ABSTRACT
OBJECTIVE To explore the mechanism of Yishen tongluo formula （YSTLF） in improving abnormal lipid metabolism based on the sterol regulatory element binding proteins （SREBPs） pathway. METHODS Using C57BLKS/J （db/db） mice as model and C57BLKS/J （db/m） mice as normal control， the mechanism of 1， 2.5 and 5 g/kg YSTLF improving abnormal lipid metabolism of db/db mice was investigated by determining the liver coefficient， the contents of serum total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein （LDL） and high-density lipoprotein （HDL）， observing steatosis and lipid accumulation in liver tissue of mice， detecting the protein expressions of SREBP-1 and SREBP-2 as well as mRNA transcription levels of Srebp- 1c， Srebp-2 and their downstream lipid metabolism-related target genes （Fasn， Acc1， Scd5， Fads1， Hmgcr， Dhcr24， Insig-1， Fdps） in liver tissue of mice. Using low-fat cultured human liver cancer cell HepG2 as an in vitro cell model for abnormal lipid metabolism， and 25-HC （SREBPs inhibitor， 10 μmol/L） as the control， the effects of 125， 250 and 500 μg/mL YSTLF on protein expressions of SREBP-1 and SREBP-2 as well as mRNA transcription of SREBP-1c， SREBP-2 and their downstream lipid metabolism-related target genes were investigated to verify the mechanism in vitro. RESULTS 1， 2.5， 5 g/kg YSTLF significantly reduced the levels of TC， TG and LDL， the percentage of lipid droplet-positive region in liver tissue and liver coefficient， significantly down-regulated protein expressions of Pre-SREBP-1， n-SREBP-1， Pre-SREBP-2 and n-SREBP-2， and mRNA transcription of Srebp-1c， Srebp-2 and their downstream target genes in liver tissue， while significantly increased HDL level， with statistical significance （P＜0.05 or P＜0.01）. In the cell experiment in vitro， the expressions of the above-mentioned proteins and genes in the cells treated with YSTLF at 125， 250 and 500 μg/mL for 24 hours were consistent with those in the animal experiment； there was no significant difference in the expressions of the above-mentioned proteins and genes between inhibitor control group and 250， 500 μg/mL YSTLF groups （P＞0.05）. CONCLUSIONS YSTLF can regulate the expression of transcription factor SREBPs， so as to inhibit the high expression of fatty acid and cholesterol synthesis-related genes， promote the degradation of TC and TG， improve the abnormality of lipid metabolism and inhibit lipid accumulation， thus playing the role of lipid-lowering.
ABSTRACT
Objective To explore the kidney protection and possible mechanism of Yishen Tongluo Formula (YTF) in rats with membranous nephropathy (MN). Methods A total of 60 SD healthy male rats were randomly divided into 10 for normal group and 50 for MN rat model group. The MN rat model was established by tail iv cationic bovine serum albumin (C-BSA). After successful modeling, they were randomly divided into model group, benazepril group, and YTF groups at low, medium, and high doses (6.61, 13.22, and 26.44 g/kg). Rats in each group were ig administrated once daily for continuous four weeks according to the corresponding dose. At the end of administration, the 24 h urine total protein (UTP), total cholesterol (TC), total protein (TP), albumin (ALB), blood urea nitrogen (BUN), and serum creatinine (Scr) levels were measured. Immunofluorescence was used to detect the deposition of IgG immune complexes in renal tissue. The glomerular basement membrane and podocyte morphology were observed under electron microscope. Immunohistochemistry and qRT-PCR were used to detect the expression of cytoskeleton-related proteins ezrin and synaptopodin in rat kidneys. Results Compared with the model group, the UTP and TC levels in the rats in each treatment group decreased significantly (P < 0.01), and the TP and ALB levels increased significantly (P < 0.01). The middle and high dose groups of YTF were similar to the benazepril group, and the effect was better than the low dose group of YTF. There was no significant difference in the BUN and Scr among the groups. Compared with the control group, the expression of ezrin and synaptopodin mRNA in the kidney of the model group was significantly decreased (P < 0.01). Compared with the model group, the expression of ezrin and synaptopodin mRNA in the podocytes of different treatment groups was increased in different degrees (P < 0.01). The expression levels of ezrin and synaptopodin mRNA in the kidney of rats in the middle and high dose groups of YTF were similar to those in the benazepril group, which were higher than that in the low dose group of YTF. Conclusion YTF has a therapeutic effect on membranous nephropathy in rats. The mechanism may be related to the inhibition of the degradation of podocyte skeleton related proteins ezrin and synaptopodin and the maintenance of the integrity of the podocyte skeleton and foot process.