Impact of tolerance on antitumor efficacy of tumor necrosis factor in mice

Repetitive sublethal doses of tumor necrosis factor (TNF) can induce tolerance or tachyphylaxis to the toxic effects of TNF. Because tumor-bearing (TB) mice are more sensitive to the toxic effects of TNF, this study investigates whether similar tolerance occurs in TB mice and whether it affects the antitumor response of TNF. Nontumor-bearing C3H/Hen mice were treated with twice daily i.p. sublethal escalating doses of human recombinant TNF (2, 2, 3, 3, 4, and 4 micrograms i.p. every 12 h for 6 days) and were challenged 2 days later with a lethal i.v. dose (40 micrograms) of TNF. TNF-pretreated mice had 100% survival as compared to 0% survival in control mice previously treated with saline (P less than 0.01). Tumor-bearing C57BL/6 mice bearing an MCA-106 or MCA-102 sarcoma were treated with an identical TNF-tolerizing regimen (2, 2, 3, 3, 4, and 4 micrograms i.p. every 12 h for 6 days) beginning 3 days following tumor inoculation and were similarly more resistant to a subsequent 100% lethal i.v. treatment dose of TNF than control TB mice. A significantly greater percentage of TNF-pretreated mice bearing the MCA-106 sarcoma survived treatment doses of 8, 12, and 16 micrograms of TNF i.v. than control TB mice. Similarly, a significantly greater percentage of TNF-pretreated mice bearing the MCA-102 sarcoma survived treatment doses of 6 and 9 micrograms of TNF i.v. than control TB mice. However, the ability to administer higher doses of TNF i.v. to TNF-pretreated TB mice did not improve therapeutic efficacy. In mice bearing the MCA-106 tumor the most efficacious treatment responses were seen in animals that were previously naive to TNF, and treatment toxicity (lethality) correlated directly with antitumor efficacy such that larger treatment doses of TNF in tolerant mice resulted in similar antitumor effects as smaller treatment doses in control TB mice. In mice bearing the MCA-102 tumor, equitoxic treatment doses of TNF produced similar antitumor effects in both control and tolerant TB mice. There were no differences in cure rate for TNF-tolerant or control TB mice bearing either tumor. The results suggest that TNF tolerance occurs in TB mice and reduces the toxicity as well as the therapeutic efficacy of TNF.     

Expression and localization of matrix metalloproteinases and tissue inhibitors of metalloproteinases as a prognostic factor in advanced colorectal carcinomas

To clarify the usefulness of matrix metallo-proteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) as prognostic factors in advanced colorectal carcinoma, the immunohistochemical expressions of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1 and TIMP-2 were examined. Specimens were selected from 67 consecutive patients undergoing surgery for advanced colorectal carcinoma. The patterns of expression were compared with the prognoses of the patients. The patients with TIMP-2 expression in stroma adjacent to the tumor mass had better prognoses than those of the patients who had no TIMP-2 expression in normal stroma adjacent to the tumor (p<0.05), which probably acted as a block of cancer cell invasion. However, the expression of MMP-2, presumably acting as an antagonist to TIMP-2 was not related to the prognosis, and the MMP-1, MMP-2, MMP-3, MMP-9 and TIMP-1 expressions were not related to any clinicopathological factors examined.     

Mechanism of antitumor activity of tumor necrosis factor alpha with hyperthermia in a tumor necrosis factor alpha-resistant tumor

Cells from a radiation-induced fibrosarcoma (RIF-1) are exceedingly resistant to tumor necrosis factor alpha (TNF-alpha) in vitro. We tested whether the addition of mild hyperthermia (42.5 degrees C, 30 minutes) could enhance TNF-alpha activity against RIF-1 tumors growing in syngeneic hosts (C3H mice). TNF-alpha was administered intratumorally. Tumor cell killing essentially was not measurable following TNF-alpha, hyperthermia, or a combination of the two. Single-modality treatments also had no effect on tumor growth delay or on the x-ray dose (given 24 hours after the primary treatment) required to sterilize 50% of the tumors. The combination of TNF-alpha and hyperthermia, however, resulted in a marked increase in tumor doubling time and a highly significant reduction in the x-ray dose required to sterilize the tumors. Syngeneic lymph nodal lymphocytes and blood leukocytes did not appear to mediate the action of TNF-alpha on RIF-1 cells in vitro. Necrosis and hemorrhage were the most prominent histopathological alterations in the treated tumors. Electron microscopic studies 6 hours after therapy showed increased damage to capillary endothelial cells and accumulation of neutrophils in the capillaries of tumors treated with TNF-alpha with or without heat, suggesting that neutrophils may mediate the endothelial cell injury. These observations indicate a greater than additive tumoricidal effect of TNF-alpha with hyperthermia. Furthermore, they support the concept that the interaction between the two agents damages the vasculature, compromising the microcirculation and ultimately causing ischemic tumor necrosis.     

