Investigation of the effect of black walnut extract on in vitro ion transport and structure of equine colonic mucosa

• Published in: American journal of veterinary research Vol. 66; no. 3; pp. 443 - 449
• Main Authors: McConnico, R.S, Stokes, A.M, Eades, S.C, Moore, R.M
• Format: Journal Article
• Language: English
• Published: United States 01.03.2005
• Subjects: Analysis of Variance; Animals; Biological Transport, Active - drug effects; Blood Chemical Analysis - veterinary; Body Temperature - drug effects; Clonixin - analogs & derivatives; Clonixin - pharmacology; colon; Colon - drug effects; Colon - pathology; edema; electrical resistance; eosinophils; flunixin; Foot - pathology; Heart Rate - drug effects; hemorrhage; Histological Techniques - veterinary; histology; horses; Horses - physiology; in vitro studies; inflammation; inhibitors; intestinal absorption; intestinal mucosa; Intestinal Mucosa - drug effects; Intestinal Mucosa - pathology; intragastric administration; ion transport; Ion Transport - drug effects; Juglans - chemistry; Juglans nigra; laminitis; microscopy; neutrophils; plant extracts; Plant Extracts - toxicity; Prostaglandin Antagonists - pharmacology; prostaglandins; Respiratory Mechanics - drug effects; Time Factors
• ISSN: 0002-9645; 1943-5681
• DOI: 10.2460/ajvr.2005.66.443

To examine the secretory response (in the presence and absence of prostaglandin inhibition) in vitro and structural alterations of colonic mucosa in horses after intragastric administration of black walnut extract (BWE). 14 adult horses. Seven horses were administered BWE intragastrically and monitored for 11 hours. Tissue samples were obtained from the right ventral, left ventral, and right dorsal colons (RVC, LVC, and RDC, respectively) of the 7 BWE-treated and 7 control horses. Tissue samples were examined via light microscopy, and the extent of hemorrhage, edema, and granulocytic cellular infiltration (neutrophils and eosinophils) was graded. Colonic mucosal segments were incubated with or without flunixin meglumine (FLM) for 240 minutes; spontaneous electrical potential difference and short-circuit current (Isc) were recorded and used to calculate mucosal resistance. Colonic tissues from BWE-treated horses (with or without FLM exposure) had an overall greater Isc during the 240-minute incubation period, compared with tissues from control horses. The resistance pattern in RVC, LVC, and RDC samples (with or without FLM exposure) from BWE-treated horses was decreased overall, compared with control tissues (with or without FLM exposure). Histologically, colonic mucosal tissues from BWE-treated horses had more severe inflammation (involving primarily eosinophils), edema, and hemorrhage, compared with tissue from control horses. In horses, BWE administration appears to cause an inflammatory response in colonic mucosal epithelium that results in mucosal barrier compromise as indicated by decreased mucosal resistance with presumed concomitant electrogenic chloride secretory response, which is not associated with prostaglandin mediation.