ABSTRACT
BACKGROUND: Gastric ulcer healing requires the reconstitution of epithelial structures and underlying connective tissue through cellular proliferation, migration, and differentiation. The systemic application of growth hormone (GH) has shown anabolic effects in postoperative and burn therapy by increasing protein synthesis and attenuating protein catabolism. There is also evidence that GH stimulates cell proliferation and differentiation. In this study we evaluated the impact of GH on gastric ulcer healing. MATERIAL/METHODS: Gastric ulcers were induced with a cryoprobe in male Wistar rats (285+/-11 g). The first group of rodents (n=10) received a daily subcutaneous dose of 2.5 mg/kg growth hormone for seven days. The second group (n=10) received only vehicle. After 7 days, ulcer size was determined photoplanimetrically. Cell proliferation and new vessel growth in the ulcer margin were evaluated by quantitative immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and smooth muscle actin (SMA), respectively. RESULTS: The systemic application of GH caused a significant increase in body weight (332+/-7 g vs. 289+/-13 g; p=0.007). Ulcer size was also reduced significantly compared with controls (5.6+/-0.8 mm2 vs. 9.9+/-1 mm2; p=0.005). Immunohistochemical analysis revealed a significant increase in cell proliferation (79.7+/-0.9% pos. cells vs. 64.7+/-1.9% pos. cells; p=0.0001) as shown by PCNA expression, and a significant increase in new vessel growth as demonstrated by SMA expression (1762+/-124 cells/mm2 vs. 1067+/-77 cells/mm2; p=0.0001). CONCLUSIONS: Growth hormone accelerates gastric ulcer healing by stimulating cell proliferation and angiogenesis.
