Effects of paecilomyces cicadidae total polysaccharides on non-specificity immune regulation in rats

AIM: To study the immune regulation of paecilomyces cicadidae total polysaccharides. METHODS: After subcutaneous injection with 200mg/L paecilomyces cicadidae total polysaccharides in the back of the rats fo17 days, the white blood cell (WBC) counts, and the levels of lipid peroxide (LPO) and reduced glutathione (GSH) in the spleen and thymus of rats were detected. The alveolar macrophages (AMφ) cultured with 10% fetal bovine serum-RPMI-1640 for 2 h in vitro, then the activity of lactate dehydrogenase (LDH) and acid phosphatase (ACP) were detected by automatic biochemistry analyzer, and the ability devouring neutral red in the AMφ were examined. RESULTS: Compared with control group, the WBC, the levels of GSH in the spleen and thymus, and the activities of LDH and ACP were significantly increased and the ability of devouring neutral red was also strengthened (P<0.01) in the AMφ of rats induced by paecilomyces cicadidae total polysaccharides, while the level of LPO in the thymus was obviously decreased (P<0.05). CONCLUSION: Paecilomyces cicadidae total polysaccharides has significant immune regulatory effect with increasing WBC and GSH.     

Immunomodulation of paecilomyces cicadidae polysaccharides on immune function of rats

AIM: To explore the immunomodulatory effect of paecilomyces cicadidae polysaccharides (PCPS).METHODS: Subcutaneous injection with 50, l00, 200 mg/kg of PCPS were given in the back of the rats everyday for l5 days. The number of white blood cells (WBC) was counted. The activities of acid phosphatase (ACP) and lactase dehydrogenase (LDH)in liver, kidney, spleen and thymus were detected by automatic biochemistry analyzer. The ability of devouring neutral red and activity of ACP, LDH, arginase in alveolar macrophages were also detected. The body weight of the rat everyday during experiment and weight of the spleen and thymus after the rats were killed were measured and wet weight index was calculated.RESULTS: The wet weight index of spleen and thymus, the activity of ACP, LDH, arginase and ability of devouring neutral red in alveolar macrophages in the test group treated with PCPS were significantly higher than those in control group. CONCLUSION: PCPS shows a significant immunomodulatory effect with the increasing counts of WBC and activation of alveolar macrophages in a dose-dependent manner.     

Effects of achyranthes bidentata polysaccharides on non-specific immune function of old rats

AIM: To study the effect of achyranthes bidentata polysaccharide (ABPS) on non-specific immune function of old rats. METHODS: After subcutaneous injection of ABPS (50 mg/kg body weight) into the back of the old rats for 21 days, the WBC and the levels of hemoglobin(Hb) and chief biochemical index in blood of old rats were determined. After the alveolar macrophages (AMΦ) and peritoneal macrophages (PMΦ) cultured with 10% fetal bovine serum-RPMI-1640 for 2 h in vitro, the activities of lactate dehydrogenase(LDH) and acid phosphatase(ACP) in the AMΦ and PMΦ were detected by automatic biochemistry analyzer, and the abilities in devouring neutral red in the AMΦ and PMΦ were observed. The levels of lipid peroxide(LPO) and reduced glutathione(GSH) in some immune organs like spleen, liver, brain, kidney and in serum were also detected.RESULTS: The levels of ACP and LDH in the AMΦ or PMΦ were increased (P<0.01), the ability of AMΦ or PMΦ in devouring neutral red was increased (P<0.01), the levels of LPO were diminished and the contents of GSH raised in the liver, brain and spleen (P<0.05 or P<0.01). CONCLUSION: ABPS has the functions of activating AMΦ and PMΦ， and enhances non-specific immunity in old rats.     

