[Effects of berberine on learning and memory ability in vascular cognitive impairment rats].

OBJECTIVE: To investigate the effects of berberine on learning and memory ability in vascular cognitive impairment rats. METHODS: Sixty-eight Wistar rats were randomly divided into control group (n=10), sham operated group (n=10) and the modeling group of vascular cognitive impairment rat (n=48), then the rats in modeling group were randomly divided into four groups (n=10): vehicle group, berberine low dose group (20 mg/kg), medium dose group (40 mg/kg) and high dose group (60 mg/kg). Bilateral common carotid arteries were occluded in rats to establish vascular cognitive impairment (VCI) model. Different doses of berberine were intraperitoneally injected into the treatment group and normal saline was intraperitoneally injected into the other groups once a day for a total of 34 days. After 28 days of administration, Morris water maze was used to test the learning and memory ability of rats. After the water maze experiment, the levels of superoxide dismutase (SOD) activity, glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor alpha(TNF-α), interleukin-1 beta (IL-1ß), 5-hydroxytryptamine (5-HT) and monoamine oxidase (MAO) in the forebrain cortex were detected. RESULTS: Compared to sham group, the escape latency in VCI group was significantly extended (P＜0.01) and the times of passing through the platform were decreased remarkably (P＜0.01). The levels of SOD, GSH and 5-HT in the hippocampus or anterior cortex were decreased significantly (P＜0.01), while the contents of MDA, TNF-α, IL-1ß and MAO were increased remarkably (P＜0.01). Compared with VCI group, the escape latency in berberine-treated groups was shortened significantly (P＜0.01, P＜0.05) and the times of passing through the platform were increased remarkably (P＜0.01, P＜0.05), the levels of SOD, GSH and 5-HT were increased significantly (P＜0.01), while the contents of TNF-α, IL-1ß and MAO were decreased remarkably (P＜0.01). CONCLUSION: Berberine could significantly improve the spatial learning and memory abilities of rats with vascular cognitive impairment. The mechanism may be related to the effects of berberine on the hippocampal antioxidant stress, anti-inflammatory response and the monoamine neurotransmitter system in the forebrain cortex. Berberine 60 mg/kg dose group had better effect.

[Synergistic analgesic effect of choline and parecoxib sodium in mice and the mechanism].

OBJECTIVE: To investigate the synergistic analgesic effect of choline and parecoxib sodium and study its mechanism. METHODS: In male Kunming mice with acetic acid-induced writhing, the ED50 of choline and parecoxib sodium (administered via the tail vein at 2 h and 30 min before modeling, respectively) and their combined use were determined. In saline (control) group, ED50 choline (C) group, ED50 parecoxib sodium (P) group, and 1/2ED50 choline and parecoxib sodium (1/2[C+P]) group, blood samples were collected from the eyeball 10 min after intraperitoneal administration of acetic acid to detect the levels of IL-1, TNF-α, PGE2, NF-κB, and I-κB levels using ELISA kits. RESULTS: In the acetic acid-induced writhing model, the ED50 of choline and parecoxib sodium was 8.64 and 6.33 mg/kg, and when combined, their ED50 was 2.13 and 1.56 mg/kg, respectively. The isobolograms of parecoxib sodium and choline showed that the measured ED50 of the two drugs combined was below the theoretical ED50 value (P<0.05) with a combination index (CI) of <0.9. Compared with the control group, C group, P group, and 1/2 (C+P) group all showed significantly lowered IL-1 and TNF-α levels (P<0.05), especially in 1/2 (C+P) group (P<0.05). PGE2 level was significantly lower in P group and 1/2 (C+P) group compared with the control group (P<0.05). NF-κB and I-κB levels were significantly lowered in C, P, and 1/2 (C+P) groups (P<0.05), and the reduction was the most obvious in 1/2 (C+P) group (P<0.05). CONCLUSION: Choline and parecoxib sodium has a synergistic analgesic effect, and their interactions may involve the in vivo expression of NF-κB.

Brain protection against ischemic stroke using choline as a new molecular bypass treatment.

