Effect Of Tetramethylpyrazine On Hepatic Stellate Cell Apoptosis And Its Possible Mechanisms

Hepatic fibrosis is repairing reactiona to chronic liver injury,whcih is chronic inflammatory disease caused by hepatitis virus,medicine and other pathogenic factors.This disease is characterized by extensive deposition of extracellular matrix.The activation of hepatic stellate cells plays an important role in the development and progression of hepatic fibrosis.It is an important and effective means to promote apoptosis of activated HSC.The presentation of endoplasmic reticulum stress is misfolding and unfolded proteins' aggregation in endoplasmic reticulum as well as calcium disorder.Activating unfolded protein response,endoplasmic reticulum overload response and Caspase-12 can not only induce GRP78 which is glucose regulated protein to have protective effect,but also induced apoptosis independently,which can directly affects the outcome of stress cells,such as adaptation,injury or apoptosis.Endoplasmic reticulum stress plays an important role in the occurrence and development of hepatic fibrosis.Tetramethylpyrazine is a kind of alkaloid in chuanxiong whcih has the function of blood stasis.Its chemical structure is tetramethylpyrazine,whcih is widely used in the treatment of various cardiovascular and cerebrovascular diseases,chronic obstructive pulmonary disease and so on.A large number of studies have shown that ligustrazine has a protective funtion on liver.Tetramethylpyrazine can promote the apoptosis of hepatic stellate cells and have liver fibrosis effects.But whether tetramethylpyrazine can induce the apoptosis of endoplasmic reticulum of hepaticstellate cells through stress? Therefore,the present study is conducted from the cellular level on the discussion that whether tetramethylpyrazine can induce the apoptosis of endoplasmic reticulum of hepatic stellate cells through stress and provide new ideas for the reversal of liver fibrosis.Objective: to study about effects of tetramethylpyrazine on stress and apoptosis of endoplasmic reticulum in rat hepatic stellate cells and provide a new method for the treatment of hepatic fibrosis.Method : to stimulate hepatic stellate cell line(HSC-T6)with platelet derived growth factor(PDGF-BB)and establish liver fibrosis cell model.On this basis,tetramethylpyrazine(30?mol /L)was used to stimulate HSC-T6.After 24 hours,expression of related protein was tested by western blot.Flow cytometry was used to detect the apoptosis rate of each group of cells.Hoechst 33258 staining was used to observe the apoptotic morphology of HSC in each group.Result: the result of western blot showed that compared with group PDGF,expression of GRP78 increased in PDGF+tetramethylpyrazine group with enhanced expression of CHOP and C-Caspase12 and decreased significantly rate of Bcl-2/Bax and p-ERK/ERK.The results of flow cytometry showed that compared with PDGF group apoptosis rate of HSC increased.Meanwhile Hoechst 33258 staining showed that HSC in the PDGF+tetramethylpyrazine group presents the typical morphological changes of apoptosis.Conclusion: tetramethylpyrazine can induce HSC activated by PDGF to produce ERS,decrease Bcl-2/Bax ratio and lead to apoptosis which is related to increased expression of CHOP and C-Caspase12 which are ERS specific apoptosis protein as well as decreased phosphorylation level of ERK1/2.