Extracapsular Lens Extraction Research Articles

The miRNA-34a/Sirt1/p53 pathway in a rat model of lens regeneration.

BackgroundThere are many molecular factors involved in Wolffian and corneal lens regeneration, but few in lens regeneration by lens epithelial cells (LECs) in mammals. Silent information regulator 1 (Sirt1) has a variety of physiological functions, such as a transport hub, and is involved in pathological conditions. We studied the expression of the microRNA (miRNA)-34a/Sirt1/tumor protein p53 (p53) pathway in a rat model of lens regeneration.MethodsWe performed extracapsular lens extraction in 42 healthy female Sprague-Dawley rats. Slit lamp observation was performed at 3, 7, 14, 21, 30, 60 and 90 days postoperatively, and the rats were killed humanely by cervical dislocation at 30, 60 and 90 days postoperatively to remove the eyeballs. We performed semiquantitative immunofluorescence analysis of Sirt1, p53, alpha-smooth muscle actin (α-SMA) and fibronectin (fn), and real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) to detect the relative expressions of miRNA-34a, Sirt1, p53, aquaporin 0 (AQP 0), γA-crystallin, and beaded filament structural protein 1 (BFSP1) mRNA in the lens and posterior capsule.ResultsThe posterior capsule wrinkled at 3 days and it increased at 7 days. At 14 days, pearl-like opacification appeared under the capsule, with increasing shrinkage. Greater mass-like proliferators in size and number accumulated under the capsule and at the equator after 21 days. A regenerated lens developed in the central depression of the capsule at 30 days, slightly protruding from it. Despite being thickened at 60 days, the central depression persisted, with a smaller change at 90 days than at 60 days. Although the relative mRNA expression of miRNA-34a and p53 in the lens and posterior capsule decreased over time (P=0.000), that of Sirt1 increased (P<0.01). α-SMA was uniformly expressed in the crystals and gradually decreased, while fn expression gradually increased.ConclusionsmiRNA-34a expression decreased and Sirt1 expression increased during lens regeneration. Furthermore, p53 expression decreased, thus reducing apoptosis. Therefore, Sirt1 acted as a key factor in the pathway, and played a protective role in lens regeneration.

Enhancement of lens extraction-induced MCP-1 upregulation and microglia response in long-term diabetes via c-jun, stat1 and ERK

AimDiabetic patients are reported to have a higher incidence of cataract surgery-induced retinal complications, possibly due to retinal inflammation. Our goal is to identify the key inflammatory cytokines, cells and regulatory pathways involved. Main methodsDiabetes mellitus (DM) induced by streptozotocin and control mice received extracapsular lens extraction (ECLE) in one eye. Neuroretinas were collected at postoperative day1(P1), day2(P2), and day7(P7). BV2 cells were harvested under the treatment of high glucose, lipopolysaccharide (LPS) and inhibitors. The method of qPCR, western blot and immunohistochemistry were used to identify the expression of cytokines and signaling pathways. Key findingsECLE induced increased inflammation in the neuroretina of surgery eye with a peak at P1. MCP-1 surge in long-term diabetes mellitus (LDM) mice at P1 is higher than short-term diabetes mellitus (SDM) mice and normal mice. Significant activation of c-jun and c-fos were found in LDM compared to normal and SDM. Advanced activation of stat1 and ERK was found at P1 in LDM instead of at P2 in SDM and Normal. Activation of microglia/macrophage was also detected in the LDM mice. Besides the inhibition of c-jun/JNK, MCP-1 expression can be attenuated by inhibiting stat1 and ERK under high glucose condition after LPS stimulation. SignificanceEnhancement of lens extraction-induced MCP-1 upregulation and microglia response in long-term diabetes might be due to the activation of cjun, stat1 and ERK, which provided potential therapeutic targets to attenuate retinal inflammation after surgery in diabetic individuals.

Curcumin Inhibits Proliferation and Epithelial-Mesenchymal Transition in Lens Epithelial Cells through Multiple Pathways.

