Hypocholesterolaemic mechanism of bitter melon aqueous extracts via inhibition of pancreatic cholesterol esterase and reduction of cholesterol micellar solubility

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.     

甲状旁腺激素对大鼠牵张成骨过程中O NC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因表达的影响

目的：探讨甲状旁腺激素（PTH）对大鼠牵张成骨（DO）过程中ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因表达的影响。方法30只雄性大鼠制备大鼠下颌骨DO模型。随机分5组，每组6只。第1组（只有牵张无PTH），术后8周取材，应用HE染色及微CT检测，以确定成骨情况。第2组（有牵张无PTH），第3组（有牵张有PTH），第4组（无牵张有PTH），第5组（对照组：无牵张无PTH）。2、3、4组及对照组术后1周取材，RT-PCR测定ONC、OPN、C-FOS、COL1、VEGF、RUNX2、ALP基因的表达。结果第1组，新骨形成，骨质充满牵张区，骨质连续，大鼠建模成功。RT-PCR检测结果显示，2、3、4组与对照组比较，OPN、COL1、RUNX2、ALP基因表达有明显提高（P＜0．05），其中第3组最为明显。ONC、C-FOS、VEGF基因2、3、4组与对照组比较差异无统计学意义（P＞0．05）。结论 PTH在 DO 过程中，间歇性给以 PTH的作用只有在牵张期发挥作用，其对 OPN、COL1、RUNX2、ALP基因表达能够获得理想的协同作用。