Paecilomyces cicadidae total polysaccharides regulates immune function in immunosuppressed rats

AIM: To study the effects of paecilomyces cicadidae total polysaccharides on the immune function and free radical scavenging of tissues in immunosuppressed rats. METHODS: The activities of lactate dehydrogenase (LDH) and arginase (Arg) in liver， kidney， spleen， thymus of immunosuppressed rats were detected by automatic biochemistry analyzer. The content of lipid peroxide (LPO) and the reduced glutathione (GSH) level in liver， kidney， spleen， thymus of immunosuppressed rats were observed. RESULTS: The activity of the LDH, Arg and GSH level were significantly increased, and the LPO content were significantly declined in liver， kidney， spleen， thymus of immunosuppressed rats induced by cyclophosphamide. CONCLUSION: Paecilomyces cicadidae total polysaccharides promote immune function and the ability of free radical scavenging of tissues in immunosuppressed rats.     

The activative effect of Paecilomyces cicadaeon peritoneal and alveolar macrophages of rats

AIM:To explore the activative effect of water extract from cultured mycelium ofPaecilomyces cicadae (P. cicadae)on peritoneal macrophages (PMΦ) and alveolar macrophages (AMΦ) of rats.METHODS:The rats were randomly divided into four groups: normal control group(Ⅰ), cyclophosphamide (Cy) group (Ⅱ),P. cicadaegroup(Ⅲ), Cy+P.cicadaegroup(Ⅳ).The rats were bred in the same circumstance and were administered with corresponding drugs by subcutaneous injection for 26 days. PMΦ and AMΦ of rats were irrigated by normal saline and collected by centrifuge and incubated in a humidified incubator for 2 h at 37 ℃. The activities of acid phosphatase (ACP) and lactate dehydrogenase (LDH) in the PMΦ and AMΦ were determined by biochemical methods, and the capability of PMΦ and AMΦ in phagocytosis of neutral red were measured by colorimetric method too. RESULTS:After administering P. cicadaeto rats, the activities of ACP and LDH in PMΦ and AMΦ of normal rats were elevated significantly,and the reduction of the activities of ACP and LDH in PMΦ and AMΦ of rats due to Cy was notably antagonized, and the capability of PMΦ and AMΦ phagocytizing the neutral red were strengthened significantly.CONCLUSION:P. cicadaecan activate the PMΦ and AMΦ of rats.     

An enzyme histochemical study of diaphragm in diabetic rats

AIM: The aim of this research is to study the earlier enzyme activity changes of the diaphragm in diabetic rats. METHODS: An enzyme histochemical method was used to observe the changes in the enzyme activities of dehydrogenases,hydrolases and oxidases in 4th week diabetic rat diaphragm. RESULTS: The activites of enzymes including SDH(Succinate dehydrogenase),MDH(Malate dehydrogenase), GDH(Glutamate dehydrogenase), ICDH(Isocitrate dehydrogenase), NADHD(NADH diaphorase), G-6-PD(Glucose-6-phosphate dehydrogenase), ACP(Acid phosphatase) and ANAE(Acid α-naphtyl acid esterase) were increased in diabetic diaphragm compared with the control. LDH (Lactate dehydrogenase)and CCO(Cytochrome oxidase) activities were decreased, whereas NADPHD(NADPH diaphorase) showed no changes in diabetic rats. Eleven kinds of enzyme were analysed with image analysis.Optical density (A) of SDH, MDH, GDH, ICDH, NADHD, G-6-PD, ACP and ANAE in diaphragm of diabetic rats were significantly higher than that of control rats (P<0.01). A value of LDH and CCO in diaphragm from diabetic rats were significantly lower than that of control rats (P<0.01). A value of NADPHD in diaphragm from diabetic rats showed no apparent alteration compared with the control rats(P>0.05). CONCLUSION: Increase in the aerobic capacity, decrease in the glycolytic capacity, and disturbance of lipid and energy metabolism were found in diaphragm of 4th week diabetic rats.     

