[The technique and application of individualized tympanic membrane flap in the repair of tympanic membrane under endoscopy ear surgery].

Objective:To investigate the technique of personalized flap making under otoscopy and its clinical application. Methods:The clinical data of patients who underwent 301 Military Hospital myringoplasty in the Department of otoendoscopic surgery, Department of Otorhinolaryngology, head and neck surgery, Department of Otorhinolaryngology, from October 2022 to 2023 August were analyzed retrospectively, all enrolled patients were performed independently by the same skilled otoendoscopic surgeon. The patients' general condition, medical history, tympanic membrane perforation scope, perforation size, need for tympanic cavity exploration, thickness of skin flap, tympanic cavity lesion scope, skin flap making method and postoperative rehabilitation were collected. Results:Many factors such as the location of tympanic membrane perforation, the thickness of the skin flap, the degree of curvature or stricture of the ear canal and the extent of the lesion in the tympanic cavity should be considered in the manufacture of the individualized tympanic membrane skin flap, the way of skin flap making does not affect the long-term postoperative rehabilitation, but it can effectively avoid unnecessary ear canal skin flap injury and improve the operation efficiency. Conclusion:Scientific flap fabrication is important for improving surgical efficiency and enhancing surgical confidence.

[The application of endoscope and microscope in the stapes surgeries].

Objective:To compare the application of endoscope and microscope in all kinds of stapes surgeries. Methods:Fifty-nine stapes surgeries have been collected from April 2020 to May 2023 in Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School. Hearing level, hospital stay post-operation, times of hospital visit post-operation, etc. have been compared between the endoscopic group and microscopic group. Patients who were failed to place the stapes prosthesis because of the poor exposure of the oval window have been analyzed. Results:Otosclerosis was the most common diagnosis in both groups. There was 1（1/23） middle ear malformation in the endoscopic group and 5（5/36） middle ear malformations in the microscopic group. There were 2 Van Der Hover syndromes and 4 Treacher Collins syndromes in the microscopic group. In the endoscopic group ABG of 10 ears（43.5%） ≤ 10 dB, and ABG of 21 ears（91.3%） ≤20 dB.In the microscopic group ABG of 13 ears（41.9%） ≤ 10 dB, and ABG of 28 ears（90.3%） ≤ 20 dB. There was no statistic difference between 2 groups. Times of hospital visit post-operation in the endoscopic group was less than in the microscopic group（P<0.01）. There was no facial palsy, tympanic perforation or profound sensorineural hearing loss in both groups. Conclusion:Endoscope is more suitable for patients who are evaluated with no severe stapes malformation, or less manipulation of drilling the bone. It could also reduce the hospital visit post-operation. Patients with narrow ear canal or severe middle ear malformation are recommended to perform the surgery with microscope, because it provides the chance of manipulation with 2-hands of surgeons.

Prolonged hypoxia alleviates prolyl hydroxylation-mediated suppression of RIPK1 to promote necroptosis and inflammation.

The prolyl hydroxylation of hypoxia-inducible factor 1α (HIF-1α) mediated by the EGLN-pVHL pathway represents a classic signalling mechanism that mediates cellular adaptation under hypoxia. Here we identify RIPK1, a known regulator of cell death mediated by tumour necrosis factor receptor 1 (TNFR1), as a target of EGLN1-pVHL. Prolyl hydroxylation of RIPK1 mediated by EGLN1 promotes the binding of RIPK1 with pVHL to suppress its activation under normoxic conditions. Prolonged hypoxia promotes the activation of RIPK1 kinase by modulating its proline hydroxylation, independent of the TNFα-TNFR1 pathway. As such, inhibiting proline hydroxylation of RIPK1 promotes RIPK1 activation to trigger cell death and inflammation. Hepatocyte-specific Vhl deficiency promoted RIPK1-dependent apoptosis to mediate liver pathology. Our findings illustrate a key role of the EGLN-pVHL pathway in suppressing RIPK1 activation under normoxic conditions to promote cell survival and a model by which hypoxia promotes RIPK1 activation through modulating its proline hydroxylation to mediate cell death and inflammation in human diseases, independent of TNFR1.

Erratum: CD151 promotes Colorectal Cancer progression by a crosstalk involving CEACAM6, LGR5 and Wnt signaling via TGFß1: Erratum.

