| Objective: The morbidity of pulmonary fibrosis (PF) has trend of increasing gradually, the pathogenesis of PF is not clarified clear now. CTGF is a recently described, 38-KD, cysteine-rich secretory polypeptide, which plays an important role in fibrosis of some organs for example skin, liver, and kidney.But there were a few reports about CTGF in pulmonary fibrosis. The traditional treatment options include corticosteroids, immunosuppressive/cytotoxic agents, antifibrotic agents, and some traditional Chinese drugs. However, such therapies can not provide obvious good effects.This study included: ①to prepare pulmonary fibrosis model induced by bleomycin in rats, observe the variation of CTGF expression, and explore the relationship between CTGF and TGF-β1. ②to interfere in and treat pulmonary fibrosis rats with Panax Notoginsenosides (PNS), and compare the effects with Tetramethylpyrazine (TMPZ) and Dexamethasone(DEX). This research aims to provide theory foundation for elucidating pathogenic mechanisms of PF and seeking novel and more precisely targeted therapies. Methods: Wistar rats were prepared with a single intratracheal instillation dose of bleomycin. Part One, The early intervention to the rats with pulmonary fibrosis: healthy Wistar rats were randomly divide into several groups: control group: CG1, model group: MG1, Tetramethylpyrazine group: TG1, Dexamethasone group: DG1, Panax Notoginsenosides group: PG1. After after bleomycin exposure 24 h,the rats in TG1,DG1,PG1 were intra-abdominally injected above-mentioned drugs respectively. On 7th,14 th,21 th and 28 th day after intervention, 6 rats of each group were sacrified and the lungs were harvest for conventional pathological observation,Masson dyeing, hydroxyproline(HyP) concentration of lung tissue. TGF-β1 and CTGF protein expression in lung tissues were detected by immunohistochemistry and the CTGF mRNA expression in lung tissues were detected by hybridization in situ and RT-PCR. Part Two,the therapy to the rats in progressive phase of pulmonary fibrosis: The therapy groups were divided into six parts after bleomycin exposure 28 days,including model group ( MG2 ) , Tetramethylpyrazine group (TG2), Dexamethasone group (DG2), high, medium,low dosage of Panax Notoginsenosides groups(PGH,PGM,PGL).The rats were treated with intra-abdominally injection above-mentioned drugs respectively on 29th day after bleomycin exposure.After treatment 30 days, 6 rats of each group were sacrified and survey indexes were same as Part One. Results: 1. The lung tissue pathomorphology of Rats in MG1 showed that typical pulmonary fibrosis process. Acute inflammation alteration of the lungs in MG1 were observed on 7th day and this kind of inflammation lessened on 14th day.Collagen fibers sediments increased obviously and the structures of pulmonary alveoli were damaged on 21th and 28 th day individually. The BALF total count and PMN of MG1 group were increased and reached peak on 7th day and returned to the level of CG1 on 28 th day. The expression of TGF-β1 elevated and reached peak on 7th day,then decreased gradually and retained a high level on 14th ,21th , 28th day.The tendency of CTGF protein and mRNA expression was same as TGF-β1. 2. After early intervention to the rats with pulmonary fibrosis,the pathomorphology of rat lungs in PG1, TG1 and DG1 showed pulmonary fibrosis variation further advanced, but the extent distinctly lower that MG1. It were similar that lungs hydroxyproline(HyP)content and expression of TGF-β1,CTGF between TG1,DG1,PG1and MG1. All those data from three treated groups are higher than CG1 and lower than MG1(P<0.01 or P<0.05). 3. After receiving corresponding therapy on advanced pulmonary fibrosis rats, the degree of pulmonary fibrosis was still progressing in rats of MG2, DG2, PGS.The pathological changes of lung in PGL,PGM,TG2 rats were distinctly milder than MG2 rats.There was an upregulation in the TGF-β1 protein expression in MG2.Compared with MG2, TGF-β1 expression in TG2,PGL,PGM very significantly decreased (P<0.01),and significantly decreased in DG2,PGS(P<0.05).The expression of CTGF retained at a high level in MG2, DG2. There was not significant difference between MG2 and DG2. The expression of CTGF in TG2, PGL, PGM was very significantly weaker than MG2 (P<0.01), and significantly weaker in PGS (P<0.05). Conclusion: 1. The rat pulmonary fibrosis model induced by a single intratracheal instillation dose of bleomycin (BLM) was stable and reliable,it exactly mimicked the clinical procedure of pulmonary fibrosis. 2. CTGF showed high level expression in bleomycin-induced rats lung tissue from beginning to end, which suggested that CTGF involved the whole procedure of pulmonary fibrosis. 3. Both TGF-β1 and CTGF are the important cytokines in the proceeding of pulmonary fibrosis. As upstream element of CTGF, some functions of TGF-β1 implemented through CTGF. 4. PNS had better intervention and anti-fibrosis effect to pulmonary fibrosis. And therapeutic effect is similar with TMPZ. Compared with DEX, the side effect was mild. So medium dosage of PNSis safety and effectiveness for long time used.
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