BLADDER ACELLULAR MATRIX GRAFT IN RATS - ITS NEUROPHYSIOLOGIC PROPERTIES AND MESSENGER-RNA EXPRESSION OF GROWTH-FACTORS TGF-ALPHA AND TGF-BETA

To assess the neurophysiologic properties and molecular mechanisms of the bladder acellular matrix graft (BAMG), we performed cystometric an d neurophysiologic studies in male Sprague-Dawley rats (n = 46) at var ying intervals; The animals were assigned to 3 groups: 1) normal, 2) p artial cystectomy (>50%), and 3) partial cystectomy (>50%) and graftin g with a BAMG of equal size. Additionally, matrix-grafted and host bla dders were processed for analysis of mRNA expression of transforming g rowth factor (TGF)-alpha, TGF-beta 1, TGF-beta 2, and TGF-beta 3 by re verse transcriptase polymerase chain reaction. Matrix-grafted bladders showed a significantly higher bladder capacity at 3 and 6 weeks and 4 months than those with partial cystectomy alone, and a significantly higher bladder capacity at 4 months than in normal controls (P less th an or equal to 0.01). Residual urine volume was significantly increase d at 4 months. Electrostimulation of the pelvic nerve provoked general ized bladder contractions, a response that was reduced by atropine and hexamethonium. Variable induction of TGF-alpha, TGF-beta 1, TGF-beta 2, and TGF-beta 3 gene transcription was evident in the BAMG, with pro minent mRNA expression of TGF-alpha and TGF-beta 1 6 months after surg ery. These cystometric results and detrusor responses to stimulation p rovide further evidence that graft components do not interfere with ho st components. Matrix-grafted rat bladders generate, although not incr eased over time, adequate intravesical pressure responses to produce s ustained voiding. Gene expression of different growth factors may be s ignificant in understanding their role in the development and differen tiation of the BAMG for partial bladder replacement. (C) 1998 Wiley-Li ss, Inc.