ABSTRACT
Objective:To compare expression levels of matrix Gla protein (MGP) and bone morphogenetic protein 2 (BMP-2) in Randall's plaque of renal papillary tissues in patients with calcium oxalate kidney stones and the underlying mechanism for stone formation.Methods:A total of 30 samples of Randall's plaque in renal papillary tissues from patients with calcium oxalate kidney stones were collected from the Department of Urology of Xiangya Hospital of Central South University from April,2015 to December,2015 and served as an experimental group.Ten samples of renal papillary tissues in patients undergone renal tumor nephrectomy were collected from the same hospital and served as a control group.The expressions of MGP and BMP-2 mRNA and protein were detected by quantitative real-time PCR and Western blot.Meanwhile,immunohistochemical technique was used to observe the expressions of MGP and BMP-2 in different parts of renal papillary tissues in the 2 groups.Results:1) The mRNA expression levels of MGP in the experimental group and the control group were 0.760±0.804 and 1.365±0.348,respectively,with significant difference between them (P＜0.05).Them RNA levels of BMP-2 in the experimental group and the control group were 2.500±0.725 and 1.485±0.870,respectively,with significant difference between them (P＜0.05).The expression levels of MGP protein in the experimental group and the control group were 0.130±0.424 and 0.202±0.704,respectively,with no significant difference between them (P＞0.05).The expression levels of BMP-2 protein in the experimental group and the control group were 0.885±0.220 and 0.682±0.272,respectively,with significant difference between them (P＜0.05).T-he immunohistochemistry showed that the protein expression of MGP in the experimental group was lower than that in the control group,while the protein expression of BMP-2 in the experimental group was higher than that in the control group (both P＜0.05).Conclusion:The BMP-2 expression is increased while MGP expression is decreased in renal papillary tissues in patients with calcium oxalate kidney stones,and the formation of calcium oxalate kidney stone might be a kind ofosteogenetic reaction or ectopic calcification.
ABSTRACT
ObjectiveTo observe the effect of parathyroid hormone on expression of matrix GLA protein (MGP) in ovariectomized SD rats and primary osteoblast,and to study the role of MGP on the possible mechanism of postmenopausal osteoporosis.MethodsThirty-six Sprague-Dawley female rats were allocated into 3 groups,12 in each:sham operation group,ovariectomized group( OVX group),ovariectomized and parathyroid hormone treatment group.Animals in the parathyroid hormone group were injected parathyroid hormone (20 μg/kg,three times a week for 12 weeks) three weeks after ovariectomy.All rats were sacrificed after 18 weeks.Urine and serum were collected every three weeks.Lumbar vertebral bones were observed by immunohistochemistry.Bone mineral density (BMD) of lumbar vertebra of rats was determined.The content of MGP in serum and urine was determined by enzyme-linked immunosorbent assay (ELISA).Expression of undercarboxylated Matrix GLA Protein (ucMGP) was detected by immunochistochemistry.Relative quantification of MGP mRNA expression in lumbar vertebra bone was detected by Fluorescent real-time quantitative polymerause chain reaction.Results ( 1 ) 18 weeks after ovariectomy,BMD of lumbar vertebra in OVX group was lower than those in sham group and parathyroid hormone group significantly ( P＜0.05 ).(2) The content of MGP in serum and urine was dynamic variation after treatment hy parathyroid hormone,and it was significant compared with OVX group ( P＜0.05 ).( 3 ) Immunohistochemical localization of ucMGP was seen in lumbar vertebra in OVX group.(4) Relative quantification of MGP mRNA expression in lumbar vertebra in OVX group was increased significantly compared with other groups ( P＜0.01 ).( 5 ) parathyroid hormone ( 1-34 ) in 10-7mol/L,10-8mol/L,10-9 mol/L up-regulated MGP mRNA expression in primary osteoblasts about 6.78,5.31,and 2.23 times than control respectively.It was in a dose-dependent manner.ConclusionThe effect of parathyroid hormone on the expression of matrix gla protein may play an important role in mechanism of postmenopausal osteoporosis
ABSTRACT
Objective To observe the expression of matrix gla protein(MGP) mRNA in primary osteoblasts of Sprague-Dawley (SD) rat in vitro after treatment with anti-osteoporosis agents [vitamin K2,PTH,1,25 (OH)2D3,and alendronate],and to investigate the potential role of MGP in the pathogenesis of osteoporosis.Methods Primary osteoblasts(OBs) were derived from sequential trypsin/collagenase-digested calvaria isolated from newborn SD rat (postnastal day 1-3).OBs of the second generation were identified by Van Gieson collagen staining,alkaline phosphatase(ALP) staining and calcified nodules staining.OBs of the fourth generation were selected to interfere with vitamin K2,PTH,1,25 (OH)2D3,and alendronate,then cultured for 24 h in mediums which contained various concentrations of vitamin K2 (10-7,10-6,and 10-5 mol/L),PTH (10-9,10-8,and 10-7 mol/L),1,25 (OH) 2D3(10-10,10-9,and 10-8mol/L),alendronate(10-6,10-5,and 10-4mol/L).After being cultured for 24 h,total RNA was extracted and examined by real-time quantitative RT-PCR.Results The primary cultured cells had typical morphological characters of osteoblast.van Gieson collagen staining,ALP staining,and calcified nodules staining were all positive.Vitamin K2,PTH,1,25 (OH)2D3,and alendronate could modulate the expression of MGP mRNA in osteoblasts in a dose-dependent fashion.MGP mRNA expressions were 2.56-fold,2.12-fold,and 1.57-fold with 10-5,10-6,and 10-7 mol/L of vitamin K2 treatment,respectively.The expressions were 6.78-fold,5.31-fold,and 2.23-fold with 10-7,10-8,and 10-9mol/L of PTH(1-34) treatment,8.93-fold,6.95-fold,and 3.47-fold with 10-8 10-9,and 10-10mol/L of 1,25 (OH)2D3 treatment,and 3.47-fold,2.49-fold,and 1.98-fold with 10-4,10-5,and 10-6mol/L of alendronate treatment.Conclusion Vitamin K2,PTH,1,25 (OH)2D3,and alendronate all canregulate MGP mRNA expression in calvarial osteoblasts in a dose-dependent manner.MGP seems to be a potent target of anti-osteoporosis agents,and involved in the pathogenesis of osteoporosis.