Activity of delayed rectifier potassium channel in alveolar macrophages from COPD rats

AIM: To explore the change of delayed rectifier potassium channel (KV) activity in alveolar macrophages (AM) in chronic obstructive pulmonary disease (COPD) rats. METHODS: COPD model was established by exposure of the animals to cigarette smoke. With whole-cell voltage- or current-clamp techniques, KV activity, membrane capacitance and resting membrane potential (Em) in AM from COPD model and control rats were compared. RESULTS: (1) Significant increases in total mononuclear cells and AM in bronchoal aveolar lavage fluid (BALF) were found in COPD group compared with in control group. (2) The AM KV current altitude in COPD group ［(520.5±38.7）pA， +50 mV, n=30］ was significantly lower than that in control group ［(713.6±44.4）pA， +50 mV, n=30， P<0.01］; (3) AM from COPD group had no significantly different capacitances (P>0.05), but had more positive Em (P<0.01) compared with those from control group. CONCLUSION: Inhibition of KV function, increase in excitability and more positive Em in AM from COPD rats may be involved in the AM contribution to the COPD development.     

Effects of extract of gingko biloba on the lipid metabolism and the function of macrophages from diabetic rats

AIM: To study effect of extract of ginkgo biloba (EGb) on the lipid metabolism and the function of macrophages from diabetic rats.METHODS: Sprague-Dauley rats were divided into four groups: normal control group, high-fat group, diabetic group and EGb treatment group.At the end of experiment, the rats were sacrificed, the blood glucose, blood insulin and serum lipid were measured.The activity of superoxide dismutase (SOD), content of malondialdehyde (MDA), nitric oxide (NO) in alveolar macrophages (AM) and peritoneal macrophages (PM) were assayed.In addition, peroxisome proliferator activated receptor γ (PPARγ), CD36 mRNA expression in AM was measured by RT-PCR.RESULTS: The concentration of the blood glucose, blood insulin and total cholesterol (TC), total triglycerides (TG), low-density lipoprotein- cholesterol (LDL-C) in blood increased significantly in type 2 diabetic group.The supplement of EGb decreased blood glucose, blood insulin and TC, TG, LDL-C levels.The activity of SOD decreased, while the content of NO, MDA increased in the diabetic macrophages, the activity of SOD became increased, but the content of NO and MDA decreased in EGb-treated group.The mRNA expression level of CD36 and PPARγ in alveolar macrophages from diabetic group increased, while expression level of CD36 and PPARγ mRNA in EGb treated rats continued to rise.CONCLUSIONS: EGb corrected insulin resistance and ameliorated disturbance of lipid metabolism caused by type2 diabetes in rats.Adjustment of PPARγ and CD36 mRNA expression of as well as reduction of lipid peroxidation and NO level may be involved in this process.     

Effects of icariin on expression of transforming growth factor β1 and type Ⅳ collagen in diabetic rat testis

AIM: To determine the beneficial effects of icariin on streptozotocin (STZ)-induced diabetic testopathy in rats. METHODS: The diabetic animal model was induced in male Sprague-Dawley rats by an injection of streptozotocin (40 mg/kg, iv). The rats were randomly divided into 3 groups: control group, model group and icariin (80 mg/kg, ig) group. Twelve weeks after injected with streptozotocin, all rats were anaesthetized and killed to remove the testes from scrotum. Serum concentrations of glucose and testosterone, and the levels of succinate dehydrogenase (SDH), acid phosphatase (ACP), γ-glutamyl transpeptidase (γ-GT) and lactate dehydrogenase (LDH) in testes were measured. The morphology of the testicular tissues was observed under light microscope. Immunohistochemistry was employed to determine the protein levels of TGF-β₁ and type Ⅳ collagen. RESULTS: Compared with control group, the content of serum glucose increased while the serum level of testosterone and the activitiy of SDH, ACP, γ-GT and LDH in testis decreased in model group (P<0.01). The histopathological examination showed that the diameters of seminiferous tubules and various grades of spermatocytes in the testis were markedly decreased. Compared with control group, the expression of TGF-β₁ and collagen Ⅳ was significantly increased in model group. These alterations were significantly attenuated in icariin group (P<0.01). CONCLUSION: Icariin evidently relieves testicular damage in rats with diabetic testopathy by improving the secretion of testosterone and reducing the expression of TGF-β₁ and collagen Ⅳ at protein level.     

