基质金属蛋白酶及其抑制物在高碳酸血症大鼠肺组织中的表达

目的:观察单纯高碳酸血症大鼠模型的血清中性粒细胞蛋白酶(NE)、基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)和金属蛋白酶组织抑制剂(TIMP-1)的活性,以及它们在肺组织中的表达,探讨高浓度二氧化碳(CO2)引起肺组织损伤的机制。方法:雄性Wistar大鼠40只,随机分为正常对照组(A组,20只大鼠)、高碳酸血症组(B组,20只大鼠)。B组大鼠置于高CO2舱中,并向舱中匀速输入6%CO2混合气体(6%CO2,21%O2,73%N2),每天7h,连续4周,完成大鼠高碳酸血症模型的复制。用ELISA法测定大鼠血清MMP-2、MMP-9、TIMP-1活性及NE活性;弹力纤维染色标本进行弹性纤维相对含量的测定;免疫组化方法检测肺组织中MMP-2、MMP-9及TIMP-1的表达及光镜下进行病理学观察。结果:B组大鼠血清MMP-2、MMP-9、TIMP-1活性与A组之间并无显著差异(P0.05);B组大鼠NE活性明显高于A组(P0.01);光镜下可见B组大鼠肺泡壁明显增厚,肺微血管内皮细胞损伤,小静脉扩张,血栓形成;小动脉内皮细胞肿胀,管腔狭窄,血管周围有袖套状水肿区;并可见小灶性肺实质出血;A组大鼠弹力纤维呈束状,连续无断裂;B组大鼠可见弹力纤维断裂降解,且肺组织中弹力纤维的含量较A组明显减少(P0.01);B组大鼠肺组织中MMP-2的表达明显低于A组(P0.01);而肺组织中MMP-9及TIMP-1的表达B组大鼠明显高于A组(P0.01)。结论:通过复制出常压、常氧、单纯高碳酸血症动物模型;单纯的PaCO2增高对肺动脉压无明显影响;高浓度CO2可以使NE活性明显增高,使弹性蛋白的降解增多,肺组织弹性纤维断裂降解,数量减少;在单纯高碳酸血症动物模型中,MMP-2的表达明显降低,MMP-9及TIMP-1在肺组织中表达明显增高,导致肺损伤。     

基质金属蛋白酶及其组织抑制因子在人前列腺组织及各种类型前列腺细胞中的表达

目的：研究基质金属蛋白酶（MMPs）及其组织抑制因子（TIMPs）在人前列腺组织及各种类型细胞中的表达。方法： 用半定量RT－PCR的方法，对癌变和非癌变部分的前列腺组织、原代培养的平滑肌细胞、成纤维细胞、上皮细胞以及4种前列腺上皮细胞系（BPH－1、LNCaP、DU－145和PC－3）中MMP2、MMP7和MMP9、膜型基质金属蛋白酶1和3（MT1－MMP和MT3－MMP）及其组织抑制因子1和2（TIMP－1和TIMP－2）的mRNA 水平进行了测定。结果：MMP-2主要在前列腺基质细胞中表达；MMP-7和MMP-9则在前列腺上皮细胞中有较高的表达；MT1-MMP、MT3-MMP、TIMP-1和TIMP-2在前列腺基质细胞和上皮细胞中均有表达，但MT1-MMP和MT3-MMP在成纤维细胞中的表达量较高；另外，各种基质金属蛋白酶及其组织抑制因子在各种前列腺细胞系中也存在差异表达。结论： MMPs和TIMPs在前列腺组织及其各种类型细胞中的差异表达提示：它们可能在前列腺癌的转移中起着不同的作用。     

