Gastric Mucosa Re-epithelisation, Oxidative Stress and Apoptosis During Healing of Acetic Acid-Induced Ulceration in Thyroxine Treatment and Thyroidectomy on Rats

Abstract

We had earlier reported that thyroxine treatment accelerates gastric ulcer healing while thyroidectomy delayed the processes of healing. Thus, this research was carried out to gain more insight about the mechanisms by which thyroxine affect ulcer healing. Male albino rats (160 – 200g) were used. They were divided into four groups viz: control, thyroidectomised, thyroidectomised with thyroxine treatment (100μg/kg/day) and Sham operated animals treated with thyroxine. After 35 days of drug treatment and surgery, ulcer was induced in stomach of animals using acetic acid method. Animals were sacrificed on days 3, 7 and 10 post ulcer induction for ulcer healing assessment. Healing was observed by measuring ulcer depth and width, lipid peroxidation and DNA fragmentation during healing. Result showed that by day 10, thyroxine treatment significantly decreased the ulcer width and depth by 69.3 ± 1.5% and 65.7 ± 1.4% (p< 0.01) respectively while thyroidectomy significantly reduced by (34.1 ± 0.5%) and (35.6 ± 7.5%) (p< 0.05) compared with control (40.5 ± 2.2%) and (53.9 ± 1.6%). Thyroxine treated animals had highest reduction in lipid peroxidation (57.0 ± 0.5% [p< 0.001]) and the least reduction in thyroidectomised animals (15.7 ± 1.6% [p< 0.05]) as compared with control (19.6 ± 1.6%). DNA fragmentation was low in all groups by day 3, but by day 10 the higher DNA fragmentation in thyroxine treated animal supports the rapid reduction in ulcer dimensions recorded. In conclusion, thyroxine treatment accelerated gastric ulcer healing by accelerating mucosa re-epithelization, reduction of lipid peroxidation and apoptotic mechanism.

Keywords: Ulcer Healing; Thyroxine; Lipid peroxidation; Apoptosis