Exosomes and Their Potential in Repairing Inferior Alveolar Nerve Injuries: A Review of Current Evidence

Vishanth M et al | DOI: 10.65188/nurexus.1045

Page 29

Journal of MedVerse Research & Practice

ISSN: 3107-4278

Exosomes and Their Potential in Repairing Inferior Alveolar Nerve

Injuries: A Review of Current Evidence

Dr.M Vishanth

, Dr. H Nishan

Postgraduate, Professor

Department of ENT, Salem Government Medical College, Salem

Email: Vishanth1234@gmail.com

Submission Date: 28.08.2025

Accepted Date: 26.09.2025

Published Date: 30.09.2025

DOI: 10.65188/nurexus.1045

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits

unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Injury to the inferior alveolar nerve (IAN) is a frequent and debilitating complication of dental and maxillofacial

procedures, often resulting in sensory deficits that significantly affect quality of life. Conventional treatments,

including pharmacological management, microsurgical repair, and autologous nerve grafting, are limited by donor

site morbidity, incomplete functional recovery, and variable outcomes. Exosomes, nano-sized extracellular vesicles

secreted by various cell types such as mesenchymal stem cells and Schwann cells, have emerged as a promising, cell-

free therapeutic approach for peripheral nerve regeneration. These vesicles carry a rich cargo of proteins, mRNAs,

and microRNAs, which collectively promote axonal growth, modulate Schwann cell behavior, regulate

neuroinflammation, and enhance angiogenesis, creating a favorable microenvironment for nerve repair. Preclinical

studies have demonstrated that exosome therapy can stimulate neurite outgrowth, promote Schwann cell proliferation

and remyelination, and reduce inflammatory responses through macrophage polarization and suppression of pro-

inflammatory cytokines. Advances in delivery systems, including localized injections, hydrogel-based sustained

release, and 3D-printed nerve conduits, have further improved their therapeutic potential. While most evidence

remains preclinical, exosome-based interventions show superior safety profiles with minimal immunogenicity,

tumorigenicity, and donor site complications compared to traditional grafts or stem cell therapies. This review

summarizes the biological mechanisms, cellular sources, optimization strategies, and preclinical evidence supporting

the application of exosomes in IAN injury. With continued translational research and clinical validation, exosome

therapy holds significant promise as a minimally invasive and effective strategy for enhancing functional recovery

following inferior alveolar nerve injuries.

Keywords: Inferior alveolar nerve, Nerve regeneration, Exosomes, Schwann cells, Axonal growth

Introduction

Injuries to the inferior alveolar nerve (IAN) are a frequent and often debilitating consequence of various

dental and maxillofacial interventions, including third molar extractions, dental implant placement,

orthognathic surgeries, and management of mandibular trauma. Such injuries commonly lead to sensory

abnormalities like paraesthesia, hypoesthesia, or dysesthesia, which can significantly diminish a patient’s

quality of life [1]. Although peripheral nerves possess an inherent ability to regenerate, recovery after IAN

damage is often partial and unpredictable. Traditional treatment strategies—including pharmacological

therapies, microsurgical repair, and autologous nerve grafting—are constrained by challenges such as donor

site morbidity, scar formation, and inconsistent functional recovery.

In recent years, exosomes have gained attention as a promising cell-free therapeutic option in regenerative

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medicine [2]. These nanoscale extracellular vesicles, typically ranging from 40 to 160 nm in diameter, are

secreted by various cell types, including Schwann cells and mesenchymal stem cells. They are enriched

with bioactive components such as proteins, messenger RNAs, and microRNAs, which facilitate

communication between cells and regulate critical processes involved in nerve repair [3]. Exosomes

support regeneration by promoting axonal growth, activating Schwann cells, modulating

neuroinflammatory responses, and enhancing angiogenesis. Compared to conventional grafting techniques,

exosome-based therapies are minimally invasive and carry a reduced risk of immune rejection or donor site

complications [4].