[This corrects the article DOI: 10.7150/ijbs.53657.].

Metabolic orchestration of cell death by AMPK-mediated phosphorylation of RIPK1.

Adenosine monophosphate-activated protein kinase (AMPK) activity is stimulated to promote metabolic adaptation upon energy stress. However, sustained metabolic stress may cause cell death. The mechanisms by which AMPK dictates cell death are not fully understood. We report that metabolic stress promoted receptor-interacting protein kinase 1 (RIPK1) activation mediated by TRAIL receptors, whereas AMPK inhibited RIPK1 by phosphorylation at Ser415 to suppress energy stress-induced cell death. Inhibiting pS415-RIPK1 by Ampk deficiency or RIPK1 S415A mutation promoted RIPK1 activation. Furthermore, genetic inactivation of RIPK1 protected against ischemic injury in myeloid Ampkα1-deficient mice. Our studies reveal that AMPK phosphorylation of RIPK1 represents a crucial metabolic checkpoint, which dictates cell fate response to metabolic stress, and highlight a previously unappreciated role for the AMPK-RIPK1 axis in integrating metabolism, cell death, and inflammation.

The Mechanism of Xiaoyao San in the Treatment of Ovarian Cancer by Network Pharmacology and the Effect of Stigmasterol on the PI3K/Akt Pathway.

PURPOSE: This study was aimed at exploring the regulatory mechanism of Xiaoyao San (XYS) and its main compound, Stigmasterol, in the biological network and signaling pathway of ovarian cancer (OC) through network pharmacology-based analyses and experimental validation. METHODS: The active compounds and targets of XYS were studied by the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). The GeneCards and OMIM databases were used to screen common targets of XYS in the treatment of OC. Combined with the STRING database and Cytoscape 3.6.0, the core compounds and targets of XYS were obtained. GO and KEGG pathway enrichment analyses of core target genes were carried out by using the Metascape and DAVID databases. Molecular docking has been achieved by using the AutoDock Vina program to discuss the interaction of the core targets and compounds of XYS in the treatment of OC. The effect of Stigmasterol on proliferation and migration were assessed by CCK8 and wound healing assay. Western blot and qRT-PCR were used to analyze the protein and mRNA expressions of PI3K, Akt, and PTEN after treatment of Stigmasterol. RESULTS: A total of 113 common targets of XYS for the treatment of OC were obtained from 975 targets related to OC and 239 targets of XYS's effect. The main compounds of XYS include Quercetin, Naringenin, Isorhamnetin, and Stigmasterol, which mainly regulate the targets such as TP53, Akt1, and MYC and PI3K/Akt, p53, and cell cycle signal pathways. At the same time, molecular docking showed that Stigmasterol and Akt1 had good docking conformation. Stigmasterol inhibited OC cell proliferation and migration in vitro and reduced the protein and mRNA expressions of the PI3K/Akt signaling pathway. CONCLUSION: Stigmasterol as the one of the main compounds of XYS suppresses OC cell activities through the PI3K-Akt signaling pathway.

CD151 promotes Colorectal Cancer progression by a crosstalk involving CEACAM6, LGR5 and Wnt signaling via TGFß1.

CD151 impacts various signaling pathways in different cancers, and promotes colorectal cancer (CRC) cell malignancy by yet undefined mechanisms. This study aimed to comprehensively assess CD151's function in CRC. CD151 levels were significantly higher in CRC tissues and cells compared with controls in the tissue microarray. Cell viability, migration and invasion were suppressed by CD151 downregulation in CRC cells. Consistently, mouse xenografts were inhibited by CD151 silencing. RNA-seq revealed that multiple genes were significantly altered by CD151 knockdown in cultured CRC cells and xenografts. Particularly, transforming growth factor ß1 (TGFß1), carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) alongside CD151 were downregulated both in vitro and in vivo. Co-immunoprecipitation and mass spectrometry results were validated by qRT-PCR and immunoblot. Moreover, pull-down assay and immunofluorescence confirmed the associations of TGFß1, CEACAM6 and LGR5 with CD151. This study demonstrated CEACAM6, LGR5 and Wnt pathway suppression by CD151 silencing might occur through TGFß1 regulation, offering a comprehensive view of CD151's roles in colorectal carcinogenesis. Our findings provide an insight into the CD151-involved signaling network in CRC oncogenesis, which could be utilized to design novel targeted therapies against CD151-based signaling in treatment for CRC.