AIM: To determine whether administration of choline could attenuate brain injury in a rat model of ischemic stroke and the underlying mechanisms. METHODS: A rat model of ischemic stroke was established through permanent middle cerebral artery occlusion (pMCAO). After the surgery, the rats were treated with choline or choline plus the specific α7 nAChR antagonist methyllycaconitine (MLA), or with the control drug nimodipine for 10 days. The neurological deficits, brain-infarct volume, pial vessel density and the number of microvessels in the cortex were assessed. Rat brain microvascular endothelial cells (rBMECs) cultured under hypoxic conditions were used in in vitro experiments. RESULTS: Oral administration of choline (100 or 200 mg·kg(-1)·d(-1)) or nimodipine (20 mg·kg(-1)·d(-1)) significantly improved neurological deficits, and reduced infarct volume and nerve cell loss in the ischemic cerebral cortices in pMCAO rats. Furthermore, oral administration of choline, but not nimodipine, promoted the pial arteriogenesis and cerebral-cortical capillary angiogenesis in the ischemic regions. Moreover, oral administration of choline significantly augmented pMCAO-induced increases in the expression levels of α7 nAChR, HIF-1α and VEGF in the ischemic cerebral cortices as well as in the serum levels of VEGF. Choline-induced protective effects were prevented by co-treatment with MLA (1 mg·kg(-1)·d(-1), ip). Treatment of rBMECs cultured under hypoxic conditions in vitro with choline (1, 10 and 100 µmol/L) dose-dependently promoted the endothelial-cell proliferation, migration and tube formation, as well as VEGF secretion, which were prevented by co-treatment with MLA (1 µmol/L) or by transfection with HIF-1α siRNA. CONCLUSION: Choline effectively attenuates brain ischemic injury in pMCAO rats, possibly by facilitating pial arteriogenesis and cerebral-cortical capillary angiogenesis via upregulating α7 nAChR levels and inducing the expression of HIF-1α and VEGF.

Synergisms of cardiovascular effects between iptakalim and amlodipine, hydrochlorothiazide or propranolol in anesthetized rats.

The primary object of this fundamental research was to survey the synergistic cardiovascular effects of iptakalim, a novel ATP-sensitive potassium channel (K(ATP)) opener, and clinical first-line antihypertensive drugs, such as calcium antagonists, thiazide diuretics and ß receptor blockers by a 2 x 2 factorial-design experiment. It would provide a theoretical basis for the development of new combined antihypertensive therapy program after iptakalim is applied to the clinic. Amlodipine besylate, hydrochlorothiazide and propranolol were chosen as clinical first-line antihypertensive drugs. Blood pressure, heart rate (HR) and cardiac functions were observed in anesthetized normal rats by an eight-channel physiological recorder. The results showed that iptakalim monotherapy in a low dose could produce significant antihypertensive effect. There was no interaction between iptakalim and amlodipine on the maximal changes of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), the left ventricular systolic pressure (LVSP), and the left ventricular end-diastolic pressure (LVEDP) (P > 0.05). However, the effects of combination iptakalim/amlodipine on the maximal changes of SBP, DBP, MABP, LVSP and LVEDP were more obvious than those of iptakalim or amlodipine monotherapy. And there was strong positive interaction between iptakalim and amlodipine on the maximal changes of HR (P>0.05). According to the maximal changes of DBP, MABP, LVSP and LVEDP (P < 0.05) of combination iptakalim with hydrochlorothiazide, there was strong positive interaction between them. But there was no interaction between iptakalim and hydrochlorothiazide on the maximal drop of SBP and HR (P > 0.05). According to the maximal drops of DBP, MABP of combination iptakalim with propranolol, there was strong positive interaction between them (P < 0.05). But there was no interaction between iptakalim and propranolol on the maximal changes of SBP, LVSP, LVEDP and HR (P > 0.05). In conclusion, it was the first time to study the effects of amlodipine, hydrochlorothiazide or propranolol, which had different mechanisms of action from iptakalim, on cardiovascular effects of iptakalim in anesthetized normal rats. This study proved that the combination of iptakalim with hydrochlorothiazide or propranolol respectively had significant synergism on lowering blood pressure, while the combination of iptakalim/amlodipine had additive action on lowering blood pressure. Meanwhile the antihypertensive effect was explicit, stable and long-lasting. Iptakalim thus appears suitable for the clinical treatment of hypertensive people who need two or more kinds of antihypertensive agents.

[Protective effect of anti-hypoxia shenggui tablet on cerebral ischemia injure].

OBJECTIVE: To investigate the protective effects of Shengui tablet (Chinese Traditional Medicine) on experimental cerebral ischemia by acute cerebral ischemia hypoxia in mice and bilateral ligation of the carotid artery in rats. METHODS: In the acute cerebral ischemia hypoxia model, the mice were randomly divided into control group, low-, middle- and high-dose (0.16, 0.33 and 1.00 g/kg) groups of Shengui tablet, after oral treatment for 30 d, gasping time of isolated heads of mice were observed. In bilateral ligation of the carotid artery cerebral ischemia model, the rats were randomly divided into control group, model group and low-, middle-, high-dose (0.072, 0.149 and 0.450 g/kg) groups of Shengui tablet. After oral treatment for 7 d, the cerebral index, superoxide dismutase (SOD) activity and the content of malondialdehyde (MDA) were measured. RESULTS: Compared with the control model, Shengui tablet middle- and high-dose could significantly prolong gasping time of isolate heads of mice. Compared with model group, Shengui tablet low-, middle- and high-dose could significantly decrease the cerebral index and enhance SOD activity in brain tissue; only high-dose could reduce the content of MDA. CONCLUSION: Shengui tablet has significant protective effect on the cerebral ischemia.

