Rutaecarpine Reverses the Altered Connexin Expression Pattern Induced by Oxidized Low-density Lipoprotein in Monocytes.

Adhesion of monocytes to the vascular endothelium is crucial in atherosclerosis development. Connexins (Cxs) which form hemichannels or gap junctions, modulate monocyte-endothelium interaction. We previously found that rutaecarpine, an active ingredient of the Chinese herbal medicine Evodia, reversed the altered Cx expression induced by oxidized low-density lipoprotein (ox-LDL) in human umbilical vein endothelial cells, and consequently decreases the adhesive properties of endothelial cells to monocytes. This study further investigated the effect of rutaecarpine on Cx expression in monocytes exposed to ox-LDL. In cultured human monocytic cell line THP-1, ox-LDL rapidly reduced the level of atheroprotective Cx37 but enhanced that of atherogenic Cx43, thereby inhibiting adenosine triphosphate release through hemichannels. Pretreatment with rutaecarpine recovered the expression of Cx37 but inhibited the upregulation of Cx43 induced by ox-LDL, thereby improving adenosine triphosphate-dependent hemichannel activity and preventing monocyte adhesion. These effects of rutaecarpine were attenuated by capsazepine, an antagonist of transient receptor potential vanilloid subtype 1. The antiadhesive effects of rutaecarpine were also attenuated by hemichannel blocker 18α-GA. This study provides additional evidence that rutaecarpine can modulate Cx expression through transient receptor potential vanilloid subtype 1 activation in monocytes, which contributes to the antiadhesive properties of rutaecarpine.

Osteopontin-induced brown adipogenesis from white preadipocytes through a PI3K-AKT dependent signaling.

Recent studies have shown that OPN (osteopontin) plays critical roles in cell survival, differentiation, bio-mineralization, cancer and cardiovascular remodeling. However, its roles in the differentiation of brown adipocytes and the underlying mechanisms remain unclear. Therefore, the aim of this study was to investigate the roles of OPN in the brown adipogenesis and the underlying mechanisms. It was shown that the OPN successfully induced the differentiation of 3T3-L1 white preadipocytes into the PRDM16(+) (PRD1-BF1-RIZ1 homologous domain containing 16) and UCP-1(+) (uncoupling protein-1) brown adipocytes in a concentration and time-dependent manner. Also, activation of PI3K (phosphatidylinositol 3-kinase)-AKT pathway was required for the OPN-induced brown adipogenesis. The findings suggest OPN plays an important role in promoting the differentiation of the brown adipocytes and might provide a potential novel therapeutic approach for the treatment of obesity and related disorders.

DJ-1 Mediates the Delayed Cardioprotection of Hypoxic Preconditioning Through Activation of Nrf2 and Subsequent Upregulation of Antioxidative Enzymes.

We have recently shown that DJ-1 is implicated in the delayed cardioprotective effect of hypoxic preconditioning (HPC) against hypoxia/reoxygenation (H/R) injury as an endogenous protective protein. This study aims to further investigate the underlying mechanism by which DJ-1 mediates the delayed cardioprotection of HPC against H/R-induced oxidative stress. Using a well-characterized cellular model of HPC from rat heart-derived H9c2 cells, we found that HPC promoted nuclear factor erythroid 2-related factor 2 (Nrf2) and its cytoplasmic inhibitor Kelch-like ECH-associated protein-1 (Keap1) dissociation and resulted in increased nuclear translocation, antioxidant response element-binding, and transcriptional activity of Nrf2 24 hours after HPC, with subsequent upregulation of manganese superoxide dismutase (MnSOD) and heme oxygenase-1 (HO-1), which provided delayed protection against H/R-induced oxidative stress in normal H9c2 cells. However, the aforementioned effects of HPC were abolished in DJ-1-knockdown H9c2 cells, which were restored by restoration of DJ-1 expression. Importantly, we showed that inhibition of the Nrf2 pathway in H9c2 cells mimicked the effects of DJ-1 knockdown and abolished HPC-derived induction of antioxidative enzymes (MnSOD and HO-1) and the delayed cardioprotection. In addition, inhibition of Nrf2 also reversed the effects of restored DJ-1 expression on induction of antioxidative enzymes and delayed cardioprotection by HPC in DJ-1-knockdown H9c2 cells. Taken together, this work revealed that activation of Nrf2 pathway and subsequent upregulation of antioxidative enzymes could be a critical mechanism by which DJ-1 mediates the delayed cardioprotection of HPC against H/R-induced oxidative stress in H9c2 cells.

