Study on changes of heme oxygenase expression in patients with chronic obstructive pulmonary disease

To investigate the changes of heme oxygenase(HO) expression in patients with chronic obstructive pulmonary disease(COPD).

The patients were divided into 3 groups: COPD(group 1,n = 36),COPD complicated by lung cancer(group 2, n = 28) and lung cancer group(group 3,n = 22). A total of 125 healthy individuals(group 4) served as control. Blood gas was analyzed and pulmonary function was assayed in all groups. The levels of carbon monoxide hemoglobin (COHb) in arterial blood of 4 groups and HO-1 activity of lung tissues resected due to lung cancer in group 2 and group 3 were tested with ultraviolet spectrop hotometry. The levels of HOmRNA and protein expressions of lung tissues in group 2,group 3 and some of group 4(the lung tissues were obtained from traffic accident operations) were measured by reverse transcription-polymerase chain reaction and by immunohistochemistry.

Partial pressure of oxygen in arterial blood fell obviously to lower than 8kPa in group 1 and group 2, but the pH values, partial pressures of carbon dioxide in arterial, blood and HCO(3) were in normal ranges. Diffusion capacity for carbon monoxide of the lung(D(L)CO,69.521 +/- 13.979), D(L)CO/alveolar ventilation(V(A),66.091 +/- 16.423), and forced expiratory volume in one second (FEV(1)) in predata (FEV(1)%/Pred, 52.408 +/- 10.635) in group 1 and D(L)CO (71.323 +/- 11.254), D(L)CO/V(A)(68.152 +/- 18.326), and FEV(1)%/Pred (53.897 +/- 9.467) in group 2 were significantly lower than those in group 3 and group 4. The ratio of residual volume(RV) to total lung capacity(TLC) was significantly higher in group 1(50.309 +/- 4.368) and group 2(49.250 +/- 4.978) than those in other groups. The levels of COHb were significantly increased in the patients of group 1[(5.63 +/- 1.07)%] and group 2[(5.86 +/- 1.82)%] compared with those in group 3 [(1.65 +/- 0.56)%] and group 4 [(1.05 +/- 0.43) %, P < 0.01]. The bilirub in production was significantly increased in the group 2 [(492.25 +/- 117.32) pmol. mg protein (-1). h (-1)] compared with those of group 3 [(289.32 +/-82.52) pmol. mg protein (-1). h (-1)] and group 4 [(253.25 +/- 66.32) pmol. mg protein (-1). h (-1)].The levels of HO-1mRNA expression of lung tissues (the area without carcinomatous changes)(2.16 +/- 0.68) and that of pulmonary vessels(1.56 +/- 0.52)in group 2 were significantly increased than those of other groups. The strong positive granules of HO-1 were observed in the cytoplasm of pulmonary alveolar wall, intrapulmonary vascular and bronchial wall in groups 2.

The overexpression of HO may be a kind of compensatory regulation. Endogenous HO-CO system was involved in the regulation of COPD.