| Objective To explore the effect of Ac-SDKP via stimulatory G protein(Gs)/inhibitory G protein(Gi) to regulate the myofibroblasts.Methods Si O2 powders were douched in the trachea of rat to make the silicotic model and treated with Ac-SDKP in postmanner. The pathological morphous was observed by Immunofluorescence staining to detect the expression of Vimention which stands for Extracellular Matrix(ECM) and Gs. The protein expression of inhibitory G protein, stimulatory G protein, c AMP and p-JNK, p-ERK1/2, α-SMA and collagen type I(Col I) protein exchange in lung tissues were measure by western blot. Human embryonic lung MRC-5 fibroblast was induced by Ang II, The pathological morphous was observed by Immunocytochemical staining to observe the expression of p-JNK, p-ERK1/2 and α-SMA, and pre-treatment with JNK signal inhibitor(SP600125), ERK1/2 signal inhibitor(PD98059) and Ac-SDKP. Western blot was profiled for expression of Gi, Gs, c AMP, pJNK, p-ERK1/2, α-SMA and Col I. to restrain these changes.Results In the pattern of silicosis, apparent silicon modules was arised, when tested with the method of immunofluorescence the result showing the positive expression of vimentin which stands for the ECM index and with the negative expression of Gs which should appear in the regular lung tissue. While after the pre-treatment of Ac-SDKP, the protein of vimentin was decreased and the protein of Gs was increased which had the same trend with the control group. When measured with the method of western blot, the protein expression of inhibitory G protein, p-JNK, p-ERK1/2, α-SMA and Col I were increased, compared to the 4 weeks control group, respectively, were 3.45 times, 2.0 times, 2.36 times, 3.48 times and 1.96 times, while compared to the 8 weeks control group, respectively, were 4.34 times, 1.94 times, 1.67 times, 3.92 times and 1.53 times. Conversely, the stimulatory G protein, c AMP protein exchange in lung tissues were decreased, compared to the 4 weeks control group, respectively, were 25.68% and 34.3%, compared to the 8 weeks control group, respectively were 10.6% and 11.25%. While after the pre-treatment of AcSDKP(Ac-SDKP antifibrotic therapy and Ac-SDKP prevent therapy), those changes were all suppressed and showing the same trend with the control group. Ang II significantly promoted the MRC-5 cell proliferation and induced their transformation to myofibroblasts. And after the treatment of Ang II in MRC-5 cell showing the positive expression of α-SMA in cytoplasm, and p-JNK or p-ERK1/2 positive expression in nucelus. While with the pre-treament of SP600125, PD98059 or Ac-SDKP, respectively suppressed the expression of JNK and ERK1/2 in nucleus, and at the same suppressed the expression of α-SMA in cytoplasm The up-regulation of Gi, p-JNK, p-ERK1/2, α-SMA and Col I, and respectively to the control group were 17.88 times, 2.46 times, 2.48 times, 2.22 times and 2.16 times.With the down-regulation of Gs and c AMP were induced by Ang II, and respectively to the control group were 13.04% and 5.3%. Pre-treatment with SP600125, PD98059 or AcSDKP could inhibit all this changes.Conclusion Ac-SDKP could attenuate myofibroblast differentiation from lung fibroblast induced by Ang II by regulation JNK and ERK1/2 signal via Gs/Gi. |
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