妊娠期基质金属蛋白酶的调控及其与胎盘发育的关系

 基质金属蛋白酶（matrix metalloproteinases，MMP） 是一类蛋白水解酶，可以降解多糖以外的细胞外基质（extracellular matrix，ECM）的多种成分，在组织塑型过程中影响着 ECM 的代谢、新生血管的形成等过程。在胎盘发育过程中滋养细胞的入侵包括细胞基质的溶解和重塑，其生物学行为与有着高度侵蚀性的肿瘤细胞相似，又被称为假恶性细胞。MMP 是降解蜕膜基质的重要酶类，可以降解几乎所有基质成分，在胚胎植入、胎盘形成及子宫螺旋动脉重构中发挥重要作用。MMP 在滋养层不同类型细胞中的分布存在特异性，在不同时期胎盘中的表达和活性也有所不同，妊娠期 MMP 的调控直接影响胎盘的发育，对维持正常妊娠至关重要。本文主要就妊娠期 MMP 的调控及其与胎盘发育关系的研究进展做一综述。 1 MMP 分类及特点 MMP 是一族 Zn2+ 依赖性内肽酶，至今已经发现至少26 种^[1]。根据蛋白结构的相似性以及降解底物不同，MMP 通常被分为 5 个亚类：①间质胶原酶（MMP-1、MMP-8和MMP-13），来源于纤维细胞、癌细胞及滋养细胞，降解底物为 Ⅰ~ Ⅲ 型胶原等。②明胶酶（MMP-2、MMP-9），部分来源于滋养细胞、纤维细胞及巨噬细胞等，酶解底物为明胶变性胶原和 Ⅳ 型胶原等。③基质溶解素（MMP-3、MMP-7、MMP-10、MMP-11、MMP-12 和 MMP-26），来源于成纤维细胞和癌细胞等，降解底物为 Ⅲ ~ Ⅴ 型胶原、明胶、蛋白聚糖及糖蛋白等。④膜型金属蛋白酶（MT-MMP），包括 MT1-MMP、MT2-MMP、MT3-MMP、MT4-MMP、MT5-MMP 及 MT6-MMP，存在于肿瘤细胞表面及滋养细胞表面，降解底物为 Ⅳ 型胶原、明胶等。有证据表明，MT1-MMP、MT2-MMP、MT3-MMP 和 MT5-MMP 参与激活 MMP-2^[2]。⑤其他基质金属蛋白酶，包括 MMP-19、MMP-20、MMP-23 等，可以降解抗胰蛋白酶及釉质。     

同型半胱氨酸对血管平滑肌细胞分泌金属蛋白酶组织抑制剂-1的影响

目的：观察同型半胱氨酸(Hcy)对血管平滑肌细胞(VSMCs)分泌金属蛋白酶组织抑制剂-1(TIMP-1)的影响。方法：体外培养大鼠VSMCs，加入不同浓度的Hcy培养48 h，应用Western blot技术观察Hcy对VSMCs分泌基质金属蛋白酶-1(MMP-1)和TIMP-1的影响，并通过半定量RT-PCR方法观察TIMP-1 mRNA表达的变化。结果：Hcy减少VSMCs MMP-1的分泌，上调TIMP-1 mRNA的表达，使TIMP-1分泌增加，并呈剂量依赖效应。结论：提示Hcy减少胶原降解可能是致动脉粥样硬化的发病机制之一。     

缺氧对肺动脉成纤维细胞MMP-2、TIMP-1表达的影响

目的：探讨缺氧对肺动脉成纤维细胞（Fpa）分泌基质金属蛋白酶（MMPs）、金属蛋白酶组织抑制剂（TIMPs）的影响。 方法： 采用酶谱法测定Fpa培养基中MMP-2的酶活性，免疫印迹法检测培养基中MMP-2、TIMP-1 的蛋白水平，免疫组化法测定细胞原位的蛋白表达， RT-PCR法检测mRNA表达量。 结果： 缺氧后Fpa分泌的MMP-2酶活性、细胞内外蛋白表达量、mRNA表达量均下降；而TIMP-1的表达则呈相反变化。 结论： 缺氧可使肺动脉成纤维细胞MMP-2/TIMP-1的表达失衡，可能参与缺氧性肺血管重建。     

