Interleukin-6 in the pathogenesis of posterior capsule opacification and the potential role for interleukin-6 inhibition in the future of cataract surgery

Shedding light on eye disease in obesity: A review

Obesity is known to be associated with numerous ocular manifestations, including but not limited to, diabetic retinopathy (DR), age-related macular degeneration (AMD), cataracts, glaucoma, and dry eye disease. This review aims to provide an overview of the ophthalmological findings in obesity. A literature search was conducted using PubMed and Cochrane databases for studies describing randomized clinical trials, meta-analyses, systematic reviews, and observational studies published from 1 January 2017 to 1 April 2023. The search terms used included relevant keywords such as 'obesity', 'body mass index', 'waist-to-hip ratio', 'bariatric', 'ophthalmology', 'eye disease', 'myopia', 'retinopathy', 'glaucoma', and 'cataract'. This literature search was performed on 1 April 2023. Obesity is associated with increased risk of developing DR, a sight-threatening complication of diabetes mellitus. Similarly, obesity has been shown to increase risk of AMD, cataracts, glaucoma, and ocular surface disease. Multiple mechanisms linking obesity to ophthalmic disease have been proposed. Adipose tissue produces various inflammatory cytokines that can affect ocular tissues, leading to disease progression. Additionally, obesity is associated with systemic metabolic changes that can influence ocular health. Bariatric surgery has been shown to be protective against development of ophthalmic disease. Obesity is a significant risk factor for several ophthalmological diseases. Healthcare providers should encourage weight loss in patients with overweight or obesity to prevent or delay the onset of ocular complications. Further research is needed to better understand the underlying mechanisms of this association, and to identify effective strategies for preventing or managing ophthalmic disease in patients with obesity.

Self-assembled coating with a metal-polyphenolic network for intraocular lens modification to prevent posterior capsule opacification

Posterior capsule opacification (PCO) is a main complication after cataract surgery and intraocular lens (IOLs) implantation and is attributed to residual lens epithelial cells (LECs) migrating to the IOL surface and posterior capsules. IOL surface modification has been a newly-developing research filed in recent years; however, the applicability and economical acquisition of modified materials remain unsolved. In this study, we first applied a metal-polyphenolic network coating with a self-assembly technique on the IOL surface by using tannic acid (TA) combined with AlCl3, which are easily acquire and applying on the IOL surface to solve the IOL transmittance affair. Using wound healing and Transwell assay to verify AZD0364 inhibits cell migration (P< 0.05), the lipopolysaccharide-induced macrophage inflammation model to verify pterostilbene (PTE) inhibits the inflammatory reaction (P< 0.01). By optimizes its self-assembly coating parameters and calculating its drug release kinetics, we successfully loaded these two drugs on the coating, named TA (AZD0364/PTE) IOL. Its surface morphology characteristics were analyzed by scanning electron microscope, x-ray photoelectron spectrometer and water contact angle. The optical performance was carefully investigated by optical instruments and equipment (n= 3). Thein vitroresults showed that TA (AZD0364/PTE) IOL can significantly inhibit cell adhesion and acute inflammation (n= 3,P< 0.0001). Importantly, afterin vivoimplantation for 28 d with eight rabbits PCO models in two groups, the TA (AZD0364/PTE) IOL group maintained clear refracting media and decreased the inflammatory reaction compared with the original IOL group (P< 0.05). This study provides a new applicable and economical strategy for preventing PCO and offers a reference for the next generation of IOLs that benefit cataract patients.

Inflammation-Involved Proteins in Blood Serum of Cataract Patients-A Preliminary Study

Approximately 50% of all global blindness is caused by cataract in adults aged ≥50 years. The mechanisms of the disease are most arguably related to a redox imbalance and inflammation; therefore, the aim of the study was to evaluate the processes associated with inflammation in cataract patients. Twenty-four patients aged 22-60 years (62.5% females) participated in the study, with 33 controls aged 28-60 years (66.7% females). Venous blood serum of the subjects was examined for alpha 1-antitrypsin, as well as selected lysosomal enzymes and adipokines. The activities of lysosomal enzymes, as well as the activity of alpha 1-antitrypsin and the concentrations of c-reactive protein and leptin, were similar in the patients versus the controls. The concentrations of interleukin 6 and resistin were lower, in turn, whereas omentin-1 and adiponectin were higher. Moreover, the study revealed the existence of many linear relationships between the parameters, including multiple linear regression, especially gender-wise. No systemic inflammation was probably noted in the cataract patients tested; nevertheless, the deregulation of adiponectin, omentin-1 and resistin secretion was observed.