This review aims to provide an in-depth examination of the biological properties of exosomes and highlight

their emerging role in peripheral nerve regeneration, with a particular emphasis on their potential

therapeutic application in the management of inferior alveolar nerve injuries.

Exosomes in Nerve Regeneration: Biological Basis

Exosomes are small extracellular vesicles, typically ranging from 40 to 160 nm, which originate from

multivesicular bodies and are secreted into the extracellular environment via exocytosis. The molecular

composition of exosomes varies depending on the type and physiological state of the parent cell, but they

generally contain a complex cargo of proteins, lipids, messenger RNAs, and microRNAs that can

profoundly influence recipient cells. In the setting of peripheral nerve regeneration, such as after inferior

alveolar nerve injury, exosomes demonstrate a range of therapeutic activities [5].

These vesicles exert neurotrophic effects by transporting essential growth factors, including brain-derived

neurotrophic factor (BDNF), nerve growth factor (NGF), glial cell line-derived neurotrophic factor

(GDNF), and neurotrophin-3 (NT-3), all of which support axonal regrowth and enhance neuronal survival.

Exosomes also promote angiogenesis at sites of nerve injury by delivering pro-angiogenic molecules such

as vascular endothelial growth factor (VEGF) and microRNA-126, improving blood supply and facilitating

tissue repair [6].

In addition to their regenerative and vascular effects, exosomes possess immunomodulatory properties.

They can induce macrophage polarization toward the anti-inflammatory M2 phenotype while suppressing

pro-inflammatory cytokine production, thereby creating a microenvironment favourable for nerve healing.

Specific exosome microRNAs, including miR-21 and miR-219, have been shown to enhance Schwann cell

proliferation, differentiation, and remyelination, which are critical steps in effective peripheral nerve repair.

Through these multifaceted actions—neurotrophic support, angiogenesis, immune modulation, and

Schwann cell activation—exosomes emerge as highly promising biological mediators for improving

functional recovery after peripheral nerve injury [7].

Axonal Regeneration and Schwann Cell Modulation by Exosomes

Exosomes are key mediators in peripheral nerve repair, particularly in processes such as axonal

regeneration and Schwann cell (SC) modulation, which are critical for recovery following inferior alveolar

nerve injuries. These extracellular vesicles serve as carriers of a diverse array of bioactive molecules -

including proteins, microRNAs (miRNAs), and messenger RNAs (mRNAs) - that regulate essential cellular

pathways involved in nerve regeneration (Yu et al., 2021; Supra et al., 2023) [6,7].

A central mechanism of action involves the uptake of exosomes by injured axons and surrounding Schwann

cells. The molecular cargo of exosomes supports neuronal survival, enhances growth cone activity, and

promotes axonal elongation by inducing a pro-regenerative state in the neurons.

Exosomes also exert a profound influence on Schwann cell function. They stimulate SC dedifferentiation,

proliferation, and activation, processes vital for debris clearance and the formation of a microenvironment

conducive to axonal growth. Activated Schwann cells, in turn, release neurotrophic factors and form

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guiding pathways through the distal nerve stump, facilitating precise axonal navigation and functional

recovery [8].By simultaneously promoting direct axonal repair and optimizing the supportive functions of

glial cells, exosomes provide a coordinated, multifaceted approach to peripheral nerve regeneration,

making them a highly promising candidate for therapeutic applications in clinical settings.

Exosome-Mediated Axonal Regrowth and Inflammatory Modulation

Exosomes play a critical role in promoting axonal regrowth and guiding regenerating nerve fibres by

delivering a variety of signalling molecules, including specific microRNAs such as miR-21 and key

neurotrophic factors. These bioactive cargos stimulate neurite extension and axonal elongation by

modulating intracellular signalling pathways. For example, exosomes can downregulate phosphatase and

tension homolog (PTEN) while activating the PI3K/Akt pathway, mechanisms that are vital for neuronal

survival and efficient axonal regeneration [9].

