Intraocular Pressure In Rats Research Articles

Synthesis of new heterocyclic derivatives (benzodioxane-2-yl)methanol and their effect on rat intraocular pressure

Objective: Synthesis of new compounds, melatonin isosters, and study of their ability to reduce intraocular pressure.
 Materials and methods: Based on the previously made forecast and on the similarity with the selected compounds, the synthesis of new compounds was carried out – melatonin isosters having a 2,3-dihydro-1,4-benzodioxin cycle connected by a linker of various chemical structure with a nitrogen-containing heterocyclic core. The structure of the synthesized compounds was proved by 1H- and 13C- NMR spectroscopy, purity and individuality – by chromatographic methods. Intraocular pressure in laboratory animals was measured using a contact veterinary tonometer Tonovet (Finland). Cytotoxicity was assessed using MTT test on normal rat skin fibroblasts.
 Results: Derivatives (benzodioxane-2-yl)methanol reduced the level of IOP in varying degrees of severity. The VMA-22-37 compound showed the greatest activity. With topical application of a 0.4% solution, the compound reduced the intraocular pressure of intact rats by 26.6%, while not affecting the control eye. This compound also has low cytotoxicity.
 Conclusion: Derivatives (benzodioxane-2-yl)methanol is promising for the search for compounds capable of reducing increased intraocular pressure.

Effect of Guanidine Derivatives of Quinazoline on the Na+/H+ Exchanger and Intraocular Pressure in Rats

Effect of Guanidine Derivatives of Quinazoline on the Na+/H+ Exchanger and Intraocular Pressure in Rats

Vascular endothelial growth factor-165b protects the blood-retinal barrier from damage after acute high intraocular pressure in rats.

To elucidate the role of vascular endothelial growth factor-165b (VEGF-165b) in blood-retinal barrier (BRB) injury in the rat acute glaucoma model. In this study, the rat acute high intraocular pressure (HIOP) model was established before and after intravitreous injection of anti-VEGF-165b antibody. The expression of VEGF-165b and zonula occludens-1 (ZO-1) in rat retina was detected by double immunofluorescence staining and Western blotting, and the breakdown of BRB was detected by Evans blue (EB) dye. The intact retina of rats expressed VEGF-165b and ZO-1 protein, which were mainly located in the retinal ganglion cell layer and the inner nuclear layer and were both co-expressed with vascular endothelial cell markers CD31. After acute HIOP, the expression of VEGF-165b was up-regulated; the expression of ZO-1 was down-regulated at 12h and then recovered at 3d; EB leakage increased, peaking at 12h. After intravitreous injection of anti-VEGF-165b antibody, the expression of VEGF-165b protein was no significantly changed; and the down-regulation of the expression of ZO-1 was more obvious; EB leakage became more serious, peaking at 3d. EB analysis also showed that EB leakage in the peripheral retina was greater than that in the central retina. The endogenous VEGF-165b protein may protect the BRB from acute HIOP by regulating the expression of ZO-1. The differential destruction of BRB after acute HIOP may be related to the selective loss of retinal ganglion cells.

The Effects of Nitroazolopyrimidines on the A1 Adenosine Receptor and Intraocular Pressure in Rats

Six compounds of the 5(7)-alkylamino-6-nitroazolopyrimidine and 8-alkylazolo[5,1-b]purine series were selected based on the structural analysis of A1 adenosine receptor inhibitors and the role of this biological target in the modulation of intraocular pressure, an important factor in the pathogenesis of glaucoma. These heterocycles were shown to exhibit a weak affinity towards the A1 adenosine receptor on an in vitro model of the adenosine-dependent change of the chronotropic effect on isolated atria of white mice. On the other hand, thiadiazolo[3,2-a]pyrimidines and triazolo[5,1-b]purine displayed an in vivo hypotensive effect in rats. The leading compound, 5-methyl-8-(hydroxyethyl)triazolo[5,1-b]purine) (0.2% solution), caused a 34% reduction of ophthalmotonus in 3 h without an adverse resorptive effect. In addition, using the MTT-test it was shown on the human HepG2 cell line that the heterocycles affecting the intraocular pressure were by one to two orders of magnitude less cytotoxic than the reference doxorubicin.

