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BACKGROUND:Intra-articular injection played an important role in the treatment of osteoarthritis and has more options with the development of novel drug delivery systems.The cartilage targeting function is aimed at the adhesion or retention of drugs in the cartilage layer to form a drug bank to achieve slow release and precise drug delivery. OBJECTIVE:To review various cartilage targeting biomaterials and their characteristics in the treatment of osteoarthritis by articular injection. METHODS:Using the term"osteoarthritis,drug carrier,drug delivery,cartilage targeting,penetrate"as key words,relevant articles were searched in CNKI,WanFang and PubMed databases.According to inclusion and exclusion criteria,67 articles were finally selected for further review. RESULTS AND CONCLUSION:The research on cartilage-targeting biomaterials is mainly divided into two directions.One is the combination of electrostatic interaction,such as the combination of positively charged biomaterials and negatively charged polysaccharides in cartilage.This kind of scheme is operable and easy to modify,but limited by the shortcomings of electrostatic interaction itself,it performs badly in advanced osteoarthritis.Another one is the specific binding of various components in cartilage which is strong and reliable,and related biomaterials have excellent performance in advanced osteoarthritis,which is an important direction for future cartilage-targeted therapy.
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Objective:To explore the effect of different HER2 expression levels and gene amplification on the efficacy of immunotherapy in metastatic urothelial carcinoma (UC).Methods:The clinical data of 77 patients with metastatic UC who received immunotherapy from June 2017 to April 2021 after failure to the previous chemotherapy were analyzed retrospectively, including 49 males and 28 females with the median age of 62 years. The primary tumors located in bladder in 28 cases (36.4%), renal pelvis in 25 cases (32.5%) and ureter in 24 cases (31.2%). The common metastatic sites included: lymph nodes (n = 45, 58.4%), lung (n = 40, 51.9%), bone (n = 20, 26.0%) and liver (n = 16, 20.8%). 27 patients with bladder UC received surgery on the primary tumors including radical cystectomy (n = 18), partial cystectomy (n = 4) and transurethral resection (n = 5). 43 patients with renal pelvis or ureteral UC received surgery on the primary tumors including radical nephroureterectomy (n = 38), local resection (n = 3) and palliative resection (n = 2). Postoperative intravesical chemotherapy was performed in 15 cases, adjuvant radiotherapy was performed in 6 cases. 3 patients who emerged postoperative bladder recurrence received local radiotherapy. 7 patients received radiotherapy and 1 case received microwave ablation to their metastatic sites. All patients had received first-line chemotherapy and 30 patients (40.0%) had received at least second-line treatment including 70 cases (90.9%) with platinum containing chemotherapy. All 77 patients received anti-PD-1 treatment. 38 patients received sequential regimen after failed to the anti-PD-1 therapy, including antibody-drug conjugate (n = 17), chemotherapy (n = 18) and chemotherapy combined with anti-angiogenesis drugs (n = 12). Immunohistochemical (IHC) staining was used to detect the expression level of HER2 protein in the tumor tissues (74 cases from primary tumors and 3 cases from metastatic tumors) obtained from the initial diagnosis. For patients with HER2 IHC (+ + ), the copy number (CN) of HER2 gene was detected by next-generation sequencing (NGS). HER2 copy number amplification [CN (+ )] was defined as CN ≥ 4, and HER2 copy number non-amplification [CN(-)] was defined as CN < 4. HER2 IHC (0) was defined as HER2 negative, IHC (+ ) or IHC (+ + ) / CN (-)was defined as HER2 low expression, while IHC (+ + ) / CN(+ ) and IHC (+ + + ) were defined as HER2 high expression. Chi-square test or Fisher exact test were used to evaluate the correlation between HER2 expression and objective response rate (ORR) after anti-PD-1 treatment. Kaplan-Meier method and log-rank test were used to compare the differences of median progression free survival (PFS) and overall survival (OS) under different HER2 expression status.Results:All the 77 patients received a median of 11 (range: 2 - 45) doses of anti-PD-1 treatment with a median duration of treatment of 6.4 (range: 1.5 - 47.8) months and the ORR was 33.8% (26/77). The median follow-up time was 30.9 months. The overall median PFS time was 5.8 (95% CI: 3.0 - 8.6) months and the median OS time was 23.6 (95% CI: 8.5 - 38.7) months. HER2 IHC tests were performed in 77 patients. HER2 IHC levels of (0), (+ ), (+ + ) and (+ + + ) were found in 33 (42.9%), 19 (24.7%), 20 (26.0%) and 5 (6.5%) patients, respectively. HER2 copy number was detected in 20 patients with IHC (+ + ), while 1 CN(+ ) and 19 CN(-) were found. The ORR of HER2 negative, low expression and high expression patients were 42.4% (14/33) vs. 31.6% (12/38) vs. 0 (0/6) ( P = 0.08), respectively. The median PFS of the three groups were 11.0 months, 3.7 months and 1.8 months, respectively, with significant differences in overall and pairwise comparison( P=0.001). The median OS of patients with HER2 negative and low expression after anti-PD-1 treatment were 23.6 months and 22.7 months, respectively, while the median OS of patients with HER2 high expression had not been reached, with no significant difference in the overall comparison ( P=0.623). Conclusions:For patients with metastatic UC received anti-PD-1 treatment, the PFS of patients with high HER2 expression was significantly worse than that of patients with low or negative HER2 expression. HER2 expression may have potential value in predicting the efficacy of immunotherapy for metastatic UC who failed the previous chemotherapy, which needs further research.