Nrf2-dependent upregulation of antioxidative enzymes: a novel pathway for hypoxic preconditioning-mediated delayed cardioprotection.

It has been well demonstrated that hypoxic preconditioning (HPC) can attenuate hypoxia/reoxygenation (H/R)-induced oxidant stress and elicit delayed cardioprotection by upregulating the expression of multiple antioxidative enzymes such as heme oxygenase-1 (HO-1), manganese superoxide dismutase (MnSOD) and so on. However, the underlying mechanisms of HPC-induced upregulation of antioxidative enzymes are not fully understood. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential transcription factor that regulates expression of several antioxidant genes via binding to the antioxidant response element (ARE) and plays a crucial role in cellular defence against oxidative stress. Here, we wondered whether activation of the Nrf2-ARE pathway is responsible for the induction of antioxidative enzymes by HPC and contributes to the delayed cardioprotection of HPC. Cellular model of HPC from rat heart-derived H9c2 cells was induced 24 h prior to H/R. The results showed that HPC efficiently attenuated H/R-induced viability loss and lactate dehydrogenase leakage. In addition, HPC increased nuclear translocation and ARE binding of Nrf2 during the late phase, upregulated the expression of antioxidative enzymes (HO-1 and MnSOD), inhibited H/R-induced oxidant stress. However, when Nrf2 was specifically knocked down by siRNA, the induction of antioxidative enzymes by HPC was completely abolished and, as a result, the inhibitory effect of HPC on H/R-induced oxidant stress was reversed, and the delayed cardioprotection induced by HPC was also abolished. These results suggest that HPC upregulates antioxidative enzymes through activating the Nrf2-ARE pathway and confers delayed cardioprotection against H/R-induced oxidative stress.

Stable overexpression of DJ-1 protects H9c2 cells against oxidative stress under a hypoxia condition.

It has been well accepted that increased reactive oxygen species (ROS) and the subsequent oxidative stress is one of the major causes of ischemia/reperfusion (I/R) injury. DJ-1 protein, as a multifunctional intracellular protein, plays an important role in regulating cell survival and antioxidant stress. Here, we wondered whether DJ-1 overexpression attenuates simulated ischemia/reperfusion (sI/R)-induced oxidative stress. A rat cDNA encoding DJ-1 was inserted into a mammalian expression vector. After introduction of this construct into H9c2 myocytes, stable clones were obtained. Western blot analysis of the derived clones showed a 2.6-fold increase in DJ-1 protein expressing. Subsequently, the DJ-1 gene-transfected and control H9c2 cells were subjected to sI/R, and then cell viability, lactate dehydrogenase, malondialdehyde, intracellular ROS and antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were measured appropriately. The results showed that stable overexpression of DJ-1 efficiently attenuated sI/R-induced viability loss and lactate dehydrogenase leakage. Additionally, stable overexpression of DJ-1 inhibited sI/R-induced the elevation of ROS and MDA contents followed by the increase of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) activities and expression. Our data indicate that overexpression of DJ-1 attenuates ROS generation, enhances the cellular antioxidant capacity and prevents sI/R-induced oxidative stress, revealing a novel mechanism of cardioprotection. Importantly, DJ-1 overexpression may be an important part of a protective strategy against ischemia/reperfusion injury.

Hypoxic preconditioning up-regulates DJ-1 protein expression in rat heart-derived H9c2 cells through the activation of extracellular-regulated kinase 1/2 pathway.

