| Partial resection of the injured meniscus, its suture or re-fixation are commonlyapplied in cases of the knee meniscus tear[1-4]. Partial meniscectomy is performed morefrequently but results in significant functional deficits, mainly the decrease of muscleforce in knee extensors[3,5]. Proper knee stability and normal distribution of loadingsbetween the joint’s surfaces significantly depend on the muscle force of thigh[3,5,6.Hurley[7]confirmed the existence of early osteoarthritis after partial meniscectomy as aconsequence of the thigh muscles force deficits[8]. The meniscus suturing protects thejoint cartilage which in general prevents the early development ofdegenerativechanges[9].Deficits of the thigh muscle force can be evoked by mechanical injuries of meniscusproprioceptors accompanied to its suturing or simply by their deficits in cases of thepartial meniscectomy[1,10-13]. This was confirmed in studies on patients aftermeniscectomy using the surface electromyography[14]. This method indirectly allows forassessment of the motor units recruitment pattern which is created by activity of spinaland supraspinal centres receiving inputs from the proprioceptive afferents of knee jointincluding the meniscus receptors. This concept of multimodal coordination was alsoconfirmed by Glatthorn[15], who indicated on disturbances in a number and/or frequencyof quadriceps muscle motor unit recruitment in patients following the partial meniscectomy. Akima[1]performed muscle functional magnetic resonance imaging(mfMRI) examinations of muscles which results did not confirm ‘‘clear’’, the muscleorigin reason of the force deficits on operated side. However, the pain of knee aftermeniscus trauma leads to disturbances of its stability and disables the patient to load theextremity prior to surgery. These factors also limit the physical activity of patient andfinally, they can cause the fast muscle atrophy as well as the decrease of force[5]. Therestoration of complete knee function after surgery lasts some weeks, especially inpatients after the meniscus suture or its re-fixation. This limitation of activity increasesthe thigh-muscle force deficits[3,4,16].The instability of knee in patients aftermeniscectomy can be frequently observed[12]. Disturbance in the proper pattern of kneeextensors and flexors co-activation is its most frequently observed reason[17]. Thestability of operated knee significantly influences the stability of whole human body,theglobal movement coordination and, on the recurrent way, the force and endurance ofthigh muscles. Studies analysing the force of knee extensors in relation to the sameparameter of flexors at submaximal loadings (which are typical for many patient’sactivities) confirmed this phenomenon[18-21].The fast restoration of the proper knee function in patients after meniscectomydescribed in studies of Burks[22]and Schimmer[23]is one of reasons to call into question anecessity of introducing the supervised, postoperative rehabilitation[12,24,25]. On the otherhand, other researchers recommended application of early rehabilitation[4,15]. Relativelylittle is known about the functional deficits in patients with the meniscus suture or itsre-fixation and the possible relevance of postoperative, supervised rehabilitation[4].Results of isokinetic muscle force examinations do not always correlate with the scoresof functional assessment (one-leg-rising test, one-leg-hope test) in patients treatedsurgically because of knee injuries[3,26,27].The aim of present study is1-year follow-up functional assessment of knee aftermeniscectomy or meniscus suture with subsequent rehabilitation lasting6months incases of the medial meniscus tear. The analysis of one-leg-hop and one-leg-rising clinicaltests results ascertained the functional efficiency of operated knee. Results of biomechanical and clinical studies were correlated to create the objective method oftreatment evaluation. We assume that the meniscus suture results in higher efficiency ofoperated extremity.Methods: A total of30patients with good KOSS scores constituted two equal groupsafter partial meniscectomy or meniscus suture. Measurements of knee extensors andflexors muscles using One-leg-hop and one-leg-rising tests ascertained the function ofoperated knee. Results of examinations were compared with reference to healthyvolunteers.Through the testing results of the two kinds of treatments,eatablish aobjective method to evaluate results of the patient’s clinical function after surgery.Result: Functional tests were decreased after meniscectomy more than meniscussuture in comparison to healthy volunteers (P≤0.001; P≤0.05). Analysis offunctional tests revealed that patients after meniscectomy showed difference betweenoperated and non-operated knee (P≤0.01) while patients with meniscus suturedif-fered the least to controls (P≤0.05).Conclusion: Results suggest worse functional effects when meniscectomy is appliedwhich