Research Progress Concerning a Novel Intraocular Lens for the Prevention of Posterior Capsular Opacification

Posterior capsular opacification (PCO) is the most common complication resulting from cataract surgery and limits the long-term postoperative visual outcome. Using Nd:YAG laser-assisted posterior capsulotomy for the clinical treatment of symptomatic PCO increases the risks of complications, such as glaucoma, retinal diseases, uveitis, and intraocular lens (IOL) pitting. Therefore, finding how to prevent PCO development is the subject of active investigations. As a replacement organ, the IOL is implanted into the lens capsule after cataract surgery, but it is also associated with the occurrence of PCO. Using IOL as a medium for PCO prophylaxis is a more facile and efficient method that has demonstrated various clinical application prospects. Thus, scientists have conducted a lot of research on new intraocular lens fabrication methods, such as optimizing IOL materials and design, and IOL surface modification (including plasma/ultraviolet/ozone treatment, chemical grafting, drug loading, coating modification, and layer-by-layer self-assembly methods). This paper summarizes the research progress for different types of intraocular lenses prepared by different surface modifications, including anti-biofouling IOLs, enhanced-adhesion IOLs, micro-patterned IOLs, photothermal IOLs, photodynamic IOLs, and drug-loading IOLs. These modified intraocular lenses inhibit PCO development by reducing the residual intraoperative lens epithelial cells or by regulating the cellular behavior of lens epithelial cells. In the future, more works are needed to improve the biosecurity and therapeutic efficacy of these modified IOLs.

Randomized Controlled Trial Comparing 1-Year Outcomes of Low-Energy Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification

Purpose: To compare 1-year clinical outcomes, phacoemulsification energy, aqueous profiles, and patient-reported outcomes of low-energy femtosecond laser-assisted cataract surgery (FLACS) vs. conventional phacoemulsification.

Methods: The study is a randomized controlled trial (RCT) with paired-eye design. Eighty-five patients were randomized to receive FLACS (Ziemer LDV Z8) in one eye and conventional phacoemulsification in the fellow eye. Clinical data including phacoemulsification energy parameters (cumulative dissipated energy, phacoemulsification power, and phacoemulsification time), uncorrected and corrected distance visual acuities (UCDVA and BCDVA), manifest refraction spherical equivalent (MRSE), central corneal thickness (CCT), endothelial cell count (ECC), anterior chamber flare, and post-operative complications were obtained for 1 year. Aqueous humor was collected for the analysis of prostaglandin (PGE)₂, cytokines and chemokines concentrations. Patients' reported-outcomes on surgical experiences were evaluated using an in-house questionnaire.

Results: Compared to conventional phacoemulsification, the low-energy assisted FLACS group had significantly less ECC reduction at 3 months (1.5 ± 0.3% vs. 7.0 ± 2.4%; P < 0.01) and 1 year (8.2 ± 2.8% vs. 11.2 ± 3.6%; P = 0.03). There were no significant differences in the phacoemulsification energy parameters, UCDVA, BCDVA, MRSE, CCT, occurrence of post-operative complications between the 2 groups throughout post-operative 1 year. Patients' subjective surgical experiences, including the surgical duration and perceived inconvenience, were comparable between the 2 groups. FLACS resulted in significantly higher aqueous PGE₂ (P < 0.01), interleukin (IL)-6 (P = 0.03), IL-8 (P = 0.03), and interferon (IFN)-γ (P = 0.04) concentrations and greater anterior chamber flare at 1 day (P = 0.02).

Conclusions: Our RCT presented 1-year longitudinal clinical and laboratory data. The long-term ECC result was more favorable in low-energy FLACS. The rest of the intraoperative and post-operative outcomes, as well as patient-reported outcomes, were comparable between these two procedures.

