin -induced pulmonary fibrosis.Though the trend of TGF-β₁ changes in pulmonary fibrosis caused by SiO2 was the same as that by bleomycin,yet a higher level was manifested in the former.Part 2 Cytokines network of silica-induced pulmonary fibrosis in rats serumObjective:To observe the change of TNF-α,TGF-β₁,IL-10, IL-1β,IFN-γ,NF-κB cytokines levels and the change of interaction between these cytokines in the rats serum of silica-treated rat.Methods:Wistar rats were randomly divided into two experimental groups: control group and silica group.The rat model of silicosis was established by intratracheal infusion of silica dust suspension.Rats were killed by exsanguinations via the abdominal aorta at 1,3,7,14,21 and 28days after instillation of silica or physiological saline.At each time point eight rats were used.The changes of lung histomorphology of rats were observed by HE staining of histological section.Total cell count and differential cell counts in BALF were estimated by cytometer.Sirius red polarization microscopy detectedâ… andâ…¢collagen.The concentration of TGF-β₁,NF-ΚB,TNF-α,IL-10, IL-1β,IFN-γprotein in serum were measured with ELISA.Use Enter independent together discriminate to analysis IFN-γ, TNF-α,NF-κB,IL-10,TGF-β₁ and IL-1βtotally 6 parameters, conduct diagnosis to the silicosis.Values are reported as the means±SD.We used SPSS15.0 software to conduct statistical analyses,withα=0.05 as the significance test level.Results: 1 Compared with that of control group, the coefficient of lung organ to body of rats of silica group increased significantly at every time points(P<0.01). 2 Significant increase of TGF-β₁ occurred in the 14,21,28 days(P<0.05)in the experiment group during the increasing trend of a 28 day period,with the maximum on the 21 day;The concentrations of NF-κB in serum were markedly elevated in silica-exposed rat compared to control groups in the 1,3,7 days (P<0.05);The expressions of IL-10 in experimental group was increased in all time points(P<0.05),with the maximum on the 21 day;The level of IL-1βwas increased in experimental group in 3,7 days(P<0.05),with the maximum on the 7 day;The decrease of TNF-αprotein level in the 1,3,7,14,21 days and increases of it appeared in the 28 day.There were no obvious changes of TNF-α during whole experiment;The increase of IFN-γprotein level in the 1 day and decreases of it appeared in the 3,7,14,21,28 days.There were no obvious changes of IFN-γduring whole experiment.3 The result shows that the 6 indexes serum IFN-γ,TNF-α, NF-κB,IL-10,TGF-β₁ and IL-1βhave some distinguish effect certainly to the control group and silica group the overall distinguish match rate is 91.4%, thereinto the distinguish match rate is 89.3% to the control group the distinguishing match rate is 93.5% to the silica group.Conclusion: 1 The levels of TGF-β₁,IL-10,IL-1β,NF-κB in serum in silica-treated rats was significantly increased. The levels of TNF-α,IFN-γin serum in silica-treated rats was decreased. Silica could shift the cytokines balance. 2 The levels of TGF-β₁,IL-10,IL-1β,NF-ΚB,TNF-αand IFN-γin the serum may play a role in the diagnosis of silicosis by discriminant analysis.