Pollen typhae total flavone suppresses A7r5 cell proliferation promoted by insulin involving the MEK1/2-ERK1/2 cascades.

Pollen typhae, a traditional medicine in China, performs an anti-diabetic function and has anti-atherosclerosis effects involving suppression of vascular smooth muscle cell proliferation. However, the potential mechanisms keep to be revealed. The present study intended to investigate the influences of Pollen typhae extract named Pollen typhae total flavone (PTF) on A7r5 cell proliferation promoted by insulin and to uncover the underlying mechanisms. Proliferation and viability were evaluated by CCK-8 method. Western blotting was adopted to analyze the protein expression. Insulin promoted A7r5 cell proliferation, while PTF suppressed insulin-promoted proliferation in a concentration-dependent fashion. Although PTF did not change c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38MAPK) or MAPK kinase 1/2 (MEK1/2) protein expression and failed to affect the phosphorylation of JNK and p38MAPK, PTF remarkably inhibited extracellular signal-regulated kinase 1 and 2 (ERK1/2) protein expression and reduced ERK1/2 and MEK1/2 phosphorylation in A7r5 cells stimulated by insulin. Insulin-induced proliferation of A7r5 cells was abolished by inhibiting ERK1/2, which was in line with PTF. These findings indicate that PTF suppresses insulin-promoted proliferation of A7r5 cells involving the MEK1/2-ERK1/2 cascades, providing new insight into the potential uses of PTF for treatment of diabetic atherosclerosis.

Protective role of Pollen Typhae total flavone against the palmitic acid-induced impairment of glucose-stimulated insulin secretion involving GPR40 signaling in INS-1 cells.

Prolonged elevated levels of free fatty acids (FFAs) contribute to the impairment of insulin secretion function of pancreatic ß cells, a hallmark of type 2 diabetes, which is partly attributed to the dysfunction of G-protein-coupled receptor 40 (GPR40) signaling. Pollen Typhae total flavone (PTF), an extract from a Chinese herbal medicine named Pollen Typhae, has been reported to effectively treat type 2 diabetes, but the underlying mechanisms remain to be fully elucidated. In the present study, palmitic acid (PA), a saturated fatty acid, severely impaired glucose-stimulated insulin secretion (GSIS) in a time-dependent manner in INS-1 cells, and PTF treatment prevented the impairment in a dose-dependent manner. Moreover, PTF improved insulin secretion function in rats presenting with type 2 diabetes induced by a high-fat diet and low-dose streptozotocin. Furthermore, PA exposure for 24 h decreased the protein expression of GPR40, phospholipase C (PLC)ß1, PLCß3, and protein kinase C (PKC), and inhibited the activity of PLC and PKC stimulated by GW9508, a GPR40 agonist. In addition, PTF enhanced the protein expression of GPR40 and to a certain extent strengthened the protein expression of PKC, increased cellular levels of triphosphoinositide (IP3) and diacylglycerol (DAG), and promoted GW9508-stimulated activity of PLC and PKC reduced by PA in INS-1 cells, which were blocked by PLC inhibitor U-73122 and PKC inhibitor staurosporine, respectively. Additionally, the improvement in PA-induced impairment of GSIS by PTF in INS-1 cells was restrained by U-73122, staurosporine, and calcium channel inhibitor nifedipine, respectively. The results indicate that PTF exerts a protective role against PA-induced impairment of GSIS involving GPR40 signaling in INS-1 cells.

ANTI-DIABETIC EFFECTS OF ZHUODUQING FORMULA, A CHINESE HERBAL DECOCTION, ON A RAT MODEL OF TYPE 2 DIABETES.

BACKGROUND: Zhuoduqing formula (ZDQ) is a Chinese herbal decoction and used to treat type 2 diabetes in clinical practice, but the potential evidence needs to be provided. MATERIALS AND METHODS: Type 2 diabetic model rats were induced by feeding high fat diet (HFD) and intraperitoneal injection of streptozotocin (STZ). The model rats were given ZDQ for 4 weeks. Insulin sensitivity was evaluated by homeostasis model assessment of basal insulin resistance (HOMA-IR) and intraperitoneal glucose tolerance test (IPGTT). Blood insulin and tumour necrosis factor-α (TNF-α) levels as well as SOCS-3 levels in skeletal muscles were analyzed by ELISA. RESULTS: ZDQ significantly decreased fasting blood glucose, ameliorated HOMA-IR and IPGTT, and reduced triglyceride and total cholesterol in type 2 diabetic rats. Moreover, ZDQ remarkably lowered blood TNF-α levels and inhibited SOCS-3 levels in skeletal muscles. CONCLUSION: The results display that ZDQ performs anti-diabetic functions in type 2 diabetic rats induced by feeding HFD and intraperitoneal injection of STZ. Abbreviations: ZDQ, zhuoduqing formula; ROS, rosiglitazone; HOMA-IR, homeostasis model assessment of basal insulin resistance; IPGTT, intraperitoneal glucose tolerance test; HFD, high fat diet; SOCS-3, suppressor of cytokine signaling-3; TNF-α, tumour necrosis factor-α.