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Objective:To evaluate the patch technique in repairing huge rotator cuff tear.Methods:A retrospective analysis was conducted of the 9 patients with huge rotator cuff tear who had been repaired with patch technique at Department of Orthopaedics, Guangzhou Red Cross Hospital from March 2017 to March 2019. They were 5 males and 4 females, aged from 53 to 79 years (average, 61 years). Shoulder movement limitation was found in 7 cases, night pain in 5, and positive Neer impingement sign and Hawkins sign in 7. By the Bigliani acromion classification, there were 6 cases of type Ⅱ and 3 cases of type Ⅲ. Comparisons were made between preoperation, 12 and 15 months postoperation in terms of scores of the visual analogue scale(VAS) and the University of California Los Angeles (UCLA) scoring system, and shoulder range of motion.Results:All the 9 patients were followed up for 15 to 24 months(mean, 18 months). Arthroscopy found tears in more than 2 tendons in all of them. The VAS scores were 6.7±1.6, 4.5±1.3 and 3.7±1.1 at preoperation, 12 and 15 months postoperation; the UCLA scores were 7.9±1.2, 21.5±4.1 and 23.9±4.3 at preoperation, 12 and 15 months postoperation. There were statistically significant differences in both the VAS and UCLA scores between preoperation, 12 and 15 months postoperation ( P<0.05). There were also statistically significant differences between the 3 groups in the shoulder range of motion at preoperation, 12 and 15 months ( P<0.05). MRI reexamination at 12 months postoperation showed minor re-tear < 3 cm in 2 patients. Conclusion:The patch technique is a reasonable and effective treatment to repair huge rotator cuff tears, resulting in good mid-term outcomes.
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Objective:To explore the prognostic value of PD-L1 expression level in patients with metastatic renal cell carcinoma (mRCC).Methods:The clinicopathological and survival data of patients with mRCC in our hospital from Jan 2014 to Apr 2016 were retrospectively analyzed including 46 males and 15 females. The median age of these patients was 56 years(range: 29-75 years), with 41 patients ≤60 years and 20 patients >60 years. The baseline data before the systemic therapy showed 36 patients(59.0%)had 1 metastatic organ and 25 patients (41.0%) had equal or more than 2 organs to be metastasized. Among them, 17 patients(27.9%)had lung metastasis and 54 patients(88.5%)had liver metastasis. Abnormal baseline LDH occurred in 4 patients and 52 patients had normal LDH. Favorite and intermediate risk patients categorized by MSKCC risk stratification accounted for 59.6%(34 patients)and 40.4%(23 patients), respectively. Six patients(9.8%)experienced distant metastasis at initial diagnosis, with 4 of them undergoing primary site resection, and the other 55 patients undergoing radical nephrectomy. PD-L1 expression was detected by the immunohistochemical staining method. PD-L1 staining rate ≥1% detected on the tumor cell membrane was defined as positive expression. The correlation between PD-L1 expression and clinicopathological characteristics were compared. Kaplan-Meier method and log-rank test were used to compare the differences about DFS and OS under different factors. Cox proportional hazards regression model is used for multivariable analysis of survival data.Results:The detailed pathological types of the 61 patients with renal cell carcinoma were classified as 53 clear cell carcinomas, 3 papillary carcinomas, 1 collecting duct carcinoma, 2 translocation renal cell carcinomas and 2 being unclassified. There were 4, 20, 19 and 9 patients categorized as WHO/ISUP nuclear grade 1, 2, 3 and 4, and 26, 12, 20 and 2 patients were categorized