Myocardial preconditioning is a powerful phenomenon that can attenuate ischemia/reperfusion-induced oxidant stress and elicit delayed cardioprotection. Its mechanisms involve activation of intracellular signaling pathways and up-regulation of the protective antioxidant proteins. DJ-1 protein, as a multifunctional intracellular protein, plays an important role in attenuating oxidant stress and promoting cell survival. In the present study, we investigated whether DJ-1 is up-regulated during the late phase of hypoxic preconditioning (HP) and the up-regulation of DJ-1 is mediated by extracellular-regulated kinase 1/2 (ERK1/2) signaling pathway. Rat heart-derived H9c2 cells were exposed to HP. Twenty-four hours later cells were subjected to hypoxia/reoxygenation (H/R) and then cell viability, lactate dehydrogenase (LDH), intracellular reactive oxygen species (ROS), ERK1/2 phosphorylation, and DJ-1 protein were measured appropriately. The results showed that HP efficiently attenuated H/R-induced viability loss and LDH leakage. In addition, HP promoted ERK1/2 activation, up-regulated DJ-1 protein expression, inhibited H/R induced the elevation of ROS. However, when ERK1/2 phosphorylation was specifically inhibited by U0126, the increase in DJ-1 expression occurring during HP was almost completely abolished and, as a result, the delayed cardioprotection induced by HP was abolished, and the inhibitory effect of HP on H/R-induced oxidant stress was also reversed. Furthermore, knocking down DJ-1 by siRNA attenuated the delayed cardioprotection induced by HP. Our data indicate that HP can up-regulate DJ-1 protein expression through the ERK1/2-dependent signaling pathway. Importantly, DJ-1 might be involved in the delayed cardioprotective effect of HP against H/R injury.

Comparison of the effects of cholecalciferol and calcitriol on calcium metabolism and bone turnover in Chinese postmenopausal women with vitamin D insufficiency.

AIM: To compare the effects of cholecalciferol (800 IU/d) and calcitriol (0.25 µg/d) on calcium metabolism and bone turnover in Chinese postmenopausal women with vitamin D insufficiency. METHODS: One hundred Chinese postmenopausal women aged 63.8±7.0 years and with serum 25-hydroxyvitamin D [25(OH)D] concentration <30 ng/mL were recruited. The subjects were divided into 2 groups based on the age and serum 25(OH)D concentration: 50 subjects (group A) received cholecalciferol (800 IU/d), and 50 subjects (group B) received calcitriol (0.25 µg/d) for 3 months. In addition, all the subjects received Caltrate D (calcium plus 125 IU cholecalciferol) daily in the form of one pill. The markers of calcium metabolism and bone turnover, including the serum levels of calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone, 25(OH)D and ß-CrossLaps of type I collagen containing cross-linked C-telopeptide (ß-CTX), were measured before and after the intervention. RESULTS: After the 3-month intervention, the serum 25(OH)D concentration in group A was significantly increased from 16.01 ± 5.0 to 20.02 ± 4.5 ng/mL, while that in group B had no significant change. The serum calcium levels in both the groups were significantly increased (group A: from 2.36 ± 0.1 to 2.45 ± 0.1 mmol/L; group B: from 2.36 ± 0.1 to 2.44 ± 0.1 mmol/L). The levels of serum intact parathyroid hormone in both the groups were significantly decreased (group A: from 48.56 ± 12.8 to 39.59 ± 12.6 pg/mL; group B: from 53.67 ± 20.0 to 40.32 ± 15.4 pg/mL). The serum levels of ß-CTX in both the groups were also significantly decreased (group A: from 373.93 ± 135.3 to 325.04 ± 149.0 ng/L; group B: from 431.00 ± 137.1 to 371.74 ± 185.0 ng/L). CONCLUSION: We concluded that both cholecalciferol (800 IU/d) and calcitriol (0.25 µg/d) plus Caltrate D modifies the serum calcium and bone turnover markers in Chinese postmenopausal women with vitamin D insufficiency. In addition, cholecalciferol (800 IU/d) significantly increased the serum 25(OH)D concentration.

Sasanquasaponin up-regulates anion exchanger 3 expression and elicits cardioprotection via NO/RAS/ERK1/2 pathway.