Transforming growth factor-β2-mediated mesenchymal transition in lens epithelial cells is repressed in the absence of RAGE

Transforming growth factor-β2 (TGFβ2)-mediated epithelial to mesenchymal transition (EMT) in lens epithelial cells (LECs) has been implicated in fibrosis associated with secondary cataracts. In this study, we investigated whether the receptor for advanced glycation end products (RAGE) plays a role in TGFβ2-mediated EMT in LECs. Unlike in the LECs from wild-type mice, TGFβ2 failed to elicit an EMT response in LECs from RAGE knockout mice. The lack of RAGE also diminished TGFβ2-mediated Smad signaling. In addition, treatment with TGFβ2 increased IL-6 levels in LECs from wild-type mice but not in those from RAGE knockout mice. Treatment of human LECs with the RAGE inhibitor FPS-ZM1 reduced TGFβ2-mediated Smad signaling and the EMT response. Unlike that in wild-type lenses, the removal of fiber cell tissue in RAGE knockout lenses did not result in elevated levels of α-smooth muscle actin (α-SMA), fibronectin (FN), and integrin β1 in capsule-adherent LECs. Taken together, these results suggest that TGFβ2 signaling is intricately linked to RAGE. Targeting RAGE could be explored as a therapeutic strategy against secondary cataracts.

Factors Affecting Posterior Capsule Opacification in the Development of Intraocular Lens Materials

Posterior capsule opacification (PCO) is the most common complication arising from the corrective surgery used to treat cataract patients. PCO arises when lens epithelial cells (LEC) residing in the capsular bag post-surgery undergo hyper-proliferation and transdifferentiation into myofibroblasts, migrating from the posterior capsule over the visual axis of the newly implanted intraocular lens (IOL). The developmental pathways underlying PCO are yet to be fully understood and the current literature is contradictory regarding the impact of the recognised risk factors of PCO. The aim of this review is firstly to collate the known biochemical pathways that lead to PCO development, providing an up-to-date chronological overview from surgery to established PCO formation. Secondly, the risk factors of PCO are evaluated, focussing on the impact of IOLs’ properties. Finally, the latest experimental model designs used in PCO research are discussed to demonstrate the ongoing development of clinical PCO models, the efficacy of newly developed IOL technology, and potential therapeutic interventions. This review will contribute to current PCO literature by presenting an updated overview of the known developmental pathways of PCO, an evaluation of the impact of the risk factors underlying its development, and the latest experimental models used to investigate PCO. Furthermore, the review should provide developmental routes for research into the investigation of potential therapeutic interventions and improvements in IOL design in the aid of preventing PCO for new and existing patients.

Expression Profiles of Inflammatory Cytokines in the Aqueous Humor of Children after Congenital Cataract Extraction

Purpose

To investigate the change in cytokine microenvironment of the aqueous humor (AH) after surgery in children with congenital or developmental cataracts.

Methods

AH samples were obtained from 59 eyes diagnosed with a congenital or developmental cataract. Thirty-three of these eyes were aphakic following previous cataract surgery and were scheduled for secondary intraocular lens (IOL) implantation. Additionally, AH samples from 26 eyes that had not undergone surgery were taken. AH samples were then analyzed for 16 different inflammatory immune mediators using multiplex bead immunoassays and enzyme-linked immunosorbent assay (ELISA).

Results

The mean interval between secondary IOL implantation and original cataract surgery was 24.85 months (range, 9–60 months). Levels of IL-6, IP-10 (CXCL10), MCP-1 (CCL2), and IL-2 were significantly elevated in the AH of eyes after surgery compared to eyes that did not undergo surgery (P < 0.001, P = 0.047, P = 0.006, P = 0.012, respectively). There was significant correlation between the levels of TGF-β2 and intraocular pressure (IOP) in postsurgical and nonsurgical eyes (r = 0.532, P = 0.006; r = 0.57, P = 0.001). Postsurgical outcomes, such as iris adhesions, capsular fibrosis, and capsular contraction, were found not to be significantly associated with cytokine levels in the AH after surgery; however, IL-6 levels in capsular exposure eyes were significantly higher than those in cortical closure eyes (P = 0.023).

Conclusions

To our knowledge, this is the first study to report significantly increased proinflammatory cytokine levels in the AH after congenital cataract extraction in children. Our study also suggests that this proinflammatory state may be maintained for a prolonged period of time. Overall, these results give us insight into the relationship between the inflammatory cytokine microenvironment of the aqueous humor and potential long-term complications following congenital cataract surgery.