Beyond their direct effects on axons, exosomes exert important immunomodulatory actions that facilitate

nerve repair. Following nerve injury, a regulated inflammatory response is essential for clearing cellular

debris; however, uncontrolled or prolonged inflammation can hinder regeneration, promote scar formation,

and obstruct axonal growth. Exosomes help balance this response by inducing macrophage polarization

toward the anti-inflammatory M2 phenotype and suppressing pro-inflammatory cytokine production. This

modulation minimizes fibrotic scarring and establishes a microenvironment favourable for neuronal repair

and functional recovery. By simultaneously enhancing axonal regrowth and shaping a supportive

inflammatory milieu, exosomes provide a dual mechanism that positions them as potent therapeutic agents

with significant potential to improve outcomes in peripheral nerve injuries [10].

Exosomes in Vascular Regeneration and Immunomodulation for Nerve Repair

Vascular regeneration is essential for effective nerve repair, as an adequate blood supply delivers oxygen

and nutrients while removing metabolic waste, thereby supporting the survival and function of regenerating

nerve tissue. Exosomes, particularly those derived from mesenchymal stem cells (MSCs), have shown

significant potential in promoting angiogenesis. They carry pro-angiogenic molecules, including

microRNAs such as miR-126 and growth factors like vascular endothelial growth factor (VEGF), which

stimulate endothelial cell proliferation and migration. This leads to the formation of new capillaries at the

site of injury, creating a metabolically favourable environment for axonal growth and Schwann cell activity

[11].

Figure 1: Role of extracellular Vesicles and exogenous stimuli in peripheral nerve regeneration

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In addition to their pro-vascular effects, exosomes play a pivotal role in modulating inflammation and

immune responses following nerve injury. They transport anti-inflammatory proteins and regulatory

microRNAs that help suppress excessive inflammatory signalling and maintain immune homeostasis. This

function is particularly important in the oral and maxillofacial region, where surgical trauma and microbial

exposure can exacerbate inflammatory responses. By promoting macrophage polarization toward the

regenerative M2 phenotype, exosomes help minimize secondary tissue damage, reduce fibrosis, and

support timely resolution of inflammation [12,13].

Through the dual actions of enhancing vascularization and regulating immune responses, exosomes act as

versatile agents that not only directly facilitate neural repair but also optimize the surrounding tissue

environment. This makes them a promising therapeutic strategy for promoting peripheral nerve

regeneration, including applications in inferior alveolar nerve injuries [14].

Cellular Sources and Optimization Strategies for Exosome-Based Nerve Regeneration

The regenerative efficacy of exosomes in peripheral nerve repair is closely linked to their cellular origin, as

different cell types produce vesicles with unique molecular profiles and functional capacities. Adipose-

derived stem cells (ADSCs) are among the most extensively studied sources, generating exosomes enriched

with neurotrophic factors, anti-inflammatory molecules, and pro-angiogenic mediators. These vesicles have

shown considerable promise in promoting axonal regeneration and functional recovery. Strategies to further

enhance their therapeutic potential, such as preconditioning ADSCs with pharmacological agents like

FK506 (Tacrolimus), have produced variable outcomes, with some studies reporting improved regenerative

effects while others observed limited benefit (Rau et al., 2021) [15].

Beyond ADSCs, exosomes derived from fibroblasts and Schwann cells have attracted attention for their

cargo of specialized RNAs and proteins that support axonal growth and simultaneously inhibit fibrotic scar

formation, a major impediment to nerve repair (Zhou et al., 2023) [16]. Each cellular source presents

distinct advantages and challenges. Mesenchymal stem cell (MSC)-derived exosomes are valued for their

rich growth factor content and ability to modulate immune responses and stimulate angiogenesis, although

their therapeutic consistency can be influenced by donor variability and cell passage number. Schwann cell-

derived exosomes are particularly effective at promoting remyelination and guiding regenerating axons, but

large-scale production remains technically demanding. Neural stem cell (NSC)-derived exosomes facilitate

neurogenesis and axonal elongation, yet their limited availability restricts widespread clinical use.