Lowering the Intraocular Pressure in Rats and Rabbits by Cordyceps cicadae Extract and Its Active Compounds.

Cordyceps cicadae (CC), an entomogenous fungus that has been reported to have therapeutic glaucoma, is a major cause of blindness worldwide and is characterized by progressive retinal ganglion cell (RGC) death, mostly due to elevated intraocular pressure (IOP). Here, an ethanolic extract of C. cicadae mycelium (CCME), a traditional medicinal mushroom, was studied for its potential in lowering IOP in rat and rabbit models. Data showed that CCME could significantly (60.5%) reduce the IOP induced by microbead occlusion after 56 days of oral administration. The apoptosis of retinal ganglion cells (RGCs) in rats decreased by 77.2%. CCME was also shown to lower the IOP of normal and dextrose-infusion-induced rabbits within 60 min after oral feeding. There were dose effects, and the effect was repeatable. The active ingredient, N6-(2-hydroxyethyl)-adenosine (HEA), was also shown to alleviate 29.6% IOP at 0.2 mg/kg body weight in this rabbit model. CCME was confirmed with only minor inhibition in the phosphorylated myosin light chain 2 (pMLC2) pathway.

Stable Gastric Pentadecapeptide BPC 157 Therapy of Rat Glaucoma

Cauterization of three episcleral veins (open-angle glaucoma model) induces venous congestion and increases intraocular pressure in rats. If not upgraded, one episcleral vein is regularly unable to acquire and take over the whole function, and glaucoma-like features persist. Recently, the rapid upgrading of the collateral pathways by a stable gastric pentadecapeptide BPC 157 has cured many severe syndromes induced by permanent occlusion of major vessels, veins and/or arteries, peripherally and centrally. In a six-week study, medication was given prophylactically (immediately before glaucoma surgery, i.e., three episcleral veins cauterization) or as curative treatment (starting at 24 h after glaucoma surgery). The daily regimen of BPC 157 (0.4 µg/eye, 0.4 ng/eye; 10 µg/kg, 10 ng/kg) was administered locally as drops in each eye, intraperitoneally (last application at 24 h before sacrifice) or per-orally in drinking water (0.16 µg/mL, 0.16 ng/mL, 12 mL/rat until the sacrifice, first application being intragastric). Consequently, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, normal retinal and choroidal blood vessel presentation and normal optic nerve presentation. As leading symptoms, increased intraocular pressure and mydriasis, as well as degeneration of retinal ganglion cells, optic nerve head excavation and reduction in optic nerve thickness, generalized severe irregularity of retinal vessels, faint presentation of choroidal vessels and severe optic nerve disc atrophy were all counteracted. In conclusion, we claim that the reversal of the episcleral veins cauterization glaucoma appeared as a consequence of the BPC 157 therapy of the vessel occlusion-induced perilous syndrome.

Synthesis and multifaceted pharmacological activity of novel quinazoline NHE-1 inhibitors

The Na+/H+ exchanger isoform 1 (NHE-1) attracts ongoing attention as a validated drug target for the management of cardiovascular and ocular diseases owing to cytoprotective, anti-ischemic and anti-inflammatory properties of NHE-1 inhibitors. Herein we report novel NHE-1 inhibitors realized via functionalization of N1-alkyl quinazoline-2,4(1H,3H)-dione and quinazoline-4(3H)-one with N-acylguanidine or 3-acyl(5-amino-1,2,4-triazole) side chain. Lead compounds show activity in a nanomolar range. Their pharmacophoric features were elucidated with neural network modeling. Several compounds combine NHE-1 inhibition with antiplatelet activity. Compound 6b reduces intraocular pressure in rats and effectively inhibits the formation of glycated proteins. Compounds 3e and 3i inhibit pro-inflammatory activation of murine macrophages, LPS-induced interleukin-6 secretion and also exhibit antidepressant activity similar to amiloride. Hence, novel compounds represent an interesting starting point for the development of agents against cardiovascular diseases, thrombotic events, excessive inflammation, long-term diabetic complications and glaucoma.