Dosing and scheduling influence the antitumor efficacy of a phosphinic peptide inhibitor of matrix metalloproteinases

The in vivo disposition and antitumor efficacy of a newly developed phosphinic matrix metalloproteinase inhibitor (RXP03) were examined. RXP03 potently inhibits MMP-11, MMP-8 and MMP-13, but not MMP-1 and MMP-7. Twenty-four hours after i.p. injection into mice, most of the RXP03 was recovered intact in plasma, feces (biliary excretion) and tumor tissue. Pharmacokinetic parameters indicated that, after an i.p. dose of 100 microg/day, the plasma concentration of RXP03 over 24 hr remained higher than the Ki values determined for MMP-11, MMP-8 and MMP-13. Efficacy of RXP03 on the growth of primary tumors induced by s.c. injection of C(26) colon carcinoma cells in mice was observed to depend both on RXP03 doses and treatment schedules. Tumor volumes in mice treated for 18 days with 50, 100 and 150 microg/day of RXP03 were decreased compared with control tumor volumes, 100 microg/day being the most effective dose. Treatment at higher dose (600 microg/day) did not significantly reduce the tumor size as compared to control. Short treatments with RXP03 100 microg/day, 3 to 7 days after C(26) inoculation, were more effective on tumor growth than continuous treatment over 18 days. Strikingly, RXP03 treatment started 6 days after the C(26) injection and continued until day 18 led to stimulation of tumor growth, as compared to control. These paradoxical effects, depending on the RXP03 treatment schedule, underline the need to define carefully the spatiotemporal function of each MMP at various stages of tumor growth to achieve optimal therapeutic effects by MMP inhibitor treatment.     

The role of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinase in microcystic meningiomas

We studied the expression of matrix metalloproteinases (MMP) and tissue inhibitors of matrix metalloproteinase (TIMP) in microcystic meningiomas to investigate a possible underlying mechanism for the development of microcysts and of peritumoral edema, which are frequent characteristics of this rare subtype. Between October 1995 and June 2004, 10 of 19 patients who had histologically confirmed pure microcystic meningiomas were enrolled in the study. Six patients with meningothelial meningiomas, three with atypical meningiomas, and one with a transitional meningioma were included as a control group. Immunohistochemistry with paraffin blocks and real-time RT-PCR analysis for MMP-2, MMP-9, TIMP-1, TIMP-2 and vascular endothelial growth factor (VEGF) were performed using stored frozen tissues. Compared with the control group, MMP-9 was invariably and highly expressed in immunohistochemical staining of microcystic meningiomas. MMP-2, TIMP-1, TIMP-2 and VEGF were weakly expressed or not expressed in both microcystic and non-microcystic meningiomas. Real-time RT-PCR showed increased ratios of MMP-9 to TIMP-1 in microcystic meningiomas compared with the control group (55.855 +/- 106.353 vs. 1.858 +/- 2.575, respectively; p = 0.00). The expression of MMP-2 (0.72 +/- 1.20 vs. 2.54 +/- 3.01, p = 0.01) and TIMP-2 (1.22 +/- 1.67 vs. 1.61 +/- 1.82, p = 0.02) was higher in the control group. The results suggested that the increased ratio of MMP-9 to TIMP-1 might be associated with the formation of microcysts and peritumoral edema in microcystic meningioma.     