Background Posterior capsule opacification (PCO), a complication of extracapsular lens extraction surgery that causes visual impairment, is characterized by aberrant proliferation and epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). Curcumin, exerting inhibitive effects on cell proliferation and EMT in cancer, serves as a possible antidote towards PCO. Methods Cellular proliferation of LECs after treatment of curcumin was measured with MTT assay and flow cytometry. The transcriptional and expressional levels of proteins related to proliferation and EMT of LECs were quantified by western blotting and real-time PCR. Results Curcumin was found to suppress the proliferation of LECs by inducing G2/M arrest via possible inhibition of cell cycle-related proteins including CDK1, cyclin B1, and CDC25C. It had also inactivated proliferation pathways involving ERK1/2 and Akt pathways in LECs. On the other hand, curcumin downregulated the EMT of LECs through blocking the TGF-β/Smad pathway and interfering Notch pathway which play important roles in PCO. Conclusions This study shows that curcumin could suppress the proliferation and EMT in LECs, and it might be a potential therapeutic protection against visual loss induced by PCO.

Surgical removal of cataract in an Asiatic black bear (Ursus thibetanus) by phacoemulsification and aspiration.

A twenty-year-old male Asiatic black bear (Ursus thibetanus) presented at the Rakuno Gakuen University Animal Medical Center with a 10-year history of bilateral blindness and cataracts. Surgical treatment of bilateral cataracts by extracapsular lensextraction using phacoemulsification and aspiration (PEA) was performed under general anesthesia. An anterior capsulectomy was performed using micro iris scissors and micro anterior lens capsule forceps. The cataract was removed with PEA using the two-handed technique. After surgery, systemic corticosteroids, anti-inflammatory drugs and antibiotics were administered. After cataract removal, the bear had recovered vision, and good quality vision has been maintained to date (15 months). PEA can be a safe and effective treatment for cataracts that impair vision in bears.

Aldose reductase inhibition enhances lens regeneration in mice

After cataract surgery, epithelial cells lining the anterior lens capsule can transition to one of two divergent pathways, including fibrosis which leads to posterior capsular opacification (PCO), or lens fiber cell differentiation which leads to regeneration of lens material. We previously showed that the PCO response can be suppressed with aldose reductase (AR) inhibitors. In this present study we show that AR inhibition, both genetic and pharmacologic with Sorbinil, can augment the process of lens regeneration. Extracapsular lens extraction (ECLE) was carried out in C57BL/6 (WT), AR overexpression (AR-Tg), and AR knockout (ARKO) mice, and in some cases in mice treated with the AR inhibitor sorbinil. Whole eyes were harvested approximately 8 weeks after ECLE and evaluated by histological analysis and immunostaining for the fiber cell marker γ-crystallin. All eyes examined for lens regeneration were paraffin embedded for serial sectioning to produce three-dimensional reconstructed models of lens morphology and size. We observed that AR-null mice respond to ECLE by regenerating a lens-like structure with a circular shape and array of cell nuclei reminiscent of the lens bow region typical of the native mammalian lens. Although WT and AR-Tg eyes also produced some regenerated lens material after ECLE, their structures were consistently smaller than ARKO regenerated lenses. WT mice treated with sorbinil showed higher levels of lens regeneration after ECLE compared to WT mice, as assessed by size and three-dimensional morphology. Altogether, this study adds evidence for a critical role for AR in the response of lens epithelial cells to cataract extraction and lens regeneration.

Aldose Reductase Inhibition Prevents Development of Posterior Capsular Opacification in an In Vivo Model of Cataract Surgery.

PurposeCataract surgery is a procedure by which the lens fiber cell mass is removed from its capsular bag and replaced with a synthetic intraocular lens. Postoperatively, remnant lens epithelial cells can undergo an aberrant wound healing response characterized by an epithelial-to-mesenchymal transition (EMT), leading to posterior capsular opacification (PCO). Aldose reductase (AR) inhibition has been shown to decrease EMT markers in cell culture models. In this study, we aim to demonstrate that AR inhibition can attenuate induction of EMT markers in an in vivo model of cataract surgery.MethodsA modified extracapsular lens extraction (ECLE) was performed on C57BL/6 wildtype, AR overexpression (AR-Tg), and AR knockout mice. Immunofluorescent staining for the myofibroblast marker α-smooth muscle actin (α-SMA), epithelial marker E-cadherin, and lens fiber cell markers αA-crystallin and Aquaporin 0 was used to characterize postoperative PCO. Quantitative reverse transcription PCR (qRT-PCR) was employed to quantify postoperative changes in α-SMA, vimentin, fibronectin, and E-cadherin. In a separate experiment, the AR inhibitor Sorbinil was applied postoperatively and qRT-PCR was used to assess changes in EMT markers.ResultsGenetic AR knockout reduced ECLE-induced upregulation of α-SMA and downregulation of E-cadherin. These immunofluorescent changes were mirrored quantitatively in changes in mRNA levels. Similarly, Sorbinil blocked characteristic postoperative EMT changes in AR-Tg mice. Interestingly, genetic AR knockout did not prevent postoperative induction of the lens fiber cell markers αA-crystallin and Aquaporin 0.ConclusionsAR inhibition prevents the postoperative changes in EMT markers characteristic of PCO yet preserves the postoperative induction of lens fiber cell markers.