We have shown recently that sasanquasaponin (SQS) can inhibit ischemia/reperfusion-induced elevation of intracellular Cl(-) concentration ([Cl(-)](i)) and elicit cardioprotection by up-regulating anion exchanger 3 (AE(3)) expression. In the present study, we futher analysed the intracellular signal transduction pathways by which SQS up-regulates AE(3) expression and elicits cardioprotection. Cardiomyocytes were incubated for 24 h with or without 10 µmol/L SQS, followed by simulated ischemia/reperfusion (sI/R). NO formation, Ras activity, and extracellular-regulated kinase 1/2 (ERK1/2) phosphorylation were measured appropriately. We showed that SQS pretreatment efficiently attenuated viability loss and lactate dehydrogenase leakage induced by sI/R in cardiomyocytes. Moreover, SQS induced NO production and promoted Ras activation, which futher promoted extracellular-regulated kinase 1/2 (ERK1/2) phosphorylation. These effects were paralleled by an increase in AE(3) expression. However, when the cardiomyocytes were treated with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (c-PTIO; an NO scavenger), S-trans-trans-farnesylthiosalicylic acid (FTS) (a Ras inhibitor), U0126 (an ERK1/2 inhibitor), respectively, the increase in AE(3) expression occurring during SQS pretreatment was almost completely abolished and, as a result, SQS-induced cardioprotection was prevented. Our findings indicate that SQS might up-regulate AE(3) expression through NO/Ras/ERK1/2 signal pathway to elicit cardioprotection in cultured cardiomyocytes.

Anion exchanger 3 is required for sasanquasaponin to inhibit ischemia/reperfusion-induced elevation of intracellular Cl- concentration and to elicit cardioprotection.

Recent studies have shown that the cardioprotection of sasanquasaponin (SQS) against ischemia/reperfusion injury is related to inhibiting ischemia/reperfusion-induced elevation of intracellular Cl(-) concentration ([Cl(-) ](i)). However, the mechanism of inhibition remains unclear. Anion exchanger 3 (AE(3)) is an important regulatory protein for [Cl(-)](i). This study investigated whether AE(3) plays the critical role in the inhibitory effect of SQS on elevation of [Cl(-)](i) induced by ischemia/reperfusion and mediates the cardioprotection of SQS in H9c2 cells. Normal and AE(3) -knockdown H9c2 cells were incubated for 24 h with or without various concentrations of SQS (0.1, 1, or 10 µM) followed by simulated ischemia/reperfusion (sI/R). AE(3) expression was detected by Western blot. Flow cytometer analysis was employed to determine [Cl(-)](i,) [Ca(2+)](i) , reactive oxygen species (ROS) production, and cell apoptosis. The results showed that SQS pretreatment concentration-dependently attenuated sI/R-induced viability loss and lactate dehydrogenase leakage in normal H9c2 cells. Additionally, SQS concentration-dependently up-regulated AE(3) protein expression, and inhibited sI/R-induced the elevation of [Cl(-)](i) followed by the attenuation of Ca(2+) overload, ROS production, and cell apoptosis. However, the dose-dependent cardioprotection induced by SQS was abolished in AE(3) -knockdown H9c2 cells, and the inhibitory effects of SQS on [Cl(-)](i), Ca(2+) overload, ROS production, and cell apoptosis were also reversed. Our data indicate that AE(3) mediates the cardioprotective effect of SQS against sI/R injury. Importantly, AE(3) is required for SQS to inhibit sI/R-induced elevation of [Cl(-)](i), which subsequently inhibited sI/R-induced Ca(2+) overload, ROS production, and cell apoptosis.

Involvement of anion exchanger-2 in apoptosis of endothelial cells induced by high glucose through an mPTP-ROS-Caspase-3 dependent pathway.

Excess apoptosis of endothelial cells (EC) plays crucial roles in the onset and progression of vasculopathy in diabetes mellitus. Anion exchanger-2 (AE2) might be involved in the vasculopathy. However, little is known about the molecular mechanisms that AE2 mediated the apoptosis of EC. The purpose of this study was to explore the role of AE2 in the apoptosis of HUVECs induced by high glucose (HG) and its possible mechanisms. First, HUVECs were exposed to different glucose concentrations (5.5, 17.8, 35.6, 71.2 and 142.4 mmol/l, respectively, pH = 7.40) for different time points (12, 24, 48, 72, 120, and 168 h, respectively). Intracellular Cl(-) concentration ([Cl(-)]i), AE2 expression and the apoptosis were assayed. Then, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), Cl(-)-free media or specific RNA interference (RNAi) for AE2 was used to confirm whether AE2 could mediate the apoptosis induced by HG. Finally, the mechanisms of the AE2-mediated apoptosis were investigated by detecting mitochondrial permeability transition pore (mPTP, DeltaPsim) openings, reactive oxygen species (ROS) levels and Caspase-3 activity. We found that HG upregulated the AE2 expression and activity, increased [Cl(-)]i and induced the apoptosis in a time- and concentration-dependent manner. The apoptosis of HUVECs by HG was possibly mediated by AE2 through an mPTP-ROS-Caspase-3 dependent pathway. These findings suggested that AE2 was likely to be a glucose-sensitive transmembrane transporter and a novel potential therapeutic target for diabetic vasculopathy.