Effects of acute stress, general anesthetics, tonometry, and temperature on intraocular pressure in rats

Intraocular pressure (IOP) is important for eye health as abnormal levels can led to ocular tissue damage. IOP is typically estimated by tonometry, which only provides snapshots of pressure history. Tonometry also requires subject cooperation and corneal contact that may influence IOP readings. The aim of this research was to investigate IOP dynamics of conscious animals in response to stressors, common anesthetics, tonometry, and temperature manipulations. An eye of male Brown-Norway rats was implanted with a fluid-filled cannula connected to a wireless telemetry system that records IOP continuously. Stress effects were examined by restricting animal movements. Anesthetic effects were examined by varying isoflurane concentration or injecting a bolus of ketamine. Tonometry effects were examined using applanation and rebound tonometers. Temperature effects were examined by exposing anesthetized and conscious animals to warm or cool surfaces. Telemetry recordings revealed that IOP fluctuates spontaneously by several mmHg, even in idle and anesthetized animals. Environmental disturbances also caused transient IOP fluctuations that were synchronous in recorded animals and could last over a half hour. Animal immobilization produced a rapid sustained elevation of IOP that was blocked by anesthetics, whereas little-to-no IOP change was detected in isoflurane- or ketamine-anesthetized animals if body temperature (BT) was maintained. IOP and BT decreased precipitously when heat support was not provided and were highly correlated during surface temperature manipulations. Surface temperature had no impact on IOP of conscious animals. IOP increased slightly during applanation tonometry but not rebound tonometry. The results show that IOP is dynamically modulated by internal and external factors that can activate rapidly and last long beyond the initiating event. Wireless telemetry indicates that animal interaction induces startle and stress responses that raise IOP. Anesthesia blocks these responses, which allows for better tonometry estimates of resting IOP provided that BT is controlled.

Long-Term Decrease of Intraocular Pressure in Rats by Viral Delivery of miR-146a.

PurposeTo evaluate the effects of miR-146a in trabecular meshwork (TM) cells and on intraocular pressure (IOP) in vivo via viral delivery of miR-146a to the anterior chamber of rat eyes.MethodsHuman TM cells were transfected with miR-146 mimic or inhibitor. Some cells from each group were then subjected to cyclic mechanical stress (CMS). Other cells from each group had no force applied. Gene expression was then analyzed by quantitative polymerase chain reaction (qPCR). Replication-deficient adenovirus and lentivirus expressing miR-146a were inoculated into the anterior segment of Brown Norway rat eyes. IOP was monitored by rebound tonometry, visual acuity was evaluated by optokinetic tracking (OKT), and inflammation markers in the anterior segment were examined by slit-lamp, qPCR, and semi-thin sections.ResultsmiR-146 affected the expression of genes potentially involved in outflow homeostasis at basal levels and under CMS. Both lentiviral and adenoviral vectors expressing miR-146a resulted in sustained decreases in IOP ranging from 2.6 to 4.4 mmHg. Long term follow-up of rats injected with lentiviral vectors showed a sustained effect on IOP of 4.4 ± 2.9 mmHg that lasted until rats were sacrificed more than 8 months later. Eyes showed no signs of inflammation, loss of visual acuity, or other visible abnormalities.ConclusionsIntracameral delivery of miR-146a can provide a long-term decrease of IOP in rats without signs of inflammation or other visible adverse effects.Transitional RelevanceThe IOP-lowering effects of miR-146 observed in rats provides a necessary step toward the development of an effective gene therapy for glaucoma in humans.