as T 1, T 2, T 3 and T 4 stage, respectively. Five patients had regional lymph node metastasis(N+), and the other 56 patients had no regional lymph node metastasis(N-). The numbers of patients categorized as stage Ⅰ, Ⅱ, Ⅲ and Ⅳ diseases according to TNM staging system were 20, 11, 21 and 8, respectively. The total PD-L1 positive rate was 24.6%(15/61). The corresponding PD-L1 expression rate of patients with WHO/ISUP nuclear grade 1-4 were 0(0 patient), 5.0%(1 patient), 31.6%(6 patients)and 44.4%(4 patients), respectively; With the increasing WHO/ISUP nuclear grade, the positive rate of PD-L1 gradually escalated with a linear correlation ( P=0.006). The PD-L1 expression of the normal and abnormal LDH group were 19.2%(10 patients)and 75.0%(3 patients), respectively, with significant difference( P=0.035). Univariate analysis of disease-free survival time(DFS)showed that the prognostic factors include PD-L1( P=0.045), age group( P=0.014), WHO/ISUP nuclear grade( P<0.001), T stage( P=0.015), N stage( P=0.026)and TNM stage( P=0.005). However multivariate analysis only suggested WHO/ISUP nuclear grade as the independent prognostic factors for DFS( HR=1.8, 95% CI 1.1-2.9, P=0.018). Either in univariate or multivariate analysis, PD-L1 was not a prognostic factor for overall survival (OS)of mRCC patients(univariate analysis: P=0.154; multivariate analysis: P=0.902). The independent prognostic factors of OS include WHO/ISUP nuclear grade( HR=3.0, 95% CI 1.1-8.0, P=0.033)and MSKCC risk stratification( HR=5.9, 95% CI 1.2-29.7, P=0.03). Conclusions:This study showed that the higher the WHO/ISUP nuclear grade of patients with mRCC, the higher the positive rate of PD-L1. PD-L1 expression was not the independent prognostic factor for DFS or OS of mRCC.
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Objective: To investigate the clinical characteristics, treatment methods, and prognosis of metastatic papillary renal cell car-cinoma (pRCC). Methods: The clinical data of metastatic pRCC patients treated at the Department of Kidney Cancer and Melanoma, Pe-king University Cancer Hospital, were retrospectively analyzed. The prognosis of these patients was stratified through international metastatic renal cell carcinoma database consortium (IMDC) model. Survival and influencing factors were further analyzed using the Kaplan-Meier method and Cox proportional risk regression model. Results: From January 2003 to March 2018, 93 patients (median age, 50.0 years) were diagnosed with metastatic pRCC: 89 (95.7%) typeⅡcases and 4 (4.3%) typeⅠcases. The median follow-up dura-tion was 23.1 months, with 90, 44, and 14 patients having received first-line, second-line, and third-line treatments, respectively. The median overall survival (OS) of the 93 patients was (31.5±5.9) months [95% confidence interval (CI): 19.9-43.1], while the median OS of patients with low-, intermediate-, and high-risk (classified as per the International Metastatic Renal Cell Carcinoma Database Con-sortium [IMDC]) were (100.0±32.8), (38.3±8.2), and (16.4±1.2) months, respectively (high-risk vs. low/intermediate-risk, P<0.001; low-risk vs. intermediate-risk, P=0.015). The median progression free survival (PFS) with first-line treatment was (6.6±0.5) months. And the median PFS of the corresponding three groups stratified by IMDC score were (17.5±5.7), (7.1±2.3), and (5.2±1.5) months, respectively (high-risk vs . low-risk, P=0.002; high-risk vs . intermediate-risk, P=0.01). Conclusions: Metastatic pRCC is noted to have unique biologi-cal characteristics. The IMDC model can be used to predict the efficacy of first-line treatment using tyrosine kinase inhibitors as well as the prognosis of metastatic papillary renal cell carcinoma in such patients.
