[Mesenchymal stem cells transplanted in mdx mice differentiate into myocytes and express dystrophin/utrophin].

OBJECTIVE: To investigate the differentiation of rat bone marrow mesenchymal stem cells (MSCs) into myocytes and their expression of dystrophin/utrophin after transplantation in mdx mice. METHODS: BrdU-labeled fifth-passage rat MSCs were transplanted in mdx mice with previous total body gamma irradiation (7 Gy). At 4, 8, 12 and 16 weeks after the transplantation, the mice were sacrificed to detect dystrophin/BrdU and utrophin expressions in the gastrocnemius muscle using immunofluorescence assay, RT-PCR and Western blotting. Five normal C57 BL/6 mice and 5 mdx mice served as the positive and negative controls, respectively. RESULTS: Four weeks after MSC transplantation, less than 1% of the muscle fibers of the mdx mice expressed dystrophin, which increased to 15% at 16 weeks. Donor-derived nuclei were detected in both single and clusters of dystrophin-positive fibers. Some BrdU-positive nuclei were centrally located, and some peripherally within myofibers. Utrophin expression decreased over time after transplantation. CONCLUSION: The myofibers of mdx mice with MSC transplantation express dystrophin, which is derived partially from the transplanted MSCs. Dystrophin expression from the transplanted MSCs partially inhibits the upregulation of utrophin in mdx mouse muscle, showing a complementary relation between them.

[Dynamic distribution of implanted human bone marrow mesenchymal stem cells in mdx mice].

OBJECTIVE: To investigate the dynamic distribution of human bone marrow mesenchymal stem cells (hBM-MSCs) in mdx mice. METHODS: Twenty-four 8-10-week-old immunocompromised mdx mice were transplanted with 1 x 10(7) passage 5 hBM-MSCs labeled with bromodeoxyuridine (BrdU) by means of injection into the tail vein. The mice were euthanized 48 hours and 2, 4, 8, 12, 16, 20, and 24 weeks after transplantation. BrdU-positive cells in tissue and organs of the mice were detected by immunofluorescence analysis. Skeletal muscle was stained for anti-human nuclei mouse monoclonal antibody (anti-Hu) and analyzed for human dystrophin (Dys) expression by immunohistochemistry and reverse transcription-polymerase chain reaction. RESULTS: After transplantation, BrdU-positive cells were found in most organs (especially in bone marrow, liver, and lung) within 4 weeks, and these cells in liver and lung decreased gradually after 4 weeks. At 48 hours after transplantation, BrdU-positive cells were found in bone marrow, which reached a peak level after 2 weeks and were still detectable after 16 weeks. BrdU-positive cells in skeletal muscle increased gradually over time of transplantation. A small number of anti-Hu positive cells were detected in skeletal muscle 2 weeks after transplantation. A small number of Dys positive cell were seldom found at 4 weeks and small Dys mRNA expression detected 4 weeks after transplantation. The proportion of anti-Hu in parallel with Dys positive cells and Dys mRNA in skeletal muscle of mdx mice increased gradually over time of transplantation. CONCLUSION: After being transplanted into mdx mice, hBM-MSCs are mainly distributed in bone marrow, liver, and lung during the early time (2-4 weeks) , and then in bone marrow and skeletal muscle (after 4 weeks).

[Association between angiotensin-converting enzyme and polymorphisms of N5, N10-methylenetetrahydrofolic acid reductase gene in patients with ischemic stroke].

OBJECTIVE: To explore the association between angiotensin-converting enzyme (ACE) and the polymorphisms of N5, N10-methylenetetrahydrofolic acid reductase (MTHFR) gene in patients with ischemic stroke (IS). METHODS: Totally 454 patients with IS (IS group) and 334 controls (control group) were recruited in our study. Their I/D polymorphisms of ACE gene and C677T polymorphisms of MTHFR gene were detected by PCR and denaturing high performance liquid chromatography. RESULTS: The frequencies of DD, ID, II and CC, CT, TT genotype in IS group were 22.5%, 43.4%, 34.1%, and 51.8%, 40.5%, 7.7%, respectively, and were 17.4%, 45.5%, 37.1% and 56.9%, 38.3%, 4.8% in the control group, respectively. DD genotype was associated with large-artery atherosclerosis (LAA), and TT genotype and T allele were associated with LAA and cardioembolism. Synergistic effects were found between TT and DD/ID DD genotypes in the pathogenesis of ischemic stroke. CONCLUSION: DD, TT genotype and T allele are risk factors of IS, and ACE gene and MTHFR gene have synergistic effects in the pathogenesis of IS.

