ADAPTATION OF RABBIT SMALL-INTESTINAL BRUSH-BORDER MEMBRANE ENZYMES AFTER EXTENSIVE BOWEL RESECTION

Short lengths of small intestine may be resected without significantly affecting the digestive and absorptive capacity; however, extensive r esection produces varying degrees of malnutrition. This study was unde rtaken to define the adaptive changes in the remaining small intestine of two of the jejunal and ileal mucosal brush-border membrane enzymes after extensive small bowel resection in rabbits. Thirty adult New Ze aland White rabbits underwent a 50% to 60% jejunoileal enterectomy wit h end-to end anastomosis. Maltase activity (UE/g protein) increased fr om 152 (preoperative) to 392 at 3 weeks in the proximal segment and fr om 85 to 259 in the distal segment; these levels decreased to 222 and 155 in the respective segments at 6 weeks, AOP activity (UE/g protein) increased from 154 (preoperative) to 171 in the proximal segment and 171 to 256 in the distal segment at 3 weeks, and was 131 and 288 in th e respective segments at 6 weeks. This marked increase in the mucosal brush-border enzymatic activities at 3 weeks postoperatively was assoc iated with a 28% increase in bowel length. By 6 weeks the enzyme level s had decreased slightly; however, there was a persistent 41% increase in bowel length over that immediately postoperation. The mucosal surf ace area increased from 295 mm(2) immediately postoperation to 5,337 m m(2) at 3 weeks and 7.635 mm(2) at 6 weeks, a 250% increase, The autho rs conclude that there is an immediate compensatory increase in villus length as well as brush-border enzymatic expression in the remaining intestine that gradually declines as the small intestinal surface area continues to increase and the bowel lengthens with time. Copyright (C ) 1995 by W.B. Saunders Company