The activation effect of maize pollen polysaccharides on human thoracic cavity macrophages

AIM: To study the activation effects of maize pollen polysaccharides(PPM) on human thoracic cavity macrophage (hTMΦ). METHODS: Activities of lactate dehydrogenase(LDH) and acid phosphatase (ACP) in the hTMΦ were detected by automatic biochemical analyzer, and the level of tumor necrosis factor alpha(TNF-α) and interleukin-6(IL-6) in the hTMΦ was analyzed by radioimmunoassay, after hTMΦ were cultured with 0.312, 0.625, 1.250, 2.500, 5.000 mg/mL PPM-RPMI 1640 for 24 and 48 hours in vitro. RESULTS: The activities of LDH and ACP increased in the hTMΦ induced by PPM, and the levels of TNF-α and IL-6 in the hTMΦ induced by PPM increased markedly too. And the induced expression effect of TNF-α and IL-6 is associated with the concentration of PPM, and time for PPM inducing. CONCLUSION: PPM can induce cytokines secretion in hTMΦ, and activate hTMΦ in vitro.     

Experimental studies on immunomodulatory and antitumor activity of polysaccharide from Paecilomyces cicadidae

AIM: To study the immunomodulatory and antitumor activity of both total polysaccharide from Paecilomyces cicadidae (PcPSt) and its fraction PcPSAc. METHODS: Five groups of mice which were composed of normal control, tumor control, group treated by PcPSt, treated by cyclophosphamide (Cy) and treated by both PcPSt and Cy were administrated by injecting to abdominis cavitas with normal saline (NS), NS, PcPSt , Cy , PcPSt+Cy correspondingly and respectively for 10 days after they had been injected B16 cell line except normal control.The white blood cells (WBC) were counted, spleen index and weight of tumor were statistically analysed. The cell counting kit 8 (CCK-8) was used to analyze proliferative activity of the cultured splenocytes. Nitric oxide (NO) kit was used to detect NO content of supernatant in each microplate. RESULTS: PcPSt increased WBC and relieved the decrease of WBC caused by Cy in tumor-bearing mice. PcPSt increasd the spleen index of tumor-bearing mice and cooperated with Cy to promote antitumor activity. PcPSAc at concentrations of 600 mg/L and 300 mg/L enhanced the proliferative activity of cultured splenocytes. Appropriate doses (15-300 mg/L) of PcPSAc promoted the secretion of NO, the effect of 300 mg/L of PcPSAc was the strongest. CONCLUSION: Paecilomyces cicadidae polysaccharide can promote immunomodulatory and antitumor activity in vivo and in vitro experiments.     

猴头菌活性多糖高产菌株的筛选

对10株猴头菌(Hericium erinaceus)菌株的菌丝多糖产量和体外免疫活性进行比较。结果表明:不同的猴头菌菌株发酵所产生的菌丝多糖量及其多糖对刺激巨噬细胞产生NO的产量不同;其中华中猴头(H10)不仅菌丝多糖量高且对巨噬细胞的刺激作用也较强,可作为深层发酵生产猴头菌菌丝多糖的优良菌株。     

Heterogeneity of basal intracellular calcium concentration and its relations to the reactivity in mouse peritoneal macrophages

AIM: To investigate the heterogeneity of basal intracellular free calcium concentration([Ca²⁺]_i) in peritoneal macrophages(PM) and whether it is relative to the reactivity of PM at the single cell level. METHODS:[Ca²⁺]_iimplicated stimulated were measured by fluorescent microscopic imaging system after loading with fluorescent probe fura-2/AM. Superoxide(O₂^-)produced by single PM was determined by modified NBT test. RESULTS: The values of basal[Ca²⁺]_idetermined in 392 PMs of 7 mice showed normal distribution [(54±24) nmol/L, n=392] with wide range(less than 20 nmol/L to more than 100 nmol/L), among which about 50% were in the range of 40-60 nmol/L. When stimulated with PMA or fMLP,[Ca²⁺]_iwas increased, the peak values were positively correlated with the basal[Ca²⁺]_iin one mouse(PMA stimulated cells: r=0.52, P<0.01, n=58; fMLP stimulated cells:r=0.59, P<0.01, n=44. Both of the experiments were repeated in 3 mice, the results in the other 2 mice were similar). The O₂^- in PMA stimulated PMs were also positively correlated with the basal i(r=0.42, P<0.01, n=43, repeated in 4 mice, the results in the other 3 mice were similar). CONCLUSION: Basal[Ca²⁺]_iin murine PM is heterogeneous, and the value of basal[Ca²⁺]_iis tightly correlated to the reactivity of PM stimulated by proinflammatory factors.     