Electroacupuncture relieves labour pain and influences the spinal dynorphin/κ-opioid receptor system in rats.

BACKGROUND: The dynorphin (DYN)/κ-opioid receptor (KOR) system plays a key role in the control of labour pain. Our previous clinical study reported that electroacupuncture (EA) provided intrapartum analgesia, but the underlying mechanisms of action have not been fully elucidated. AIMS: To observe the effect of EA on labour pain and to explore the underlying mechanisms of action in a rat model. METHODS: Copulation-confirmed pregnant rats (n=120) were given castor oil to induce labour. Rats remained untreated (control group, n=20) or received either meperidine (an opioid that is commonly used to treat labour pain, n=20) or EA at SP6, LI4, SP6+LI4 or SP10 (four groups, n=20 each). Labour pain was evaluated by the warm water tail-flick test. Serum DYN values were measured by ELISA. Protein and mRNA expression of prodynorphin (PDYN, the precursor protein of DYN) and KOR were analysed by Western blotting and real-time PCR, respectively. RESULTS: EA treatment at all acupuncture point combinations studied significantly relieved labour pain and increased serum DYN concentrations, to a degree similar to that achieved with meperidine. EA notably enhanced protein expression of KOR and PDYN and mRNA expression in the lumbar spinal cord but not in the cerebral cortex. The size of effect varied by EA group in the order: SP6>LI4>SP6+LI4>SP10 for all parameters measured, indicating differential effects relating to acupuncture point selection/combination. CONCLUSIONS: The present study indicates that EA relieves labour pain, at least in part, by regulation of the spinal DYN/KOR system in a rat model.

Pollen Typhae total flavone improves insulin resistance in high-fat diet and low-dose streptozotocin-induced type 2 diabetic rats.

Pollen Typhae total flavone (PTF), the extract from Pollen Typhae, is reported to enhance glucose uptake in C2C12 myotubes in vitro, but the convincing evidence is lacking in vivo. In this study, PTF ameliorated insulin resistance and dyslipidemia, but failed to significantly increase body weight in type 2 diabetic rats induced by high-fat diet and low-dose streptozotocin.

Effects of Chinese herbal medicine Yiqi Huaju Qingli Formula in metabolic syndrome patients with microalbuminuria: a randomized placebo-controlled trial.

BACKGROUND: Microalbuminuria (MAU) is a key component of metabolic syndrome (MetS) and is an early sign of diabetic nephropathy as well. Although routine Western medicine treatments are given to MetS patients to control high blood pressure, hyperglycemia and dyslipidemia, some patients still experience progressive renal lesions and it is necessary to modify and improve the treatment strategy for MetS patients. OBJECTIVE: To investigate the efficacy of Yiqi Huaju Qingli Herb Formula, a compound traditional Chinese herbal medicine, in MetS patients with MAU when it is combined with routine Western medicine treatment. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: Sixty patients with MetS were randomized into the Chinese herbal formula group (CHF, Yiqi Huaju Qingli formula treatment in combination with Western medicine) and control group (placebo in combination with Western medicine). All treatments were administered for 12 weeks. MAIN OUTCOME MEASURES: Urinary microalbumin (MA), urinary albumin-to-creatinine ratio (UACR), 24-hour total urine protein (24-hTP), body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2-hPPG), glycosylated hemoglobin (HbA1c), homeostasis model assessment for insulin resistance (HOMA-IR), blood lipid profile and blood pressure were observed. RESULTS: Compared with the control group, CHF treatment significantly decreased BMI (P<0.05), WC (P<0.01) and WHR (P<0.01). Both groups had significant decreases in FPG, 2-hPPG, HbA1c, HOMA-IR, MA, and UACR, with CHF treatment showing better effects on these parameters compared with the control treatment (P<0.05). Both treatments significantly reduced the levels of total cholesterol, low-density lipoprotein cholesterol and triacylglycerol (TAG), and a greater reduction in TAG was observed with CHF treatment (P<0.05). The level of high-density lipoprotein cholesterol did not change in the control group after treatment (P>0.05), whereas it significantly increased with CHF treatment (P<0.01). Compared with before the treatment, significant decreases in systolic blood pressure, diastolic blood pressure and mean arterial blood pressure were observed in both groups (P<0.01). However, there was no significant difference between the two groups (P>0.05). CONCLUSION: Combined treatment of Yiqi Huaju Qingli Formula and Western medicine significantly alleviated MAU, which may correlate with the improvement of insulin sensitivity and glucose and lipid metabolism. TRIAL REGISTRATION IDENTIFIER: This trial was registered in the Chinese Clinical Trial Registry with the identifier ChiCTR-TRC-11001633.

Effects of Chinese herbal medicine Yiqi Huaju Formula on hypertensive patients with metabolic syndrome: a randomized, placebo-controlled trial.

