The Role of Stem Cells Derived From the Mesenchyme of the Umbilical Cord in Reducing Immunosuppressive Drug Doses Used in Allogenic Transplantations.

BACKGROUND: This study evaluated the potential of Wharton's jelly mesenchymal stem cells with high tolerogenic properties in reducing immunosuppressive dosage and related adverse effects. METHODS: A 4- to 6-week-old, 30-40 g weight, male inbred CD57BL/6 mice were used as skin allograft donors, whereas Balb/c mice with similar characteristics were used as recipients. Wharton's jelly stem cells were obtained from a commercial kit sourced from human umbilical cord. Skin allografts were performed from CD57Bl6 to Balb/c mice (day 0). Group 1 (control) received no treatment. Group 2 received 15 mg/kg cyclosporin A on days 0 to 30. Group 3 received 5.7 × 10 6 and 10.3 × 10 6 cell/kg Wharton's jelly stem cells on days 0 and 3, respectively. Groups 4, 5, and 6 received a combination of 15, 10, and 5 mg/kg per day cyclosporine A (days 0 to 30) with the same stem cell dose with group 3, respectively. Graft rejection was evaluated with digital photography and thermal imaging, histopathology (Banff grading, epithelialization scores, dermoepidermal dissociation), immunochemistry (Ki-67 and Bcl-2), and biochemical methods (interleukin 10, interleukin 2, interferon γ, tumor necrosis factor α) (day 10). Cumulative adverse effects of cyclosporin A occurring in the groups were revealed by histopathological evaluation of kidney and liver (a modified semiquantitative method of infiltration of inflammatory cells around the portal area and lobular region in liver; modification of the Banff rating of proximal tubules and hypertrophia of juxtaglomerular apparatus cells in kidney) (day 30). RESULTS: There was no rejection in groups 2, 4, and 5 until the end of study. These were statistically different versus groups 1 (day 10 ± 0.71), 3 (day 11 ± 0.82), and 6 (day 11 ± 0.58) (all P 's < 0.05). Groups 4 and 5 have exhibited statistically similar findings in histopathological (4 epithelization score: 3.7 ± 1.3; 5 epithelization score: 3.5 ± 0.5; 4 Banff grading score: 0.8 ± 0.6; 5 Banff grading score: 1.0 ± 0.5; both P 's = 1.00), immunohistochemical (4 Bcl-2 score: 3.5 ± 0.5, P = 0.618; 5 Bcl-2 score: 3.4 ± 0.5, P = 1.00; 4 Ki-67 score: 3.7 ± 0.4, P = 1.00; 5 Ki-67 score: 3.5 ± 0.5, both P 's = 1.00), and levels of cytokines (both P 's = 1.00) versus group 2. Adverse effects on kidneys and liver were lowest and statistically similar in groups 3, 5, and 6 (all P 's = 00) versus group 1. CONCLUSIONS: Wharton's jelly mesenchymal stem cells alter bioavailability of cyclosporine, albeit at much lower doses and with fewer systemic adverse effects.

Reconstruction of Previously Failed Alveolar Bone Grafts with Medial Femoral Condyle Flap in Pediatric Cleft Lip and Palate Patients.

Alveolar cleft reconstruction is important to increase the quality of life of cleft lip and palate patients. Usually, alveolar clefts can be reconstructed using bone grafts. However, bone grafting can be insufficient, and other alternatives may be necessary in wide and recalcitrant clefts. The medial femoral condyle (MFC) flap may be the solution for alveolar clefts that are impossible to reconstruct with bone grafting. In this study, the reconstruction of alveolar clefts in the pediatric cleft lip and palate population, using the MFC flap, is described. This study examined 9 pediatric patients whose alveolar clefts were reconstructed prospectively using MFC flap in 2015 and 2019. The age, gender, follow-up times, independent parameters, and existence of concomitant vestibulonasal fistulas of the patients were recorded. Computerized tomography images of the patients were evaluated to detect defect characteristics and evaluate the volume of flap postoperatively. Flap viability was confirmed with bone scintigraphy, and donor area morbidity was evaluated with the Dynamic Gait Index (DGI) in the postoperative period. The study included 7 male and 2 female patients. The mean age of the patients was 13. In addition to an alveolar cleft, 6 patients also had vestibulonasal fistula. It was observed that the volume of the flaps had not changed one year after the operation. The DGI score of all the patients was 24. Existing techniques may be inadequate in the reconstruction of wide and recalcitrant alveolar clefts. MFC flap may be the start of a new era for the treatment of alveolar clefts.

