Role of interaction between reactive oxygen species and ferroptosis pathway in methylglyoxal-induced injury in mouse embryonic osteoblasts / 南方医科大学学报

OBJECTIVE@#To explore the interaction between reactive oxygen species (ROS) and ferroptosis in methylglyoxalinduced injury of mouse embryonic osteoblasts (MC3T3-E1 cells).@*METHODS@#MC3T3-E1 cells were treated with methylglyoxal to establish a cell model of diabetic osteoporosis. CCK-8 assay was used to detect the viability of MC3T3-E1 cells. Rhodamine 123 staining followed by photofluorography was used to examine mitochondrial membrane potential (MMP). The intracellular ROS level was detected by 2', 7'-dichlorodihydrofluorescein diacetate staining with photofluorograph. Alkaline phosphatase (ALP) activity in the cells was detected using an ALP kit, the number of mineralized nodules was determined with alizarin red S staining, and the level of iron ions was detected using a detection kit. The expression level of glutathione peroxidase 4 (GPX4, a marker protein that inhibits ferroptosis) in the osteoblasts was determined using Western blotting.@*RESULTS@#Treatment of MC3T3-E1 cells with 0.6 mmol/L methylglyoxal for 24 h significantly inhibited the expression level of GPX4 (P < 0.001), increased intracellular iron ion concentration, decreased the cell viability, increased the loss of MMP and intracellular ROS level, decreased both ALP activity and the number of mineralized nodules in the cells (P < 0.001). Co-treatment of MC3T3-E1 cells with 2 mmol/L N-acetylcysteine (NAC, a ROS scavenger) and methylglyoxal significantly increased the expression level of GPX4 (P < 0.01); co-treatment with 4 mmo/L FER-1 (a ferroptosis inhibitor) and methylglyoxal obviously decreased the intracellular ROS level (P < 0.001). Co-treatment of the cells either with NAC and methylglyoxal or with FER-1 and methylglyoxal attenuated methylglyoxal-induced injuries in the osteoblasts (P < 0.001).@*CONCLUSION@#The interaction between ROS and ferroptosis pathway plays an important role in methylglyoxal-induced injury of mouse embryonic osteoblasts.

Angiotensin-(1-7) protects cardiac myocytes against high glucose-induced injury by inhibiting ClC-3 chloride channels / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore whether angiotensin-(1-7) [Ang-(1-7)] protects cardiac myocytes against high glucose (HG)-induced injury by inhibiting ClC-3 chloride channels.</p><p><b>METHOD</b>H9c2 cardiac cells were exposed to 35 mmol/L glucose for 24 h to establish a cell injury model. The cells were treated with Ang-(1-7) or the inhibitor of chloride channel (NPPB) in the presence of HG for 24 h to observe the changes in HG-induced cell injury. Cell counter kit 8 (CCK-8) assay was used to test the cell viability, and the morphological changes of the apoptotic cells were detected using Hoechst 33258 staining and fluorescent microscopy. The intracellular level of reactive oxygen species (ROS) was examined by DCFH-DA staining, SOD activity in the culture medium was measured using commercial kits, and the mitochondrial membrane potential (MMP) of the cells was tested with rodamine 123 staining. The expression level of cardiac ClC-3 chloride channels was detected with Western blotting.</p><p><b>RESULTS</b>Exposure of H9c2 cardiac cells to 35 mmol/L glucose for 24 h markedly enhanced the expressions of cardiac ClC-3 channel protein (P<0.01). Co-treatment of the cells with 1 µmol/L Ang-(1-7) and HG for 24 h significantly attenuated HG- induced upregulation of ClC-3 channel protein expression (P<0.01). Co-treatment of the cells exposed to HG with 1 µmol/L Ang-(1-7) or 100 µmol/L NPPB for 24 h obviously ameliorated HG-induced injuries as shown by increased cell viability, enhanced SOD activity, decreased number of apoptotic cells, and reduced intracellular ROS generation and loss of MMP (P<0.01).</p><p><b>CONCLUSION</b>ClC-3 channels are involved in HG-induced injury in cardiac cells. Ang-(1-7) protects cardiac cells against HG-induced injury by inhibiting ClC-3 channels.</p>

