Effects of radiofrequency thermocoagulation on trigeminal ganglions in rabbits

Abstract

To study the histological effects of different temperatures and durations of radiofrequency on the trigeminal ganglions in rabbits. Trigeminal ganglions of 80 rabbits were treated by R-2000B RF thermocoagulation at 60, 70, 80°C respectively and the thermal electrode of 50 mm long and 0.4 mm in diameter. The treaded trigeminal ganglions were removed for HE (hematoxylin & eosin) dying at Days 1, 7, 14 and 28. And the expressions of neurofilament protein (NF200), acetylcholinesterase (ACHE) and muscarinic receptors (M-receptor) were observed after an immunohistochemical detection of HE positive samples. The positive manifestations of HE were degeneration of trigeminal ganglionic cells, the distribution of nerve fibers and a loss of myelinic membrane. The positive features of immunohistochemistry were as follows: NF200: dark yellow-brown particles within cytoplasm of ganglionic cells and nerve fibers cells; ACHE: deep yellow-brown particles within cytoplasm of ganglion cells and nerve fibers cells; M-receptor: yellow-brown particles within cytoplasm of ganglionic cells and nerve fibers cells. The expressions of NF200, ACHE and M-receptor increased while the temperature and radio frequency time remained constant. There was no significant difference between the expression rates of NF200, ACHE, M receptor at the same temperature for 1 and 3 minutes (P > 0.05). When treated for the same time, the expressions of NF200, ACHE and M receptor decreased more significantly at 70°C versus 60°C (P < 0.05). However, there was no significant difference between 70°C and 80°C (P > 0.05). 70°C may be a suitable temperature at which radiofrequency causes the greatest harm to trigeminal ganglions so that nerve activity decreases significantly.