EFFECTS OF STREPTOZOTOCIN-INDUCED DIABETES ON POSTPNEUMONECTOMY LUNG GROWTH AND CONNECTIVE-TISSUE LEVELS

Diabetes is generally accompanied by abnormal levels of growth hormone and adrenal steroids, hormones known to modulate postpneumonectomy (post-PNX) compensatory lung growth. Thus, we examined the possibility that diabetes may affect post-PNX lung growth processes. Left PNX was performed in young diabetic rats (streptozotocin-induced; 75 mg/kg body weight) (DM-PNX) and in control rats (C-PNX), for comparison with sham-operated control rats (C-SHAM). The rats were permitted free access to food and water. Examination at day 7 after surgery showed that right lung absolute dry weight and absolute DNA, collagen and elastin contents were increased in C-PNX and DM-PNX rats (but only C-PNX values reached those of both lungs in C-SHAM rats). Body weights (BW) of DM-PNX rats were lower than those of C-PNX and C-SHAM rats. Lung DNA/BW in C-PNX and DM-PNX rats were comparable, and matched values for both lungs in C-SHAM rats. Lung dry weight/BW, collagen/BW, and elastin/BW in DM-PNX rats exceeded values in C-PNX rats and even more for values of both lungs in C-SHAM rats. Data of another experiment, comparing DM-PNX rats with body weight-matched (by food limitation) PNX and control rats (WMC-PNX and WMC-SHAM rats, respectively) indicated comparable lung absolute DNA contents in DM-PNX and WMC-PNX rats (which matched values for both lungs in WMC-SHAM rats), however, lung absolute collagen and elastic contents were greater in the DM-PNX rats. These findings demonstrate that an underlying diabetic state per se does not prevent post-PNX compensatory hyperplastic lung growth, but can result in increased connective tissue contents. Pediatr Pulmonol, 1995; 19:365-370. (C) 1995 Wiley-Liss, Inc.