ABSTRACT
ObjectiveTo investigate the effect of Gegen Qinliantang on glucose and lipid metabolism in the rat model of catch-up growth （CUG） induced by a high-fat diet and the underlying mechanism. MethodA total of 60 SD rats were randomized into a normal control group （n=18） and a modeling group （n=42）. The rat model of CUG was established with a restricted diet followed by a high-fat diet， and the changes of general status and body weight were observed. The levels of fasting blood glucose （FBG）， fasting insulin （FINS）， triglyceride （TG）， and total cholesterol （TC） were measured in 6 rats in each group at the end of the 4th and 8th week， respectively. The homeostasis model assessment of insulin resistance index （HOMA-IR） was calculated， and the insulin sensitivity and body composition changes of CUG rats were evaluated. The successfully modeled rats were assigned into 6 groups： normal control， model， high-， medium-， and low-dose Gegen Qinliantang （2.5， 5， 10 g·kg-1）， and pioglitazone （3.125 mg·kg-1）. The rats were administrated with corresponding drugs by gavage for 6 weeks， and the normal control group and model group were administrated with the same amount of normal saline. During the experiment period， the changes of body weight were recorded， and the FBG， FINS， HOMA-IR， TG， and TC were determined at the end of the experiment. Hematoxylin-eosin （HE） staining was employed to observe the pathological changes of skeletal muscle in rats. The levels of reactive oxygen species （ROS） and malondialdehyde （MDA） in the skeletal muscle were measured strictly according to the manuals of the reagent kits. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was performed to measure the mRNA levels of silencing information regulator 1 （SIRT1）， peroxisome proliferator-activated receptor-gamma coactivator1α （PGC1α）， and nuclear respiratory factor 1 （Nrf1） in the skeletal muscle. Western blot and immunohistochemistry were employed to assess the expression of SIRT1， PGC1α， and Nrf1 in the skeletal muscle. ResultCompared with the normal control group， the model group presented elevated levels of FBG， FINS， TG， and TC （P<0.05， P<0.01）， increased HOMA-IR （P<0.01）， increased diameter of muscle fibers and adipocytes between muscle cells in the skeletal muscle， rising levels of ROS and MDA in the skeletal muscle （P<0.01）， and down-regulated mRNA and protein levels of SIRT1， PGC1α， and Nrf1 （P<0.05， P<0.01）. Compared with the model group， Gegen Qinliantang （especially the medium and high doses） and pioglitazone decreased the body weight， FINS， HOMA-IR， and TG （P<0.05， P<0.01） and reduced interstitial components such as intermuscular fat in the skeletal muscles and the diameter of muscle fibers. Furthermore， the drugs lowerd the levels of ROS and MDA （P<0.05， P<0.01） and up-regulated the mRNA and protein levels of SIRT1， PGC1α， and Nrf1 （P<0.05， P<0.01） in the skeletal muscle. ConclusionGegen Qinliantang can ameliorate the glucose and lipid metabolism disorders and insulin resistance in CUG rats by regulating the SIRT1/PGC1α/Nrf1 signaling pathway.
ABSTRACT
Objective:To evaluate the role of silencing information regulator 1 (SIRT1)/nuclear factors E2-related factor2 (Nrf2) signaling pathway in berberine-induced reduction of renal ischemia-reperfusion (I/R) injury in mice.Methods:Thirty SPF healthy male C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were divided into 5 groups ( n=6 each) using a random number table method: sham operation group (S group), renal I/R group (RIR group), berberine+ I/R group (B group), berberine+ I/R+ SIRT1 inhibitor EX527 group (BE group) and berberine+ I/R+ Nrf2 inhibitor ATRA group (BA group). After the right kidney was removed, the left renal artery was clamped for 45 min followed by reperfusion to establish the model of renal I/R injury.In B, BE, and BA groups, berberine 100 mg·kg -1·d -1 was given for intragastric administration at 14 days before surgery.In group BE and group BA, EX527 5 mg·kg -1·d -1 and ATRA 10 mg·kg -1·d -1 were injected intraperitoneally at 3 days before surgery, respectively.The equal volume of normal saline was given for 14 consecutive days in group S and group RIR.Blood samples were collected from orbital vein at 24 h of reperfusion for measurement of serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations, for determination of the interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) contents (by enzyme-linked immunosorbent assay) and expression of SIRT1, Nrf2, apoptosis-associated speck-like protein containing CARD (ASC), caspase-1, nucleotide-binding oligomerization domain-like receptor containing pyrin domain (NLRP3) (by Western blot) and for examination of the pathological changes of renal tubules (with a light microscope). The damage to the renal tubules was scored. Results:Compared with group S, the concentrations of serum Cr and BUN, the contents of renal IL-1β and TNF-α and renal tubular injury score were significantly increased in RIR, B, BE and BA groups, the expression of SIRT1, Nrf2, ASC, caspase-1 and NLRP3 was up-regulated in RIR, BE and BA groups, and the expression of SIRT1, Nrf2, caspase-1 and NLRP3 was up-regulated in group B ( P<0.05). Compared with group RIR, the concentrations of serum Cr and BUN, the contents of renal IL-1β and TNF-α and renal tubular injury score were significantly decreased in B, BE and BA groups, the expression of SIRT1 and Nrf2 in group B, Nrf2 and ASC in BE group and SIRT1, ASC and caspase-1 in BA group was up-regulated, and the expression of ASC, caspase-1 and NLRP3 in group B, SIRT1 and NLRP3 in BE group and Nrf2 in BA group was down-regulated ( P<0.05). Compared with group B, the serum concentrations of Cr and BUN, the contents of IL-1β and TNF-α and renal tubular injury score were significantly increased in BE and BA groups, the expression of ASC, caspase-1 and NLRP3 in BE and BA groups was up-regulated, and the expression of SIRT1 in BE and Nrf2 in BA groups was down-regulated ( P<0.05). Conclusion:SIRT1/Nrf2 signaling pathway is involved in the process of berberine-induced reduction of renal I/R, which is related to inhibiting pyroptosis in mice.