Reduction of mNAT1/hNAT2 Contributes to Cerebral Endothelial Necroptosis and Aß Accumulation in Alzheimer's Disease.

The contribution and mechanism of cerebrovascular pathology in Alzheimer's disease (AD) pathogenesis are still unclear. Here, we show that venular and capillary cerebral endothelial cells (ECs) are selectively vulnerable to necroptosis in AD. We identify reduced cerebromicrovascular expression of murine N-acetyltransferase 1 (mNat1) in two AD mouse models and hNat2, the human ortholog of mNat1 and a genetic risk factor for type-2 diabetes and insulin resistance, in human AD. mNat1 deficiency in Nat1-/- mice and two AD mouse models promotes blood-brain barrier (BBB) damage and endothelial necroptosis. Decreased mNat1 expression induces lysosomal degradation of A20, an important regulator of necroptosis, and LRP1ß, a key component of LRP1 complex that exports Aß in cerebral ECs. Selective restoration of cerebral EC expression of mNAT1 delivered by adeno-associated virus (AAV) rescues cerebromicrovascular levels of A20 and LRP1ß, inhibits endothelial necroptosis and activation, ameliorates mitochondrial fragmentation, reduces Aß deposits, and improves cognitive function in the AD mouse model.

6,12-Diphenyl-3, 9-diazatetraasterane-1, 5, 7, 11-tetracarboxylate Inhibits Proliferation, Migration and Promotes Apoptosis in Ovarian Cancer Cells.

6,12-Diphenyl-3,9-diazatetraasterane-1, 5, 7, 11-tetracarboxylate (DDTC) has been synthesized by the photodimerization of 4-phenyl-1,4-dihydropyridine-3,5-dicarboxylate. The potential of theercvantitumor activity and mechanism were investigated in vitro using MTT assay in human lung cancer cell line A549, ovarian cancer cell lines SKOV3 and A2780, breast cancer cell line MCF-7, gastric cancer cell line BGC-823, colon cancer cell line HT29, prostate cancer cell line DU145, and liver cancer cell line SMMC7721. The results show that DDTC can inhibit the growth of ovarian cancer SKOV3 and A2780 cells. The best IC50 value is approximately 5.29 ± 0.38 and 4.29 ± 0.39 µM, respectively. DDTC induced the cell cycle arrest in the G2 phase by flow cytometric analysis. The migration and invasion of ovarian cancer SKOV3 and A2780 cells were inhibited by DDTC. DDTC could increase the expression protein level of E-cadherin in A2780 cells and ascend the expression protein and mRNA levels of E-cadherin in SKOV3 cells. DDTC could also decrease the protein and mRNA expression of EMT (epithelial-to-mesenchymal transition) markers of N-cadherin and Vimentin. mRNA and protein expression level of checkpoint kinase 1 (Chk1) were significantly increased and expressions of cyclin-dependent kinase (CDK1) and cell division cycle 25a (Cdc25a) were decreased in the SKOV3 and A2780 cell lines. Moreover, DDTC induced apoptosis by the cleavage and activation of caspase 3 and caspase 9.

[Efficacy of semicircular canal occlusion in the treatment of fifteen pateints with Meniere's disease].

Objective:To investigate the long-term efficacy of semicircular canal occlusion in the treatment of refractory Meniere's disease. Method:Fifteen patients with Meniere's disease who underwent semicircular canal occlusion were reviewed. The preoperative and postoperative frequency of vertigo ,quality of life, hearing and tinnitus level were compared. All patients were followed for more than 24 months. Result:Postoperatively, vertigo was controlled effectively in all 15 cases, and the control rate was 100%, of which 11 cases were completely controlled（Grade A） and 4 cases were basically controlled（Grade B）. The improvement rate of quality of life was 100%. The hearing worse in 4 cases（26.7%） and stabilized in 11 cases（73.3%）. The tinnitus was relieved in 7 cases（46.7%）, unchanged in 7 cases（46.7%） and aggravated in 1 case（6.7%）. Conclusion:Semicircular canal occlusion can effectively control the vertigo symptoms of refractory Meniere's disease and improve the quality of life. The long-term efficacy of semicircular canal occlusion is definite, but there is a risk of hearing loss.

