Enteric neuropathy evoked by repeated cisplatin in the rat

BACKGROUND: Acute administration of the antitumoral drug cisplatin can induce nausea/emesis and diarrhea. The long-term effects of cisplatin on gastrointestinal motility, particularly after repeated administration, are not well known. Because cisplatin is highly neurotoxic, myenteric neurons can be affected. Our aim was to study the prolonged effects of repeated cisplatin administration in a rat model, focusing on gastrointestinal motor function and myenteric neurons. METHODS: Rats received saline or cisplatin (1 or 3 mg kg(-1), i.p.) once weekly for 5 weeks. One week after treatment, both upper gastrointestinal transit and colonic activity were evaluated, and tissue samples from ileum, colon and rectum were processed for histological analysis. Intestinal transit was measured invasively (charcoal method). Colonic activity was determined electromyographically. The gut wall structure was evaluated in sections using conventional histology and immunohistochemistry. Whole-mount preparations from the distal colon were labeled for different markers, including nitric oxide synthase (NOS) and calcitonin-gene related peptide (CGRP) to determine relative proportions of myenteric neurons vs the total neuronal population labeled with HuC/D. KEY RESULTS: One week after repeated cisplatin exposure, the upper gastrointestinal transit rate and colonic activity were dose-dependently reduced. The number of NSE- or HuC/D-immunoreactive myenteric neurons per ganglion was decreased; the proportion of CGRP-immunoreactive neurons was decreased, whereas that of NOS-immunoreactive cells was increased. CONCLUSIONS & INFERENCES: Chronic cisplatin may induce an enteric neuropathy characterized by changes in myenteric neurons associated with marked gastrointestinal motor dysfunction.