[Protective effect of Dendrobium candidum on isoproterenol induced cardiac hypertrophy in rats].

To study the effect and mechanism of Dendrobium candidum on isoproterenol-induced myocardial hypertrophy in rats, 60 healthy SD rats(30 males and 30 females) were randomly divided into 5 groups(12 in each group): normal group, model group, three D. candidum preventive administration groups(0.09, 0.18, 1.1 g·kg⁻¹). Except for the normal group, rats of other groups were injected back subcutaneously with ISO(5 mg·kg⁻¹) for 10 consecutive days. At the same time, preventive administration groups began to give different doses of the sample for 30 days and model group began to give normal saline. Left ventricular systolic pressure(LVSP) was measured in each group by common carotid artery cannulation, and the left ventricle(LW)/tibia length, heart weight index(HWI) and myocardial hydroxyproline(Hydro) content were calculated. Myocardial tissue HE staining and Masson staining were used to observe the myocardial structure and the degree of myocardial fibrosis respectively. Atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), and cardiac troponin I(cTN-I) concentration were measured by enzyme-linked immunosorbent assay(ELISA). The results showed that as compared with the normal group, the levels of ANP, BNP and cTN-I in plasma were significantly increased in ISO-induced hypertrophic rats; as compared with the model group, D. candidumcan inhibit ISO-induced ventricular pressure and ventricular hypertrophy, reduce myocardial collagen synthesis, improve myocardial fibrosis and ventricular remodeling, and significantly down-regulate ANP, BNP and cTN-I levels in plasma. This study shows that D. candidum has a protective effect on isoproterenol-induced cardiac hypertrophy.

[Comparative study on effects of rutin and quercetin on metabolism in osteoblast cells].

OBJECTIVE: To investigate the mechanism of rutin and its aglycone (quercetin) in preventing and treating osteoporosis and their effects on stimulating bone formation were studied comparatively in osteoblast cells. METHODS: The effects of rutin and quercetin on the proliferation, differentiation and mineralization were studied respectively by using tetrazolium (MTT), alkaline phosphatase (ALP) and mineralized nodules assays in newborn rat calvarial osteoblast (ROB) cells. RESULTS: Quercetin showed significant stimulatory effects on proliferation and mineralization in ROB cells, so it could promote bone formation. However, rutin could not imporve stimulation of bone formation because it increased proliferation and inhibited differentation and had no remarkable influence on ROB cells in vitro. CONCLUSION: Rutin showed less activity than quercetin on bone formation in ROB cells in vitro. Therefore the mechanism that some foods and traditional Chinese medicine containing rutin can prevent and treat osteoporosis is that its metaboite in vivo can promote bone formation in ROB cells.