N-乙酰基-丝氨酰-天冬氨酰-赖氨酰-脯氨酸对基质金属蛋白酶-1和基质金属蛋白酶组织抑制因子-1的调节在大鼠矽肺纤维化形成中的作用

目的:探讨N-乙酰基-丝氨酰-天冬氨酰-赖氨酰-脯氨酸(AcSDKP)对大鼠肺内基质金属蛋白酶-1(MMP-1)和基质金属蛋白酶组织抑制因子-1(TIMP-1)表达的调节在拮抗矽肺纤维化形成过程中的作用.方法:气管内灌注染尘法制作大鼠矽肺模型,将含有AcSDKP的微量药物释放泵埋入腹腔.实验动物随机分为矽肺模型对照4周组,矽肺模型对照8周组,矽肺模型4周组,矽肺模型8周组,抗纤维化治疗组及预防治疗组.H-E染色和免疫组织化学显色对矽肺纤维化病变和MMP-1和TIMP-1在肺组织内的表达进行形态学观察;免疫印迹法对肺内MMP-1和TIMP-1酶蛋白表达进行检测.结果:与模型对照组比较,矽肺大鼠肺内MMP-1和TIMP-1表达增强.与矽肺模型组比较,AcSDKP能够上调矽肺大鼠肺内MMP-1的表达,下调TIMP-1的表达,使MMP-1/TIMP-1的比值升高.结论:AcSDKP能够促进矽肺大鼠肺内MMP-1的表达,抑制TIMP-1的表达,从而加速了细胞外基质(包括胶原)的降解,这可能与AcSDKP抗矽肺纤维化的作用有关.     

机械牵张对兔角膜成纤维细胞细胞外基质基因表达的影响

目的 研究机械牵张与白介素-1β（IL-1β）联合作用对兔角膜成纤维细胞细胞外基质相关基因表达的影响。方法 对原代提取的兔角膜成纤维细胞进行牵张幅度15%、频率0.1 Hz的周期性牵张12、24、36 h,同时给予IL-1β处理,采用实时荧光定量PCR检测细胞基质金属蛋白酶（MMPs）、基质金属蛋白酶的组织抑制剂（TIMP-1）和I型胶原α1（Collagen Iα1）mRNA表达变化水平。结果 IL-1β单独作用可以诱导角膜成纤维细胞MMP-1、MMP-3和MMP-9 mRNA表达;MMP-1和MMP-3 mRNA表达随时间而降低,MMP-9、TIMP-1、Collagen Iα1 mRNA则随时间而增加;IL-1β与机械牵张联合作用使MMP-1、MMP-3、MMP-9 mRNA表达水平上调,TIMP-1和Collagen Iα1 mRNA表达下调,且具有时间依赖。单独机械牵张使Collagen Iα1 mRNA表达下降,IL-1β与机械牵张联合作用使其表达进一步下调,且具有时间依赖性。结论 机械牵张与炎性因子联合作用可加剧角膜组织破坏,促进角膜膨隆的发生发展。     

子宫腺肌症与肿瘤转移相关基因之间关系的研究

目的：探讨肿瘤转移相关基因在子宫腺肌症发生中的作用。 方法： 采用免疫组织化学方法，对43例子宫腺肌症患者、22例对照组（正常子宫内膜）的nm23-H1、基质金属蛋白酶-2（MMP-2）、基质金属蛋白酶-9（MMP-9）、膜型1-基质金属蛋白酶（MT1-MMP）和基质金属蛋白酶组织抑制因子-1（TIMP-1）的表达进行研究。 结果： 子宫腺肌症中，MMP-2、MMP-9和MT1-MMP的表达水平明显高于对照组（P<0.01），nm23-H1和TIMP-1的表达水平无显著差异（P>0.05）。 结论： MMP-2、MMP-9和MT1-MMP在子宫腺肌症的发病过程中可能起重要的作用。     