Effects of Pranoprofen on Aqueous Humor Monocyte Chemoattractant Protein-1 Level and Pain Relief During Second-Eye Cataract Surgery

The aim of our present study is to evaluate the efficacy of pranoprofen eye drops as pain relief during sequential second-eye cataract surgery and to investigate the possible mechanism. Seventy-six patients scheduled for bilateral sequential cataract surgery were randomly assigned to two groups: (1) treatment group (administered pranoprofen eye drops), or (2) control group (administered artificial tears). Preoperative anxiety and intraoperative pain were assessed. Monocyte chemoattractant protein 1 (MCP-1) in the aqueous humor was measured with a suspension cytokine array. An extracapsular lens extraction model was established in the Wistar rat and the MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. We found that in the control group, the pain scores were significantly higher during second-eye surgery than during first-eye surgery (both scores P < 0.001). In the treatment group, there was no significant difference in the pain scores during first-eye and second-eye surgery (both scores P > 0.1). The pain during second-eye surgery was significantly lower in the treatment group than in the control group (both scores P < 0.01). And in the 1-week and 6-week interval subgroups, the pain scores during second-eye surgery were significantly lower in the treatment group than the control group (P = 0.047 and P = 0.035, respectively). While the second-eye MCP-1 level was significantly lower after a 1-week interval in the treatment group than in the control group (P = 0.012), but did not differ significantly after a 6-week interval (P > 0.1). A parallel trend in the MCP-1 concentration was detected in the rat model. In conclusion, the preoperative administration of pranoprofen eye drops reduced the perceived pain during second-eye cataract surgery, especially when performed after 1-week and 6-week intervals between the first-eye and second-eye surgery. MCP-1, a pain-related cytokine, was associated with the pain-relief mechanism of pranoprofen when second-eye surgery was performed 1 week after second-eye surgery.

Intraocular silicone implant to treat chronic ocular hypotony: an in vivo trial.

The management of chronic ocular hypotony and complicated proliferative vitreoretinopathy-related retinal detachment represents a challenge. Being non-absorbable and non-biodegradable, a silicone oil implant is expected to restore the volume and the intraocular pressure of the globe, as well as to approximate the detached retina. Further advantages could be a long-term tamponade potential, absence of toxicity, and prevention of silicone oil emulsification or anterior chamber oil-prolapse. The aim of this study was to assess the histological tolerance of the silicone oil implant in a pig model. A seamless silicone balloon implant with optional surface modifications was developed. Mini pigs were used as experimental animals, and three variants of silicone implants with different surfaces were tested: uncoated, NCO-sP(EO-stat-PO) coated, and heparin-NCO-sP(EO-stat-PO) coated silicone implants. An extracapsular lens extraction was achieved via a standard phacoemulsification followed by a standard three-port vitrectomy. The implant was then placed in the posterior segment and filled with 5000 centistoke silicone oil. One month later, the pigs were euthanized, the eyes were enucleated, and histological specimens were prepared for microscopy. The analysis of the histology revealed that adverse histological changes in conjunctiva, cornea, iris, and ciliary body could be excluded in all eyes operated on regardless of which variant of implant had been employed. The retina as the implant-contacting ocular tissue showed overall good tolerance, although some inflammatory reaction and fibrous proliferation was evident in some cases. The silicone oil implant is a promising candidate and has the potential to fulfill clinical requirements to act as a long-term intraocular tamponade agent. The heparin-NCO-sP(EO-stat-PO) coating approach could lead to a novel bioactive surface for intraocular devices with excellent properties to hinder cell adhesion and protein adsorption, although further studies will be necessary to evaluate long-term biocompatibility and long-term resistance to biological attacks.

