Effect of Tetrodotoxin Pellets in a Rat Model of Postherpetic Neuralgia
Bihong Hong,
Jipeng Sun,
Hongzhi Zheng,
Qingqing Le,
Changsen Wang,
Kaikai Bai,
Jianlin He,
Huanghuang He,
Yanming Dong
Affiliations
Bihong Hong
Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China
Jipeng Sun
Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
Hongzhi Zheng
School of pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
Qingqing Le
Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
Changsen Wang
Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
Kaikai Bai
Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
Jianlin He
Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
Huanghuang He
Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
Yanming Dong
Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China
Postherpetic neuralgia (PHN) is nerve pain caused by a reactivation of the varicella zoster virus. Medications are used to reduce PHN but their use is limited by serious side effects. Tetrodotoxin (TTX) is a latent neurotoxin that can block neuropathic pain, but its therapeutic index is only 3–5 times with intravenous or intramuscular injection. Therefore, we prepared oral TTX pellets and examined their effect in a rat model of PHN induced by resiniferatoxin (RTX). Oral TTX pellets were significantly effective at preventing RTX-induced mechanical and thermal allodynia, and similar to pregabalin. Moreover, oral administration of TTX pellets dose-dependently inhibited RTX-induced PHN compared with intramuscular administration of TTX injection. We also studied the pharmacokinetic profile of TTX pellets. Our results showed that the blood concentration of TTX reached a maximum plasma concentration (Cmax) at around 2 h, with an elimination half-life time (t1/2) of 3.23 ± 1.74 h after intragastric administration. The median lethal dose (LD50) of TTX pellets was 517.43 μg/kg via oral administration to rats, while the median effective dose (ED50) was approximately 5.85 μg/kg, and the therapeutic index was 88.45. Altogether, this has indicated that oral TTX pellets greatly enhance safety when compared with TTX injection.