The protective effects of Polygonum multiflorum stilbeneglycoside preconditioning in an ischemia/reperfusion model of HUVECs.

AIM: To investigate the protective effects of preconditioning human umbilical vein endothelial cells (HUVECs) with Polygonum multiflorum stilbeneglycoside (PMS) under anoxia/reoxygenation (A/R), and the mechanism of protection. METHODS: Prior to A/R, HUVECs were incubated with PMS (0.6 x 10(-11), 1.2 x 10(-11), or 2.4 x 10(-11) mol/L) for 3 h. Cell injury was subsequently evaluated by measuring cell viability with an MTT assay and lactate dehydrogenase (LDH) release, whereas lipid peroxidation was assayed by measuring malondialdehyde (MDA) content. Antioxidant capacity was quantified by superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. Nitric oxide (NO) production was determined by nitrite accumulation. Endothelial NO synthase (eNOS) and inducible NOS (iNOS) protein expression was detected by Western blotting. Guanylate cyclase activity and cyclic GMP (cGMP) activity were assessed by an enzyme immunoassay kit. RESULTS: PMS incubation attenuated A/R-induced injury in a concentration-dependent manner, as evidenced by a decrease in LDH activity and an increase in cell viability. PMS exerted its protective effect by inhibiting the A/R-mediated elevation of MDA content, as well as by promoting the recovery of SOD and GSH-Px activities. Additionally, PMS incubation enhanced NO and cGMP formation by increasing iNOS expression and guanylate cyclase activity. The protective effects of PMS were markedly attenuated by NOS inhibitor L-NAME, soluble guanylate cyclase inhibitor ODQ or PKG inhibitor KT5823. CONCLUSION: PMS preincubation resulted in the enhancement of antioxidant activity and anti-lipid peroxidation. The NO/cGMP/cGMP-dependent protein kinase (PKG) signaling pathway was involved in the effect of PMS on HUVECs.

Hip axis length changes in 10,554 males and females and the association with femoral neck fracture.

Hip axis length (HAL) has been proposed as an independent predictor of hip fracture risk in Caucasian females. There are, however, few data concerning its predictive risk in Chinese. The aim of this study was to investigate the changes of HAL in healthy Chinese population and the relationship between HAL and femoral neck fracture. The study population included 10,554 healthy Chinese people (8665 females, 1889 males) aged 20-97 yrs living in Shanghai. Cases were 106 patients (82 females, 24 males) aged 52 yrs old and over with femoral neck fracture. Controls were 106 age-matched healthy persons. All subjects were measured bone mineral density (BMD) at any site of proximal femur and HAL using dual-energy X-ray absorptiometry. HAL had significantly positive correlations with height and weight. After the adjustment of height and weight, HAL increased with age at 50 yrs of age and over in females, and no difference was found among the age groups in males. Males had longer HAL than females in all age groups. The peak BMD appeared in 30-44 yrs for females and 20-24 yrs for males and decreased thereafter, especially for females at 50 yrs old and over. HAL was similar in both fracture and control groups, whereas the BMD values at proximal femur were significantly lower in fracture group than in controls. There was no evidence that subjects with femoral neck fracture had longer HAL. Because of the limitations of retrospective study and relatively small fracture sample, prospective studies are required to determine the conclusions.

Sasanquasaponin protects rat cardiomyocytes against oxidative stress induced by anoxia-reoxygenation injury.