"Abdominoplasty with "En block" removal of the skin island: a safe and fast approach".

The aim of abdominoplasty is to restore a normal abdominal contour, with minimal signs of the surgery. The purpose of this study was to determine the feasibility, safety, and advantages of en block removal of a skin island before upper abdominal dissection during abdominoplasty. Five hundred-forty female patients who underwent abdominoplasties between January 2004 and December 2018 were retrospectively analyzed. In these cases, the planned skin resection was initially made en block, as done with an elliptic skin excision. In this way, symmetric skin removal is achieved. After the removal of this skin, epigastric skin undermining was easily achieved. The mean age of the patients was 41.4 y, and the mean body mass of index was 27.3 kg/m2. The mean operative time for abdominoplasty only was 98 min. Eight patients had minor skin problems, 22 patients needed aspiration for seroma formation, and 7 patients needed scar revision surgery. There was only one hematoma postoperatively. The final position of the scar from the upper vulvar commissure was 8.9 cm. The results obtained were comparable to those of classical abdominoplasty, suggesting that en block removal of the skin before upper flap dissection is a safe maneuver. En block removal of skin island at the start of the surgery has the added advantage of a reduced operative time and acceptable aesthetic outcome, without an increase in complication rates. In cases of planned abdominoplasties, we suggest that removal of the abdominal skin at the beginning of the operation is a safe and feasible procedure.Abbreviation: PDS: polydioxanone.

Median Nerve's Microcirculation in Carpal Tunnel Syndrome: Superb Microvascular Imaging.

BACKGROUND: The objectivity of physical and electrodiagnostic tests is limited in detecting carpal tunnel syndrome and its recurrence. Predicting the median nerve blood supply using superb microvascular imaging will allow exact diagnosis and a good follow-up system. The aims of this study include using superb microvascular imaging to correlate with electromyographic diagnosis, and to determine the impact of surgery on improvement in superb microvascular imaging. METHODS: Between July of 2019 and January of 2020, 32 wrists of 21 patients were evaluated prospectively. After preoperative electrodiagnostic studies and vascular index measurement with superb microvascular imaging, open carpal tunnel release was performed by a single surgeon, and 3 months later standardized superb microvascular imaging was performed. Preoperative vascular indexes were compared with the mild, moderate, and severe electrodiagnostic study results. Preoperative and postoperative vascular index results were compared. RESULTS: The average of the preoperative and postoperative imaging groups was 2.77 and 1.48, respectively, and there was a statistically significant difference between the two groups (p < 0.05). Although no significant difference was found between preoperative and postoperative vascular index values in patients presenting with mild carpal tunnel syndrome (p > 0.05), there was a significant decrease in vascular index values in patients presenting with moderate and severe carpal tunnel syndrome after surgical decompression. CONCLUSIONS: Superb microvascular imaging is emerging as a groundbreaking, new, and reliable technique. Evaluation of the median nerve blood supply is a reliable method that would be helpful for early diagnosis, planning treatment, determining the severity of carpal tunnel syndrome, and postoperative follow-up. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, IV.

High-pressure injection injuries to the upper extremity and the review of the literature.

BACKGROUND: High-pressure injection injuries of the hand are rare severe injuries. This study aimed to present a retrospective analysis of current and possible prognostic factors, treatment modalities and evaluation criteria. METHODS: Ten patients who had high-pressure injection injury to their upper extremity between 2005-2018 were included in this study. All patients were evaluated for the compartment syndrome; if exists fasciotomy and wide debridement were performed. After the first debridement, the second debridement was considered within the first 24 hours. RESULTS: In this study, 10 patients (mean age: 30) were evaluated retrospectively. The injected materials were the animal vaccine, thinner, oil, diesel, water, plastic and paint. Preoperative and postoperative mean WBC levels were 14.73 K/µL and 9.62 K/µL, respectively. Preoperative and postoperative mean neutrophil levels were 11.4 K/µL and 6.49 K/µL, respectively. CONCLUSION: Early and serial debridement and compartment syndrome evaluation are required. Despite these cautions, amputation may occur. Material, injection force and the time elapsed are the main determinants in prognosis. Aggressive debridement is required in high-pressure injection injuries. However, the adequacy of debridement should be evaluated because it is mostly impossible to completely clean the tissue from diesel or thinner. According to the experience of 10 cases in our series, when clinical and macroscopic debridement adequacy was observed, a decrease in WBC and neutrophil levels was observed simultaneously. For this reason, WBC and neutrophil levels may be an indicator of the adequacy of debridement, although these injuries are very rare, larger series are needed for this interpretation.

