2002 Fiscal Year Final Research Report Summary
Hyaluronan and CD44 in models of emphysema
| Project/Area Number |
12670577
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Respiratory organ internal medicine
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| Research Institution | Tokai University |
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Principal Investigator |
SHIOYA sumie Tokai University, School of Medicine, Associate Professor, 医学部, 助教授 (20102840)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGAKI Toshimori Tokai University, School of Medicine, Assistant Professor, 医学部, 講師 (90246091)
TSUJI Chizuko Tokai University, School of Medicine, Assistant Professor, 医学部, 講師 (80130079)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Emphysema / Hyaluronan / Dielectric spectroscopy / CD44 |
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| Research Abstract |
Degradation and loss of glycosaminoglycan (GAG) in alveolar walls may play an important role in the development of emphysema by affecting water reservoir function of alveolar walls since GAG, especially hyaluronan, has water structuring ability to keep alveolar walls to be moist and elastic. We investigated changes in hyaluronan and CD44 (adhesion molecules of hyaluronan) in the models of emphysema. Two types of models of emphysema were prepared using rats by injection of 20 mg/kg of hyaluronidase (H-4272, Sigma) (H) and exposure to 60% oxygen for 4 weeks (O). Severity of emphysema was evaluated with measurements of air content by point-counting method and lung function using body plethysmograph. Content of hyaluronan was measured using hyaluronan kit (Chugai, Japan) and Expression of mRNA for CD44 was measured by RT-PCR. With the microwave dielectric spectroscopy, we quantified changes in free-water in lung tissue. Emphysematous change was histologically observed for 0 group and 2 wee
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ks after injection in H group. The air content and FRC were greater in H than normal control C (57 vs. 40% and 5.8 vs. 4.3 ml). The content of hyaluronan in the serum, bronchoalveolar lavage fluid, and homogenized lung tissue obtained from 0 group was not significantly different from samples of control. The expression of CD44 for lung tissue was significantly lower for both H and O groups compared with the control, but no significant change was observed for alveolar macrophages obtained by BAL. The dielectric relaxation was measured with a time domain reflectometry (TDK) method. The dielectric strength (Αε) of the peak reflecting the amount of free water was measured and corrected for each sample with a tissue density determined by a microscopy to eliminate the effect of alveolar air onΑε. The corrected dielectric strength (Αε) of free water was greater in H than C (43.3 vs. 34.9). The content of free water was 59.2% for H and 47.8% for C. The increase in free-water fraction in the emphysematous lung tissue suggested decreased ability of alveolar walls for restricting mobility of water-molecules. This may cause loss of reservoir function of the lung result in the intolerance for volume overload in emphysema patients. Less
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Research Products
(12 results)
