Late hyaluronidase injection in local anesthesia: Morphofunctional evaluation in rat sciatic nerve block

Introduction: Despite the enhancing effects of hyaluronidase (HYAL) over duration of anesthesia, this enzyme could cause adverse effects when injected concomitantly with local anesthetics in dental blocks. Objective: This study aimed to assess the tissue alterations caused by a local anesthetic protocol consisting of a late HYAL injection and confirm its functional effectiveness. Materials and Methods: The protocol efficacy was proved by evaluating sensory and motor functions in rats. The sciatic nerve was blocked with 2% lidocaine (LID) with epinephrine (n = 25). Thirty minutes later, 75 TRU/ml HYAL was injected into the same site (experimental group, LID/HYAL). One week later, this protocol was repeated in the contralateral hindlimb, injecting only HYAL's vehicle (control group, LID/vehicle [LID/V]). To observe the integrity of the local tissues, histological specimens were obtained 1, 24, 48, and 72 h after treatment with LID/HYAL or LID/V (n = 16 each) and stained with hematoxylin/eosin and picrosirius red. Results: Local inflammation was similar in both groups. The integrity of the nerve fibers was preserved, in spite of some inflammation-associated injuries in the surrounding tissues. The reversible tissue disorganization caused by HYAL, probably facilitated the diffusion of the residual anesthetic to the nerve, resulting in a prolonged anesthetic effect (P < 0.05). Conclusions: No irreversible morphological alterations are caused by the administration of HYAL prior the end of the LID-induced block. Moreover, this protocol prolongs LID's anesthetic effect.

Keywords

Anesthesia adjuvants, anesthetics, hyaluronic acid, hyaluronoglucosaminidase

Citation

Tempestini-Horliana Anna Carolina Ratto, Lamers Marcelo Lazzaron, Yonamine Maurício, Aulestia-Viera Patricia Verónica, Santos Marinilce Fagundes Dos, Borsatti Maria Aparecida . Late hyaluronidase injection in local anesthesia: Morphofunctional evaluation in rat sciatic nerve block. Indian Journal of Dental Research. 2019 Sep; 30(5): 692-696

URI

https://imsear.searo.who.int/handle/123456789/192300

Collections

Indian Journal of Dental Research

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