A novel nerve transfer: The first palmar interosseous motor branch of the ulnar nerve to the recurrent motor branch of the median nerve.

INTRODUCTION: The recovery of recurrent motor branch of the median nerve might be delayed in high level median nerve injuries due to the long reinnervation distance. The aim of this study is to define a novel nerve transfer to restore the opposition and pinch. METHODS: Two fresh frozen hand cadavers were used for the study. The motor branch of the first palmar interosseous muscle of the ulnar nerve was identified and dissected. Thenar branch of the median nerve was dissected from its insertion site. The motor branch of the first palmar interosseous muscle of the ulnar nerve was transferred to the thenar motor branch of the median nerve. Axon counts were examined histopathologically. Clinically this nerve transfer was performed for two female patients with a high-level median nerve injury. Mehta opposition scores were 21 and 20, respectively and the results were satisfactory six months after the surgery. DISCUSSION: Although exploration and repair are recommended as the first treatment for median nerve injuries, the waiting time until the motor branch is reinnervated is critical in high level lesions. Nerve transfers become very important for fast recovery. CONCLUSIONS: This new nerve transfer proposal may be an important step in nerve transfer surgery.

Long-Term Outcomes of Digital Nerve Repair Accompanied by Digital Artery Injury in Flexor Zone 2.

Objectives Better healing results of any tissue or area is closely linked with a well-blood supply in reconstructive surgery. Peripheric nerve healing is closely related to blood supply as well. We aimed to assess whether there was any difference between digital nerve healing with and without extrinsic blood supply. Methods We assessed 48 patients with unilateral digital nerve injury at zone 2. Twenty-four of them had unrepairable arterial injury and other 24 had no arterial injury. The 24 patients in the "unrepaired artery group" (UA) and 24 patients in the "intact artery group" (IA) were compared. Results Mean follow-up time was 17.7 months. The mean two-point discrimination (2PD) was 5.29 mm in IA group and 5.37 mm in UA group. One neuroma in IA group and two neuromas in UA group were determined. We found no statistically significant difference between these groups in terms of neuroma, 2PD, and cold intolerance. The results of British Medical Research Council sensory recovery clinical scale were comparable for these two groups. Conclusion Digital nerve healing is related to numerous factors. We hypothesized that blood flow may be one of these factors; however, at this zone digital artery repair is not the foremost determinant for digital nerve healing. Further researches should be done for upper injury levels. Despite this result, we argue not to leave the digital artery without repairment and we propose to repair both artery and nerve to achieve the normal anatomical integrity and to warrant finger blood flow in possible future injuries.

Foreign Body Inside the Tunnel: A Rare Cause of Acute Cubital Tunnel Syndrome.

Foreign bodies are common entities found in hand surgery practice. However, they are a very rare cause of the acute cubital tunnel syndrome. A 48-year-old male patient was consulted for cubital tunnel symptoms after 2-day unconscious state in the intensive care unit. The ulnar nerve was explored, a piece of glass was removed inside the cubital tunnel, and the nerve was repaired. However, compression neuropathy symptoms due to the acute trauma are interesting. Nerve laceration with a foreign body should be considered in acute-onset cubital tunnel syndrome, in which the foreign body history of a trauma patient cannot be determined explicitly.

Role of Active Range of Motion in Hand and Wrist Joint Photography: A Preliminary Analysis.

INTRODUCTION: Hand photography is effective and advantageous for assessing functional deficits and improvements related to surgery. In this study, it is aimed to investigate whether the correct active range of motion (ROM) is masked by the passive ROM in a wrist joint. METHOD: Eleven patients who were treated for unilateral wrist fractures were included in the study. Photography was performed in all patients by the same surgeon according to the conventional hand surgery photography approach and the active ROM photography approach. Differences between the noninjured side and injured side were assessed. RESULTS: No differences were found between the active ROM and passive ROM during the extension and flexion movements in the noninjured side group. However, in the injured side group, the results from the photographs obtained with the conventional method were significantly better than the results from the photographs obtained when the wrist was actively moved. CONCLUSION: These findings suggest that photographs of wrists during passive motion may affect the results of a treatment or study by showing false positivity. We propose obtaining images of active ROM instead of passive ROM in hand photography.

Arteriovenous Fistula Occurring After Alveolar Arch Repair With Free Medial Femoral Condyle Flap.