The Epigenetic Modification of Epigallocatechin Gallate (EGCG) on Cancer.

Among the major components of green tea, epigallocatechin-3-gallate (EGCG) is the most effective for its anti-cancer characteristics. The bulk of studies provide the mechanisms of suppressive function of EGCG are involved in alteration of cancer cell cycle, development, and apoptosis through activation/inhibition of several signal pathways. Another mechanism that explains the multiple effects exerted by EGCG in cancer is the epigenetic change by DNA methylation or methyltransferases, histone acetylation or deacetylases, and no coding RNAs (micoRNAs). Furthermore, decontrolled expression of miRNA transcription has been tested to be directly regulated by oncogenic and tumor-suppressor transcription factors. Recently, several proteins have been identified as miRNA direct interactors by EGCG. However, the mechanisms explaining the action of miRNA being modulated by EGCG have not been completely understood yet. This review summarizes the state of epigenetic change being modulated by EGCG in a variety of cancers and oncogenic and tumor-suppressor transcription factors.

Regulation of a distinct activated RIPK1 intermediate bridging complex I and complex II in TNFα-mediated apoptosis.

Stimulation of cells with TNFα can promote distinct cell death pathways, including RIPK1-independent apoptosis, necroptosis, and RIPK1-dependent apoptosis (RDA)-the latter of which we still know little about. Here we show that RDA involves the rapid formation of a distinct detergent-insoluble, highly ubiquitinated, and activated RIPK1 pool, termed "iuRIPK1." iuRIPK1 forms after RIPK1 activation in TNF-receptor-associated complex I, and before cytosolic complex II formation and caspase activation. To identify regulators of iuRIPK1 formation and RIPK1 activation in RDA, we conducted a targeted siRNA screen of 1,288 genes. We found that NEK1, whose loss-of-function mutations have been identified in 3% of ALS patients, binds to activated RIPK1 and restricts RDA by negatively regulating formation of iuRIPK1, while LRRK2, a kinase implicated in Parkinson's disease, promotes RIPK1 activation and association with complex I in RDA. Further, the E3 ligases APC11 and c-Cbl promote RDA, and c-Cbl is recruited to complex I in RDA, where it promotes prodeath K63-ubiquitination of RIPK1 to lead to iuRIPK1 formation. Finally, we show that two different modes of necroptosis induction by TNFα exist which are differentially regulated by iuRIPK1 formation. Overall, this work reveals a distinct mechanism of RIPK1 activation that mediates the signaling mechanism of RDA as well as a type of necroptosis.

Death-domain dimerization-mediated activation of RIPK1 controls necroptosis and RIPK1-dependent apoptosis.

RIPK1 is a critical mediator of cell death and inflammation downstream of TNFR1 upon stimulation by TNFα, a potent proinflammatory cytokine involved in a multitude of human inflammatory and degenerative diseases. RIPK1 contains an N-terminal kinase domain, an intermediate domain, and a C-terminal death domain (DD). The kinase activity of RIPK1 promotes cell death and inflammation. Here, we investigated the involvement of RIPK1-DD in the regulation of RIPK1 kinase activity. We show that a charge-conserved mutation of a lysine located on the surface of DD (K599R in human RIPK1 or K584R in murine RIPK1) blocks RIPK1 activation in necroptosis and RIPK1-dependent apoptosis and the formation of complex II. Ripk1K584R/K584R knockin mutant cells are resistant to RIPK1 kinase-dependent apoptosis and necroptosis. The resistance of K584R cells, however, can be overcome by forced dimerization of RIPK1. Finally, we show that the K584R RIPK1 knockin mutation protects mice against TNFα-induced systematic inflammatory response syndrome. Our study demonstrates the role of RIPK1-DD in mediating RIPK1 dimerization and activation of its kinase activity during necroptosis and RIPK1-dependent apoptosis.

FBXL20-mediated Vps34 ubiquitination as a p53 controlled checkpoint in regulating autophagy and receptor degradation.

