The Effect of Estrogen on the Restoration of Bone Mass and Bone Quality in Ovariectomized Rats

To evaluate the effect of estrogen on its ability to restore the bone mass and bone quality in ovariectomized rats by examining the changes of bone morphology and histomorphometry, 3- month-old rats were divided randomly into 4 groups: normal control, ovariectomized (OVX), sham- operated (Sham-O) and OVX plus estrogen (OVX+E2). Treatment initiated from the day 8 weeks after operation and continued for 12 weeks. Bone morphology and histomorphometry were examined afterwards. Results showed that comparing to control group, the trabecular bone in OVX appeared thinner and reduced in the amount. The connectivity between trabecula was decreased and the struc- ture disordered. The free-end of trabecula was increased. The cavity of bone marrow enlarged. After treatment with estrogen, above changes improved remarkably by different degree, although did not reach the normal face. The bone histomorphometry results damonstrated that estrogen treatment in- creased bone mass and the amount of trabecula by 129% and 132% respectively (P<0. 05). The activity of bone resorption decreased significantly and the rate of bone formation increased to 203%. These results suggest that treatment of ovariectomized rats with estrogen can not only increase bone mass, also improve the bone structure and enhance the property of bone mechanics.

Regulation of Insulin Secretion and Expression of SUR1 Gene by Chronic Exposure to Free Fatty Acids in Rat Pancreatic β Cells

To study the effects of free fatty acids on insulin secretion and expression of SUR1 gene in rat pancreatic B cells in vitro, and to explore the molecular mechanisms in lipotoxicity inducing insulin secretion dysfunction, pancreatic islet cells were isolated and digested from male SD rats. Purified islets were incubated with either 0.25 mmol/L palmitate or 0.125 mmol/L oleate for 48 h in vitro. Then islets were stimulated with either 5.6 mmol/L or 16.7 mmol/L glucose for 1 h. Insulin release was measured by using radioimmunoassay, and the expression of SUR1 gene mRNA was quantified by reserve transcription-polymerase chain reaction (RT-PCR). The islets exposed to both palmitate and oleate for 48 h showed an increased basal and a decreased glucose-indused insulin release as compared with control islets. Palmitate increased basal insulin secretion by 110 % (P<0.01), decreased glucose stimulated insulin secretion by 43 % (P<0.01); while oleate increased basal insulin secretion by 80 % (P<0.01) and decreased glucose stimulated insulin secretion by 32 % (P<0.05). RT-PCR showed that oleate significantly suppressed SUR1 gene expression by 64 % (P<0.01)as compared with the control group, while palmitate group manifested a light decrease of 15 % (P >0.05) of SUR1 gene expression. Our results suggested that chronic exposure to free fatty acids of pancreatic β cells inhibited glucose stimulated insulin secretion. Regulation of SUR1 gene expression may be involved in such effects, which may also be one of the molecular mechanisms in lipotoxocity inducing β cells secretion dysfunction.

体重指数与初诊2型糖尿病代谢状态及慢性并发症的关系

目的探讨肥胖程度与糖尿病患者代谢状态及慢性并发症的关系。方法将新诊断的2型糖尿病患者以体重指数分为3组,分别比较空腹血糖及餐后血糖、血压、血脂、胰岛素抵抗指数、空腹C肽水平及大血管/微血管并发症患病率。结果低体重患者主要临床特征为胰岛素分泌水平低下,HbA_lc及空腹血糖增高。超重、肥胖的糖尿病患者主要表现为高血压、胰岛素抵抗、高甘油三酯和低高密度脂蛋白胆固醇血症。超重组易伴发高血压及冠心病等大血管病变,而低体重组微血管病变尤其是视网膜病变较为突出。结论对于初诊的低体重患者,应尽早补充胰岛素并及时筛查视网膜病变等微血管并发症;对于超重患者应强调减肥、降压、调脂等综合治疗。

地特胰岛素与中效胰岛素对血糖控制不佳的2型糖尿病患者血糖变异性的影响

目的比较地特胰岛素(Det)和中性精蛋白锌胰岛素(NPH)对口服降糖药控制不佳的T2DM患者血糖水平及其变异性的影响。方法 32例口服降糖药(OAD)控制不佳(HbA1c>7.5%)的T2DM患者随机分为两组,分别加用Det和NPH胰岛素治疗,治疗12周后,动态血糖监测系统(CGMS)进行连续72h的血糖监测。结果 (1)两组患者治疗12周后FBG、2hBG和HbA1c水平均较治疗前明显降低(P<0.01);而在治疗前后两组间FBG、2hBG和HbA1c均无统计学差异;(2)CGMS结果显示,两组间平均血糖水平差异无统计学意义(P>0.05),但Det组日内血糖最高值、日内血糖漂移最大幅度均明显低于NPH组(P<0.01)。结论 Det在改善T2DM患者血糖变异性方面优于NPH。