Translational Relevance

The inflammatory cytokine microenvironment of the aqueous humor might help explain potential long-term complications after surgery in patients with congenital or developmental cataracts.

Phacoemulsification in patients with uveitis: long-term outcomes

BACKGROUND

To assess the long-term outcomes of phacoemulsification and intraocular lens (IOL) implantation in eyes with uveitis.

METHODS

One hundred and five eyes of 81 patients, who underwent phacoemulsification and IOL implantation between January 2009 and July 2016, were included in this study. The demographic data, preoperative clinical findings, postoperative outcomes, and intraoperative and postoperative complications were recorded. All collected data and risk factors with regard to visual prognosis were analyzed with the help of the Statistical Package for the Social Sciences version 20.0 software program (IBM Corp., Armonk, NY, USA).

RESULTS

During follow-up (mean: 35.2 ± 22.2 months), corrected distance visual acuity (CDVA) improved in 87.7% of all eyes and reached a level of 0.3 LogMAR or greater in 61.3% of eyes. Postoperative complications included posterior capsule opacification (50.9%), posterior synechiae (21.7%), cystoid macular edema (16%), epiretinal membrane (13.2%), glaucoma (11.3%), increased intraocular pressure (8.5%), and severe inflammation (6.6%). Uveitis recurred in 55.7% of all eyes. The risk for the development of cystoid macular edema was found to be associated with recurrence in the early postoperative period. Low visual acuity risk was 11.1-fold higher with macular scarring (p = 0.001) and 14-fold higher with optic atrophy (p < 0.001), respectively.

CONCLUSIONS

With appropriate management during the pre- and postoperative periods, phacoemulsification and IOL implantation surgery can be safe and effective in eyes with uveitis. However, great caution must be taken to prevent complications both before and after the surgery.

Interleukin-6 inhibition in the management of non-infectious uveitis and beyond

Background

Uveitis consists of a spectrum of inflammatory disorders characterized by ocular inflammation. The underlying pathophysiology consists of a complex interplay of various inflammatory pathways. Interleukin 6 is an important mediator of inflammation in uveitis and constitutes focus of research toward development of newer biological therapies in the management of non-infectious uveitis.

Main body

Pan-blockade of the inflammatory pathways with steroids is generally the first step in the management of acute non-infectious uveitis. However, long-term therapy with steroids is associated with systemic and ocular side effects, thereby necessitating the need for development of steroid sparing agents. IL-6 is a cytokine produced by various immune cells, in response to molecular patterns and affects multiple inflammatory cells. In particular, IL-6 is involved in differentiation of CD-4 cells into Th-17 cells that have been shown to play a significant role in various immune-mediated diseases such as uveitis. This broad-spectrum immunomodulatory activity makes IL-6 an excellent target for immunomodulatory therapy. Tocilizumab was the first IL-6 inhibitor to demonstrate efficacy in humans. It inhibits IL-6 from binding to both membrane-bound and soluble receptor and can be administered via intravenous (IV) and subcutaneous (SC) routes. It has been FDA approved for treatment of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). Following the approval in systemic diseases, its efficacy was demonstrated in various uveitis studies including a phase 2 clinical trial (STOP-Uveitis). Overall, tocilizumab has shown a good safety profile with the risk of malignancy consistent with that expected in patients with rheumatoid arthritis. However, tocilizumab therapy has been shown to increase the risk for gastrointestinal perforation and dose-dependent neutropenia. Following the success of tocilizumab, several other agents targeting the IL-6 pathway are in the pipeline. These include sirukumab, siltuximab, olokizumab, clazakizumab, and EBI-031 which target IL-6; Sarilumab and ALX-0061 act on the IL-6 receptor.

Conclusion

Studies have shown that IL-6 inhibitors can be effective in the management of NIU. In addition, the levels of IL-6 are elevated in other ocular vascular diseases such as retinal vein occlusion and diabetic macular edema. The roles of IL-6 inhibition may be broadened in the future to include the management of retinal vascular diseases and non-uveitic macular edema.

