Synergism of amlodipine and candesartan on blood pressure reduction and organ protection in hypertensive rats.

This study was designed to investigate the possible synergism of amlodipine and candesartan on the reduction of blood pressure (BP) in hypertensive rats. The end organ protection was also observed. In acute experiment, spontaneously hypertensive rats (SHRs) were treated with intragastric administration of amlodipine (0.5, 1, 2, 3 mg/kg), candesartan (1, 2, 3, 4, 6, 8 mg/kg), and 14 different combinations to find the possible ratio of synergistic interaction. In two kidneys, one clip (2K1C) rats, the effects of amlodipine (1 mg/kg), canderastan (2 mg/kg) and their combination on BP reduction were also observed. In chronic study, SHRs were treated with amlodipine (1 mg/kg), candesartan (2 mg/kg), and their combination for 5 months. Organ damage evaluation was performed after BP recording. The probability sum test (q test) was used to evaluate the synergistic action. There is a synergistic interaction between amlodipine and candesartan on BP reduction. The optimal dose ratio is 1:2. The synergistic effect was also confirmed by 2K1C hypertensive rats. In chronic study, this combination (1:2) possessed an obvious synergism on the reduction of BP and BP variability (BPV) and protection on end organs. Multiple regression analysis showed that heart and aortic hypertrophy indexes and glomerular damage parameters were positively related to BP and BPV. In conclusion, combination of amlodipine and candesartan exhibited a potent antihypertensive effect and possessed an obvious synergism on BP reduction and organ protection in hypertension. The optimal proportion was 1:2. BP and BPV reduction may both importantly contribute to end organ protection.

Involvement of arterial baroreflex and nicotinic acetylcholine receptor α7 subunit pathway in the protection of metformin against stroke in stroke-prone spontaneously hypertensive rats.

Stroke is a leading cause of mortality and disability worldwide. There is growing evidence that metformin (Met) has potent neuroprotective effects; however, its mechanisms remain unclear. We examined the role of the arterial baroreflex and cholinergic-α7 nicotinic acetylcholine receptor (α7nAChR) anti-inflammory pathway in the beneficial effects of Met against stroke. Stroke-prone spontaneously hypertensive rats (SHRSP) were used to observe stroke development indicated by lifespan of SHRSP and the ischemic injury induced by permanent middle cerebral artery occlusion (MCAO). Sinoaortic denervation was used to inactivate the arterial baroreflex. MCAO were also performed in α7nAChR knockout (KO) mice. Briefly, Met increased the life span of SHRSP and reduced the infarct area induced by MCAO. Met also improved the function of arterial baroreflex. The beneficial effects of Met on stroke were markedly attenuated by blunting the arterial baroreflex. Met up-regulated the expression of vesicular acetylcholine transporter (VAChT) and α7nAChR, down-regulated the level of pro-inflammtory cytokines in serum and peri-infarct of ischemic brain. Arterial baroreflex dysfunction decreased the expression of VAchT and α7nAChR, showed upward tendency in the level of pro-inflammtory cytokines. Most importantly, arterial baroreflex dysfunction nearly abolished such effect of Met on cholinergic signaling. In addition, the α7nAChR KO mice also had significantly worse ischemic damage induced by MCAO, and neuroprotection of Met disappeared in α7nAChR KO mice. In conclusion, Met improved the arterial baroreflex function, and then enhancing cholinergic anti-inflammatory pathway in an α7nAChR-dependent manner, thereby effectively prevent ischemic induced brain injury and delayed stroke onset in SHRSP.

Amelioration of mitochondrial dysfunction in heart failure through S-sulfhydration of Ca2+/calmodulin-dependent protein kinaseⅡ / 中国药理学与毒理学杂志

OBJECTIVE To determine the functional role of hydrogen sulfide (H2S) in protecting against mitochondrial dysfunction in heart failure through the inhibition of Ca2 +/calmodulin-dependent protein kinaseⅡ (CaMKⅡ) using wild type and CSE knockout mouse models. METHODS Continuous subcutaneous injection isoprenaline (7.5 mg·kg-1 per day), once a day for 4 weeks to induce heart failure in male C57BL/6 (6-8 weeks old) mice and CSE-/- mice. 150 μmol·L-1 H2O2 was used to induce oxidative stress in H9c2 cells. Echocardiograph was used to detect cardiac parameters. H&E stain and Masson stain was to observation histopathological changes. Western blot was used to detect protein expression and activity. The siRNA was used to silence protein expression. HPLC was used to detect H2S level. Biotin assay was used to detect the level of S-sulfhydration protein. RESULTS Treatment with S-propyl-L-cysteine (SPRC) or sodium hydrosulfide (NaHS), modulators of blood H2S levels, attenuated the development of heart failure in animals, reduced lipid peroxidation, and preserved mitochondrial function. The inhibition CaMKⅡ phosphorylation by SPRC and NaHS as demonstrated using both in vivo and in vitro models corresponded with the cardioprotective effects of these compounds. Interestingly, CaMKⅡ activity was found to be elevated in CSE-/- mice as compared to wild type animals and the phosphorylation status of CaMK Ⅱ appeared to relate to the severity of heart failure. Importantly, in wild type mice SPRC was found to promote S-sulfhydration of CaMKⅡ leading to reduced activity of this protein however, in CSE-/- mice S-sulfhydration was abolished following SPRC treatment. CONCLUSION A novel mechanism depicting a role of S-sulfhydration in the regulation of CaMKⅡ is presented. SPRC mediated S-sulfhydration of CaMKⅡ was found to inhibit CaMKⅡ activity and to preserve cardiovascular homeostasis.