Effect of tumor necrosis factor on the antitumor efficacy and toxicity of aminopterin-monoclonal antibody conjugates: parameters for optimization of therapy

Immunoconjugates of monoclonal antibodies with drugs, isotopes, or toxins are currently being investigated for their therapeutic effect on tumors. However, all have problems of access of the immunoconjugate to the tumor, particularly with solid tumors. To address this problem, we have used aminopterin-monoclonal antibody (AMN-mAb) conjugates combines with murine tumor necrosis factor (mTNF-alpha), which is known to have specific effects on tumor vasculature. In a murine model, well-established tumors (measuring 1.0-1.4 cm in diameter) were either totally eradicated or considerably reduced in size with combined therapy--a greater effect than with either mTNF-alpha or AMN-mAb used alone. The mechanisms involved in the improved antitumor effect were investigated using in vitro assays, autoradiography, and biodistribution experiments. mTNF-alpha was found both to increase the cytotoxic activity of the conjugate in vitro and to increase in vivo tumor localization of mAb up to 5-fold. The timing of mTNF-alpha administration was crucial to effects on tumor localization; mTNF-alpha given with mAb caused the greatest increase in localization and mTNF-alpha given well before mAb decreased localization. mTNF-alpha also reduced the toxicity to mice of AMN-mAb depending on the timing of injection. These results indicate that mTNF-alpha has a useful role in potentiation of immunoconjugate therapy but shows the need for careful planning of the dose regimen.     

Crucial role for interferon gamma in the synergism between tumor vasculature-targeted tumor necrosis factor alpha (NGR-TNF) and doxorubicin

NGR-TNF is a derivative of TNF-alpha, consisting of TNF fused to CNGRCG, a tumor vasculature-targeting peptide. Previous studies showed that NGR-TNF can exert synergistic antitumor effects with doxorubicin and with other chemotherapeutic drugs in murine models. In this study, we have investigated the role of endogenous IFN-gamma on the antitumor activity of NGR-TNF in combination with doxorubicin. The study was carried out using murine B16F1 melanoma and TS/A mammary adenocarcinoma implanted subcutaneously in (a) immunocompetent mice, (b) athymic nude mice, and (c) IFN-gamma-knockout mice. Synergism between NGR-TNF and doxorubicin was observed in immunocompetent mice but not in nude or IFN-gamma-knockout mice. Preadministration of a neutralizing anti-IFN-gamma antibody to immunocompetent mice inhibited the NGR-TNF/doxorubicin synergism, whereas administration of IFN-gamma to nude and to IFN-gamma-knockout mice restored the synergistic activity. The synergism in nude mice was restored also by transfecting tumor cells with the IFN-gamma cDNA. Administration of NGR-TNF in combination with IFN-gamma to nude mice, but not of NGR-TNF alone, doubled the penetration of doxorubicin in TS/A tumors. These findings point to a crucial role for locally produced IFN-gamma in tumor vascular targeting with NGR-TNF and doxorubicin. Finally, addition of IFN-gamma to the treatment of immunocompetent mice with NGR-TNF/doxorubicin induced only modest improvement in response, suggesting that exogenous IFN-gamma can improve the therapeutic activity of these drugs only in case of suboptimal production of endogenous IFN-gamma.     

Augmentation of antitumor efficacy by the combination of recombinant tumor necrosis factor and chemotherapeutic agents in vivo

We evaluated the in vivo antitumor effects of the combination of recombinant human tumor necrosis factor (rhTNF) and three chemotherapeutic agents in an established murine tumor model. C57BL/6 mice bearing a subdermal weakly immunogenic 3-methylcholanthrene-induced sarcoma (MCA-106) received one i.v. dose of cyclophosphamide (Cy) (100 mg/kg), doxorubicin (5 mg/kg), or 5-fluorouracil (75 mg/kg) on either Day 8, 10, or 12. All animals received one i.v. dose of rhTNF (4 or 6 micrograms/mouse) on Day 10. The most effective time for administration of the chemotherapeutic agent was determined to be 48 h following rhTNF administration of all agents tested. The combined results of four separate experiments evaluating tumor size on Day 28 following tumor inoculation revealed that the groups treated with 4 or 6 micrograms of rhTNF and Cy (on Day 12) had tumor size reductions of 70 and 94%, respectively, compared to untreated controls (P2 less than 0.005). Mice treated with Cy alone, or with 4 or 6 micrograms of rhTNF alone had tumor size reductions of 30, 35, and 41%, respectively, compared to untreated controls (P2 less than 0.02). Analysis of cure rates demonstrates that the combination of Cy with 4 or 6 micrograms tumor necrosis factor cured 35 and 48% of the animals, respectively (P2 less than 0.01), compared to 10, 0, and 14% of mice treated with single agent Cy, 4 micrograms rhTNF, or 6 micrograms rhTNF, respectively. The timing of Cy and TNF administration was critical since administration of Cy prior to or concurrent with rhTNF was not effective in reducing tumor area or increasing cure rates over those achieved with either agent alone. Mice treated with doxorubicin alone had an increase in tumor size of 139 +/- 29% over untreated controls (P2 less than 0.05) on Day 28 following tumor inoculation and none were cured. In contrast, mice treated with doxorubicin plus 4 or 6 micrograms rhTNF exhibited early reductions in tumor size such that on Day 28 the average tumor areas were decreased by 66 +/- 34% (P2 less than 0.05) and 73 +/- 1% (P2 less than 0.02) of untreated controls with cure rates of 29% and 43% (P2 less than 0.02), respectively. However, the combination of 6 micrograms rhTNF plus doxorubicin led to substantial lethal toxicity with only 29% of mice surviving treatment. 5-Fluorouracil alone resulted in an increase in tumor area of 164% (P2 less than 0.05) over that of untreated controls on Day 28 following tumor inoculation.(ABSTRACT TRUNCATED AT 400 WORDS)     