Risk factors for the occurrence of visual-threatening posterior capsule opacification

Background

To evaluate the potential risk factor of visual-threatening posterior capsule opacification (PCO) via the analysis of National Health Insurance Research Database in Taiwan.

Patients and methods

A total of 8571 patients (3767 male and 4804 female) were recruited in the study group and 17,142 patients (7534 male and 9608 female) in the control group. Patients undergoing cataract surgery, acrysof single-piece intraocular lens implantation and Nd:YAG capsulotomy were selected as the study group. After exclusion which aimed to standardize the ocular condition and exclude the possibility that patients undergoing cataract surgery and Nd:YAG capsulotomy in different eyes, each patient in the study group was age-gender matched to two patients undergoing cataract surgery but without Nd:YAG capsulotomy. The demographic data, systemic disease, and ocular co-morbidities were obtained and analyzed. Adjusted odds ratio (OR) of each demographic data and co-morbidities to the development of visual-threatening PCO, and adjusted OR of co-morbidities to visual-threatening PCO develop within 1 year postoperatively.

Results

The dry eye disease (DED), glaucoma, uveitis, age-related macular degeneration (AMD), hyperlipidemia, peptic ulcer disease and liver disease showed significant crude OR while the DED, glaucoma, AMD, hyperlipidemia and peptic ulcer disease revealed a significant adjusted OR. In the subgroup analysis, the DED, glaucoma, AMD, and hyperlipidemia still illustrated a higher adjusted OR to develop visual-threatening PCO within 1 year after the cataract surgery.

Conclusion

The DED, glaucoma, AMD, hyperlipidemia and peptic ulcer disease may serve as the risk factor for the developing of visual-threatening PCO.

Lens Epithelial Cells Initiate an Inflammatory Response Following Cataract Surgery

Purpose

Lens epithelial cell (LEC) conversion to myofibroblast is responsible for fibrotic cataract surgery complications including posterior capsular opacification. While transforming growth factor beta (TGFβ) signaling is important, the mechanisms by which the TGFβ pathway is activated post cataract surgery (PCS) are not well understood.

Methods

RNA-seq was performed on LECs obtained from a mouse cataract surgery model at the time of surgery and 24 hours later. Bioinformatic analysis was performed with iPathwayGuide. Expression dynamics were determined by immunofluorescence.

Results

The LEC transcriptome is massively altered by 24 hours PCS. The differentially expressed genes included those important for lens biology, and fibrotic markers. However, the most dramatic changes were in the expression of genes regulating the innate immune response, with the top three altered genes exhibiting greater than 1000-fold upregulation. Immunolocalization revealed that CXCL1, S100a9, CSF3, COX-2, CCL2, LCN2, and HMOX1 protein levels upregulate in LECs between 1 hour and 6 hours PCS and peak at 24 hours PCS, while their levels sharply attenuate by 3 days PCS. This massive upregulation of known inflammatory mediators precedes the infiltration of neutrophils into the eye at 18 hours PCS, the upregulation of canonical TGFβ signaling at 48 hours PCS, and the infiltration of macrophages at 3 days PCS.

Conclusions

These data demonstrate that LECs produce proinflammatory cytokines immediately following lens injury that could drive postsurgical flare, and suggest that inflammation may be a major player in the onset of lens-associated fibrotic disease PCS.

Effects of Interleukin-6 on posterior capsular opacification

The purpose of this work was to determine the effects of interleukin-6 (IL-6) on the development of posterior capsular opacification (PCO) in vitro and in vivo. Western blot and real-time PCR were used to test the IL-6-induced epithelial-mesenchymal transition (EMT) marker α-smooth muscle actin (α-SMA), the extracellular matrix (ECM) markers fibronectin (Fn) and type I collagen (COL-1), transforming growth factor β₂ (TGF-β₂), and the activation and role of the JAK/STAT3 signaling pathway in human lens epithelial cells (HLECs). Immunocytofluorescence staining was performed to detect gp130 and IL-6Rα expression in HLECs. Rat PCO models were then established to examine the impact of STAT3 knockdown by shRNA adeno-associated virus on PCO development, and immunohistochemical staining was performed to detect the expression of Fn in the anterior and posterior capsule in vivo. We found that IL-6 promotes the expression of Fn, COL-1, TGF-β₂, p-JAK2 and p-STAT3 in HLECs but exerts little effect on α-SMA. The JAK/STAT3 inhibitor WP1066 effectively suppressed the IL-6-induced expression of Fn and COL-1 in lens epithelial cells. STAT3 knockdown effectively inhibited the development of PCO in rats and significantly reduced the expression of Fn in the anterior and posterior capsule. These data suggest that IL-6 contributes to the development of PCO by promoting TGF-β₂ activation and ECM synthesis through a JAK/STAT3 signaling-dependent mechanism. Furthermore, inhibiting JAK/STAT3 signaling effectively impairs both PCO development in rats and ECM synthesis in the lens capsule.

