Hypoxia enhances periodontal ligament stem cell proliferation via the MAPK signaling pathway.

There is high incidence of periodontal disease in high-altitude environments; hypoxia may influence the proliferation and clone-forming ability of periodontal ligament stem cells (PDLSCs). The MAPK signaling pathway is closely correlated with cell proliferation, differentiation, and apoptosis. Thus, we isolated and cultured PDLSCs under hypoxic conditions to clarify the impact of hypoxia on PDLSC proliferation and the underlying mechanism. PDLSCs were separated and purified by the limiting dilution method and identified by flow cytometry. PDLSCs were cultured under hypoxic or normoxic conditions to observe their cloning efficiency. PDLSC proliferation at different oxygen concentrations was evaluated by MTT assay. Expression of p38/MAPK and MAPK/ERK signaling pathway members was detected by western blotting. Inhibitors for p38/MAPK or ERK were applied to PDLSCs to observe their impacts on clone formation and proliferation. Isolated PDLSCs exhibited typical stem cell morphological characteristics, strong abilities of globular clone formation and proliferation, and upregulated expression of mesenchymal stem cell markers. Stem cell marker expression was not statistically different between PDLSCs cultured under hypoxia and normoxia (P > 0.05). The clone number in the hypoxia group was significantly higher than that in the control (P < 0.05). PDLSC proliferation under hypoxia was higher than that of the control (P < 0.001). p38 and ERK1/2 phosphorylation in hypoxic PDLSCs was markedly enhanced compared to that in the control (P < 0.05). Either P38/MAPK inhibitor or ERK inhibitor treatment reduced clone formation and proliferation. Therefore, hypoxia enhanced PDLSC clone formation and proliferation by activating the p38/MAPK and ERK/MAPK signaling pathways.

Comparative study of clinical efficacy of laparoscopy-assisted radical gastrectomy versus open radical gastrectomy for advanced gastric cancer.

The purpose of this study is to compare the efficacy of laparoscopy-assisted radical gastrectomy (LARG) versus that of open radical gastrectomy (ORG). Clinical data of 355 patients who underwent radical gastrectomy (160 in the LARG group and 195 in the ORG group) were analyzed retrospectively. Efficacy indices were compared and analyzed between the two groups. The operating time of LARG was longer than that of ORG (228.43 ± 34.77 versus 207.59 ± 28.39 min). However, patients in the LARG group lost less blood than did those in the ORG group (169.46 ± 82.92 versus 193.86 ± 82.09 mL), and more lymph nodes were removed in the LARG group (19.84 ± 4.7 versus 18.04 ± 4.14 per case). The recovery of intestinal function was faster (3.72 ± 1.03 versus 4.41 ± 1.30 days) in the LARG group. Patients in the LARG group were administered a semi-fluid diet earlier (5.66 ± 2.27 versus 7.09 ± 2.33 days) and had a shorter hospital stay (9.44 ± 3.06 versus 11.07 ± 7.91 days) than did those in the ORG group, and these differences were statistically significant (P < 0.05). No significant differences were found in the length of proximal and distal resection margin and the incidence of complications (P > 0.05) between the two groups. Thus, LARG is safe, feasible, and effective for treating advanced gastric cancer.