Factors associated with acute febrile reaction in elderly patients receiving intravenous zoledronic acid for osteoporosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To survey the incidence of acute febrile reaction in elderly patients receiving intravenous zoledronic acid for osteoporosis and identify the related factors.</p><p><b>METHODS</b>Thirty-eight elderly patients with osteoporosis were hospitalized and treated with intravenous infusion of 5 mg zoledronic acid in 2010. The incidence of acute fever reaction was observed in these patients , and the time of fever onset, duration, average maximum temperature, and antipyretic drug used were recorded. The patients with and without acute febrile reaction were compared for age, duration of osteoporosis, sex ratio, use of parathyroid hormone before zoledronic acid treatment, β-fragment of collagen breakdown, calcitonin, osteocalcin, serum calcium, and use of anti-osteoporosis drugs before the treatment.</p><p><b>RESULTS</b>Acute fever reaction occurred in 12 (31.6%) of the patients. Two of the patients had fever on the day of zoledronic acid treatment, and the other patients developed fever after the first day of treatment, with a mean duration of 1 day and a maximum temperature of (38.5∓0.84) degrees celsius;. The fever was treated with a mean of 3.55∓1.21 pseudoephedrine tablets. The patients with fever showed significantly higher parathyroid hormone levels before treatment than those without fever (P<0.05); osteocalcin, calcitonin, β-fragment of collagen breakdown, or serum calcium showed no significant difference between the two groups.</p><p><b>CONCLUSION</b>Acute febrile reaction, often moderate and transient, is common in elderly patients receiving intravenous zoledronic acid for osteoporosis, and its occurrence is possibly associated with parathyroid hormone levels before the treatment.</p>

Vitamin D receptor gene polymorphism is not associated with bone mineral density of pre-menopausal women in Guangzhou / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the prevalence of vitamin D receptor (VDR) gene polymorphism in pre-menopausal women in Guangzhou and study its relationship with bone mineral density(BMD).</p><p><b>METHODS</b>The genotypes of VDR gene in 193 per-menopausal women in Guangzhou were analyzed by polymerase chain reaction-restriction fragment length polymorphism. BMD of the lumbar spine, femoral neck, greater trochanter and Ward's triangle were measured by dual-energy X-ray absorptiometry.</p><p><b>RESULTS</b>In the 193 subjects, 120 (66.2%) were identified as VDR bb genotype, 64 (33.2%) as Bb, and 9 (4.6%) as BB. The b allele frequencies reached 78.76%, and B allele frequencies was 21.24%. The distribution followed the Hardy-Weinberg equilibrium. No significant difference was found in BMD among the subjects with different genotypes.</p><p><b>CONCLUSION</b>VDR genotype is not related to BMD, and VDR polymorphism can not be used as a genetic marker for predicting the risk of osteoporosis in pre-menopausal women in Guangzhou.</p>

Relationship of collagen type I alpha 1 and alpha 2 gene polymorphisms with bone mineral density / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate collagen type I alpha 1 (COL1A1) and alpha 2 (COL1A2) gene polymorphisms in Chinese and their relationship with bone mineral density.</p><p><b>METHODS</b>Totalling 628 residents of Han nationality in Guangzhou aged 53.4-15.9 (range 20-79) years were surveyed for COL1A1 and COL1A2 gene genotypes by polymerase chain reaction-restriction fragment length polymorphism. Bone mineral density of the lumbar vertebrae, greater trochanter, femur neck and Ward's triangle was measured by dual-energy X-ray absorptiometry.</p><p><b>RESULTS</b>COL1A1 Sp1 polymorphism was not found in these subjects, and the genotype of all samples were type SS. COL1A2 genotyping revealed the distribution of EE genotype in 49.7%, Ee in 40.9% and ee in 9.4% of the subjects. The frequency distribution of EcoR1 alleles followed the Hardy-Weinberg equilibrium. The mean bone mineral density did no significantly differ among these genotype groups (P>0.05 by analysis of variance).</p><p><b>CONCLUSION</b>COL1A1 Sp1 binding site polymorphism is absent and COL1A2 EcoR1 site polymorphism is not associated with bone mineral density in Chinese of Han nationality.</p>