In Vivo Observation of Lens Regeneration in Rat Using Ultra-Long Scan Depth Optical Coherence Tomography.

To evaluate morphologic changes of lens regeneration in rats in vivo after extracapsular lens extraction (ECLE) by ultra-long scan depth optical coherence tomography (UL-OCT). A total of 42 Sprague-Dawley rats were used in this study. We performed ECLE on the right eyes of animals in the surgery group (n = 34). Biomicroscopy and UL-OCT scans were carried out for the surgery group immediately (within 1 hour postoperatively) and at days 1 and 3, weeks 1 and 2, and months 1, 2, and 3 postoperatively. After in vivo examination, three animals of the surgery group were euthanized at each time point for histology study, while the other 10 animals were examined continuously at those time points. The regenerated lens was evaluated in OCT images at 2 and 3 months postoperatively. The control group consisted of eight untreated rats that had OCT examination at the age of 5 months. Lens regeneration could be observed from 2 weeks postoperatively. Regeneration was mainly at the peripheral capsular bag in the first month and central region thereafter. The average thickness of regenerated lenses was 2222 ± 309 and 2324 ± 352 μm at 2 and 3 months, respectively. Regeneration was faster in the first 2 months and slowed down thereafter. Although anterior capsule opening and posterior capsule adhesion and wrinkling existed, the regenerated lens still could form a relatively regular shape, however, the size was much smaller than that of the normal lenses from rats with the same age. Ultra-long OCT provides longitudinal data of the process of lens regeneration on a single individual rat in vivo, which may allow one to follow and compare the lens regenerative process under different interventions or therapy after ECLE in rats.

Effect of femtosecond laser‐assisted lens surgery on posterior capsule opacification in the human capsular bag in vitro

To compare posterior capsule opacification (PCO) by observing lens epithelial cell growth in the human capsular bag invitro between conventional lens surgery using phacoemulsification (Phaco) technique and femtosecond laser-assisted lens surgery (FLACS). For the invitro human capsular bag model, 18 cadaver eyes from nine human donors underwent three types of lens surgery. Three groups consisting of six capsular bags were established, that is FLACS, Phaco and extracapsular lens extraction (ECCE). The capsular bag was transferred into equal cell culture conditions after using one of the defined surgical approaches. Cellular growth of lens epithelial cells was observed and photo-documented. The time until full cell-coverage of the capsular bag was measured. The human capsular bag model can be successfully prepared using FLACS. There was no statistically significant difference in time until cell-coverage of the human donor capsular bag invitro in all three surgical settings (ECCE versus Phaco p=0.6; ECCE versus FLACS p=1.0; Phaco versus FLACS p=1.0). In our invitro human capsular bag model, we could not observe a statistically significant difference in PCO formation using different surgical approaches of lens extraction. Therefore, PCO formation might not be attributed to the type of surgery. Furthermore, this study shows that FLACS can be used for the human capsular bag model preparation and validates the human capsular bag model for future research.

Clinical study of lens induced glaucoma

Background: Lens induced glaucoma is a common occurrence. Secondary glaucoma has been found in 10% of senile cortical cataracts. Ruling out the coexisting primary glaucomas, lens induced glaucomas has been taken up for this interesting study. Objective: To analyze the different mechanisms and clinical features of lens induced gluacomas. Methods: This clinical study included 50 cases of different types of lens induced glaucomas in individuals whose age group varied from 12 to 90 years and both the sexes conducted on the in patients of Ophthalmology department. All the cases of secondary glaucomas suspected to be lens induced were admitted to the wards. Detailed history was ascertained. Previous history of extra-capsular lens extraction in the other eye was carefully noted. Results: Majority of the patients were in the age group of 50-75 years. The incidence of lens induced glaucoma was more among females (68%) than males (32%). Right eye was found to be more commonly affected (58%) than the left eye (38%) and both eyes were involved in 4% of cases.. The majority of the eyes affected had hypermature cataract (44%) followed by mature cataract (34%). Phacomorphic glaucoma caused by intumescent lens has been the major cause contributing to 54% of cases. 27 cases (54%) showed shallow anterior chamber. Conclusion: The incidence of lens induced glaucoma was more among females (68%) than males (32%). Right eye was found to be more commonly affected (58%) than the left eye (38%).Both eyes were involved in 4% of cases. The majority of the eyes affected had hypermature cataract (44%).