三氧化二砷对皮肤成纤维细胞、中性粒细胞MMPs活性，TIMP-1及TGF-β1表达的影响

目的:砒石是化腐生肌的常用中药,其主要成分是三氧化二砷(As2O3)。本研究通过观察As2O3对基质金属蛋白酶(MMPs)活性、基质金属蛋白酶组织抑制因子-1(TIMP-1)及转化生长因子β1(TGF-β1)表达影响,探讨化腐中药能否调节胶原代谢,从而治疗慢性皮肤溃疡。方法:明胶酶谱法检测大鼠中性粒细胞(PMNs)来源的MMP-9活性、人成纤维细胞(hFb)分泌的MMP-1、MMP-2的活性,免疫细胞化学法检测hFb TIMP-1、TGF-β1的表达。结果:As2O3浓度在50mg/L时可以提高大鼠PMNs来源的MMP-9的活性(P<0.01);在0.8mg/L可以提高hFb分泌的MMP-1、MMP-2的活性(分别P<0.01);同时As2O3作用于hFb6h、12h、18h后,TIMP-1、TGF-β1表达持续降低(P<0.01)。结论:As2O3在一定范围内可提高PMNs来源的MMP-9的活性;也可提高hFb分泌的MMP-1、MMP-2的活性,同时抑制hFbTIMP-1、TGF-β1的表达。提示砷类制剂可通过提高多种MMPs的活性,降低TIMP-1的表达从而发挥化腐作用。     

骨桥蛋白单抗抑制大鼠肺纤维化的研究

探讨骨桥蛋白(osteopontin,OPN)对博莱霉素(bleomycin,BLM)诱导的大鼠肺纤维化肺组织基质金属蛋白酶-9(MMP-9)、金属基质蛋白酶抑制剂-1(TIMP-1)和Ⅰ、Ⅲ型胶原mRNA表达的影响。取72只健康雌性Wistar大鼠随机分成生理盐水对照组(NS组)、博莱霉素模型组(BLM组)和骨桥蛋白抗体干预组(OPN-Ab组)各24只,气管内灌注BLM复制肺纤维化模型(BLM组、OPN-Ab干预组),NS组气管内灌注生理盐水,OPN-Ab组于0d、2d、4d、6d尾静脉注射骨桥蛋白抗体(1:32),BLM组和NS组尾静脉注射生理盐水,各组分别于7d、14d、28d处死动物8只。收集肺组织作切片行HE、MASSON染色测定肺泡炎症和纤维化改变,免疫组织化学PAP法测定肺组织中OPN、MMP-9、TIMP-1的表达;RT-PCR测定肺组织Ⅰ/Ⅲ型胶原mRNA的表达。结果与BLM组比较,在第7天和第14天OPN-Ab组肺泡炎明显减轻(P0.01);而肺纤维化程度在各时间点均明显减轻(P0.05);与NS组比较,BLM组、OPN-Ab组肺组织中OPN、MMP-9、TIMP-1表达水平均显著升高(P0.01)。BLM组第7天OPN、MMP-9、TIMP-1在肺组织中表达水平显著升高,随后下降,第28天时仍高于NS组(P0.01)。与BLM组比较,OPN-Ab组各时间点OPN、MMP-9、TIMP-1表达水平降低(P0.01)。OPN-Ab组第7、14、28天肺组织Ⅰ、Ⅲ型胶原mRNA表达均较同时间点BLM组明显降低(P0.05)。OPN可能是肺纤维化形成机制中的重要因素,骨桥蛋白抗体可能通过抑制细胞因子MMP-9、TIMP-1表达,减少肺组织中胶原的生成,最终抑制肺纤维化。     

Retinoic acid attenuates cytokine-driven fibroblast degradation of extracellular matrix in three-dimensional culture.