The in vivo immunomodulatory effects of recombinant interferon gamma plus recombinant tumor necrosis factor-alfa

We conducted a phase I study in which an intramuscular injection of interferon gamma (IFN gamma) at 10, 50, or 100 micrograms/m2 was followed 5 minutes later by an intramuscular injection of 10, 50, or 100 micrograms/m2 of tumor necrosis factor-alfa (TNF alpha) at another site every other day for 20 days (10 doses). The addition of TNF alpha to IFN gamma reduced both the magnitude and duration of IFN gamma-mediated effects on peripheral blood monocyte expression of Fc receptors (FcRs) and HLA-DR and production of hydrogen peroxide. This inhibition was related to the dose of TNF alpha. On the other hand, TNF alpha and IFN gamma appeared to have an additive stimulatory effect on the production of neopterin by monocytes. The highest serum levels of neopterin were detected in patients who received the highest doses of both IFN gamma and TNF alpha. Thus, conflicting conclusions regarding the effect of the combination on immune activation are possible. If the activation of peripheral blood monocytes is the appropriate surrogate measure of the immune enhancement of the combination, then the simultaneous administration of IFN gamma and TNF alpha is ineffective, and future attempts to exploit the potential additive or synergistic effects of this combination of cytokines in humans may need to explore sequential administration schemata. On the other hand, if serum neopterin levels are a more reliable index of immune activation, simultaneous administration of 100 micrograms/m2 IFN gamma and 50 micrograms/m2 TNF alpha every other day (the maximally tolerated dose [MTD]) should be used in phase II testing. This dilemma points out the limitations of currently available methods of human immune assessment and the inadequacies in our capacity to gauge what particular immune measure or set of measures predict for in vivo antitumor effects.     

Anti-proliferative effects of tumor necrosis factor, gamma interferon and 5-fluorouracil on human colorectal carcinoma cell lines

We have previously utilized a bank of diverse human colorectal carcinoma cell lines to assess the synergistic antiproliferative effect of tumor necrosis factor (TNF) and IFN-gamma (IFN-gamma) in combination. In this study, we used 3 of these cell lines (HCT 116, SKO1 and VACO 9P) to study the growth-inhibitory effects of TNF and IFN-gamma (TNF/IFN-gamma) on these cells when administered in conjunction with 5-fluorouracil (5-FU). All 3 cell lines were sensitive to suprapharmacologic concentrations of 5-FU. However, the 3 lines varied in their sensitivities to clinically achievable concentrations of 5-FU. Concentrations of 0.1 microgram/ml of 5-FU administered for 96 hr, and 50 micrograms/ml administered for 1 hr, inhibited the growth of HCT 116 cells by 20% and 77%, that of SKCO1 cells by 25% and 66%, and that of VACO 9P cells by 25% and 55%, respectively. All 3 cell lines were sensitive to the anti-proliferative effects of TNF/IFN-gamma in a dose-dependent and duration-dependent fashion. TNF/IFN-gamma was administered for 1 hr every other day on days 1, 3 and 5 to the 3 cell lines. Cells were also exposed to 5-FU, administered either concomitantly for 96 hr, or for 1 hr on day 1. The addition of TNF/IFN-gamma to clinically achievable concentrations of 5-FU in both schedules resulted in additive cytotoxicity. For example, the addition of 10 ng/ml of both TNF and IFN-gamma to 96 hr of 0.1 microgram/ml 5-FU resulted in 10%, 5%, and 20% of control growth for the HCT 116 cell line, SKCO1 cell line, and VACO 9P cell line, respectively. The addition of 10 ng/ml of both TNF and IFN-gamma to 1 hr of 50 micrograms/ml of 5-FU inhibited all cell growth in all 3 cell lines. We conclude that TNF/IFN-gamma and 5-FU can be combined to achieve higher anti-tumor activity than either 5-FU or TNF/IFN-gamma alone in this in vitro model, that the 3-drug combination has potent growth-inhibitory effects at pharmacologic concentrations which are not schedule-dependent, and that this combination warrants further study in clinical trials.     

