ObjectiveTo explore the correlation between the degree of bone marrow edema (BME) and the content change of tumor necrosis factor α (TNF-α) and matrix metalloproteinase 3 (MMP-3) and the knee pain symptoms in patients with bone contusion around the knee joint. MethodsThirty patients (30 knees) of bone contusion around the knee joint were chosen as the trial group between October 2009 and April 2012. According to visual analogue scale (VAS), 30 patients were divided into mild group (10 cases), moderate group (10 cases), and severe group (10 cases); according to MRI morphological changes, the patients were divided into type I group (12 cases), type Ⅱ group (11 cases), and type Ⅲ group (7 cases). Ten patients (10 knees) with soft tissue injury of the knee were chosen as control group. No significant difference was found (P>0.05) in gender, age, causes, side, and admission time after injury between 2 groups. The serum contents of MMP-3 and TNF-α were detected and statistically analysed between different degrees of pain groups and between different degrees of BME groups. Correlation was analysed between BME and inflammatory factor changes and VAS score. ResultsThe MMP-3 and TNF-α contents in trial group[(29.580±6.870) μg/L and (23.750±7.096) ng/L] were significantly higher than those in control group[(8.219±1.355) μg/L and (6.485±1.168) ng/L](t=9.686, P=0.000; t=7.596, P=0.000). The MMP-3 and TNF-α contents in patients with different degrees of pain and BME were significantly higher than those in patients of control group (P<0.05), and significant difference was found between patients with different degrees of pain (P<0.05), but no significant difference between patients with different degrees of BME (P>0.05). Multiple linear regression analysis showed that TNF-α content was significantly correlated with VAS score (P=0.000). ConclusionKnee pain symptoms are not related to the degree of BME in patients with bone contusion around the knee joint. Inflammatory factor TNF-α content is the main influence factor of knee joint pain symptoms.
Drug-eluting stents used to inhibit granulation tissue hyperplasia after tracheal stent implantation rely on passive drug release mechanisms, which make precise controlled release difficult and may lead to either insufficient efficacy or toxic side effects. This study aims to design a piezoelectric effect-based adaptive drug-releasing film for tracheal stents, capable of self-regulating the release of anti-inflammatory drugs according to the mechanical changes in the pathological environment within the patient’s airway. First, a polyvinylidene fluoride piezoelectric film was prepared on a metal stent surface via electrospinning. Curcumin-loaded poly(3,4-ethylenedioxythiophene) conductive nanoparticles were dispersed in a polyvinyl alcohol hydrogel and adhered to the upper and lower edges of the stent (prone to hyperplasia areas). Experiments showed uniform nanoparticle morphology with a curcumin loading rate of (12.6 ± 1.80)%. Electrochemical tests indicated that the curcumin release rate was highest (approximately 90%) at a reduction potential of –1.5 V, and “on/off” controlled release could be achieved through intermittent electrical stimulation. When periodic pressure was applied to the film, its output voltage increased with loading speed (up to –8 V). Furthermore, the curcumin release rate was positively correlated with the pressure speed, reaching a cumulative release of about 15% within 48 h at a loading speed of 2.5 m/min. The drug-loaded piezoelectric film-covered stent developed in this study successfully achieves mechanically controlled release of the anti-inflammatory drug curcumin under intermittent cyclic pressure, providing an effective strategy for developing intelligent tracheal stents with adaptive and controllable drug release.