Reactive oxygen species can play an important role in the pathogenesis of anoxia-reoxygenation injury. Sasanquasaponin (SQS) is a biologically active ingredient extracted from the Chinese medicinal plant Camellia oleifera Abel. Some studies have shown that SQS possesses potent antioxidant activities. However, it has not been elucidated whether SQS diminishes reactive oxygen species stress induced by anoxia-reoxygenation injury in cardiomyocytes. In this work, neonatal rat cardiomyocytes pretreated with the test compound were subjected to anoxia-reoxygenation. The extent of cellular damage was accessed by cell viability and the amount of released lactate dehydrogenase (LDH). Superoxide dismutase, catalase and glutathione peroxidase activities, reduced (GSH) and oxidized glutathione (GSSG) levels, and malondialdehyde contents were measured by a colorimetric method. The levels of intracellular reactive oxygen species and calcium were determined by flow cytometry. The results showed that SQS reduced LDH release and increased cell viability in a dose-dependent manner up to 10 microM and concomitantly decreased malondialdehyde and GSSG contents, while significantly increased GSH contents and the activities of superoxide dismutase, catalase and glutathione peroxidase. Moreover, treatment with SQS decreased intracellular reactive oxygen species levels and alleviated calcium accumulation in cardiomyocytes undergoing anoxia-reoxygenation. It is suggested that SQS could protect cardiomyocytes against oxidative stress induced by anoxia-reoxygenation by attenuating reactive oxygen species generation and increasing activities of endogenous antioxidants.

Anoxic preconditioning up-regulates 14-3-3 protein expression in neonatal rat cardiomyocytes through extracellular signal-regulated protein kinase 1/2.

Anoxic preconditioning (APC) attenuates myocardial injury caused by ischemia/reperfusion. The protective mechanisms of APC involve up-regulation of the protective proteins and inhibition of apoptosis. 14-3-3 protein, as a molecular chaperone, plays an important role in regulating cell survival and apoptosis. However, the role of 14-3-3 protein in cardioprotection of APC and the pathways determining 14-3-3 protein expression during APC are not clear. In this work, Western blotting analysis was used to detect the 14-3-3 protein expression and activity of extracellular signal-regulated protein kinase 1/2 (ERK1/2) in cardiomyocytes subjected to anoxia-reoxygenation injury with and without APC and control. The cardiomyocytes from APC group were more resistant to injury induced by anoxia-reoxygenation and had much stronger phosphorylation of ERK1/2 than the control. The 14-3-3 protein expression was positively correlated with the phosphorylation of ERK1/2. Furthermore, inhibition of the ERK1/2 with PD98059 abolished the 14-3-3 protein up-regulation in cardiomyocytes induced by APC. The results indicate that APC up-regulates 14-3-3 protein expression through the ERK1/2 signaling pathways.

Age-related bone mineral density, bone loss rate, prevalence of osteoporosis, and reference database of women at multiple centers in China.

Our study surveyed age-related bone mineral density (BMD), bone loss rate, and prevalence of osteoporosis in women at multiple research centers in China. Survey results were used to establish a BMD reference database for the diagnosis of osteoporosis in Chinese women nationwide. We used dual-energy X-ray absorptiometry bone densitometers to measure BMD at posteroanterior (PA) lumbar spine (L1-L4; n=8142) and proximal femur (n=7290) in female subjects of age 20-89 yr from Beijing, Shanghai, Guangzhou, Chengdu, Nanjing, and Jiaxing. A cubic regression-fitting model was used to describe the change of BMD with age at various skeletal sites. Peak BMD occurred between 30 and 34 yr of age for femur neck and total femur, and between 40 and 44 yr for spine and trochanter measurement sites. Young adult (YA) BMD values (mean and standard deviation [SD], calculated as the average BMD in the age range of 20-39, were 1.116+/-0.12, 0.927+/-0.12, 0.756+/-0.11, and 0.963+/-0.13 g/cm2 at PA spine, femoral neck, trochanter, and total femur, respectively. The BMD of 85-yr-old women reflected a loss of 32% at the spine and 30-35% at femur measurement sites. The prevalence of osteoporosis, defined as a BMD of

Delayed protection of tetramethylpyrazine on neonatal rat cardiomyocytes subjected to anoxia-reoxygenation injury.