Proteolytic degradation of extracellular matrix is thought to play an important role both in emphysema and in tissue development and repair. Retinoic acid has been suggested to modify tissue injury, and in an animal model of emphysema may induce alveolar repair. Since cytokines can induce matrix metalloproteinase (MMP) production in fibroblasts and neutrophil elastase (NE) can activate MMPs, we hypothesized that retinoic acid could attenuate collagen degradation by modifying MMP production and activation. To evaluate this, human lung fibroblasts were cast into native type I collagen gels and floated in medium containing cytomix (TNF-alpha, IL-1beta, and IFN-gamma) alone or in combination with NE in the presence and absence of retinoic acid (1 microM). After 5 d, cytomix with elastase induced significant degradation of the collagen gels assessed by quantifying total hydroxyproline (41.6 +/- 1.6 microg versus 3.3 +/- 1.5 microg, P < 0.01). Retinoic acid significantly inhibited this degradation (23.3 +/- 1.5 microg versus 3.3 +/- 1.5 microg, P < 0.01). Gelatin zymography and Western blot revealed that MMP-1, MMP-3, and MMP-9 were induced by cytomix and that co-exposure to NE resulted in increased production of activated forms of these enzymes. Retinoic acid attenuated the induction and activation of MMP-1 and MMP-3. The current study, therefore, suggests that in addition to stimulating anabolic effects, retinoic acid may modulate proteolytic processes thought to contribute to tissue destruction in emphysema.     

Thrombin and TNF-alpha/IL-1beta synergistically induce fibroblast-mediated collagen gel degradation

Degradation of preexisting and newly synthesized extracellular matrix is thought to play an important role in tissue remodeling. The current study evaluated whether thrombin and TNF-alpha/IL-1beta could collaboratively induce collagen degradation by human fetal lung fibroblasts (HFL-1) and adult bronchial fibroblasts cultured in three-dimensional collagen gels. TNF-alpha/IL-1beta alone induced production of matrix metalloproteinases (MMPs)-1, -3, and -9, which were released in latent form. With the addition of thrombin, the latent MMPs were converted into active forms and this resulted in collagen gel degradation. Part of the activation of MMPs by thrombin resulted from direct activation of MMP-1, MMP-2, MMP-3, and MMP-9 in the absence of cells. In addition, tissue inhibitor of metalloproteinase-1 production was inhibited by the combination of thrombin and TNF-alpha/IL-1beta. These results suggest that thrombin and TNF-alpha/IL-1beta synergize to induce degradation of three-dimensional collagen gels through increasing the production and activation of MMPs, and that this effect is mediated through both direct activation of MMPs by thrombin and indirectly by thrombin activation of fibroblasts. Through such mechanisms, thrombin could contribute to many chronic lung disorders characterized by tissue remodeling.     

Regenerative potentials of platelet-rich plasma enhanced by collagen in retrieving pro-inflammatory cytokine-inhibited chondrogenesis

This study was undertaken to evaluate the role of collagen matrix to enhance platelet-rich plasma (PRP) effects on pro-inflammatory cytokine-induced arthritic model. We have previously demonstrated the highly regenerative roles of PRP to restore disc degeneration and osteoporosis. In this study, PRP modulated by collagen matrix was used as a regenerative and anti-inflammatory mediator to rescue the chondrocyte degeneration induced by pro-inflammatory cytokines IL-1β (10 ng/ml)+TNF-α (20 ng/ml). First, the MTT result indicated that 1 ng/ml TGF-β1 in PRP showed an optimal dosage for chondrocytes proliferation. The chondrogenic-specific gene expressions were rescued by PRP from the inhibition of IL-1β+TNF-α, especially under the modulation of collagen matrix. The inflammatory molecules activated by IL-1β+TNF-α were also significantly diminished by PRP with collagen matrix. The membrane receptors integrin α1β1 and CD44 were strongly inhibited by IL-1β+TNF-α, while this inhibition was then recovered by PRP in collagen coating condition. In a 3D model encapsulated with collagen, PRP-induced chondrogenesis were highly enhanced, such as strong restoration of type II collagen and proteoglycan from the inhibition of IL-1β+TNF-α. The result indicated that collagen matrix enhances the effect of PRP on chondrogenesis in response to pro-inflammatory cytokines. The combination of PRP and collagen matrix might facilitate a physiological microenvironment beneficial for maintaining chondrocyte homeostasis and represents an advanced osteoarthritis therapy for clinical applications.     