Recently, gingival mesenchymal stem cells (GMSCs) have emerged as a promising, accessible source of

exosomes, offering potent immunomodulatory effects and minimal risk of immune rejection. Although

research is still in early stages, GMSC-derived exosomes may provide a practical and scalable option for

future therapeutic applications. Overall, careful selection of the exosome-producing cell type, along with

strategies to enhance their regenerative properties, is crucial for developing effective cell-free approaches

for nerve repair and functional restoration [13,14].

Preclinical Evidence and Emerging Applications of Exosomes in Inferior Alveolar Nerve Injury

Recent preclinical studies underscore the therapeutic potential of exosomes in peripheral nerve repair, with

most research focusing on models of sciatic and facial nerve injuries. For instance, Li et al. (2020)

demonstrated that exosomes derived from human umbilical cord mesenchymal stem cells (MSCs) enhanced

sciatic nerve regeneration by activating the PI3K/Akt signalling pathway, a critical mediator of neuronal

survival and axonal growth. Similarly, Zhang et al. (2022) showed that exosome miR-21 reduced

inflammation and stimulated Schwann cell proliferation in a rat model of nerve injury, highlighting both

anti-inflammatory and neurodegenerative effects. Although direct investigations in inferior alveolar nerve

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injury (IANI) remain limited, these findings can be reasonably extrapolated due to the shared biological

mechanisms governing peripheral nerve repair [15]. MSC-derived exosomes in IANI models hold

particular promise for enhancing Schwann cell functions, including proliferation, migration, and

myelination, which collectively support axonal regeneration and facilitate functional reinnervation of target

muscles [16].

To maximize therapeutic outcomes, advanced delivery strategies are being developed. Direct local injection

at the injury site provides targeted effects, while sustained-release systems - such as exosome-loaded

hydrogels composed of biocompatible materials like chitosan, fibrin, or collagen-help maintain effective

concentrations over time. Additionally, innovative approaches like 3D-printed nerve conduits embedded

with exosomes offer structural guidance for axonal growth across nerve gaps. Stem cells from dental

tissues, including dental pulp stem cells and periodontal ligament stem cells, also exhibit neurotrophic and

immunomodulatory properties, making them particularly relevant for dental-specific nerve injuries such as

IANI. These preclinical findings provide a strong foundation for developing clinical protocols aimed at

restoring function following inferior alveolar nerve injuries [17].

Advantages, Challenges, and Future Directions of Exosome Therapy for IAN Regeneration

Exosome-based therapies offer several notable advantages over traditional approaches such as autologous

nerve grafts, particularly for inferior alveolar nerve (IAN) repair. A major benefit is their low

immunogenicity, which substantially reduces the risk of immune rejection compared to conventional grafts.

Unlike certain stem cell treatments, exosomes also carry minimal tumorigenic potential. Additionally,

exosome therapy eliminates donor site morbidity associated with autologous graft harvesting, making it a

safer and less invasive option [18]. Exosomes are also easier to handle, store, and standardize, improving

logistical feasibility in clinical settings. Their ability to enable localized, targeted delivery-via controlled-

release systems or direct injections - further enhances their therapeutic utility, which is often challenging

with conventional grafts.

Despite these advantages, several challenges must be addressed before exosome therapy can become a

mainstream clinical option. Standardization remains a key concern, as optimal cell sources, dosing

regimens, and delivery methods need to be clearly established and validated. Most current evidence comes

from preclinical animal models, underscoring the need for well-designed clinical trials (Phase I/II) focusing

on IAN or trigeminal nerve injuries to determine safety, efficacy, and reproducibility in human patients

[19].