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Objective:To study the positive expression rate of M2 subtype of macrophage cell surface molecules and the inflammatory factors of PPS in IL-4-induced M2 macrophage.Methods:The experiment was divided into 5 groups:blank control group, Model group,PPS groups(50 μg/ml,100 μg/ml and 200 μg/ml).The expression of CD206 and CD23 was used as bio-maker to confirm IL-4 induced macrophages by treating RAW264.7 with 20ng/ml of IL-4.IL-4 induced RAW264.7 cells were treated with PPS of 50μg/ml,100μg/ml and 200μg/ml for 24 h.Then the expression of CD206,CD16/32 and CD40 were analyzed by flow cytometry, and the mRNA expression of IL-1β,TNF-α,IL-10 and iNOS were detect by qRT-PCR.Results: After treated with IL-4,the positive rate of CD206 of RAW264.7 were high.After treated with PPS ,the rate of CD16/32 and CD40 in IL-4 induced RAW264.7 cells were high ,the expression of CD206 decreased,and the mRNA level of IL-1βand TNF-αincreased.Conclusion:RAW264.7 cells can be polarlized to M2 subtype macrophage by using 20 ng/ml IL-4.PPS enhances the mRNA of IL-1β,TNF-αand the expression of CD40, CD16/32 in IL-4-induced RAW264.7 cells .These results indicate that PPS can induce the M2 subtype to become M1 macrophages, can improve immune function of macrophages.
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<p><b>OBJECTIVE</b>To investigate the efficacy and safety of sunitinib as first-line therapy for metastatic renal cell carcinoma (mRCC) on a 2 weeks on/1 week off intermittent dosing schedule.</p><p><b>METHODS</b>A total of 11 mRCC patients were enrolled to receive sunitinib 50 mg/day in 2 weeks on/1 week off schedule per 6 weeks till disease progression or intolerable toxicity occurred. The primary end point was progression free survival (PFS), the secondary end points were overall survival (OS), incidence of adverse effects and objective response.</p><p><b>RESULTS</b>The objective response rate in the 11 cases was 45.5% and disease control rate 72.7% (partial response n = 5, stable disease n = 3). Till the last follow up on Dec 2013, the median PFS was 17.0 months (95% CI 7.3 to 26.7 months), and median OS 26.0 months (95% CI 2.2 to 49.8 months). The common adverse events included leucopenia, thrombocytopenia, diarrhea, mucositis and hand-foot skin reaction. Dose reduction to 37.5 mg was seen only in 2 patients without discontinuation.</p><p><b>CONCLUSIONS</b>Sunitinib on an intermittent dosing schedule 2 weeks on /1 week off as first-line therapy for mRCC patients shows a good efficacy and tolerance, with less grade 3-4 drug-related toxicities and a tendency of prolonged PFS in mRCC patients.</p>
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Humanos , Antineoplásicos , Farmacología , Usos Terapéuticos , Carcinoma de Células Renales , Quimioterapia , Supervivencia sin Enfermedad , Esquema de Medicación , Indoles , Farmacología , Usos Terapéuticos , Neoplasias Renales , Quimioterapia , Proyectos Piloto , Pirroles , Farmacología , Usos Terapéuticos , Resultado del TratamientoRESUMEN
To investigate the cell-killing effect and its possible mechanism of rClone30-hDR5 in combination with TRAIL on human hepatic carcinoma (HCC) cell line, first of all, recombinant plasmid pee12.4-hDR5 was introduced into HepG2 cells by liposome transfection. After five rounds of screening by flow cytometry, HepG2 cells expressing high levels of DR5 on cell surface were isolated. The cytotoxicity of TRAIL to selected cells was higher than that of TRAIL to HepG2 cells by MTT method (P < 0.01). The result suggested that the cloned hDR5 gene had biological activity. MTT assay showed that, rClone30- hDR5 in combination with TRAIL more efficiently inhibited the tumor growth of HepG2 cells compared to rClone30-hDR5 or TRAIL in vitro. The results of Annexin V-FITC/PI staining and Quantitative Real-time PCR indicated that rClone30-hDR5 in combination with TRAIL significantly increased the mRNA levels of caspase 3 and caspase 8, and induced the apoptosis of tumor cells. HepG2 cells were infected with rClone30-hDR5 or rClone30 at MOI of 1. The expression of hDR5 on tumor surface increased significantly by rClone30-hDR5 compared to that by rClone30, which contributed to the sensitivity to TRAIL. In conclusion, rClone30-hDR5 in combination with TRAIL has potential application value in cancer treatment.