Vacuolar protein-sorting 34 (Vps34), the catalytic subunit in the class III PtdIns3 (phosphatidylinositol 3) kinase complexes, mediates the production of PtdIns3P, a key intracellular lipid involved in regulating autophagy and receptor degradation. However, the signal transduction pathways by which extracellular signals regulate Vps34 complexes and the downstream cellular mechanisms are not well understood. Here we show that DNA damage-activated mitotic arrest and CDK activation lead to the phosphorylation of Vps34, which provides a signal to promote its ubiquitination and proteasomal degradation mediated by FBXL20 (an F-box protein) and the associated Skp1 (S-phase kinase-associated protein-1)-Cullin1 complex, leading to inhibition of autophagy and receptor endocytosis. Furthermore, we show that the expression of FBXL20 is regulated by p53-dependent transcription. Our study provides a molecular pathway by which DNA damage regulates Vps34 complexes and its downstream mechanisms, including autophagy and receptor endocytosis, through SCF (Skp1-Cul1-F-box)-mediated ubiquitination and degradation. Since the expression of FBXL20 is regulated by p53-dependent transcription, the control of Vps34 ubiquitination and proteasomal degradation by FBXL20 and the associated SCF complex expression provides a novel checkpoint for p53 to regulate autophagy and receptor degradation in DNA damage response.

[Anatomical measurements and clinical applications through facial recess approach].

OBJECTIVE: To provide the anatomic data for the correlated otologic microsurgery by the microdissection of temporal bone through facial recess approach. METHOD: Sixteen human temporal bones of eight adult cadaveric heads were dissected under surgical microscope through facial recess approach, and the relative anatomic structures were observed and measured, such as the bony entrance of facial recess approach, facial nerve, stapes, round window, round window niche, pyramidal eminence, cochleariform process, etc. The data were analyzed statistically. RESULT: The width of the bony entrance of facial recess approach was (2.94 +/- 0.32) mm, the height was (8.83 +/- 0.84) mm, the depth was (3.51 +/- 0.17) mm. The distances from stapes to tympanic segment of facial nerve, mastoid segment of facial nerve, round window, cochleariform process and anterior ligament of malleus were (1.38 +/- 0.21) mm, (6.94 +/- 0.47) mm, (3.60 +/- 0.55)mm, (2.23 +/- 0.33)mm, (4.93 +/- 0.61) mm, respectively. The distances from pyramidal eminence to tympanic segment of facial nerve, mastoid segment of facial nerve, round window, round window niche and cochleariform process were (1.05 +/- 0.09) mm, (5.63 +/- 0.41) mm, (3.01 +/- 0.34) mm, (3.29 +/- 0.44) mm, (4.13 +/- 0.51) mm, respectively. The distances from round window to cochleariform process and tympanic segment of facial nerve were (5.11 +/- 0.61) mm and (3.97 +/- 0.61) mm. The distances from round window niche to tympanic segment of facial nerve and mastoid segment of facial nerve were (4.13 +/- 0.38) mm and (7.28 +/- 0.29) mm. CONCLUSION: The facial recess approach played an important role in modern otologic microsurgery. The position of anatomical structure was constant relatively, including short crus of incus, stapes, pyramidal eminence and cochleariform process, etc. These could be used as reference marks for otologic microsurgery.

[Clinical characteristics and surgical management of extensive cholesteatoma of external auditory canal].

OBJECTIVE: To classify the external auditory canal cholesteatoma(EACC) by high-resolution temporal bone CT scans and the clinical findings of the patients, and to discuss the clinical and imaging characteristics and the surgical management of the extensive EACC. METHOD: A retrospective study was carried out among 56 patients (58 ears) with EACC and their clinical data were carefully analyzed. We classified EACC as the extensive type and the localized type. The operation strategy depended on the extent of lesion. All cases were followed up for 1 to 6 years after surgery. RESULT: There were 31 patients with localized EACC, 2 with no bone erosion and 29 (31 ears) with bone erosion within external auditory canal, and 25 patients with extensive EACC, 16 with bone erosion of intra temporal bone and 9 with bone erosion of extra temporal bone. Among all the 25 patients with the extensive type, the most common symptoms were otorrhea, otalgia and hearing loss, with 25, 23, 22 cases, respectively. The tympanic membrane (TM) was intact in 23 patients and perforated in two. The mastoid air cells in 23 patients were involved by the lesion, as well as tympanic antrum in eight, tympanic cavity in two, sigmoid sinus bony wall in five, mastoid segment of facial canal in four, and temporomandibular joint in two patients. Twenty patients underwent modified radical mastoidectomy, only one underwent reconstruction of ossicular chain, and four underwent canaloplasty. The average time of ear dry after surgery was 29 days. The postoperative hearing was improved by an average of 15 dB. No recurrence except for one patient was found during the follow-up period. CONCLUSION: It was of important clinical significance to classify EACC as the extensive type and the localized type. The extensive EACC was misdiagnosed easily because of the complicated clinical manifestations. The classification was helpful for the diagnosis and the selection of surgery strategy of EACC.