Effects of lipopolysaccharide on proliferating cell nuclear antigen expression on alveolar macrophages and Fas/FasL system expression on alveolar type Ⅱ epitelial cells in smoking rats

AIM:To study the effect of proliferating cell nuclear antigen (PCNA) expression on alveolar macrophages (AM) and Fas/FasL expression on alveolar type Ⅱ epithelial cells induced by lipopolysaccharide (LPS) in smoking rats. METHODS:Immunohistochemistry SABC and immunofluorescence techniques were used to examine PCNA expression on AM and Fas/FasL system expression on alveolar type Ⅱ epithelial cells in smoking rats of different stages induced by LPS. RESULTS:The AM PCNA expression in smoking rats reached the highest level after 3 or 4 months. The AM PCNA expression in every groups stimulated by LPS significantly increased ( P＜0.01). The Fas/FasL system expression on alveolar type Ⅱepithelial induced by LPS were higher than control groups ( P＜0.01). Both the AM PCNA expression and Fas/FasL system expression on alveolar type Ⅱ epithelial cells were parallel. CONCLUSION:Smoking caused the increase in proliferous rate of AM and it may play an important role in the regulation of the injury and repair of alveolar type Ⅱ epithelial cells.     

Low density lipoprotein from patients of diabetes mellitus induces apoptosis of murine macrophages via activating caspase-12 pathway

AIM:To explore the effect of low density lipoprotein from the patients of diabetes mellitus (DM-LDL) on the activation of caspase-12 an important molecule in endoplasmic reticulum stress (ERS)-associated apoptotic pathway, in the murine macrophages, and to clarify the underlying molecular mechanisms of apoptosis. METHODS:Murine macrophage RAW264.7 was exposed to DM-LDL (25, 50 and 100 mg/L), normal low density lipoprotein (n-LDL, 50 mg/L), or tunicamycin (TM, 4 mg/L) for 24 h. Additionally, RAW264.7 macrophages were precultured with 4-phenylbutyric acid (PBA, 5 mmol/L) for 1 h and then exposed to DM-LDL (100 mg/L) for 24 h. The cell viability and apoptosis were detected by MTT assay and flow cytometry with Annexin V-FITC/propidium iodide staining, respectively. Lactate dehydrogenase (LDH) activity in the media was measured by assay kit. The protein level of caspase-12 was determined by Western blot. RESULTS:Similar to TM (an ERS inducer), treatment with DM-LDL caused significantly decrease in the viability and increase in LDH activity in the media and apoptotic rate of the RAW264.7 macrophages (P<0.05). Additionally, DM-LDL induced activation of caspase-12 especially at the dose of 50 and 100 mg/L (P<0.01). However, the ERS inhibitor PBA protected RAW264.7 macrophages from DM-LDL-induced decrease in viability and increase in LDH activity and apoptosis (P<0.05). Furthermore, PBA attenuated DM-LDL-induced activation of caspase-12 (P<0.05). CONCLUSION:DM-LDL may induce apoptosis in RAW264.7 macrophages, and the mechanism may be related to the activation of caspase-12.     

Protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats

AIM: To investigate the protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats and its mechanism. METHODS: Thirty-two rats were randomized into 4 groups (8 rats in each group): sham operated group (Sham), ischemia-reperfusion (I/R) group, ischemic-preconditioning (IP) group, mild hypothermia ischemic-preconditioning (MHIP) group. The wet/dry ratio, Ca²⁺-Mg²⁺-ATPase activity in intestine tissue, the malondialdehyde (MDA) content, activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and total antioxdase (TAX) in blood were determined. Ultrastructure, Bcl-2 and Bax expression in intestinal mucosa tissue were also observed. RESULTS: After I/R, the intestinal tissue wet/dry ratio, the content of MDA, LDH activity, the optic density of Bcl-2 and Bax proteins were significantly higher in I/R group than those in sham group (P<0.01). The activities of Ca²⁺-Mg²⁺-ATPase, SOD, TAX were significantly lower in I/R group than those in sham group (P<0.01). The intestinal tissue wet/dry ratio, the content of MDA, LDH activity and the optic density of Bax protein were significantly lower in IP group than those in I/R group (P<0.01), and also lower in MHIP group than in IP group (P<0.05). The activities of Ca²⁺-Mg²⁺-ATPase, SOD, TAX and the optic density of Bcl-2 protein were significantly higher in IP group than in I/R group (P<0.01). CONCLUSION: MHIP can protect intestine against I/R injury in rats, which may be related to enhancing oxidation-resistance of intestine, inhibiting lipid peroxidation, upregulating the expression of Bcl-2 protein and downregulating the expression of Bax protein.     

Effect of breviscapine on the oxidative stress in the liver and kidney in diabetic rats

AIM: To study the effect of breviscapine on the oxidative stress in the liver and kidney in diabetic rats. METHODS: Diabetes was induced by injection of streptozotocin (STZ). Rats were randomly divided into three groups: control group, model group, model group treated with breviscapine. 8 weeks after STZ injection, liver lesion was evaluated using HE, oil red O staining and kideny lesion using PAS staining. Malondiadehyde (MDA) levels and antioxidant activities in liver and kidney tissue were determined by spectrophotometric method. RESULTS: Light microscopy in HE staining showed that liver fatty score was significantly lower in the breviscapine group compared with model animals (0.55±0.43 vs 1.54±0.65, P<0.01). In model group, the presence of cytoplasmic lipid deposits was confirmed by oil red O staining, and these changes were significantly lower in the breviscapine group than those in the model group (0.75±0.66 vs 2.11±0.82, P<0.01). In addition, increased kidney weight (KW), KW/body weight (KW/BW), 24 h albumin excretion rate (AER) and glomerular area (AG), glomerular volume (VG) as well as mesangial area (AM) on histological examination of the kidney significantly attenuated by treatment with breviscapine (P<0.05, P<0.01). Levels of MDA were higher and superoxide diamutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-Px) activities were significantly lower in liver and kidney tissue in model rats than those in control group. Breviscapine administration could all remit these changes (P<0.05). CONCLUSION: The mechanism of protective effect of breviscapine on liver and kidney may be at least partly correlated with the suppression of increase in oxidative stress in diabetic rats.     

Allicin attenuates macrophage-derived foam cell apoptosis by inhibiting caspase-12

AIM: To investigate the inhibitory effect of allicin on apoptosis and caspase-12 activation of macrophage-derived foam cells, and to elucidate the underlying molecular mechanisms. METHODS: RAW264.7 macrophages were pretreated with allicin (12.5, 25 and 50 mg/L) or 4-phenylbutyric acid (PBA, 4 mmol/L) for 1 h and then treated with oxidized low-density lipoprotein (ox-LDL, 100 mg/L) or tunicamycin (TM, 4 mg/L) for 24 h. The cell viability and apoptosis were examined by MTT assay and flow cytometry with Annexin V-FITC/PI staining, respectively. The activities of caspase-3 in the cells and lactic dehydrogenase (LDH) in the medium were measured. The protein levels of caspase-12 were determined by Western blot. The intracellular lipid accumulation was measured with oil red O staining and the content of intracellular total cholesterol was determined by enzymatic colorimetry. RESULTS: Similar to the endoplasmic reticulum stress (ERS) inhibitor PBA, allicin inhibited ox-LDL-induced injury of RAW264.7 macrophages in a concentration-dependent manner, as determined by the increased cell viability and the decreased LDH leakage, apoptosis and caspase-3 activity. The decrease in cell viability and increases in LDH leakage and apoptosis induced by TM (an ERS inducer) were also suppressed by allicin. Moreover, similar to PBA, allicin remarkably inhibited ox-LDL- or TM-induced activation of caspase-12. Furthermore, allicin remarkably attenuated ox-LDL-induced lipid accumulation in the RAW264.7 cells and foam cells formation in a concentration-dependent manner. CONCLUSION: Allicin may inhibit macrophage-derived foam cell apoptosis induced by ox-LDL, and the mechanism is partially related to suppressing the activation of caspase-12.     