Accommodative movements of the lens/capsule and the strand that extends between the posterior vitreous zonule insertion zone & the lens equator, in relation to the vitreous face and aging.

To elucidate the dynamic accommodative movements of the lens capsule, posterior lens and the strand that attaches to the posterior vitreous zonule insertion zone and posterior lens equator (PVZ INS-LE), and their age-related changes. Twelve human subjects (ages 19-65years) and 12 rhesus monkeys (ages 6-27years) were studied. Accommodation was induced pharmacologically (humans) or by central electrical stimulation (monkeys). Ultrasound biomicroscopy was used to image intraocular structures in both species. Surgical procedures and contrast agents were utilized in the monkey eyes to elucidate function and allow visualization of the intraocular accommodative structures. Human: The posterior pole of the lens moves posteriorly during accommodation in proportion to accommodative amplitude and ciliary muscle movement. Monkey: Similar accommodative movements of the posterior lens pole were seen in the monkey eyes. Following extracapsular lens extraction (ECLE), the central capsule bows backward during accommodation in proportion to accommodative amplitude and ciliary muscle movement, while the peripheral capsule moves forward. During accommodation the ciliary muscle moved forward by ~1.0mm, pulling forward the vitreous zonule and the PVZ INS-LE structure. During the accommodative response the PVZ INS-LE structure moved forward when the lens was intact and when the lens substance and capsule were removed. In both the monkey and the human eyes these movements declined with age. The accommodative shape change of the central capsule may be due to the elastic properties of the capsule itself. For these capsule/lens accommodative posterior movements to occur, the vitreous face must either allow for it or facilitate it. The PVZ INS-LE structure may act as a 'strut' to the posterior lens equator (pushing the lens equator forward) and thereby facilitate accommodative forward lens equator movement and lens thickening. The age-related posterior restriction of the ciliary muscle, vitreous zonule and the PVZ-INS LE structure dampens the accommodative lens shape change. Future descriptions of the accommodative mechanism, and approaches to presbyopia therapy, may need to incorporate these findings.

Effect of Dexmedetomidine on cognitive function after lens extraction in mice

Objective To investigate the effect of Dexmedetomidine (Dex) on long-term cognitive function after extracapsular lens extraction (ECLE) in mice. Methods Forty adult male C57BL/6J mice were randomly divided into control group (C group), ECLE group, normal saline group (NS group) and Dex group with 10 mice in each group. Three days after ECLE model was made, the mouse in C group and ECLE group underwent Morris water maze test, then they were euthanized and hippocampus tissue was immediately excised for determination of wet weight to dry weight (W/D) and total water content (TWC). The transcription levels of cycteinyl aspirate-specific protease-12 (caspase-12) mRNA and its protein in hippocampus tissue were detected respectively by reverse transcription polymerase chain reaction (PCR) and Western Blot. Apoptosis index (AI) of hippocampus tissue was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay. After the mice regained consciousness post the operation, animals received intraperitoneally Dex at a dose of 25 μg·kg-1·d-1 for 30 consecutive days in Dex group. Animals of NS group were accepted intraperitoneally injection with the same volume of normal saline. The evaluation indexes mentioned above were programmed at 30 dyas post intraperitonedlly injection. Results Compared with C group, the escape latency and swimming distance were prolonged transcription in ECLE group (both P<0.05), the value of W/D, TWC and AI were increased (all P<0.05), and the expression of caspase-12 and mRNA transcription in hippocampus tissue were significantly higher (both P<0.05) in ECLE group. Compared with NS group, the escape latency and swimming distance were shortened in Dex group(both P<0.05), the value of W/D, TWC and AI were decreased (all P<0.05), and the expression of caspase-12 and mRNA protein transcription in hippocampus tissue were significantly lower (both P<0.05) in Dex group. Conclusion The treatment of Dex could improve the long-term cognitive function after ECLE in mice, and the mechanism may be through inhibiting apoptosis mediated by caspase-12 in hippocampus tissue. Key words: Disorders, cognition; Dexmedetomidine; Cycteinyl aspirate-specific protease; Apoptosis; Extracapsular lens extraction

A novel murine model for keratoprosthesis.