Use of vasoactive agents to increase tumor perfusion and the antitumor efficacy of drug-monoclonal antibody conjugates

The effects of both alpha 1- and beta-adrenergic blocking agents on the vascular perfusion of tumors were studied with the ultimate goal of improving diagnosis and therapy of solid tumors with the use of monoclonal antibody (MAb) conjugates. With the use of a subcutaneously growing murine thymoma, it was demonstrated that nonselective and cardioselective beta-adrenergic blocking agents were capable of increasing threefold tumor-to-blood and tumor-to-liver perfusion of 125I-labeled MAbs. Subsequently, these beta-adrenergic blocking agents were found to increase the antitumor efficacy of idarubicin (Ida)-MAb conjugates. Conjugate-treated mice that also received beta-adrenergic blocking agents had a smaller mean tumor size and a greater number of regressions than mice receiving Ida-MAb conjugate alone. By contrast, prazosin HCl, an alpha 1-adrenergic blocking agent, and Cyclospasmol, a peripheral vasodilator, did not enhance the tumor perfusion and antitumor efficacy of 125I- or Ida-conjugated MAbs, and no vasoactive agent enhanced the antitumor effect of Ida when used alone. By their selective action on normal blood vessels, vasoactive drugs can change the tumor-to-normal tissue perfusion ratio, thereby enhancing the access of drug-MAb conjugates to tumors and increasing the effectiveness of tumor therapy with the use of drug-MAb conjugates.     

Antitumoral effects of lipopolysaccharides, tumor necrosis factor, interferon and activated macrophages: synergism and tissue distribution

Treatment of C57BL/6 mice bearing Lewis lung carcinoma or of BALB/c mice bearing EMT6 sarcoma with tumor necrosis factor (TNF), lipopolysaccharides (LPS) or interferon caused necrosis of the solid tumors and regression. Toxicity was observed in tumor-bearing animals when TNF or LPS were used at effective antitumoral doses. Similar antitumoral effects could be achieved using less than 1 million macrophages from C57BL/6, lung of from BALB/c peritoneal cavity expanded in vitro, and spontaneously fully activated to cytotoxicity during culture. This effect, observed after transfer twice a week by intravenous or peritumoral route, was not dependent on histocompatibility. Additive effects were observed after combined treatment with activated macrophages and a low dose of LPS or TNF. The biodistribution of labelled LPS and of labelled cytotoxic macrophages was studied in tumor-bearing mice. Although, as expected, LPS was concentrated essentially in the liver, a slow accumulation in the center of the tumor was observed. Macrophages injected intravenously accumulated in the lung and were then redistributed towards liver, kidney and the tumor periphery. Macrophages injected locally remained essentially in the tumor periphery with a slow redistribution in the body. The complementary localization of LPS and of cytotoxic macrophages respectively in the center and periphery of solid tumors might explain their synergism.     