Extraction of capsanthin from Capsicum annum L fruits and its effect on carbomer-induced intraocular pressure in Albino Wistar rats.

The present study was aimed to explore the antiglaucoma activity of capsanthin enriched fraction (CEF) of Capsicum annum L fruits against carbomer-induced experimental glaucoma in Albino Wistar rats. CEF was orally administered to carbomer-induced glaucomatous rats, and pilocarpine 2% eye drops were used as a standard drug. Intraocular pressure (IOP) levels were determined after oral administration of a low, medium, and a high dose of CEF (20, 40, and 80mg/kg bwt) in glaucomatous rats. In rats with elevated IOP in both eyes, oral administration of CEF resulted in a significant reduction in IOP (p<.05) even at a low dose of 20mg/Kg body weight. There were no treatment-related changes in histopathology, hematology, and clinical chemistry parameters. Thus, CEF when administered orally in IOP-bearing rats successfully reduced IOP without any adverse effects. PRACTICAL APPLICATIONS: Capsanthin enriched fraction can be used to prevent permanent vision loss due to age-related macular diseases and high intraocular pressure. The intraocular pressure reduction action of capsanthin can be useful in the treatment of glaucoma. The medication available to treat glaucoma are topical drugs, and for the first time, we proved the oral supplementation of capsanthin from a food source can reduce the intraocular pressure in rats.

Hyperbranched Cationic Glycogen Derivative-Mediated IκBα Gene Silencing Regulates the Uveoscleral Outflow Pathway in Rats.

The role of the IκB/NF-κB signaling pathway in the uveoscleral outflow pathway was investigated with IκBα gene silencing mediated by the 3-(dimethylamino)-1-propylamine-conjugated glycogen (DMAPA-Glyp) derivative. The IκBα-siRNA-loaded DMAPA-Glyp complex was transfected into the ciliary muscles of rats by intracameral injection (labeled as the DMAPA-Glyp+siRNA group). The Lipofectamine™ 2000 (Lipo)/siRNA complex and the naked siRNA were set as the controls. The mRNA and protein expression of IκBα, NF-κBp65, and MMP-2 were analyzed by real-time PCR, western blotting, and in situ gelatin zymography. Nuclear translocation of NF-κBp65 was analyzed by immunofluorescence. Rat intraocular pressure (IOP) was monitored pre- and postinjection. Gene transfection efficiency and toxicity of the DMAPA-Glyp derivative were also evaluated. After RNA interference (RNAi), IκBα mRNA and protein expression were significantly inhibited. NF-κBp65 mRNA and protein expression showed no significant differences. Nevertheless, nuclear translocation of NF-κBp65 occurred in the DMAPA-Glyp+siRNA group. Both mRNA expression and activity of MMP-2 increased, with the largest increase in the DMAPA-Glyp+siRNA group. IOP in the DMAPA-Glyp+siRNA group fell to the lowest level on day 3 after RNAi. The levels of Cy3-siRNA in the ciliary muscle of the DMAPA-Glyp+siRNA group did not significantly decrease over time. At 7 and 14 d after RNAi, no significant pathological damage was detectable in the eyes injected with the DMAPA-Glyp derivative or the DMAPA-Glyp/siRNA complex. Taken together, our results suggest that downregulation of IκBα expression in the ciliary muscle plays a crucial role in reducing the IOP values of rats. IκBα may become a new molecular target for lowering IOP in glaucoma. The DMAPA-Glyp derivative is safe and feasible as an effective siRNA vector in rat eyes.

Valeric Acid, a Gut Microbiota Product, Penetrates to the Eye and Lowers Intraocular Pressure in Rats.

