Objective To investigate the influence of nerve growth factor (NGF) on neuroal regeneration of somatovisceral heterogenic reinnervation using a rat phrenic-to-vagus anastomosis model. Methods Forty male SD rats, aging 3 months and weighing 200 g, were selected and randomly divided into 3 groups. In group A (n=10, control group), phrenic and vagus
nerves were exposed and no neurorraphy was performed. In group B (n=15) and group C (n=15), both nerves were transected and proximal stump of phrenic nevers were microsurgically anastomosed to the distal stump of vagus nerves. Postoperatively, group C was intraperitoneally injected with NGF (20 μg/kg·d), while groups A and B were given matching sal ine solution. Twelve weeks later, cardiac function was examined under electrical stimulation of the regenerated nerve. Light and electron microscopies were used to examine the heterogenic regenerated nerve, and the passing rate of axon and thickness of myel in sheath were calculated. Results Under electrical never stimulation in groups A, B, and C, the decreases of blood pressure were (20.12 ± 2.57), (10.63 ± 2.44), and (14.18 ± 2.93) mmHg (1 mmHg=0.133 kPa), respectively; and the decreases of heart rate were (66.77 ± 9.96), (33.44 ± 11.82), and (43.27 ± 11.02)/minutes, respectively. In group B, the decrease ampl itudes of blood pressure and heart rate were 52.83% and
50.08% of group A, respectively. Blood pressure and heart rate in group C also decreased dramatically; the decrease ampl itudes of blood pressure and heart rate in group C were 70.48% and 64.80% of group A. There were significant differences in the decrease ampl itudes of blood pressure and heart rate (P  lt; 0.05) between group B and group C. Morphological observation showed that heterogenic nerve fibers had the structure of matured myel in sheath and their axons could regenerate into the vagus nerve. In group B and group C, the passing rates of axon were 66.83% ± 4.46% and 81.63% ± 3.56%, respectively; and the thicknesses of myel in sheath were (0.25 ± 0.10) μm and (0.46 ± 0.08) μm, respectively; showing significant differences (P  lt; 0.05) between group B and group C. Conclusion Heterogenic nerve is primarily a somatic motor nerve; NGF can promote the axons of heterogenic nerve to regenerate into the parasympathetic nerve.

Citation： DU Shouchao,ZHANG Shimin,YE Xiaosheng,YE Hongfeng.. EXPERIMENTAL STUDY ON PROMOTION OF SOMATO-VISCERAL HETEROGENIC REINNERVATION WITH NERVE GROWTH FACTOR IN RAT PHRENIC-TO-VAGUS ANASTOMOSIS MODEL. Chinese Journal of Reparative and Reconstructive Surgery, 2010, 24(5): 584-587. doi: Copy