Porous nano-hydroxyapatite/collagen scaffold containing drug-loaded ADM-PLGA microspheres for bone cancer treatment.

To develop adriamycin (ADM)-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a porous nano-hydroxyapatite/collagen scaffold (ADM-PLGA-NHAC). To provide novel strategies for future treatment of osteosarcoma, the properties of the scaffold, including its in vitro extended-release properties, the inhibition effects of ADM-PLGA-NHAC on the osteosarcoma MG63 cells, and its bone repair capacity, were investigated in vivo and in vitro. The PLGA copolymer was utilized as a drug carrier to deliver ADM-PLGA nanoparticles (ADM-PLGA-NP). Porous nano-hydroxyapatite and collagen were used to materials to produce the porous nano-hydroxyapatite/collagen scaffold (NHAC), into which the ADM-PLGA-NP was loaded. The performance of the drug-carrying scaffold was assessed using multiple techniques, including scanning electron microscopy and in vitro extended release. The antineoplastic activities of scaffold extracts on the human osteosarcoma MG63 cell line were evaluated in vitro using the cell counting kit-8 (CCK8) method and live-dead cell staining. The bone repair ability of the scaffold was assessed based on the establishment of a femoral condyle defect model in rabbits. ADM-PLGA-NHAC and NHAC were implanted into the rat muscle bag for immune response experiments. A tumor-bearing nude mice model was created, and the TUNEL and HE staining results were observed under optical microscopy to evaluate the antineoplastic activity and toxic side effects of the scaffold. The composite scaffold demonstrated extraordinary extended-release properties, and its extracts also exhibited significant inhibition of the growth of osteosarcoma MG63 cells. In the bone repair experiment, no significant difference was observed between ADM-PLGA-NHAC and NHAC by itself. In the immune response experiments, ADM-PLGA-NHAC exhibited remarkable biocompatibility. The in vivo antitumor experiment revealed that the implantation of ADM-PLGA-NHAC in the tumor resulted in a improved antineoplastic effect and fewer adverse side effects than direct intraperitoneal injection of ADM. The ADM-PLGA-NHAC developed in this study exhibited excellent extended-release drug properties, bone repairing and antineoplastic efficacy, which make it a promising osteoconductivity material with the capability to inhibit osteosarcoma.

[Exercises at different intensities and sequential changes of rat skeletal muscle cell apoptosis].

OBJECTIVE: To study the effect of exercises of different intensities on rat skeletal muscle cell apoptosis. METHODS: Rat models of exhaustive exercise-induced skeletal muscle injury was established using tread mill exercises at different speeds, and the skeletal muscle cell apoptosis was detected using propidium iodide (PI) staining and flow cytometry. RESULT: No obvious gastrocnemius cell apoptosis was observed in rats with normal exercise (P>0.05), but the cell apoptosis index was statistically significant in moderate and exhaustive exercise groups (P<0.05), reaching the highest level in exhaustive exercise group after exercising. The gastrocnemius cell apoptosis index increased obviously on days 1 and 3 of exercise, and stabilized in moderate and exhaustive exercise groups. CONCLUSION: Exercises can evoke cell apoptosis and accelerate apoptotic cell clearance, and the imbalance between the two events during exercises may contribute to skeletal muscle injury.

Effect of occlusive wound dressing supplemented with antiphlogistic and analgesic agents on plasma beta-endorphin in hot and humid environments: a study in pigs.

OBJECTIVE: To study the changes of plasma beta-endorphin (beta-EP) in pigs with traumatic injury after occlusive wound dressing supplemented with antiphlogistic and analgesic agents in hot and humid environments (HHE). METHODS: Traumatic models were established in 10 pigs, 5 of which received antiphlogistic- and analgesic-supplemented occlusive dressings of the wounds (experiment group, EG), while the rest pigs were assigned to control group (CG) to receive routine wound management. The pigs in both groups were then exposed to artificial HHE and at different time points during the exposure, the plasma beta-EP level, respiratory frequency and heart rates were measured respectively. RESULTS: The plasma beta-EP concentration of EG was significantly lower than that of CG (P <0.01) after the injury, but in both groups, the levels before the injury were similar to those measured at hour 8 during HHE exposure and at hour 24 following the injury. The variation range of the respiratory frequency and heart rates during HHE exposure were significantly smaller in EG than CG (P <0.01). CONCLUSION: This supplemented occlusive wound dressing can help restrain the peak of plasma beta-EP level and the variation range of respiratory frequency and heart rates of pigs exposed to HHE.