Amelioration of mitochondrial dysfunction in heart failure through S-sulfhydration of Ca2+/calmodulin-dependent protein kinaseⅡ / 中国药理学与毒理学杂志

OBJECTIVE To determine the functional role of hydrogen sulfide (H2S) in protecting against mitochondrial dysfunction in heart failure through the inhibition of Ca2 +/calmodulin-dependent protein kinaseⅡ (CaMKⅡ) using wild type and CSE knockout mouse models. METHODS Continuous subcutaneous injection isoprenaline (7.5 mg·kg-1·d-1), once a day for 4 weeks to induce heart failure in Male C57BL/6 (6-8 weeks old) mice and CSE-/- mice. 150 μmol·L-1 H2O2 was used to induce oxidative stress in H9c2 cells. Echocardiograph was used to detect cardiac parameters. H&E stain and Masson stain was to observation histopathological changes. Western blot was used to detect protein expression and activity. The siRNA was used to silence protein expression. HPLC was used to detect H2S level. Biotin assay was used to detect the level of S- sulfhydration protein. RESULTS Treatment with S-propyl-L-cysteine (SPRC) or sodium hydrosulfide (NaHS), modulators of blood H2S levels, attenuated the development of heart failure in animals, reduced lipid peroxidation, and preserved mitochondrial function. The inhibition CaMKⅡ phosphorylation by SPRC and NaHS as demonstrated using both in vivo and in vitro models corresponded with the cardioprotective effects of these compounds. Interestingly, CaMKⅡ activity was found to be elevated in CSE-/- mice as compared to wild type animals and the phosphorylation status of CaMKⅡ appeared to relate to the severity of heart failure. Importantly, in wild type mice SPRC was found to promote S-sulfhydration of CaMKII leading to reduced activity of this protein however, in CSE-/- mice S-sulfhydration was abolished following SPRC treatment. CONCLUSION A novel mechanism depicting a role of S-sulfhydration in the regulation of CaMKⅡ is presented. SPRC mediated S-sulfhydration of CaMKII was found to inhibit CaMKⅡ activity and to preserve cardiovascular homeostasis.

Nucleotidyl transferase TUT1 inhibits lipogenesis in osteosarcoma cells through regulation of microRNA-24 and microRNA-29a.

Osteosarcoma is the most common type of bone cancer. In the present study, by way of PCR-based microarrays, we found that TUT1, a nucleotidyl transferase, was significantly downregulated in osteosarcoma, compared with adjacent normal tissues. In the current study, we performed PCR-based microarrays using the cDNA prepared from osteosarcoma and adjacent normal tissues. The enforced expression of TUT1 was able to inhibit cell proliferation in U2OS and MG63 cells, while its knockdown using small interfering RNA (siRNA) oligos promoted cell proliferation. At the molecular level, we found that TUT1 could inhibit the expression levels of PPARgamma and SREBP-1c, two key regulators in lipogenesis, through upregulation of microRNA-24 and microRNA-29a. Therefore, our results suggest that TUT1 may act as a tumor suppressor for osteosarcoma, which might provide a novel mechanism for the tumor development.

Evaluation of the bioequivalence and pharmacokinetics of two formulations of secnidazole after single oral administration in healthy volunteers.

The pharmacokinetic parameters of two oral formulations of a 1 g dose of secnidazole (CAS 3366-95-8, secnidazole tablet as reference and another capsule preparation as test) were compared in an open-label, randomized, single oral dose, two-period cross-over design in 18 healthy volunteers under fasting conditions. Plasma concentrations of secnidazole were measured by a validated HPLC chromatographic assay. The parametric 90% confidence intervals of the geometric mean values of the test/reference ratios were 91.9% to 105.9% (point estimate: 99.39%) for AUC(0-infinity), 92.7% to 104.4% (point estimate: 98.61%) for AUC(0-t), 97.6% to 107.1% (point estimate: 102.31%) for C(max), being within the acceptance criteria for bioequivalence (80%-125%). T(max) values were analyzed by the nonparametric Wilcoxon test and the difference was not statistically significant. Therefore, it is concluded that the test and reference secnidazole formulations are bioequivalent for both the extent and the rate of absorption.