[Relationship between angiotensin converting enzyme gene and ischemic stroke].

OBJECTIVE: To study relationship between angiotensin converting enzyme (ACE) gene and ischemic stroke (IS). METHODS: (1)Four hundred and fifty-four patients and 334 controls were recruited in our study, their I/D polymorphisms of ACE gene were detected by polymerase chain reaction (PCR) and denaturing high performance liquid chromatogram, and their risk factors of IS were recorded at the same time. (2)In addition, 29 stroke-prone spontaneously hypertensive rats (SHR-SP) and 40 Sprague-Dawley (SD) rats were enrolled, and hypoxia- apnoea animal models and simple apnoea animal models were used at the same time. Their plasma angiotensin II (Ang II) levels were determined. RESULTS: The frequencies of DD, ID and II genotype in IS patients were 22.5%, 43.4% and 34.1%, respectively, and 17.4%, 45.5% and 37.1%, respectively in controls. DD genotype was associated with large artery arteriosclerosis (LAA). Plasma Ang II level in SHR-SP group was (164.49+/-34.58) ng/L, and it was higher than that in control group [(150.92+/-24.92)ng/L] with no significant difference (P>0.05). Ang II levels in apnoea and hypoxia-apnoea group were (382.84+/-62.75) ng/L and (295.90+/-55.07) ng/L, respectively, and they were significantly higher than that in control group (all P<0.01). The relative risks of DD genotype and D alleles in IS patients with smoking, alcohol abuse, or with diabetes mellitus were higher than those in controls, but II genotype and I alleles were lower than those in controls. CONCLUSION: DD genotype is a risk factor for IS, Ang II takes part in the course of hypoxia-stress, and it is correlated with smoking, alcohol abuse and diabetes mellitus in the pathogenesis of IS.

[Relationship between methylenetrahydrofolate reductase gene and ischemic stroke].

OBJECTIVE: To study the relationship between methylenetrahydrofolate reductase (MTHFR) gene and ischemic stroke. METHODS: Four hundred and fifty four ischemic stroke patients were enrolled in the study. They were divided into large artery atherosclerosis (LAA), cardioembolism (CE), small artery occlusion (SAA), stroke of other determined etiology (SOE) and stroke of undetermined etiology (SUE) according to TOAST (Trail of ORG 10172 in Acute Stroke Treatment) criteria; and they were divided into mild, moderate and severe types ischemic stroke according to their scores of neurologic impairment. Three hundred and thirty four subjects, in whom hypertension, coronary heart disease, cerebral vascular disease, diabetes mellitus, cancer, renal failure etc. were excluded, served as controls in the study. Their C677T polymorphisms of MTHFR gene were determined with polymerase chain reaction (PCR) and denaturing high performance liquid chromatography (DHPLC), and their risk factors of ischemic stroke were recorded at the same time. RESULTS: The frequencies of CC, CT and TT genotype in ischemic stroke were 51.8%, 40.5% and 7.7%, respectively, and they were 56.9%, 38.3% and 4.8% respectively in controls. TT genotype and T allele were associated with LAA and CE, moderate type and severe type of ischemic stroke. The frequencies of TT genotype and T allele in ischemic stroke patients were significantly higher in those with smoking, alcohol abuse or diabetes mellitus than those in controls (all P<0.10), but CC genotype and C allele were significantly lower in them than those in controls (all P<0.05). On the other hand, all of genotypes and alleles in ischemic stroke patients with no history of smoking, alcohol abuse or diabetes mellitus were not significantly different from those in controls. CONCLUSION: TT genotype and T allele are risk factors for ischemic stroke. It exists interactions between smoking, alcohol abuse, diabetes mellitus and MTHFR gene in the pathogenesis of ischemic stroke.

[Detecting the polymorphism of methylenetetrahydrofolate reductase gene by denaturing high performance liquid chromatography].

OBJECTIVE: To establish a method for detecting the polymorphism of methylenetetrahydrofolate reductase gene (MTHFR). METHODS: The MTHFR was amplified, and the amplified products were detected by denaturing high performance liquid chromatography (DHPLC), and the amplified MTHFR was confirmed by sequencing and restriction enzyme digesting. RESULTS: A total of 334 individuals of Han people in southern China were recruited in our study, and their polymorphisms of MTHFR were detected. The accurate rate of the DHPLC method, that was very sensitive with 100% detection rate available, was over 99%. The frequencies of CC, CT and TT genotypes were 56.9%, 38.3% and 4.8% individually, and the frequencies of T and C alleles were 23.95% and 76.05% individually. CONCLUSION: The DHPLC method can detect polymorphism of MTHFR rapidly, effectively and economically. And there is the existence of different MTHFR polymorphisms in area and race.