implies modification of the rehabilitative methods in a postoperative period. Tissue engineering provides much promises in developing relevant repair orreplacement tissues in clinical for damaged by injury or disease, specially, like cartilageor fibrocartilage. Fibrocartilage is uniquely situated within specific joint spaces of thebody to facilitate the distribution of peak loads. Fibrocartilage has limits in self-repairfollowing disease or injury and treatment option is also lack in clinical currently.Considering that, effects to generate fibrocartilage tissue with function in vitro offernew hope as a long term treatment option to repair or replace injured or degeneratedfibro-cartilaginous tissues.Consisting of the majority of the extracellular matrix (ECM) of afibro-cartilaginous tissue, collagen fibers align with the peak tensile loads in a givenjoint space, situating the tissue to best distribute complex forces. Chondrocytes, as theunique cell living in fibro-cartilage, tend to differentiate to fibroblast phenotype inconventional culture in vitro and have to grow in three-dimension with high density orscaffolds supporting to maintain cartilaginous phenotype. Recently, efforts towardgenerating fibro-cartilaginous tissue most commonly focus on a scaffolding materialformed into the native tissue.Electrospun polymers or their composites, in the form of nano-fbrous structure,have recently gained much interest for bone tissue engineering. One important reason is that electrospun scaffold has specifc characteristics than conventional scaffoldingsystem. For example, it possesses high surface area, high porosity, and wellinterconnected open pore network quite similar to native bone ECM. Considering thematrix anisotropy, electrospinning has been used to aligen either organnic or inorganicfibers as template for directed tissue growth. These structural characteristics arenecessary to enhance the osteogenic cell attachment and to expedite the tissue in-growthboth in vitro and in vivo; therefore, the electrospun scaffolding system is of particularinterest in bone tissue regenerative applications.Objectives: In this work, we provide a simple strategy to mimic the fibrocartilagestructure in vitro and investigate the topography influence the chondrocytes phenotypeand differentiation into fibrocartilage. We established the parallel, perpendicular andangle structure of Poly-(lactic-co-glycolic) acid (PLGA) nano-electrospan for culturechondrocytes respectively to investigate how oriented fiber influence the chondrocytedifferentiation into fibrocartilage.Methods:1. Isolation and Culture of Rat chondrocytes.2. Fabrication of PLGA nano-electrospan: voltage:7.5kV; fluid velocity:8μl/min.3. Immunofluorescence staining and image analysis and quantitative Real-timeRT-PCR to identify type Ⅰ,Ⅱ collagen and aggrecans expressions at protein andRNA levels.Result:1. Characterization of PLGA Electrospan by SEM: the diameter of fibers: about200nm.2. The morphology of chondrocytes in plate and parallel PLGA fibers andperpendicular PLGA fibers. The chondrocytes displayed different morphohlogies ondifferent PLGA fibers. On plat surface, cells grew in free style and were like polygonshape. Chondrocytes grew in aglined lines between parallel PLAG fibers; however,tended to grow on surface of perpendicular PLGA fibers. 3. Type Ⅰ,Ⅱ collagen and aggrecans were analyzed using by immunostaining.Chondrocytes were cultured on plat surface, parallel PLGA fibers and perpendicularPLGA fibers for7days and then analyzed type Ⅰ, Ⅱ collagen and aggrecansexpression in protein level. The collagen Ⅱ and aggrecan increased for both paralleland perpendicular PLGA fibers, and there was significant difference between the platsurface and parallel PLGA fibers, and also between parallel PLGA fibers in aggrecan byimmunostaining.4. The distinct expressions of these matrix synthesis genes were evaluated byquantitative PCR analysis, respectively. Collagen Ⅰ, Ⅱ and aggrecan genes wereup-regulated in parallel PLAG fiber group compare with plat surface and perpendicularPLGA fibers. There were significant different between parallel PLGA fibers and platsurface in all three genes.Conclusion:We provided a simple strategy to mimic the fibrocartilage structure in vitro andinvestigate the topography influence the chondrocytes phenotype and differentiationinto fibrocartilage. We established the parallel and perpendicular structure ofPoly-lactic-co-glycolic acid (PLGA) nano electric spining to culture chondrocytesrespectively to investigate how oriented fiber influence the chondrocyte differentiationinto fibrocartilage. The results show that parallel PLGA nano-fibers can improvechondrocytes differentiate into fibrocartilage and maintain the phenotype. This systemprovided a powerful tool for fibrocartilage tissue engineering and autotransplantation,promising effective therapy for clinical. |
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