To establish a murine model for keratoprosthesis. A miniature keratoprosthesis (m-KPro) device was created consisting of a poly[methyl methacrylate] front part and a titanium back plate, designed after the Boston KPro, which is in widespread clinical use. BALB/c mice were used and a 2 mm in diameter donor cornea was punched out. After 2-mm trepanation of the syngeneic recipient cornea, extracapsular crystalline lens extraction was performed. The m-KPro was assembled onto the cornea button in a similar manner to human KPro implantation. The cornea-device complex was secured to the recipient bed with eight interrupted 11-0 sutures. All mice (n = 10) were followed up for 8 weeks postoperatively. All m-KPros were successfully implanted and retained in all 10 animals. There were no critical complications such as endophthalmitis, corneal melting, device extrusions, leakage, extensive inflammation, or weight loss in the animals. We observed mild to moderate donor and host corneal neovascularization in all cases throughout the follow-up period. We have established a novel murine model of KPro implantation that we anticipate will serve as a good experimental system for evaluating host responses after KPro surgery.

Reliable intraocular pressure measurement using automated radio-wave telemetry

PurposeTo present an autonomous intraocular pressure (IOP) measurement technique using a wireless implantable transducer (WIT) and a motion sensor.MethodsThe WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS) comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline) IOP.ResultsOn average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg) and mean vehicle IOP (13.27±2.1 mmHg) (P=0.45), suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001), and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001). Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001). Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute), during which the IOP is not expected to change.ConclusionIOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results.

LMWH inhibits anterior chamber inflammation after extra capsular lens extraction through down regulation of bFGF content in aqueous humor.

To observe the changes of basic fibroblast growth factor (bFGF) content in anterior chamber before and after extra capsular lens extraction for investigating the mechanism of low molecular weight heparin (LMWH) inhibiting anterior chamber inflammation. Eighty-four rabbits were randomly divided into control and experimental group, 42 rabbits in each group. Extra capsular lens extraction was done on unilateral eye in each rabbit. LMWH was perfused into anterior chamber by the concentration of 50U/mL at the end of operation in experimental group. The degrees of corneal edema, aqueous flare and fibrin were evaluated with slit lamp microscope on postoperative day 1, 3, 6, 15, 30, 45 and 60, respectively. Six eyes of each group were at each time point. Contents of bFGF in aqueous humor were determined by ELISA after animals were killed. Another six eyes were used for determining the base line level of bFGF in aqueous humor. The degrees of corneal edema, aqueous flare and fibrin in experimental group were significantly lighter than those in control group (P<0.01) on postoperative day 1, 3 and 6, respectively. No difference was showed between the two groups at other point time. Contents of bFGF in aqueous humor increased at the same time. bFGF content reached peak on postoperative day 1 in experimental group, while on postoperative day 6 in control group. Contents of bFGF in the two groups declined slowly after reaching peak. The bFGF content in control group were significantly higher than that in experimental group 1-30 days after surgery (P<0.05). No significant differences were shown between the two groups on postoperative day 45 and 60, respectively. Perfusion with LMWH by the concentration of 50U/mL can significantly reduce anterior chamber inflammation after extra capsular lens extraction in rabbits, which may be related to down regulation of bFGF content in aqueous humor.

Intraocular Pressure Measurement by Radio Wave Telemetry

To determine the biocompatibility of a new wireless intraocular pressure (IOP) transducer (WIT) in rabbit eyes and to correlate its measurements with other pressure-measuring devices. The WIT is a ring-shaped intraocular device that allows wireless IOP measurements through radiofrequency. It was implanted into six eyes of New Zealand White rabbits after extracapsular lens extraction. A sham rabbit eye with no transducer implanted was used as a control. The animals were observed and examined by microscopy at various intervals up to 25 months after surgery. IOP was measured at various intervals by pneumotonometry, tonometry, WIT, and manometry. The data from the various devices were compared and analyzed for reproducibility. Two eyes were enucleated at 5.5 and 20 months after implantation and analyzed by histology. The WIT appears to be well tolerated in the rabbit eye, with no evidence of significant inflammation or scar formation by microscopic in vivo examination. Histology did not reveal intraocular inflammation or membrane formation. Repeated IOP measurements with pneumotonometry, tonometry, and the WIT resulted in SDs of 2.70 mm Hg, 3.35 mm Hg, and 0.81 mm Hg, respectively. The concordance between the WIT and direct manometry measurements was high. A downward drift in IOP measured by the WIT was noted in three rabbits, necessitating recalibration. The WIT is well tolerated by the rabbit eye. Its measurements are reproducible and in close concordance with manometry. A downward IOP drift warrants further investigation.

