OBJECTIVEThis study is performed to investigate the cell topographies and biomechanical properties of two different types of temporomandibular joint (TMJ) discs from goats by using JPK Nano Wizard 3 biological atomic force microscopy (AFM). This process provides a guideline for selecting seed cells for TMJ disc tissue engineering.

METHODSTMJ disc cells from primary goats were cultured by monolayer culture method. AFM was used to contact scan the topographies of the two types of TMJ disc cells under physiological environment. Approximately 20 chondrocyte-like and fibroblast-like cells were selected randomly to plot the force-versus-distance curves of the cytoplasm and nucleus. Young's modulus and adhesion were analyzed by JPK Data Processing.

RESULTSThe triangle-shapednucleus of the chondrocyte-like cell occupied a large portion of the cell. Cytoskeleton was arranged dendritically on the surface. Pseudopodia were extended from cell edges. The spindle-shaped nucleus of the fibroblast-like cell occupied a significantly larger region compared with the cytoplasmic region. Cytoskeleton was arranged regularly. Cell edges were smooth with less pseudopodia extended. No difference was found in the surface roughness between the two types of cells. According to the force-versus-distance curves, the Young's moduli of the two types of cells were not statistically different (P>0.05), but differences were found in the cytoplasmic regions (P=0.047). No statistical difference was found in the adhesions between the two types of cells (P>0.05).

CONCLUSIONThe AFM topography and curves were compared and analyzed. The two types of TMJ disc cells exhibited significantly different topographies, but only slight difference in their mechanical abilities.

Animals ; Chondrocytes ; Elastic Modulus ; Fibroblasts ; Goats ; Temporomandibular Joint Disc ; Tissue Engineering

BACKGROUND:Our preliminary studies have shown that basic fibroblast growth factor can induce the differentiation of bone marrow mesenchymal stem cells into disc cells of the temporomandibular joint, and for basic fibroblast growth factor, 10μg/L is superior to 5μg/L in col agen synthesis.
OBJECTIVE:To observe ultrastructural changes of bone marrow mesenchymal stem cells after being induced by different concentrations of basic fibroblast growth factor.
METHODS:We cultured primary sheep bone marrow mesenchymal stem cells and selected passage 3 and 4 cells at good growth state. Bone marrow mesenchymal stem cells were stimulated with 5 and 10μg/L basic fibroblast growth factor and their growth state was observed under inverted phase contrast microscope. Uninduced cells served as controls. The slides with cellcrawling pieces were stained with Safranin O, picrosirius and type I col agen immunohistochemistry at days 7, 14 and 21, respectively. Simultaneously we col ected the cells at day 21 to observe the ultrastructural changes of bone marrow mesenchymal stem cells.
RESULTS AND CONCLUSION:After being induced with different concentrations of basic fibroblast growth factor, bone marrow mesenchymal stem cells were able to differentiate into disc cells of the temporomandibular joint;and after being induced with 10μg/L basic fibroblast growth factor, cells were more like fibroblast-like cells of the temporomandibular joint disc. These findings indicate that bone marrow mesenchymal stem cells have morphological basis for differentiation to the fibroblast-like cells of the temporomandibular joint disc.

Objective:To evaluate the effect of lower limb neuromuscular electrical stimulation (NMES) on mechanical ventilation patients in intensive care unit (ICU).Methods:Databases including the Cochrane Library, PubMed, Web of Science, Embase, SinoMed, CNKI, VIP and Wanfang database were searched from inception to May 2021. Randomized controlled trails (RCT) about the influence of NMES of lower limbs in patients with mechanical ventilation in ICU were collected. Routine rehabilitation measures were implemented in the control group, while the combination of routine rehabilitation and NMES on the lower limbs was implemented in the observation group. The literature screening, data extracting, and bias risk assessment of included studies were conducted independently by two reviewers. RevMan 5.3 software was used to perform Meta-analysis. Funnel plot was used to test publication bias.Results:A total of 8 RCT were eventually enrolled. The literature quality evaluation results showed that 1 study was grade A and 7 studies were grade B, suggesting that the quality of the included literature was relatively high. The Meta-analysis results showed that NMES in the lower extremities could effectively shorten the duration of mechanical ventilation in ICU patients [standardized mean difference ( SMD) = -0.51, 95% confidence interval (95% CI) was -0.72 to -0.31, P < 0.000 01], increase the maximum inspiratory pressure [MIP; mean difference ( MD) = 14.19, 95% CI was 9.30 to 19.09, P < 0.000 01], and improve the functional status of critically ill patients [functional status score for ICU (FSS-ICU); MD = 10.44, 95% CI was 3.12 to 17.77, P = 0.005] with statistically significances. However, there were no significant advantages in increasing the Medical Research Council (MRC) score ( MD = 2.13, 95% CI was -1.38 to 5.63, P = 0.23), reducing ICU mortality [relative risk ( RR) = 0.80, 95% CI was 0.51 to 1.24, P = 0.31], shortening length of ICU stay ( MD = -0.54, 95% CI was -3.67 to 2.59, P = 0.74), and the combined effect was not statistically significant. Funnel plot based on the duration of mechanical ventilation showed that the distribution of included articles was basically symmetrical, and no publication bias was detected. Conclusions:NMES of the lower limbs can not only shorten the ventilation duration effectively, but also improve the MIP and functional status of mechanically ventilated patients in ICU. However, it has no significant effect on the MRC score, ICU mortality and length of ICU stay of patients with mechanical ventilation. In the future, high-quality, large sample size and multi-center RCT are needed to verify the effects of NMES.