BACKGROUND: Patients with hypertension coupled with metabolic syndrome (MetS) are among the high risk population in cardiovascular and cerebrovascular diseases. To reduce the prevalence of cardiovascular and cerebrovascular diseases, it is essential to appropriately control blood pressure together with other cardiovascular risk factors. OBJECTIVE: The current study was designed to investigate the therapeutic effects on blood pressure, blood pressure variability and other cardiovascular risk factors by giving Yiqi Huaju Formula, a compound traditional Chinese herbal medicine, in addition to routine treatment to hypertensive patients coupled with MetS. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: A total of 43 patients with hypertension coupled with MetS were recruited into this study. The enrolled patients were randomly divided into the Chinese herbal formula group (anti-hypertensive drugs plus Yiqi Huaju Formula, CHF) and the control group (anti-hypertensive drugs plus placebo). The CHF group enrolled 22 patients while the control group received 21 cases. Treatments were given for 12 weeks in both groups. MAIN OUTCOME MEASURES: Parameters examined include 24-hour ambulatory blood pressure monitoring, body mass index, waist circumference, waist-to-hip ratio, homeostatic model assessment for insulin resistance (HOMA-IR), fasting glycosylated hemoglobin (HbA1c), fasting plasma glucose, 2-hour postprandial plasma glucose (PPG), fasting plasma insulin, serum lipid, etc. RESULTS: Compared with the control group, the CHF group had significant improvement (P<0.01) in anthropometric parameters, FPG, HOMA-IR, blood pressure amplitude, blood pressure variability and blood pressure load. CONCLUSION: This study showed that integrated traditional Chinese and Western medicine treatment can achieve better results in controlling blood pressure as well as other cardiovascular risk factors. The mechanism of controlling of blood pressure may be associated with the improvement of insulin sensitivity due to the Yiqi Huaju intervention. TRIAL REGISTRATION IDENTIFIER: ChiCTR-TRC-11001633.

GPR40: a therapeutic target for mediating insulin secretion (review).

G-protein-coupled receptor 40 (GPR40), known as free fatty acid receptor 1, is mainly expressed in pancreatic ß-cells and activated by medium- and long-chain fatty acids. Increasing evidence indicates that the activation of GPR40 in cells causes insulin secretion, and GPR40 has become an attractive therapeutic target for type 2 diabetes. Recently, certain novel GPR40 agonists have been identified that regulate glucose-stimulated insulin secretion, leading to the development of new drugs for the treatment of type 2 diabetes. In this review, we focus on progress in the physiological role of GPR40 and potential drugs targeting GPR40 over the past decade.

Pollen Typhae total flavone improves insulin-induced glucose uptake through the ß-arrestin-2-mediated signaling in C2C12 myotubes.

Defects in insulin-stimulated glucose uptake in skeletal muscle result from the dysfunction of insulin signaling including the phosphatidylinositol-3 kinase (PI3K) pathway and a novel ß-arrestin-2-mediated signaling, which leads to insulin resistance (IR). Pollen Typhae, a Chinese herb, has been used for thousands of years in traditional Chinese medicine, and has the potential to inhibit the development of IR. We have previously reported that Pollen Typhae total flavone (PTF), the extract from Pollen Typhae, ameliorates high-glucose- and high-insulin-induced impairment of glucose uptake in 3T3-L1 adipocytes, but the mechanisms remain unclear. The objective of this study was to investigate the effects of PTF on glucose uptake, and to explore the underlying mechanisms in C2C12 myotubes. PTF improved insulin-stimulated glucose uptake in a dose- and time-dependent manner in C2C12 myotubes, and prevented palmitate-induced IR. Furthermore, PTF enhanced the basal gene expression of Src and Akt2, elevated the protein expression of ß-arrestin-2, Src and Akt, increased the phosphorylation of insulin receptor-ß at Tyr1150/1151 and Akt at Thr308/Ser473 in an insulin-dependent manner, but had no effects on the protein expression of PI3K-p85 or the activity of PI3K. Inhibition of Src but not PI3K restrained PTF-induced phosphorylation of Akt and glucose uptake. Our findings indicate that PTF improves insulin-induced glucose uptake via the ß-arrestin-2-mediated signaling in C2C12 myotubes.

Yidiyin, a Chinese herbal decoction, improves erectile dysfunction in diabetic patients and rats through the NO-cGMP pathway.

The nitric-oxide (NO)-cyclic-guanosine-monophosphate (cGMP) pathway plays a key role in penile erection. Erectile dysfunction (ED) is a complication in male diabetic patients that impacts their quality of 1ife. Recently, Yidiyin, a Chinese herbal decoction, is used to treat diabetic ED, but convincing evidence is lacking, and the potential mechanisms remain uncertain. In the study, diabetic ED patients had low scores on international index of erectile function-5 (IIEF-5), and administration of Yidiyin and hypoglycemic drugs for 16 weeks ameliorated patients' scores on IIEF-5 more than the hypoglycemic drug alone. Moreover, streptozotocin-induced diabetes severely impaired rats' erectile function and the activity of the NO-cGMP pathway in the corpora cavernosum, and treatment with Yidiyin for 4 weeks obviously increased the rats' erectile function, remarkably enhanced the activity of nitric oxide synthase (NOS), and elevated the contents of NO and cGMP. Our findings indicate that Yidiyin improves diabetic ED probably by enhancing the NO-cGMP pathway.