慢性阻塞性肺疾病合并骨质疏松患者血清肿瘤坏死因子α、转化生长因子β1、白细胞介素6水平的变化

背景:肿瘤坏死因子α、白细胞介素6、转化生长因子β是临床已明确与慢性阻塞性肺疾病发病发展有关的重要系统性炎症相关因子,但其与慢性阻塞性肺疾病合并骨质疏松间关系如何,鲜见报道。目的:探究慢性阻塞性肺疾病合并骨质疏松患者血清肿瘤坏死因子α、转化生长因子β、白细胞介素6水平变化的临床意义。方法:按照前瞻性病例对照原则选取120例慢性阻塞性肺疾病患者,根据骨量分为慢性阻塞性肺疾病骨量正常组40例,慢性阻塞性肺疾病合并骨量减少组40例,慢性阻塞性肺疾病合并骨质疏松组40例。比较3组临床资料、血清肿瘤坏死因子α、转化生长因子β1及白细胞介素6水平;分析骨质疏松组血清3种因子水平与肺功能、骨密度、骨代谢相关性;并采用偏相关性分析血清3种因子水平与慢性阻塞性肺疾病合并骨质疏松的关系;受试者工作特征(ROC)曲线评价血清肿瘤坏死因子α、转化生长因子β1、白细胞介素6的诊断价值。研究方案符合青海大学附属医院的相关伦理要求。结果与结论:①Pearson相关性分析,骨质疏松组血清肿瘤坏死因子α、白细胞介素6与第1秒用力呼气容积占预计值百分比(FEV1%Pre)、第1秒用力呼气量与用力肺活量比值(FEV1/FVC)、腰椎骨密度、股骨颈骨密度呈负相关,与骨保护素、Ⅰ型胶原交联羧基末端肽降解产物呈正相关;转化生长因子β1与FEV1%Pre、FEV1/FVC、腰椎骨密度、股骨颈骨密度呈正相关,与骨保护素、Ⅰ型胶原交联羧基末端肽降解产物呈负相关(P<0.05);②将肺功能、骨代谢、骨密度等其他因素控制后,血清肿瘤坏死因子α、转化生长因子β1、白细胞介素6仍与慢性阻塞性肺疾病合并骨质疏松显著相关(P<0.05);③血清肿瘤坏死因子α、转化生长因子β1、白细胞介素6联合对诊断慢性阻塞性肺疾病合并骨量减少及慢性阻塞性肺疾病合并骨质疏松的ROC曲线下的面积(AUC值)分别为0.870、0.850;④结果说明,血清肿瘤坏死因子α、转化生长因子β1、白细胞介素6水平与肺功能及骨代谢有关,三者联合检测可为临床评价慢性阻塞性肺疾病合并骨质疏松提供参考依据。     

Inhibition of histone deacetylases antagonized FGF2 and IL-1β effects on MMP expression in human articular chondrocytes