miR-499 attenuates myocardial injury in rats by targeting PTEN

AIM:To investigate the effect of microRNA-499 (miR-499) on myocardial injury in rats and its mechanism. METHODS:The rat model of ischemia-reperfusion (I/R) injury was established and the myocardial cells were primarily cultured. The expression level of miR-499 was detected by RT-qPCR. After hydrogen peroxide stimulation, CCK-8 assay and LDH kit were used to detect the viability and LDH release of the cells transfected with miR-499 mimic and siR-PTEN. The targeting relationship between miR-499 and PTEN was predicted by TargetScan and confirmed by luciferase test. RT-qPCR and Western blot were used to detect the effect of miR-499 mimic and inhibitor on the mRNA and protein expression levels of PTEN. After miR-499 inhibitor and siR-PTEN were co-transfected into the cells, CCK-8 assay and LDH kit were used to detect the viability and LDH release of the myocardial cells induced by hydrogen peroxide. RESULTS:The expression level of miR-499 in the I/R rats was increased rapidly, and then was decreased gradually in a time-dependent manner (P<0.05). miR-499 mimic and siR-PTEN significantly promoted the viability and decreased the LDH release of cardiomyocytes induced by hydrogen peroxide (P<0.05). miR-499 and PTEN had a targeting relationship. The expression of PTEN was significantly down-regulated by miR-499 mimic, and up-regulated by miR-499 inhibitor (P<0.05). Transfection with siR-PTEN reversed the inhibitory effect of miR-499 inhibitor on the cells. CONCLUSION:miR-499 attenuates the myocardial injury in rats by targeting PTEN.     

Effects of simvastatin on expression of Bcl-2 and Bax in myocardium of rats with renal ischemia-reperfusion injury

AIM: To observe the effect of simvastatin on myocardial tissue after renal ischemia-reperfusion injury and its mechanism. METHODS: A rat model of renal ischemia-reperfusion injury was prepared by clamping the bilateral renal arteries for 45 min. The rats (n=36) were randomly divided into sham operation group, renal ischemia-reperfusion (I/R) group and simvastatin group with 12 rats in each group. The content of serum creatinine (SCr), blood urea nitrogen (BUN) and myocardial tissue malondialdehyde (MDA), the myocardial activity of lactate dehydrogenase (LDH), creatine kinase (CK) and superoxide dismutase (SOD), and the myocardial protein expression of Bcl-2 and Bax were detected. RESULTS: Compared with sham operation group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in I/R group were significantly increased (P<0.05), and the activity of SOD was significantly decreased (P<0.05). Compared with I/R group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in simvastatin group were significantly decreased (P<0.05), while SOD activity was enhanced (P<0.05). The protein expression of Bcl-2 and Bax in sham operation group was less than that in I/R group (P<0.05), and the protein level of Bax in simvastatin group was significantly lower than that in I/R group (P<0.05), while the protein level of Bcl-2 was increased (P<0.05). CONCLUSION: Simvastatin has a protective effect on the myocardium of the rats with renal ischemia-reperfusion injury, and the protective mechanism may be related to the elimination of free radicals by simvastatin, increase in the protein expression of Bcl-2 and decrease in the protein expression of Bax.