[Transplantation of 3H-thymidine-labeled human bone marrow-derived mesenchymal stem cells in mdx mice].

OBJECTIVE: To investigate the feasibility of using human bone marrow-derived mesenchymal stem cells (hBM- MSCs) for repairing the skeletal muscle sarcolemma lesions in mdx mice and characterize the distribution of the transplanted hBM-MSCs. METHODS: Eighteen 8- to 10-week-old immunosuppressed mdx mice received transplantation with 1x10(7) of hBM-MSCs (the fifth passage) with 3H-thymidine (3H-TdR) labeling by injection of the cells into the tail vein. The mice were killed at 24 h, 48 h, 2 weeks, and 1, 2 and 4 months after the transplantation, respectively, to measure the radioactivity in the tissues and organs. Dystrophin expression on the sarcolemma was detected by immunofluorescence analysis. RESULTS: One month after transplantation, the mice with cell transplantation showed greater radioactivity in most of the tissues and organs than the control mice, especially in the bone marrow, liver and spleen. The radioactivity was then gradually lowered but in the skeletal muscle, the radioactivity increased progressively since 2 weeks after transplantation, reaching the peak of 27.65+/-3.53 Bq/mg at 1 month. Compared with that in the control mice, the radioactivity in the bone marrow and skeletal muscle was persistently higher in mice with cell transplantation 1 month after transplantation. No dystrophin-positive cells were found in the mdx mice at 2 weeks but detected at 1 month. The percentage of dystrophin-positive fibers in each section ranged from a 6.6% (1 month) to 8.9% (4 months). CONCLUSIONS: hBM-MSCs engrafted in immunosuppressed mdx mice may differentiate into skeletal muscle cells to repair the pathological lesion of the skeletal muscle sarcolemma. The hBM-MSCs reside mainly in the bone marrow, liver and spleen in the early stage following transplantation, homing into the bone marrow and skeletal muscle later.

[Relationships between polymorphisms of angiotensin-converting enzyme and methylenetetrahydrofolate reductase genes and genetic susceptibility to pregnancy induced hypertension].

OBJECTIVE: To study the relationships between polymorphisms of angiotensin-converting enzyme (ACE) gene and methylenetetrahydrofolate reductase (MTHFR) gene and pregnancy induced hypertension (PIH). METHODS: Ninety-nine PIH patients (PIH group), including 21 mild cases, 24 moderate cases and 54 severe cases and 54 normal pregnant women (control group) were recruited. The polymorphism of ACE gene was detected by PCR, and that of MTHFR gene was detected by PCR-RFLP. RESULTS: In PIH group, the frequencies of genotypes II, ID, and DD of ACE gene were 20.2%, 37.4% and 42.4% respectively, the frequencies of genotypes CC, CT, and TT of MTHFR gene were 53.5%, 31.3% and 15.2% respectively. There existed significant difference between genotypes DD, CT and D allele in PIH group and control group. Compared to mild PIH group, the frequencies of genotypes DD and CT in severe PIH group were significantly higher. The susceptibility to PIH in individuals with genotypes CC + DD was 2.648 times that of the controls. However, individuals with genotypes CT + II and CC + II were less susceptible to PIH in comparison to the controls. Logistic regression analysis showed that genotype DD and D allele were associated with PIH, genotype CT was associated with severe PIH. CONCLUSION: Genotypes DD and CT may be the risk factors of PIH; genotype II may have a protective effect against PIH. There may exist some interaction between polymorphisms of ACE gene and MTHFR gene in the pathogenesis of PIH.

[Dynamic changes in the expressions of myogenic regulatory factors MyoD and myogenin during repair of muscle injury].

OBJECTIVE: To observe the dynamic changes in the expressions of myogenic regulatory factors MyoD and myogenin during the repair of injured muscle. METHODS: Muscular injury model was established by local injection of bupivacain, and at different time points following the injection, the gastrocnemius muscles were collected for preparation of cryosections. HE staining was performed for examination of the pathological changes in the injured muscles, and the expressions of MyoD and myogenin were detected by SABC. RESULTS: MyoD-positive nuclei began to appear 18 h after muscle injury, reaching the peak till 48 h after the injury. Myogenin-positive nuclei appeared 24 h after muscle injury and peaked at 72 h. CONCLUSIONS: MyoD and myogenin play a role in muscle regeneration after muscle injury, and they may serve as the indexes to identify muscle precursor cells and mark muscle regeneration process.