Anti-inflammatory effect of the alpha-melanocyte stimulating hormonein animal eyes undergoing extracapsular lens extraction

In this study anti-inflammatory effects of the alpha-melanocyte stimulating hormone (alpha-MSH) on ocular inflammation caused by extracapsular lens extraction (ECLE) have been investigated and the potential mechanism of an anti-inflammatory effect is discussed. Pigmented rabbit eyes after ECLE were treated locally with alpha-MSH, dexamethasone, diclofenac, or saline 4 times a day (q.i.d.) for 4 weeks. The inhibitory effect of alpha-MSH on infiltrating cells in the aqueous humor (AqH) was almost twice as good as that of dexamethasone or diclofenac for 3 days, 1 week, and 2 weeks after the operation. The eyes of Sprague-Dawley rats were treated with an intravenous injection of alpha-MSH or saline immediately after ECLE. Six hours postoperatively, the iris/ciliary body exhibited increased expression of TNF-alpha and IL-6 mRNAs, which were significantly decreased after alpha-MSH treatment. The number of activated NF-kappa B (NFkappaB)-positive cells in the iris/ciliary body was also significantly reduced by the alpha-MSH treatment. These results suggested that alpha-MSH could effectively reduce ocular inflammation after ECLE, and the potential mechanism for this is by down-regulating the expression of proinflammatory cytokines and inhibiting the NFkappaB-dependent signaling pathway.

Cataract Surgery Induces Retinal Pro-inflammatory Gene Expression and Protein Secretion

To investigate the effect(s) of cataract surgery on the expression of pro-inflammatory genes and proteins in the retina using an experimental rodent model. An extracapsular lens extraction was performed in one eye of C57BL/6 mice (n = 24); the contralateral unoperated eyes (n = 24) as well as eyes from unoperated animals (n = 9) served as controls. The neurosensory retina and retinal pigment epithelium (RPE)/choroid were collected postoperatively. Expression of genes involved in the acute inflammatory/injury response, including IL-1β, fibroblast growth factor, transforming growth factor β, chemokine CCL2, SDF-1, and complements C3, C4, and factor B (CFB), were examined by real-time PCR and, selectively, by immunohistochemistry. The expression of IL-1β and CCL2 genes was markedly upregulated (>20-fold, P < 0.01) in the neurosensory retina 30 minutes postoperatively and maintained for the 2-week postoperative period of observation; IL-1β expression was also upregulated in RPE/choroid. The expression of complement C3 (>5-fold) and CFB (>30-fold) genes in the neurosensory retina was also significantly upregulated (P < 0.01 in both cases). Increased IL-1b, CCL2, and CFB as well as enhanced C5b-9 immunostaining were observed by confocal microscopy. In rodents, lens extraction elicited an acute pro-inflammatory gene and protein response in the posterior segment of the eye, indicating induction of the inflammasome as well as complement activation, as occurs in the "danger" response. A similar response in humans might explain the pathogenesis of cataract surgery-associated retinal complications such as cystoid macular edema.

Anaesthetic management of a patient with homocystinuria

Homocystinuria is an autosomal recessive disease with multiple systemic involvement. Extracapsular extraction of lens is the most commonly performed elective ocular procedure for homocystinuric children. These children present with particular anaesthetic concerns during surgery. Here we report a case of a 14 year old boy with homocystinuria posted for extracapsular lens extraction under general anaesthesia. Precautions were taken perioperatively to prevent the various complications associated with this condition for a favourable perioperative outcome. Key words: homocystinuria; thromboembolism; hypoglycemia; general anaesthesia; homocysteine metabolism. DOI: 10.4038/slja.v18i2.1463 Sri Lankan Journal of Anaesthesiology 18(2): 84-86 (2010)