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Objective To evaluate the efficacy and safety of sunitinib as first line treatment in patients with metastatic renal cell carcinoma (RCC). Methods This study included 46 Chinese patients who were diagnosed with metastatic RCC after radical nephrectomy. The patients received oral sunitinib (50 mg once daily on a 4 weeks on, 2 weeks off) on a 6 weeks cycle dose schedule until disease progression or intolerable toxicities occurred. Results The overall objective response rate was 32.6% (95% confidence interval [CI, 19.1% to 46. 1%]), and the disease control rate was 86.9%,with complete response (CR) 0 (0%), partial responses (PRs) 15 (32.6%), stable disease (SD) 25(54.3 %), and progression disease (PD) 6 ( 13. 1%). The median progression-free survival was 11 months, and the 1-year survival rate was 65.2%, while the median overall survival (mOS) has not been reached. The main adverse events included fatigue 33 (71.7%), skin discoloration 29 (63.0 %),anorexia 28 (60.9%), hand-foot syndrome 26 (56.5%), oral mucositis 25 (54.3%), hypertension 19 (41.3%), facial edema 18 (39.1%), diarrhea 17 (37.0%), hemorrhage 17 (37.0%), nausea 15 (32.6%), and hematological toxicity: leukopenia 32 (69.6%), neutropenia 30 (65.2%), thrombocytopenia 28 (60.9%), anemia 21 (45.7%). Most of grade 3/4 serious adverse events were thrombocytopenia in 15 (32. 6%) patients. Conclusions Sunitinib has a prominent effect in metastatic renal cell cancer in a Chinese population with mostly mild to moderate adverse reactions. More attention should be paid to grade 3/4 adverse reaction of thrombocytopenia.
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[Objective]To study the transfection and expression of green fluorescent protein gene in rat chondrocytes by constructing a combination lentiviral vector containing green fluorescent protein gene.[Method]293T cells were co-transfected with the vector plasmids pLentiLox 3.7,the packaging plasmids pRSV-REV,pMDL g/p RRE and the envelope plasmids VSV-G to produce lentiviral vector particles.Rat chondrocytes were isolated,cultured and infected by the lentiviral vector particles.The expression of reporter gene GFP was observed under fluorescent microscope.[Result]At 96 hours after transfection,a strong expression of GFP could be found in 293T cells.The viral titer was 3.0?103ifu/?l.GFP expression was observed in about 80% of the rat chondrocytes.[Conclusion]A combination lentiviral vector containing green fluorescent protein gene was successfully established and it could infect rat chondrocytes efficiently,which will provide a basis for gene modification of chondrocytes through RNA interference.
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BACKGROUND: The repair of articular cartilage defect is always a problem that is dedicatedly solved by doctors of orthopaedics. Autologous perichondrium, periosteum or allografting of cartilage have been used previously; however, the source of the donor is limited, the fixation is difficult as well as the occurrence of endochondrial ossification and delamination between the inferior cartilage and reparative cartilage, etc. Type Ⅱ collagen, the main component of cartilage matrix, has certain effects in the repair of articular cartilage defect.OBJECTIVE: To investigate the effects of type Ⅱ collagen sponge filling on the repair of articular cartilage defect.DESIGN: A randomized controlled trial.SETTING and MATERIALS: The study was conducted in the Guangzhou Institute of Traumatic Surgery. Materials were 24 adult male purebred New Zealand Rabbits(48 knees), ordinary grade, with a body mass of (2.29 ±0. 25) kg. Animals were fed with standard feeding in separate cage.INTERVENTIONS: A full-thickness defect in articular cartilage was made on the femoral trochlear surface by a drill of 5 mm in diameter and 3 mm in depth. Rabbits were allocated into filling group(type Ⅱ collagen sponge was grafted into left keen joint defect) and control group(right knee joint defect site was set as control) according to random number table.MAIN OUTCOME MEASURES: Gross morphological and histological observation of the defect repair in each dual week within 12 weeks after operation.RESULTS: During 10 - 12 weeks, in cuntrol group: The defect area was repaired by white and soft tissue that had no resistance to press. The repaired tissue was still lower than the surrounding articular surface with clear boundary. By histological observation, it was found that the defect was repaired by the mechanism similar to inflammatory reaction and the defect is ultimately filled by the hyperplasia of hyaline degenerative fibrous tissues. In filling group: the defect was repaired by semi-transparent, smooth, textured tissues with polish that had resistance to press as well as elasticity. The repaired tissue was almost similar to the shape of the surrounding cartilage,difficult to be distinguished. After histological observation, it was found that there was no inflammatory reaction, but active hyperplasia of inner bonetissue and cartilage tissues; a lot of osteoid tissues and trabeculation were found. Newlborn cartilage was fused with surrounding cartilage tissue and connected with surrounding tissues. Type Ⅱ collagen had significantly promoting effects in the repair of articular cartilage defect, and the repaired cartilage was close to normal cartilage. CONCLUSION: The self-made high purity type Ⅱ collagen sponge has favorable promoting effects in the repair of articular cartilage defect with good histocompatibility but without obvious toxic side effect.