The novel ATP-sensitive potassium channel opener iptakalim prevents insulin resistance associated with hypertension via restoring endothelial function.

AIM: To investigate the effects of iptakalim on endothelial dysfunction induced by insulin resistance (IR) and to determine whether iptakalim improved IR associated with hypertension in fructose-fed rats (FFRs) and spontaneously hypertensive rats (SHRs). METHODS: Human umbilical vein endothelial cells (HUVECs) were used for in vitro study. The levels of endothelial vasoactive mediators and eNOS protein expression were determined using radioimmunoassays, ELISAs, colorimetric assays or Western blotting. Sprague-Dawley rats were fed with a high-fructose diet. In both FFRs and SHRs, tail-cuff method was used to measure systolic blood pressure (SBP), and hyperinsulinemic- euglycemic clamp was used to evaluate IR states. RESULTS: (1) Cultured HUVECs incubated with the PI3-kinase inhibitor wortmannin (50 nmol/L) and insulin (100 nmol/L) induced endothelial dysfunction characterized by significantly reduced release of NO and expression of eNOS protein, and significantly increased production of ET-1. Pretreatment with iptakalim (0.1-10 µmol/L) could prevent the endothelial dysfunction. (2) In FFRs, the levels of SBP, fasting plasma glucose and insulin were significantly elevated, whereas the glucose infusion rate (GIR) and insulin sensitive index (ISI) were significantly decreased, and the endothelium-dependent vascular relaxation response to ACh was impaired. These changes could be prevented by oral administration of iptakalim (1, 3, or 9 mg·kg(-1)·d(-1), for 4 weeks). The imbalance between serum NO and ET-1 was also ameliorated by iptakalim. (3) In 2-4 month-old SHRs (IR was established at the age of 4 months), oral administration of iptakalim (1, 3, or 9 mg·kg(-1)·d(-1), for 8 weeks) significantly ameliorated hypertension and increased the GIR to the normal level. CONCLUSION: These results demonstrate that iptakalim could protect against IR-induced endothelial dysfunction, and ameliorate IR associated with hypertension, possibly via restoring the balance between NO and ET-1 signaling.

[Effects of iptakalim on pressure-overload induced cardiac remodeling and plasma PGI2 content in rats].

OBJECTIVE: To study the effects of iptakalim (IPT) on pressure-overload induced cardiac remodeling in rats, and investigate correlation between this protection effects and plasma PGI2 content. METHOD: The pressure-overload induced cardiac remodeling model was induced by abdominal aorta constriction for 6 weeks, and the rats were divided into 5 groups repectively: (1) sham group, (2) control group, (3) IPT 3 mg/kg group (IPT 3), (4) indomethacin 2 mg/kg group (Indo 2), (5) indomethacin 2 mg/kg + IPT 3 mg/kg group (Indo 2 + IPT 3). RM6000 eight channel physiological recorder was used to record haemodynamics index, heart weight was weighed and the cardiac remodeling index was calculated, HE stain and Masson's stain were employed to perform histological analysis, colorimetric method was used to detect the hydroxyproline content in cardiac tissue, radioimmunological method was used to measure the plasma PGI2 content. RESULTS: After 42 days of aortic banding, the hyperdynamic circulation state, cardiac remodeling and decreased plasma PGI2 content were observed in the model group compared with those in the sham group, which were effectively reserved by treatment with IPT 3 mg/kg. Single-use indomethacin led to further deterioration of this pathophysiological changes, however, combination administration of IPT 3 mg/kg prevented these from worsening characteristic by ameliorating hyperdynamic circulation state and cardiac remodeling, augmnent plasma PGI2 content. CONCLUSION: IPT can significantly reverse abdominal aorta binding/pressure-overload induced cardiac remodeling, its mechanism may contribute to binding K(ATP) channel in endothelial cells, ameliorating endothelium cells function, augmenting PGI2 synthesis and secretion.

Activation of SUR2B/Kir6.1 subtype of adenosine triphosphate-sensitive potassium channel improves pressure overload-induced cardiac remodeling via protecting endothelial function.

