Comparison the use of bupivacaine or dexmedetomidin with bee venom applied to the rat sciatic nerve in terms of action potential, block quality and neurotoxicity

Aim: In order to avoid the dose- dependent toxic effects of local anesthetics in peripheral nerve blocks, the use of adjuvant drugs that increase the effectiveness of the block, the comparison of the effects on the duration of the block is only available in clinical studies. Objective of our study is to compare the effects of bee venom added to bupivacain and dexmedetomidine on compound action potential and nerve conduction velocity, to clinically observe the effects of drugs infiltrated into rat sciatic nerves with sensory and motor tests and to examine histologically the presence of degeneration and inflammation in the sciatic nerve sections taken. Material and methods: 35 rats are used in our study, 5 groups are formed. Study groups S: Saline (0.9% NaCl, n=7), group A: Bee venom (bee venom 0.075 mg/ml, n=7), group B: Bupivacain (% 0.5 bupivakain, n =7), group BA: Bupivacine+bee venom ( 0,25 % bupivacaine +bee venom 0.075mg/ml, n=7), group DA: Dexmedetomidine + bee venom (0.005% dexmedetomidine+ bee venom 0.075mg/ml, n:7) capsaicin + 0.25 % bupivacaine, n=7).After the rats were anesthetized by administering ketamine hydrochloride 90 mg/kg and xylazine 3 mg/kg intraperitoneally, the left sciatic nerves are opened by making a longitudinal incision. Control recording are taken by placing two recording electrodes distal and proximal to the explored part. Study drugs are prepared in 0.2 ml volume and dripped onto the rat sciatic nerve. Compound action potentials and nerve conduction velocities are recorded electronically by giving 10 currents of 10 mA at 5-minute intervals with a bioamplifier device (0.min, 5.min, 10.min, 15.min, 20.min, 25.min, 30.min, 35.min, 40.min, 45.min). In order to evaluate the motor and sensory block caused by the drugs independently of the pain due to surgery, 18 hours after the procedure, after the same drug is infiltrated into the right sciatic nerve region, which is the intact side, motor and sensory tests of the rats are performed with 0.min, 30.min, 1, 2, 6, 12 and 24 hours with Hot-Plate and Paw-Withdrawal tests in both extremities. Afterwards, sciatic nerve samples taken from the sacrificed rats are evaluated histopathologically. Results: Time - group interaction is found to be statistically significant in terms of nerve conduction velocity. In additon time main effect and grop main effect are also found to be statistically significant. When compared within the group, a significant correlation was found between the S, DA and BA groups in terms of nerve conduction velocity from the 0th minute to the 45th minute. In our study, in rats administered bee venom alone, both the right and left sciatic nerve has similar results to the saline group, while application of bupivacaine alone caused a significant increase in the number of mast cells. When bupivacaine is applied together with bee venom, it is determined that there was a significant decrease in the number of mast cells. When bee venom is applied together with dexmedetomidine, it is observed that it caused a significant increase in the number of mast cells in the left sciatic nerve where surgical incision is made, and it is found that right sciatic nerve infiltration does not cause a significant change. Conclusion: In particular, the co-administration of 10 mcg dexmedetomidine and 0.015 mg bee venom may cause more acceleration in nerve conduction velocity than the administration of bupivacaine alone or together with bee venom. Bee venom does not cause neurodegeneration when applied to the peripheral nerve, either alone or in combination with bupivacaine and dexmedetomidine. While the administration of bupivacaine alone caused a neuroinflammatory response, no neuroinflammatory response is observed when bee venom is administered together with bupivacaine.