The aim of this study was to investigate the cardioprotective effects and the possible mechanisms of delayed preconditioning induced by tetramethylpyrazine (TMP) in cultured neonatal rat cardiomyocytes subjected to anoxia-reoxygenation injury. Cultured neonatal rat cardiomyocytes were preconditioned using TMP at different concentrations (100, 200 and 500 microM). Cell viability, lactate dehydrogenase release, malondialdehyde formation, superoxide dismutase activity and glutathione peroxidase activity were measured to determine the protective effects against anoxia-reoxygenation injury. The expression of heat shock protein 70 (Hsp70) was measured 24 hr after TMP preconditioning by Western blot analysis. The results showed that TMP decreased lactate dehydrogenase release, increased cell viability, suppressed malondialdehyde formation and augmented activities of superoxide dismutase and glutathione peroxidase in a concentration-dependent manner. Moreover, the delayed protection was abolished by pre-treating with either protein kinase C inhibitor chelerythrine chloride or PD98059, a selective inhibitor of extracellular signal-regulated protein kinase 1/2, respectively, and the expression of Hsp70 was significantly increased in 24 hr after TMP preconditioning that was also suppressed by chelerythrine chloride or PD98059. These results suggest that TMP can induce delayed cardioprotective effects by activation of protein kinase C and extracellular signal-regulated protein kinase 1/2 signalling pathways and subsequent increased expression of Hsp70 in rat neonatal cardiomyocytes.

[Protection of camelliasaponin C against injury of myocardial cells by anoxia/reoxygenation and mechanism thereof].

OBJECTIVE: To investigate the protective effects of camelliasaponin C (CS-C) pretreatment on myocardial cell injury induced by anoxia/reoxygenation. METHODS: Myocardial cells were obtained from neonatal SD rats, cultured for 3 to 4 days, added into the wells of a 24-well plate, and were divided randomly into five groups (8 wells for each group): control group, anoxia/reoxygenation (A/R) group, added with anoxia culture fluid for 3 h and then added with imitation reperfusion fluid for 1 h, anoxia preconditioning (AP) group, undergoing anoxia for 10 min before A/R, CS-C pretreated group, added with CS-C 3.75 x 10(-7) mol/L 1 h before A/R, and glibenclamide (Glib) pretreated group, added with CS-C 3.75 x 10(-7) mol/L and Glib 12 microm 1 h before A/R. Trypan blue exclusion was used to detect the viability of the cardiomyocytes, the contents of lactate dehydrogenase (LDH) in the supernatant of culture medium was measured. Electron microscopy was used to observe the ultrastructure of the cardiomyocytes. RESULTS: The contents of LDH of the A/R group was 57.8 U/L +/- 6.4 U/L, significantly higher than that of the control group (12.3 U/L +/- 1.7 U/L, P < 0.01), and the LDH value of the CS-C group was 39.8 U/L +/- 3.9 U/L, significantly lower than that of the A/R group (P < 0.01), not significantly different from that of the AP group (32.4 U/L +/- 5.2 U/L, P > 0.05), but significantly higher than that of the control group. The cardiomyocyte viability of the A/R group was 51.0% +/- 1.9%, significantly lower than that of the control group (92.0% +/- 2.0%, P < 0.01), the cardiomyocyte viability of the CS-C pretreatment group was 76.4% +/- 3.5%, significantly higher than that of the A/R group (P < 0.01), but not significantly different from that of the AP group (78.0% +/- 2.0%, P > 0.05). The cardiomyocyte ultrastructure of the A/R group was significantly changed, and the changes of cardiomyocyte ultrastructure in the CS-C pretreatment group were significantly attenuated compared with the A/R group. The content of LDH of the Glib group was 55.8 U/L +/- 5.0 U/L, significantly higher than that of the CS-C pretreatment group (P < 0.05), and the cardiomyocyte viability of the Glib group was 54.1% +/- 3.7%, significantly lower than that of the CS-C pretreatment group (P < 0.05), and the damage to the cardiomyocyte ultrastructure in the Glib group was more severe than in the CS-C group. CONCLUSION: The cardioprotective effect of CS-C pretreatment is similar to that of anoxia preconditioning and the effective mechanism would be related to the opening of ATP-sensitive K(+) channel. Glib can abolish the cardioprotective effect of CS-C pretreatment.