Interleukin-6 participation in pathology of ocular diseases

Interleukin-6 (IL-6) is a multifunctional cytokine that affects a variety of cells in the body such as osteoclasts, hepatocytes, endothelial cells, epithelial cells, white and red blood cells and etc. Elevated levels of IL-6 have been detected in many ocular diseases. Studies show that IL-6 has a major role in the pathology of glaucoma, CRVO, macular edema, ocular neovascularization, posterior capsule opacity formation, keratitis, dry eye disease, allergic eye disease, ocular autoimmune disease, corneal chemical burn, ocular inflammation and so on. IL-6 does its effects through the classic or trans-signal pathways in cells. Blocking of IL-6 signal pathways via Tocilizumab or other chemicals and therapeutics will help to overcome complications related to ocular diseases.

Surface Modification of Intraocular Lenses

Objective:

This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs).

Data Sources:

All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect.

Study Selection:

The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded.

Results:

Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO₂, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments.

Conclusion:

The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs.

IL-6 as a corneal wound healing mediator in an in vitro scratch assay

Corneal healing process under inflammatory conditions is not fully understood. We aimed at determining the effect of an inflammatory (presence of IL-6) or anti-inflammatory (presence of IL-10) environment and a mixture of both in the expression of IL-6 signaling pathway mediators, and on corneal wound healing in an in vitro scratch assay. For that purpose, human corneal epithelial cells were cultured until confluence. The effect of IL-6 (10 ng/ml), IL-10 (20 ng/ml) or IL-6 + IL-10 exposure on the expression of IL-6R, gp130, and STAT3 was determined by Western blotting and quantitative PCR, at different time points. The monolayer was mechanically wounded using a sterile 10 μl pipette tip. Wound healing rate in the presence or absence of these cytokines was measured immediately after cytokine exposure and after 4, 8, and 24 h. The effect of mitomycin C on wound healing rate, in control and IL-6-stimulated cells, was also evaluated. Detection of proliferative cells was performed with an EdU imaging kit. For the visualization of migrating cells, cold methanol-fixed cells were incubated with an α-actinin antibody. For the statistical analysis a two-factor design of experiment method was applied. Levene test was used to contrast equality of variances. If variances were equal, ANOVA was performed to test the equality of means. If variances were not equal, a Mood's median test was performed. We observed that IL-6 and IL-10 stimulation, and their combination, increased gp130 production at different time points. STAT3 production was increased in IL-6-stimulated cells, at 72 h. An increase in pSTAT3 production was found in IL-6- and IL-10-stimulated cells, that was sustained in time in IL-6 + IL-10 co-stimulated cultures. Scraped areas had an initial width of 570.57 ± 75.82 μm. In IL-6-exposed cells wound healing closure was faster than in control cells or IL-10-exposed cells. After 8 h, wound width in IL-10-exposed cells, was also significantly smaller than that of control cells. Cells exposed to IL-6 + IL-10 had the slowest wound healing rate, similar to control cells. Wounds were closed after 24 h regardless the experimental condition. Mitomycin C exposure increased the wound closure rate in every experimental condition. No significant differences in the percentage of proliferative cells at the edge of the scratch and in distant areas of the monolayer were found. At the edge of the scratch, some actin filaments of non-proliferative cells were directed through the cell-free area, independently of the stimulating condition. In conclusion, the presence of IL-10 and, most importantly, of IL-6, increased the wound healing rate in an in vitro corneal wound healing model. The combination of both cytokines did not have a synergistic action in wound healing. In our model, wound closure was the result of the combination of cell proliferation and cell migration.