PTU-171Oestrogen plays a critical role in murine epithelial healing in a buccal model of reflux injury

IntroductionSevere oesophagitis, oesophageal adenocarcinoma (OAC) are more common in men and post-menopausal women. Female sex hormones may protect pre-menopausal women from gastro-oesophageal reflux mediated mucosal damage, delaying the onset of BO and development of OAC in women. We have demonstrated more rapid mucosal healing and less inflammatory response in females in a murine buccal model of reflux injury. We have used a model comparing intact female mice with oestrogen deprived mice (by removal of their ovaries) to determine if this effect may be oestrogen driven.MethodsFemale mice (C57 strain) were divided into three groups of 5: ovariectomised (OVX), OVX with oestrogen replacement (OVX+E) (50 mu g oestradiol per day dorsal implants) and intact females. 1.5mm buccal ulcers were induced using a punch biopsy and treated with 1M hydrochloric acid. Wounds were harvested at day 4. Wound planimetry and immunohistochemistry for macrophages and neutrophils were compared in a blinded fashion.ResultsResults: Re-epithelialisation was greatest in the intact group (mean 0.88mm SEM plus or minus 0.22) compared to the OVX (0.51mm plus or minus 0.13) or OVX+E (0.79mm plus or minus 0.12) groups. The difference between intact and OVX groups was statistically significant (p=0.04). Neutrophil wound infiltration (cells/wound area) was greater in the OVX group (1842 plus or minus 75) than the intact group (1279 plus or minus 169, p There was a greater number of macrophages in the OVX wounds (1556 plus or minus 128) than both OVX+E (984 plus or minus 95 (p=0.02) and the intact group (1026 plus or minus 91, p=0.01).ConclusionLack of systemic oestrogen delays mucosal healing in buccal wounds. This may explain gender differences in the oesophageal epithelial response to gastro-oesophageal reflux injury.Competing interestsNone declared.