Looking ahead, future strategies may involve combining exosomes with biomaterials, such as injectable

hydrogels or 3D-printed nerve conduits, to provide site-specific, sustained therapeutic effects. Advances in

genetic engineering could allow donor cells to produce exosomes enriched with critical regenerative

molecules like miR-133b, BDNF, or NT-3. The development of point-of-care systems for producing

autologous, patient-specific exosomes could further minimize immunological risks and improve clinical

outcomes. Collectively, these innovations, coupled with rigorous translational research, position exosome

therapy as a promising and potentially transformative approach for the management of inferior alveolar

nerve injuries [20].

Discussion on Recent Literatures

Study

(Year)

Model / Design

Exosome

source

Delivery / Method

Key findings

Main

limitations

Yu et al

2021

In vivo (rat)

experimental

Schwann

cell-derived

Local implantation /

graft containing

Enhanced axonal

regeneration and

Limited to

animal models

Vishanth M et al | DOI: 10.65188/nurexus.1045

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exosomes

remyelination

Namini et

., 2023

(review)

Systematic review

of preclinical

studies

MSC-

derived

Multiple delivery

strategies

summarized

(injection, hydrogels,

conduits)

Activated

PI3K/Akt

pathway,

improved axonal

growth

Donor

variability

Xia et al

2024

Review /

translational

perspective

PRP + MSC

exosomes

Discusses local

injection and

biomaterial carriers

Combined

therapy boosted

nerve repair

Complex design

Li et al

2025

(MDPI)

Preclinical studies

summarized

iPSC-derived

Discusses

mechanisms

(paracrine signalling,

PI3K/Akt activation)

Promoted

regeneration, safe

short-term

Long-term

safety unclear

Zhang et

., 2024

(J Control

Release)

In vivo /

translational study

MSC

exosomes +

3D conduit

Local delivery;

combined therapy

Sustained release

improved repair

Manufacturing

challenges

Wang et

., 2025

In vivo (rat

sciatic)

safety/efficacy

Hypoxia-

conditioned

MSC

Local injection:

safety assessment

Increased pro-

regenerative

factors

Needs

standardization

Yao et al

2025 / 3D

conduit

papers

Bioengineering +

in vivo tests

Schwann

cell-derived

Exosome-loaded

hydrogel inside

aligned 3D nerve

conduits

Enhanced axonal

regeneration and

remyelination

Limited to

animal models

Zeng et

., 2025

Preconditioning

study (in vitro / in

vivo)

MSC-

derived

Preconditioning of

parent cells prior to

exosome harvest

Activated

PI3K/Akt

pathway,

improved axonal

growth

Donor

variability

Summary

Injuries to the inferior alveolar nerve (IAN) during dental and maxillofacial procedures can cause sensory

disturbances that impair quality of life. Conventional treatments like nerve grafting and microsurgery often

yield inconsistent outcomes. Exosomes, nanosized vesicles secreted by various cells, have emerged as a

promising cell-free therapy for nerve regeneration. They deliver bioactive molecules that promote axonal

growth, Schwann cell activation, angiogenesis, and immune regulation, creating an environment favorable

for nerve repair.

Derived from sources such as mesenchymal stem cells (MSCs), Schwann cells, and gingival stem cells,

exosomes enhance regeneration through pathways like PI3K/Akt activation and macrophage M2

polarization. They offer several advantages—low immunogenicity, no donor site morbidity, and ease of

handling but require further standardization and clinical trials. With advancements in genetic engineering

and biomaterial-based delivery systems, exosome therapy holds strong potential as a safe, minimally

invasive, and effective approach for inferior alveolar nerve regeneration.

Conclusion

Exosome-based therapy offers a novel and promising strategy for enhancing nerve regeneration following

inferior alveolar nerve injury. Through their ability to modulate Schwann cell activity, support axonal

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growth, and establish a favourable regenerative microenvironment, exosomes have the potential to address

many of the limitations associated with current treatment approaches. Ongoing research, along with

carefully designed clinical studies, will be crucial to translating these preclinical advances into effective

and standardized therapies for dental nerve injuries.

Conflict of Interest: Nil

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