We sought to explore new strategies targeting SUR2B/Kir6.1, a subtype of adenosine triphosphate (ATP)-sensitive potassium channels (KATP), against pressure overload-induced heart failure. The effects of natakalim, a SUR2B/Kir6.1 selective channel opener, on progression of cardiac remodeling were investigated. Pressure overload-induced heart failure was induced in Wistar rats by abdominal aortic banding. The effects of natakalim (1, 3, and 9 mg·kg⁻¹·d⁻¹ for 10 weeks) on myocardial hypertrophy and heart failure, cardiac histology, vasoactive compounds, and gene expression were assessed. Ten weeks after the onset of pressure overload, natakalim treatment potently inhibited cardiac hypertrophy and prevented heart failure. Natakalim remarkably inhibited the changes of left ventricular hemodynamic parameters and reversed the increase of heart mass index, left ventricular weight index, and lung weight index. Histological examination demonstrated that there was no significant hypertrophy or fibrosis in pressure-overloaded hearts of natakalim-treated rats. Ultrastructural examination of hearts revealed well-organized myofibrils with mitochondria grouped along the periphery of longitudinally oriented fibers in rats from the natakalim group. The content of serum nitric oxide and plasma prostacyclin was increased, whereas that of plasma endothelin-1 and cardiac tissue hydroxyproline and atrial and B-type natriuretic peptide messenger RNA was downregulated in natakalim-treated rats. Natakalim at 0.01-100 µM had no effects on isolated working hearts derived from Wistar rats; however, natakalim had endothelium-dependent vasodilatory effects on the isolated tail artery helical strips precontracted with norepinephrine. These results indicate that natakalim reduces heart failure caused by pressure overloading by activating the SUR2B/Kir6.1 KATP channel subtype and protecting against endothelial dysfunction.

[Therapeutic effects of benthiactzine against respiratory failure induced by cholinesterase inhibitor in rats].

OBJECTIVE: To investigate the therapeutic effects of benthiactzine against respiratory failure induced by cholinesterase inhibitor dimethyl dichloro-vinyl phosphate (DDVP) in rats. METHODS: Forty-five male Wistar rats were divided into five groups randomly: control group, model group, and benthiactzine 0.5, 1.0, 2.0 mg/kg treatment groups (each n=9). Rats were treated with DDVP by intraperitoneal injection to reproduce respiratory failure model. The symptoms, respiratory rate (RR), blood gas analysis, electrolyte and plasma superoxide dismutase (SOD), malondialdehyde (MDA) and the pathological changes were observed before poisoning, during respiratory failure, and in different periods after the treatment. RESULTS: In rats with respiratory failure induced by DDVP, cyanosis and convulsion occurred in all groups. The success rates in three benthiactzine groups were 66.7% (6/9), 77.8% (7/9) and 88.9% (8/9). The rats of benthiactzine treatment groups recovered in 1-5 minutes after treatment and returned to normal state in 30 minutes. RR also returned to normal in 30 minutes. When respiratory failure occurred, arterial oxygen partial pressure (PaO2), arterial oxygen saturation (SaO2) and plasma SOD were decreased, plasma MDA was increased, and mixed acidosis was found. Thirty minutes after the treatment of benthiactzine, all above parameters in three groups returned to normal (all P<0.01). In respiratory failure rats, pathological examination of lung tissue revealed dilatation of pulmonary vessels with aggregation of erythrocytes, widening of alveolar space with presence of red blood cells in alveoli with heavy infiltration of inflammatory cells, and pulmonary edema and hemorrhage. The lungs of rats treated with benthiactzine showed less intense pathological changes. CONCLUSION: The new medicine against poisoning benthiactzine can be a favourable drug against respiratory failure induced by organophosphorus pesticides.

K(ATP) activation prevents progression of cardiac hypertrophy to failure induced by pressure overload via protecting endothelial function.

AIMS: We investigated the effects of iptakalim, a new ATP-sensitive potassium channel (K(ATP)) opener providing endothelial protection, on the progression of cardiac hypertrophy to failure in a rat model of pressure overloading caused by abdominal aortic banding (AAB). Endothelial dysfunction is central to cardiac hypertrophy and failure induced by pressure overload. It would be useful to clarify whether iptakalim could prevent this. METHODS AND RESULTS: The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, evidence of left ventricular hypertrophy (LVH), and transition to heart failure. LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These could be prevented by treatment with iptakalim at daily oral doses of 1, 3, and 9 mg/kg for 6 weeks. Progression to cardiac failure, demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial and B-type natriuretic peptide mRNA, could also be prevented. The downregulated nitric oxide signalling system was enhanced, whereas the upregulated endothelin signalling system was inhibited, resulting in normalization of the balance between these two systems. CONCLUSION: Iptakalim protected the endothelium and prevented progression of cardiac hypertrophy to failure induced by a pressure overload.