The occurrence of an arteriovenous fistula (AVF) after microvascular tissue transfer is extremely rare. This paper presents the development of an AVF in a patient who underwent a free-flap procedure for alveolar arch reconstruction and discusses the mechanisms of AVF formation and its current treatments.

Posterior interosseous flap versus reverse adipofascial radial forearm flap for soft tissue reconstruction of dorsal hand defects.

BACKGROUND: Our objective was to compare the outcomes of dorsal hand defect reconstruction using a posterior interosseous artery flap (PIAF) and a reverse adipofascial radial forearm flap (RARFF). METHODS: From 2008 to 2013, 23 patients who underwent hand soft tissue defect reconstruction with PIAF (11 patients) and RARFF (12 patients) were included in this retrospective study. Reconstruction methods were compared in terms of functionality with disability of the arm, shoulder, and hand (DASH) score and range of motion (ROM) and aesthetically with scar assessment. Operation times, length of hospital stay, and donor site problems were compared. RESULTS: We found no statistically significant differences between PIAF and RARFF in terms of ROM, DASH score, and length of hospital stay. Statistically significant differences were found in operation time, scar assessment, and donor site problems between PIAF and RARFF patients. CONCLUSION: RARFF showed better results than PIAF in dorsal hand defects, but in RARFF, the major arteries of the hand are sacrificed.

The outcome of coronoidectomy in bilateral coronoid process hyperplasia.

OBJECTIVE: Coronoid process hyperplasia (CPH) of the mandible is a rare condition that can be defined as an abnormal bony elongation of histologically normal bone with the symptoms of progressive, painless difficulty in opening the mouth. The purpose of this study is to evaluate the outcomes of five patients with CPH treated by coronoidectomy, relative to post surgery jaw function. METHODS: Five patients with CPH were included in this study. The diagnosis of CPH was confirmed by radiographic and clinical examination of the mandible. All five patients underwent bilateral intraoral coronoidectomy under general anesthesia. The mean maximum interincisal mouth opening for the patients was determined by measurements taken pre-surgery, intraoperative, and at longest follow-up. All five patients underwent postsurgical physical therapy directed towards jaw function. RESULTS: All the patients with limited mouth openings presented with a preoperative maximum interincisal mouth opening of 12.4 mm (range 9-20.3 mm), which was increased to 37 mm (range 22-52 mm) in the operating room after bilateral intraoral coronoidectomy and 42 mm (range 32-52 mm) during the late follow-up. CONCLUSIONS: Patients with limited jaw function related to bilateral CPH can benefit by undergoing bilateral coronoidectomies and physiotherapy.

Foot and ankle reconstruction with vertically designed deep inferior epigastric perforator flap.

INTRODUCTION: The deep inferior epigastric perforator (DIEP) flap is one of the most commonly utilized flaps of reconstructive surgery. Although the horizontal flap design is the most commonly used, this flap can be vertically designed to avoid drawbacks such as excessive tissue dissection, relatively reduced flap perfusion, and scarification of the contralateral flap opportunity. The aim of this report is to present our case series for foot and ankle reconstruction with vertical designed DIEP flap. PATIENTS AND METHODS: The free vertically designed DIEP flaps (VDIEP) were used in eight patients (7 male, 1 female) whose age is in a range of 20-66 years for soft tissue reconstructions in the ankle and foot region over a five-year period. The range of defects' size was from 8 × 5 cm to 15 × 7 cm and the causes were electrical burn, trauma and diabetic foot infections. RESULTS: Flap dimensions varied from 10 × 6 cm to 17 × 9 cm. All the flaps had two or more perforators, and all flaps survived completely. There were no early or late complications. We followed up the patients for 10 months in average. We observed no functional problems, especially in main motions of foot and ankle like eversion, inversion, flexion or extension except one patient. Donor site scars were acceptable in all patients. CONCLUSIONS: The VDIEP flap may be an option for selected lower extremity soft tissue reconstructions, and it may be an alternative to classically designed abdominal flaps.

The Use of Platelet-Rich Plasma for Storage of Surplus Harvested Skin Grafts.