Endothelial cell production of nitrogen oxides in response to interferon gamma in combination with tumor necrosis factor, interleukin-1, or endotoxin

Clinical studies using biological response modifiers in cancer therapy have shown that the major dose-limiting toxic effects are hypotension and diffuse microvascular leakage. The cause and pathophysiology of this hypotension remains unknown. Previous experiments have demonstrated that a number of cell types, including endothelial cells, neutrophils, and macrophages, can secrete a potent hypotensive agent--endothelium-derived relaxing factor, which has recently been identified as nitric oxide. In this study, we tested interferon gamma, tumor necrosis factor, interleukin-1, interleukin-2, muramyl dipeptide, and endotoxin for their effects on production of nitrogen oxides by endothelial cells. Interferon gamma, in combination with tumor necrosis factor, interleukin-1 (IL-1), or endotoxin, induced murine brain endothelial cells to secrete nitrites (20-45 microM within 48 hr), which are breakdown products of nitric oxide. Nitrite production was blocked by incubation of endothelial cells in medium without L-arginine, a substrate for nitric-oxide synthase. Accumulation of nitrites was also inhibited by addition of NG-monomethyl-L-arginine (L-NMMA), which acts as a competitive inhibitor of this enzyme. The inhibitory effects of L-NMMA were reversed by addition of excess L-arginine. These results suggest (a) that endothelial cells produce nitric oxide in response to immunomodulators and (b) that endothelial cell-derived nitric oxide plays a role in the development of hypotension in patients treated with tumor necrosis factor or interleukins. Furthermore, administration of substrate analogues such as L-NMMA may favorably alter the toxicity associated with these immunomodulators and result in a higher maximum tolerated dose, with subsequent improvement in the antitumor activity.     

The cellular sensitivity of the primary tumor and its metastases in breast cancer patients to cytostatics, interferon and tumor necrosis factor

Samples of tumor tissue obtained from 47 patients with primary and metastatic breast cancer were implanted under the renal capsule of mice (SRCA-test) to assess individual sensitivity of these malignancies to cytostatics, recombinant interferon (rIFN) and--in some cases--to tumor necrosis factor (TNF). Primary tumor was shown to respond to cytostatics and rIFN in as few as 33.3 and 26.7% of cases, respectively. Xenografts of metastases displayed higher rates of response to all the drugs studied, viz. 64.2, 86.7 and 90% for cytostatics, rIFN and TNF, respectively.     

阿托伐他汀对糖皮质激素性股骨头坏死骨组织MMP/TIMP系统的影响

目的：观察阿托伐他汀对长期应用皮质激素大鼠骨组织中基质金属蛋白酶-2（matrixmetallo-proteinase-2,MMP-2）、基质金属蛋白酶-9（ matrix metalloproteinase-9,MMP-9）及其特异性抑制因子基质金属蛋白酶组织抑制剂-1（ tissue inhibitor of matrix metalloproteinases-1,TIMP-1）和基质金属蛋白酶组织抑制剂-2（ tissue inhibitor of matrix metalloproteinases-2,TIMP-2） mRNA表达的影响,探讨阿托伐他汀预防激素性股骨头坏死的效果及其作用机制。方法健康SD大鼠30只,采用数字随机法,分为激素组、阿托伐他汀组和对照组3个组,每组10只。激素组和阿托伐他汀组给予肌内注射醋酸泼尼松龙12.5 mg/kg,每周2次;阿托伐他汀组同时给予阿托伐他汀1 mg/kg灌胃,每日1次（按每千克体重最大用量给药,每天最大用量是60 mg,实验动物给药量为60 mg/60 kg体重）;对照组只给予相同体积生理盐水肌注。给药后4周取左侧股骨头骨组织石蜡包埋,HE 染色,鉴定骨质疏松和股骨头坏死情况;取右侧股骨头骨组织提取总 RNA,采用逆转录聚合酶链反应（RT-PCR）技术检测MMP-2、MMP-9、TIMP-1和TIMP-2的mRNA表达水平。结果激素组与阿托伐他汀组各有1只动物死亡。对照组股骨头骨组织切片HE染色可见骨小梁由板层骨构成,绝大多数小梁骨陷窝内可见骨细胞,小梁间为血管和骨髓。激素组表现为骨小梁稀疏和大量不连续的骨碎片及骨髓坏死,碎片骨陷窝内骨细胞大部分消失,周围有大量炎性肉芽组织,阿托伐他汀组介于两者之间,轻度炎性细胞浸润,骨小梁略纤细,多数小梁骨陷窝内可见骨细胞,小梁间为血管和骨髓。MMP-2在激素组、阿托伐他汀组、对照组中的表达分别为0.15±0.04、0.10±0.09、0.09±0.03;MMP-9在3组中的表达分别为0.13±0.03,0.11±0.05和0.08±0.02;TIMP-1在3组中的表达分别为0.07±0.02,0.15±0.05和0.18±0