[Clinical analysis of bilateral same-day myringoplasty for 22 cases with bilateral tympanic membrane perforation].

OBJECTIVE: To investigate the feasibility of bilateral same-day myringoplasty and the indications for myringoplasty for patients with bilateral tympanic membrane perforation, and to summarize relevant experience. METHODS: Twenty-two patients underwent bilateral same-day underlay myringoplasty, and all cases were consistent with the indications for myringoplasty. The preoperative hearing and postoperative hearing at three months were compared, and the postoperative symptoms and complications were observed. Forty patients underwent monaural myringoplasty as the control group over the same period. All cases were followed up for 1 - 3 years. RESULTS: The postoperative hearing was increased by an average of 18 dB, and the rate of closure of tympanic membrane perforation was 93.2% (41/44). There were seven patients with ear fullness after operation in the bilateral myringoplasty group and two patients in the control group (χ(2) = 4.5374, P = 0.0332). There were no differences in the postoperative hearing improvement, the rate of closure and the rates of other discomfort symptoms except for ear fullness between the two groups (P > 0.05). CONCLUSION: It was feasible and safe to perform bilateral same-day myringoplasty for bilateral tympanic membrane perforation, but the postoperative temporary discomfort of bilateral ear fullness should be informed the patients in advance.

[The value of computed tomography scans of temporal bone and eustachian tubal function tests for lesions at tympanic opening of eustachian tube in middle ear cholesteatoma].

OBJECTIVE: To investigate the value of high resolution computed tomography (HRCT) of temporal bone and eustachian tubal function tests for lesions at tympanic opening of eustachian tube in the patients of otitis media with cholesteatoma prior to surgery. METHOD: The clinical data of 38 cases (41 ears) with cholesteatoma, which were examined by HRCT scans and eustachian tubal function tests before mastoidectomy (29 ears) or mastoidectomy+ tympanoplasty (12 ears), were analyzed. RESULT: The rate of conformation between the radiographic and the operative findings was 94.1% in the tympanic opening of eustachian tube. We found that the rate of the process tissue in the tympanic opening of eustachian tube was 86.5% (32/37) during the operation and that they were mainly granulation tissues and cholesteatoma. The rate of eustachian tubal hypofunction was 90.2% (37/41), the obstructive type and the incompetent type were 32 ears and five ears, respectively, only four were normal. CONCLUSION: HRCT scans and eustachian tubal function tests by Sonotubometry and Tubotymanoaerodynamic (TTAG) play vital roles in diagnosis of the tympanic opening lesion of eustachian tube and in assessment of eustachian tubal function pre-operation of middle ear cholesteatoma.

[Detection of the activity of MMP2 and MMP9 in middle ear cholesteatoma].

OBJECTIVE: To study the relationship between the activity of MMP2, and bone resorption in middle ear cholesteatoma. METHOD: Specimens from 41 cases of middle ear cholesteatoma and 20 cases of external auditory canal skin were analysed for molecular corresponding to MMP2 and MMP9 by using Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) Zymography. RESULT: The active levels of MMP2 and MMP9 in the cholesteatoma, which were (0.954+/-0.411) and (2.676+/-0.734) respectively, were obviously higher than that in the external auditory canal skins, which were (0.355+/-0.160) and (1.166+/-0.443) gray area x mg(-1) x ml(-1) respectively, and showed close relationship (P < 0.01). The active levels of MMP2 and MMP9 in extensive cholesteatoma, which were (1.062+/-0.401) and (2.946+/-0.134) respectively, were significantly increased in comparison with in localized cholesteatoma which were (0.701+/-0.318) and (2.193+/-0.601) gray area x mg(-1) x ml(-1) respectively. No significant difference was observed between recurrent cases and first cases (P > 0.05). CONCLUSION: The increase of activity of MMP2 and MMP9 in cholesteatoma indicated that MMP2 and MMP9 may play a vital role in the bone destruction associated with cholesteatoma.