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BACKGROUND: Intra-articular injection of hormone has been applied in the treatment of arthritis because it can alleviate arthralgia rapidly, which is accompanied commonly by progressive cartilage impairments. It is not clear if supplement of growth factor like insulin effect can play a protective role in articular chondrocytes.OBJECTIVE: To observe the effects of insulin or hydrocortisone alone and the combination on the proliferation of chondrocytes.DESIGN: Grouping comparative study, the effect of one medicine was analyzed by using one-factor analysis of variance, while the combined effect was analyzed with multi-factor analysis of variance.SETTING: Guangdong Institute of Trauma Sugery.MATERIALS: Articular cartilage from the knees of New Zealand white rabbits of 4 - 6 weeks old.METHODS: This study was carried out at Guangzhou Traumatic Research Institute from Feberary 2000 to May 2001. Chondrocytes were isolated from the knee joints of New Zealand white rabbits, digested with hyaluronidase,pancreatin and type Ⅱ collagenase and exposed to insulin, hydrocortisone or the combination of insulin and hydrocortisone of different dosage. They were divided into four groups:Control group ( without adding insulin and hydrocortisone), insulin group (0. 035,0. 35,3.5,35 mg/L subgroups), hydrocortisone group(1,5,10,50,100 mg/L subgroups) and insulin(0. 35 mg/L) combined with hydrocortisone(50 mg/L) group. Their influence on chondrocytes proliferation was observed with methyl thiazolyl tetrazolium(MTT) method.sulin.at the concentration of 0. 035 mg/L( P ＜ 0.01 ), reaching the maximum at could inhibit the proliferation of chondrocytes ( P ＜ 0.05 ), which became significant with increasing concentration and no viable chondrocytes could be exposed to 0 . 35 mg/L insulin combined with 50 mg/L hydrocortisone, the promoting effect of insulin was inhibited due to negative cooperation.CONCLUSION: Insulin at low concentration could enhance the proliferation of chondrocytes, but hydrocortisone displayed inhibiting effect on the growth of chondrocytes. The function of insulin was antagonized when combined with hydrocortisone.
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<p><b>OBJECTIVE</b>To culture fibroblast cells from the knee ligaments and to study the biological characteristics of these cells.</p><p><b>METHODS</b>Cells of the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) from New Zealand white rabbit were cultured in vitro. Cellular growth and expression of the collagen were analyzed. Moreover, an in vitro wound closure model was established and the healing of the ACL and the MCL cells was compared.</p><p><b>RESULTS</b>Maximal growth for all these cells were obtained with Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, but RPMI 1640 and Ham's F12 media were not suitable to maintain these cells. Morphology of both ACL and MCL cells from New Zealand white rabbit was alike in vitro, but the MCL cells grew faster than the ACL cells. Both cell types produced similar amount of collagen in culture, but the ratio of collage type I to type III produced by ACL cells was higher than that produced by MCL cells. Wound closure assay showed that at 36 hours after injury, cell-free zones created in the ACL cultures were occupied partially by the ACL cells; in contrast, the wounded zone in the MCL cultures was almost completely covered by the cells.</p><p><b>CONCLUSIONS</b>Although the ACL cells and the MCL cells from New Zealand white rabbit show similar appearance in morphology in culture, the cellular growth and the biochemical synthesis of collagen as well as the healing in vitro were significantly different. These differences in intrinsic properties of the two types of cells in vitro might contribute to the differential healing potentials of these ligaments in vivo.</p>