[Development of a simple predicting tool for low bone mass of postmenopausal women: a study in Shanghai].

OBJECTIVE: To develop a simple screening tool for low bone mass of postmenopausal women. METHODS: 405 postmenopausal women in Shanghai who visited the department of osteoporosis consecutively, aged 62.8 +/- 8.0 (47 approximately 90), underwent questionnaire survey on the risk factors of osteoporosis and fracture. Dual energy X-ray absorptiometry (DXA) was conducted on the left or right femoral neck to measure the bone mineral density (BMD) to identify osteoporosis (T-score

Bone mineral density of the spine and femur in healthy Chinese men.

AIM: To establish bone mineral density (BMD) reference database in healthy Chinese men of Han ethnicity, and to estimate the prevalence of osteoporosis in the population. METHODS: The BMD in the lumbar spine 1-4 (L1-4) and proximal femur was measured using dual energy X-ray absorptiometry in a total of 1 385 healthy Chinese men of Han ethnicity aged 20-89 years old in Shanghai. RESULTS: The highly significant negative correlation between age and BMD at any sites of proximal femur was found in the studied population, wheras no correlation between age and BMD at lumbar spine was observed. The peak BMD of the lumbar spine and any sites of hip in Chinese men was defined as the mean BMD for the subjects aged 20-89 years. According to World Health Organization (WHO) criteria, the BMD cut-off values for osteoporosis of the L1-4, total hip, femoral neck, trochanter and intertrochanter in Chinese men are 0.719, 0.638, 0.575, 0.437 and 0.725 g/cm(2), respectively. Using the current Chinese reference data, the prevalence of osteoporosis at the L1-4, total hip, femoral neck, trochanter and intertrochanter is 5.4%, 3.8%, 6.3%, 1.8% and 2.8% in 1 084 men aged 50 years or older, respectively. However, using a database for US non-Hispanic white men (NHANES III), the prevalence of osteoporosis or osteopenia at any sites of the hip was significantly higher than that while using the current Chinese reference data. CONCLUSION: The BMD reference database was established in healthy Chinese men of Han ethnicity, and will facilitate more accurate diagnosis of osteoporosis in Chinese men.

[Relationship between the polymorphism of start codon and CDX2 site in vitamin D receptor gene and the effect of calcium supplementation on bone mineral density of postmenopausal women].

OBJECTIVE: To investigate the association of polymorphisms of start codon (Fok I site) and CDX2 binding site in vitamin D receptor gene (VDR) concerned with the effect of calcium supplementation on bone mineral density (BMD) and bone turnover markers of postmenopausal women. METHODS: Two hundreds unrelated postmenopausal women of Han ethnicity in Shanghai were randomly divided into 2 groups of 100 women: high calcium group (1000 mg element calcium and 400 units of vitamin D were given daily for 12 months) and low calcium group (300 mg element calcium and 300 units of vitamin D were given daily for 12 months). BMD and bone turnover markers were measured at baseline and 12 months after calcium supplementation. VDR gene Fok I and CDX2 polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele-specific multiplex PCR, respectively. RESULTS: One hundred and seventy-one women completed 12-month study period. The frequency of VDR Fok I genotypes was 48.0 % for Ff, 31.0 % for FF, and 21.0 % for ff, and the frequency of CDX2 genotypes was 56.7 % for AG, 25.7% for GG, and 17.6% for AA. The frequencies distribution of Fok I and CDX2 alleles in the entire population or in two subgroups all followed the Hardy-Weinberg equilibrium. No significant difference of baseline BMD and bone turnover markers in Fok I genotypes or CDX2 genotypes was observed in the entire population or in two subgroups. Moreover, regardless of calcium supplementation given for 12 months, no significant association was found between Fok I or CDX2 polymorphisms and the endpoint values or percentage changes of any BMD and bone turnover markers in either high calcium group or low calcium group. CONCLUSION: There is no significant relationship between VDR gene Fok I or CDX2 polymorphisms and the effect of high or low doses calcium supplementation on BMD and bone turnover markers in Shanghai postmenopausal women of Han ethnicity.