The Effect Of BNP/PKG Pathway In Trigeminal Neurons In Trigeminal Neuralgia Model Of Rats

Objective The trigemina neuropathic pain model was established by infraorbital nerve constriction through lower edge of cheekbone in male SD rats.To investigative the effects of BNP/PKG pathway on trigeminal neurons in trigeminal neuralgia model rats,the animal behavior test and molecular biology technology,such as Elisa and Western Blot,were used.Methods 50 SD Male rats(180-200 g)were trained as standardization and adaptability for a week.Then,the SD Male rats which facial mechanical threshold ? 14.9g were randomly assigned into four groups: sham group,ION-CCI 1 week group,ION-CCI 2week group and ION-CCI 3 week group.After operated,the rats were continuously monitored the tentacles pad of mechanical pain threshold.In ION-CCI group,the rats with facial mechanical pain threshold ? 5g were regarded as success in trigeminal neuropathy(TN)pain model.After the TN model established,the rats were sacrificed at the end of the first week,second week and third week after anesthesia,removed the trigeminal ganglion and extracted the ganglion protein.The NPR-A and PKG protein expressions were detected by Western Blot,and the second messengers,c GMP,were detected by Elisa.The data were statistically analysed to investigate the effect of the BNP/PKG signaling pathway in the trigeminal neuropathic pain model of rat.Results 1.Compared with sham group,the facial mechanical pain thresholds of rat in ION-CCI group were declined continuously.The facial mechanical pain thresholds of rat in ION-CCI group decreased significantly in the seventh days after operation(from16.43 ± 1.16 g reduce to 6.45 ± 1.36 g).There was a significant difference compared with preoperative(P < 0.01).14 days after surgery,mechanical pain threshold of rat in ION-CCI group fell to the lowest(3.04 ± 0.44g),then began slowly to rise,but which still was differences with preoperative and hard to restore to preoperative levels.However,the mechanical pain thresholds of rat in the sham group were no significant differences in preoperative and postoperative(P > 0.05),only manifested a slight fluctuations in the first week,postoperative inflammation was considered.Therefore,the trigeminal neuralgia model of rats by ION-CCI was established successfully.2.Both NPR-A and PKG were expressed in trigeminal ganglion of the two groups by Western Blot detection.Compared with sham group,the expression levels of NPR-A and PKG in the ION-CCI group were significantly higher(P < 0.05).3.The expression of c GMP could be detected by Elisa in the trigeminal ganglion of the two groups,and the expression of c GMP in the ION-CCI group was significantly higher than that in the sham group(P < 0.01).Conclusions In the ION-CCI model of rats,the expression of BNP/PKG signal pathway was increased,which was positively correlated with hyperalgesia in rats.Those results suggest that BNP may be closely related to the occurrence and development of TN.