Fibroblast growth factor-2 (FGF2) and interleukin-1β (IL-1β) stimulate the expression of matrix metalloproteinases (MMPs) in articular chondrocytes, which may contribute to cartilage degradation and development of osteoarthritis. Histone deacetylases (HDACs) have recently been implicated in the regulation of MMP gene expression. To investigate the functional involvement of HDACs in the signaling pathway of FGF2 and IL-1β, we examined the effects of HDAC inhibition on activities of FGF2 or IL-1β on gene expression of MMP-1, MMP-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5), collagen type II, and aggrecan. Human articular chondrocyte cultures were treated with FGF2 or IL-1β in the presence or absence of HDAC inhibitor (trichostatin A, TSA). Gene expression levels after treatments were assessed using quantitative real time PCR. Results showed that FGF2 and IL-1β both increased MMP-1 and -13 expression, while IL-1β also increased MMP-3 mRNA levels. These effects were attenuated in the presence of TSA in a dose dependent manner. In contrast to the effects on MMPs, FGF2 decreased mRNA levels of ADAMTS-5, which was not affected by HDAC inhibition. FGF2, IL-1β, and TSA inhibited expression of aggrecan, while TSA also decreased mRNA levels of collagen type II. These findings showed that HDAC inhibition antagonized FGF2 and IL-1β induced MMP expression. Combination of FGF2 and the HDAC inhibitor decreases both anabolic and catabolic genes, which may slow the cartilage turnover and be beneficial for maintaining cartilage integrity.     

肺气肿模型大鼠肾组织水通道蛋白2的表达及机制研究

目的: 观察肺气肿模型大鼠肾组织AQP2表达以及血中ET、IL-1β、TNF-α水平的变化,探讨在体液代谢过程中肺与肾脏之间关系。方法: 用气管内注入脂多糖加熏香烟方法复制肺气肿大鼠模型,应用免疫组化、Western blotting、RT-PCR方法测定肾组织AQP2蛋白及mRNA表达的变化,应用放免法测定血中、肺组织匀浆中ET、IL-1β及TNF-α含量。结果: 与对照组比较,肾组织AQP2蛋白及mRNA表达增强(P<0.01);同时模型组血、肺组织ET、IL-1β及TNF-α含量明显升高(P<0.01)。结论: 肺气肿模型大鼠肾组织AQP2表达上调;其机制可能与血中ET、IL-1β、TNF-α含量升高有关。     

Interleukin‐1 and Tumor Necrosis Factor‐α Induce Collagenolysis and Bone Resorption by Regulation of Matrix Metalloproteinase‐2 in Mouse Calvarial Bone Cells

Abstract

Interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α) greatly induces osteoclast formation and stimulates bone resorption of mouse calvaria in culture. We examined the effects of the two cytokines on the collagenolysis and bone resorption by induction of matrix metalloproteinases (MMPs). The cells were analyzed using zymographic analysis. It was shown that the mouse calvarial osteoblasts constitutively synthesize progelatinase‐A (MMP‐2). Interleukin‐1β markedly enhanced the messenger RNAs (mRNAs) expression of MMP‐2 (gelatinase A), but slightly MMP‐9 (gelatinase B), which associated with increases in bone matrix degradation. Both pro‐ and active‐forms of MMP‐2 were detected in the conditioned medium collected from calvarial cultures, and IL‐1β markedly stimulated both pro‐ and active‐forms of the MMP‐2. The expression of MMP‐2 mRNAs could be detected, and they were markedly enhanced by IL‐1β on days 1 and 2. These results demonstrate that the potency of induction of MMP‐2 by IL‐1β and TNF‐α is closely linked to the respective bone‐resorbing activity, suggesting that MMP‐2‐dependent degradation of bone matrix plays a key role in bone resorption induced by these cytokines. On the other hand, when the mouse osteoblasts were stimulated with parathyroid hormone, 1,25(OH)₂D₃, mononuclear cell conditioned medium (MCM) and IL‐1 as bone resorption agents, collagenolysis was increased by producing the active gelatinase. Interleukin‐1 in stimulating bone resorption was examined using fetal mouse long bone organ culture. Interleukin‐1 stimulated bone resorption and produced marked resorption when present simultaneously. Furthermore, treatment of indomethacin and dexamethasone clearly abolished the responses of IL‐1α and IL‐1β.