The treatment effects and mechanisms of pyrroloquinoline quinone on defective teeth and mandible in Bmi-1 knockout mice / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the treatment effects and mechanisms of pyrroloquinoline quinine(PQQ) on defective teeth and mandible in Bmi-1 knockout mice.</p><p><b>METHODS</b>Male and female Bmi1(+/-) mice were paired with each other from the same nest. At the age of 7 weeks, the mice were divided into three groups, the wild type mice received normal diet(10 mice, WT group), Bmi1(-/-) mice received normal diet (10 mice, BKO group), and the Bmi1(-/-) mice received normal diet and PQQ diet(10 mice, BKO+PQQ group). X-ray and micro- CT were used to detect mandible and dental size and bone mineral density. HE staining, histochemical and immunohistochemical methods were respectively used to detect alveolar bone thickness of cortical bone, predentin thickness of mandibular first molar, mandibular osteoblast number and osteoclast number. Flow cytometry was used to detect reactive oxygen species(ROS) levels of various organs(femur, thymus and liver). The data were statistically analyzed with one-way ANOVA and t test.</p><p><b>RESULTS</b>Compared with BKO mice, BKO+PQQ mice partially rescued total body phenotype, increased body weight and prolonged survival time. X- ray and micro- CT showed the size of the mandible and teeth and bone mineral density of PQQ+BKO mice increased compared with BKO mice. In PQQ+BKO mice, mandibular alveolar bone cortical thickness [(68.65 ± 0.25) µm] was significantly different from that in BKO mice [(42.45 ± 0.35) µm] (P<0.01). There was significant difference in predentin thickness of mandibular first molar between PQQ+BKO mice [(4.25 ± 0.15) µm] and BKO mice [(31.55 ± 0.35) µm] (P<0.001). The number of osteoblasts in the mandible of BKO+PQQ mice [(38.45 ± 0.25) cell/mm³] was significantly higher than that in the BKO mice [(18.15 ± 0.55) cell/mm³] (P<0.01). However, the number of osteoclasts in the BKO+PQQ mice [(9.45 ± 0.25) cell/mm³] was significantly lower than that in the BKO group [(14.25 ± 0.35) cell/mm³] (P<0.01). Compared with the BKO group, ROS levels of the femur, thymus and liver in the BKO+PQQ mice were significantly decreased (P<0.01).</p><p><b>CONCLUSIONS</b>The results indicate that PQQ may have treatment effects on defective teeth and mandible through promoting osteoblast bone formation and reducing osteoclast bone resorption, scavenging ROS and reducing DNA damage.</p>

Non-adherent bone marrow-derived mesenchymal stem cells differentiate into neuron-like cells in mice / 中华围产医学杂志

Objecttve To determine whether non-adherent bone marrow-derived mesenchymal stem cells (NA-BM-MSC) can differentiate into neuron-like cells in vitro and in vivo,especially in ischemic brain of mice. Methods NA-BM-MSC of mouse were indueed with conditioned medium containing epidermal growth factor and basic-fibroblast growth factor and demonstrated by immunocytochemistry for the expression of neuron specific nuclear protein and neurofilament-200. NA-BM-MSC from β-galactosidase transgenic mice constitutively expressing β-galactosidase were transplanted into the mice model of middle cerebral artery occlusion.LacZ staining and immunobistochemistry staining were performed to detect the survival,distribution and the differentiation of the donor cells in the ischemic brain. Results NA-BM-MSC can be induced into neuron specific nuclear protein and neurofilament-200 positive cells in vitro.LacZ staining showed that NA-BM-MSC can survive in ischemic brain and express β-galactosidase.Also,numbers of the neuron specific nuclear protein positive cells in β-galactosidase-positive cells were detected in the ischemic brain with double immunohistochemistry staining. Conclusions NA-BM-BMC can be induced to differentiate into neuron-like cells in vitro,and also can differentiate into neuron-like cells in ischemic brain tissue of the mice.