Age-related changes in haematological parameters and biochemical markers of healing in the stomach of rats with acetic acid induced injury

This study examined the changes in haematological and biochemical variables in response to gastric mucosa injury in male Wistar rats divided into four groups according to their ages (3, 6, 12, and 18 months). 0.2 ml of acetic acid was injected intraluminal into the stomach glandular portion of each rat for 45 seconds under anaesthesia. Collection of blood and stomach samples occurred on days 3, 7, 14 and 21 post-induction of gastric ulcer. The results obtained from this study showed 100 % area of gastric mucosa healed in 3-month old rats, 91.72 %, 68.52 % and 62.81 % area of mucosa treated in 6, 12 and 18-month old rats respectively on day 21 post-induction of gastric ulcer. Increased circulation of blood cells in younger rats occurred, neutrophil-lymphocyte ratio (NLR) was decreased in younger rats (3 and 6 months) significantly (p < 0.05) when compared to older rats (12 and 18 months). Lipid peroxidation and glutathione (GSH) levels were elevated in older rats (12 and 18 months) significantly (p < 0.05) when compared to younger rats (3 and 6 months). In comparison, superoxide dismutase (SOD) and catalase levels were decreased in older rats (12 and 18 months) significantly (p < 0.05) when compared to younger rats (3 and 6 months). Histological evaluation showed evidence of early healing with re-epithelialisation and angiogenesis in younger rats, but older rats showed delayed healing. The study showed that the slower rate of healing of gastric ulcer with advancing age in rats might be due to reducing circulating blood cells and anti-inflammatory activities during healing via a lipid peroxidation-dependent mechanism.