Ginkgo biloba extract reducing myocardium cells apoptosis by regulating apoptotic related proteins expression in myocardium tissues.

The Bax, cyt-c and caspase-3 proteins play an important role in regulating the myocardial apoptosis. Although very little is known about the specific signal pathways modulated by Ginkgo biloba extract (GBE), it seems advisable to suppose that GBE-induced antiapoptotic effect might be attributed to the regulation of the expression of these proteins. Our aim was to investigate whether GBE could attenuate ischemia/reperfusion-induced apoptosis in cardiac myocytes and its potential mechanisms. In the myocardium ischemia reperfusion (IR) rat model, treatment of GBE (400 mg/kg) significantly decreased the cardiomyocyte cell apoptosis and myocardium infarction. Immunohistochemical analysis showed that GBE significantly inhibited I/R-induced increase of myocardial Bax, caspase-3, and cyt-c proteins expression. Western blot analysis confirmed results of immunohistochemical analysis. It is most likely that multiple pathways are involved in IR-induced apoptosis in rat myocardium cells. Therefore, these results demonstrate that GBE exhibits significant protective effect against myocardial I/R injury in rat heart, which is related to down-regulate Bax, cyt-c and caspase-3. Bcl-2 overexpression might prevent IR-induced apoptosis by inhibiting cytochrome c release from the mitochondria and block activation of caspase-3.

The effects of subclinical hypothyroidism on serum lipid level and TLR4 expression of monocyte in peripheral blood of rats.

OBJECTIVE: To observe effect of subclinical hypothyroidism (SCH) on serum lipid level and expression of toll-like receptor 4 (TLR4) in rats' peripheral blood mononuclear cells (PBMC). METHODS: Fifty Wistar female rats were divided into three groups: normal control (NC group; n=10), sham group (n=10), and L-T-4 (L-thyroxine) group (n=30, with thyroidectomy, fed with rich-calcium water after operation. 5 weeks later, abdominal subcutaneous injection of L-T-4: 0.95 µg/100g/d). 8 weeks later, the rats were killed then the peripheral blood was collected to determine the levels of serum thyroid-stimulating hormone (TSH), total thyroid hormone (TT4), total cholesterol (TC) and low density lipoprotein cholesterin (LDL-C). Rats in L-T-4 group were divided into normal lipid (NL) group) and high lipid (HL) group) according to lipid value of NC group. Monocytes were separated from blood to determine TLR4 expression by flow cytometry. RESULTS: In NL and HL groups TSH were higher than in NC and Sham groups (p<0.05). TT4 have no significant differences (p>0.05). TLR4, TLR4 mRNA, NF-κB (p65) were increased (p<0.05). TNF-α, IL-6 and IL-1ß were higher than in NC and sham groups (p<0.01). There were no significant differences of TLR4, TLR4 mRNA, NF-κB (p65), TNF-α, IL-6 and IL-1ß expression between NL and HL groups (p>0.05). CONCLUSION: TLR4, TLR4 mRNA, NF-κB (p65) of PBMC and TNF-α, IL-6, IL-1ß expression in serum were all increased in SCH rats, which was not related to serum dyslipidemia.

Glucagon-like peptide-1 protects against cardiac microvascular endothelial cells injured by high glucose.

OBJECTIVE: To investigate the protective effect of glucagon-like peptid-1 (GLP-1) against cardiac microvascular endothelial cell (CMECs) injured by high glucose. METHODS: CMECs were isolated and cultured. Superoxide assay kit and dihydroethidine (DHE) staining were used to assess oxidative stress. TUNEL staining and caspase 3 expression were used to assess the apoptosis of CMECs. H89 was used to inhibit cAMP/PKA pathway; fasudil was used to inhibit Rho/ROCK pathway. The protein expressions of Rho, ROCK were examined by Western blot analysis. RESULTS: High glucose increased the production of ROS, the activity of NADPH, the apoptosis rate and the expression level of Rho/ROCK in CMECs, while GLP-1 decreased high glucose-induced ROS production, the NADPH activity and the apoptosis rate and the expression level of Rho/ROCK in CMECs, the difference were statistically significant (P<0.05). CONCLUSIONS: GLP-1 could protect the cardiac microvessels against oxidative stress and apoptosis. The protective effects of GLP-1 are dependent on downstream inhibition of Rho through a cAMP/PKA-dependent manner, resulting in a subsequent decrease in the expression of NADPH oxidase.