BACKGROUND: There is a need for improved methods and storage media to sustain the tissue viability of autologous skin grafts. OBJECTIVE: To compare histological changes in human skin grafts stored in platelet-rich plasma (PRP) with those of grafts stored in saline. METHODS: Eight circular, 3-mm full-thickness skin graft samples were harvested from the abdominal skin of each of 5 patients scheduled to undergo an abdominoplasty procedure. Four of these graft samples were stored in saline, and the other 4 were stored in saline mixed with PRP prepared from the patient's own venous blood. Histological assessment of the microscopic appearance of the samples was performed on days 5, 8, 11, and 14. The integrity of the epidermal-dermal junction, number of keratinocytes with perinuclear halos, collagen organization, and number of fibroblasts per field were assessed. The cellular apoptosis rate was also measured on these same days. RESULTS: On day 5, significant differences were observed microscopically between the PRP- and saline-stored grafts (P < .05). The grafts preserved in saline exhibited early marked cellular and nuclear swelling with pleomorphism, as well as early nuclear halo formation. The cell viability rate of the PRP group was significantly higher than that of the saline-stored group on day 8 (P < .05). CONCLUSION: Platelet-rich plasma and its inherent growth factors supported longer graft survival; however, its effect lasted only until day 8. Platelet-rich plasma may be beneficial if grafts need to be stored for delayed application(s).

HISTORIQUE: Il faut améliorer les méthodes et les milieux de conservation pour maintenir la viabilité des greffons autologues de peau. OBJECTIF: Comparer les changements histologiques des greffons de peau humaine conservés dans du plasma riche en plaquettes (PRP) à ceux des greffons conservés dans un soluté physiologique. MÉTHODOLOGIE: Les chercheurs ont prélevé huit échantillons de greffons circulaires de trois millimètres de peau pleine épaisseur sur la peau de l'abdomen de chacun des cinq patients qui devaient subir une abdominoplastie. Quatre d'entre eux ont été conservés dans un soluté physiologique et les quatre autres, dans un soluté physiologique mélangé à du PRP préparé à partir du propre sang veineux du patient. Les chercheurs ont procédé à l'évaluation histologique de l'aspect microscopique des échantillons les cinquième, huitième, onzième et quatorzième jours après le prélèvement. Ils ont examiné l'intégrité de la jonction dermoépidermique, le nombre de kératinocytes dotés de halos périnucléaires, l'organisation du collagène et le nombre de fibroblastes par champ. Les mêmes jours, ils ont mesuré le taux d'apoptose cellulaire. RÉSULTATS: Le cinquième jour, les chercheurs ont observé des différences microscopiques significatives entre les greffons conservés dans le PRP et ceux conservés dans un soluté physiologique (P<0,05). Les greffons conservés dans le soluté physiologique présentaient une hypertrophie cellulaire et nucléaire précoce marquée accompagnée de pléomorphisme ainsi que la formation précoce de halos nucléaires. Le huitième jour, le taux de viabilité des cellules du groupe de PRP était considérablement plus élevé que celui des cellules du groupe de soluté physiologique (P<0,05). CONCLUSION: Le plasma riche en plaquettes et les facteurs de croissance inhérents favorisaient une plus longue survie, mais seulement jusqu'au huitième jour. Le plasma riche en plaquettes peut être bénéfique si les greffes doivent être conservées en vue d'être utilisées plus tard.

Reduction of the Areolar Diameter After Ultrasound-Assisted Liposuction for Gynecomastia.

BACKGROUND: One of the clinical aspects characterizing gynecomastia is the enlargement of the nipple-areolar complex (NAC) due to hypertrophic breast glands, and the excessive fatty tissue underneath. OBJECTIVE: The purpose of this study was to quantify the reduction of the areolar diameter after ultrasound-assisted liposuction (UAL) of the male breast. METHODS: The horizontal diameters of the NACs of 30 men who underwent UAL were measured before surgery, 1 month after surgery and 6 months after surgery in a standard fashion. Those patients with surgical gland removals of any kind were not included in this study. RESULTS: The mean age of the patients was 27.9 years, and all of the patients had bilateral grade I, II, or III gynecomastia. The mean diameter of the NACs before surgery was 35.36 mm (range, 26-55 mm), and after surgery, the mean diameter of the NACs was initially reduced to 28.8 mm (range, 23-44 mm) and later to 28.57 mm (range, 23-42 mm). The mean volume of breast tissue aspirated was 382 mL per breast, and the percentage of reduction was 17.3%. The reduction of areola diameter was statistically significant after first month. A significant positive correlation was identified between the liposuction volume and areolar diameter reduction. CONCLUSIONS: In cases of gynecomastia, the removal of the glandular and fatty tissue underneath the areola releases the expanding forces and pressure that enlarge it. In many cases of gynecomastia, UAL alone is effective in reducing the size of the NAC and allows the surgeon to avoid placing scars on the breast.

Exposure to Tumescent Solution Significantly Increases Phosphorylation of Perilipin in Adipocytes.

BACKGROUND: Lidocaine and epinephrine could potentially decrease adipocyte viability, but these effects have not been substantiated. The phosphorylation status of perilipin in adipocytes may be predictive of cell viability. Perilipin coats lipid droplets and restricts access of lipases; phospho-perilipin lacks this protective function. OBJECTIVES: The authors investigated the effects of tumescent solution containing lidocaine and epinephrine on the phosphorylation status of perilipin in adipocytes. METHODS: In this in vitro study, lipoaspirates were collected before and after tumescence from 15 women who underwent abdominoplasty. Fat samples were fixed, sectioned, and stained for histologic and immunohistochemical analyses. Relative phosphorylation of perilipin was inferred from pixel intensities of immunostained adipocytes observed with confocal microscopy. RESULTS: For adipocytes collected before tumescent infiltration, 10.08% of total perilipin was phosphorylated. In contrast, 30.62% of total perilipin was phosphorylated for adipocytes collected from tumescent tissue (P < .01). CONCLUSIONS: The tumescent technique increases the relative phosphorylation of perilipin in adipocytes, making these cells more vulnerable to lipolysis. Tumescent solution applied for analgesia or hemostasis of the donor site should contain the lowest possible concentrations of lidocaine and epinephrine. LEVEL OF EVIDENCE 5.

Reverse Adipofascial Radial Forearm Flap Surgery for Soft-Tissue Reconstruction of Hand Defects.

Objective: The reverse radial forearm flap has been used for soft-tissue hand defect surgical procedures worldwide. One of the major drawbacks of this flap, however, is donor site morbidity, as the donor site is closed with a skin graft. Problems with skin graft donor areas include adhesion, contracture, and wound-healing complications. In this study, only the adipofascial component of a reverse radial forearm flap was used to prevent these problems; in addition, a skin graft was applied over the flap instead of over the donor site. Methods: Between January 2011 and December 2013, a total of 13 hand defects were reconstructed with a reverse adipofascial radial forearm flap. Patients were evaluated for functional results using total active motion criteria and disability of the arm, shoulder, and hand scores, operation time, hospitalization time, and patient satisfaction. Results: All flaps and grafts placed on flaps survived completely and donor sites healed without complications. The total active motion criteria and the disability of the arm, shoulder, and hand score demonstrated that the functional outcomes were successful. Patient satisfaction scores using the visual analog scale had a mean of 88.3 (SD = 2.95) mm. Operation time for the flap surgery was 126.1 (SD = 21.80) minutes, and patients were discharged at an average of 6.3 (SD = 1.44) days. Conclusion: Use of an adipofascial component in reverse radial forearm flap surgery is appropriate for reducing problems with donor site skin grafts. Patients' functional outcomes denoted that the reverse adipofascial radial forearm flap is a reliable and effective method to cover soft-tissue defects of the hand. Level of Evidence: IV.

Evaluation of neuroprotection by melatonin against adverse effects of prenatal exposure to a nonsteroidal anti-inflammatory drug during peripheral nerve development.

The potential ability of melatonin to protect against impairment of the fetal peripheral nerve system due to maternal consumption of diclofenac sodium (DS) was investigated. Eighty-four pregnant rats were divided into seven groups: control (CONT), saline administered (PS), DS administered (DS), DS with low-dose melatonin administered (DS+MLT10), DS with high-dose melatonin administered (DS+MLT50), low-dose melatonin administered (MLT10), and high-dose melatonin administered (MLT50). After the pregnancy, six male newborn rats from each group were sacrificed at 4 and 20 weeks of age. Their right sciatic nerves were harvested, and nerve fibers were evaluated using stereological techniques. Mean numbers of myelinated axons, axon cross-section areas and the mean thickness of the myelin sheet were estimated. Four-week-old prenatally DS-exposed rats had significantly fewer axons, a smaller myelinated axonal area, and a thinner myelin sheath compared to CONT group (p<0.05). Although melatonin at both doses significantly increased axon numbers, only a high dose of melatonin increased the diameter of those axons (p<0.05). At 20-weeks of age, myelinated axon number in the DS group was not only significantly lower than all other groups (p<0.05) but also the cross-sectional area of these axons was smaller than all other groups (p<0.05). There were no differences between the groups regarding the mean thickness of the myelin sheet. The current study indicates that prenatal exposure to DS decreases the number and the diameter of sciatic nerve axons and that melatonin prophylaxis can prevent these effects.