Mechanisms controlling intraocular pressure (IOP) and arterial blood pressure (BP) share similar mediators, including gut bacteria metabolites. Here, we investigated the effects of valeric acid (VA), a short chain fatty acid produced by microbiota from undigested carbohydrates, on IOP and BP. To test if gut VA penetrates to the eye we evaluated eyes’ homogenates after the administration of D9-VA into the colon. Additionally, the following experimental series were performed on 16-week-old Sprague Dawley rats to analyze the influence of VA on IOP: vehicle treatment; VA treatment; VA + hydroxybutyrate - a short chain fatty acids’ G protein-coupled receptor 41/43 (GPR 41/43) blocker (ANT); hydroxybutyrate; VA + angiotensin II; angiotensin II; VA treatment in rats with superior cervical ganglion excision and sham operated rats. D9-VA rapidly penetrated from the colon to the eye. VA significantly decreased IOP and BP. The decrease in IOP was gradual and lasted through the experiment. In contrast, a decrease in BP was instantaneous and lasted no longer than 10 min. Angiotensin II, ANT, and sympathetic denervation did not influence the effect of VA on IOP. In conclusion, colon-derived VA penetrates to the eye and decreases IOP. The effect is independent from BP changes, angiotensin II, GPR41/43, and sympathetic eye innervation.

Experimental study of reducing intraocular pressure in rats with acupuncture in the corresponding area of trabecular meshwork

Objective To evaluate the efficacy of acupuncture in the corresponding area of trabecular meshwork in reducing intraocular pressure. Methods There were 40 SD rats with successful modeling of high IOP. All rats were divided into 4 groups randomly, with 10 rat models in each group. The trabecular mesh work group was acupunctured at 3, 6, 9 and 12 o’clock in the corresponding area of trabecular mesh work of the limbus sclerae of the eyeball. The routine acupoint group was acupunctured at JingMing acupoint, QiuHou acupoint, SiBai acupoint, Temple acupoint, FengChi acupoint and XingJian acupoint.The trabecular and conventional acupoint group was acupunctured in the corresponding area of trabecular meshwork of the limbus sclera of the eyeball, combined with acupuncture points of 6 acupoints. The control group was not acupunctured. All rats were measureed immediate IOP and the next day IOP. Acupuncture was performed once a day, for 1 week. Results The immediate IOP and the following day IOP in trabecular mesh work group was lower than acupuncture before, the difference was statistically significant (P 0.05). Combined acupuncture group, the immediate IOP and the following day IOP was lower than that acupuncture before, and the difference was statistically significant (P 0.05). Conclusion The corresponding area of trabecular mesh work can effectively reduce intraocular pressure, which is better than the traditional acupoints. Key words: Acupuncture; Corresponding area, trabecular mesh work; Model, rats; Pressure, intraocular, high

Effects of Lentivirus-Mediated C3 Expression on Trabecular Meshwork Cells and Intraocular Pressure.

PurposeWe evaluated the effects of lentivirus-mediated exoenzyme C3 transferase (C3) expression on cultured primary human trabecular meshwork (HTM) cells in vitro, and on rat intraocular pressure (IOP).MethodsHTM cells were cultured and treated with lentivirus vectors expressing either green fluorescent protein (GFP) only (LV-GFP) or GFP and C3 together (LV-C3-GFP). Changes in cell morphology and actin stress fibers were assessed. The vectors were also injected into the anterior chamber of rats, and GFP expression was visualized by a Micron III Retinal Imaging Microscope in vivo and a fluorescence microscope ex vivo. Changes in rat IOP were monitored by using a rebound tonometer and the eyes were evaluated by slit lamp.ResultsLV-mediated C3 expression induced morphologic changes in HTM cells. The cells became retracted and rounded. GFP expression in the anterior chamber angle of rats was observed in vivo from 8 days to 48 days after injection of LV-C3-GFP or LV-GFP. IOP was significantly decreased in the LV-C3-GFP group starting 3 days post injection, and lasting for at least 40 days, when compared to either the contralateral control eyes (the LV-GFP group) or the ipsilateral baseline before injection (P < 0.05). No obvious inflammatory signs were observed in either the LV-C3-GFP or LV-GFP groups.ConclusionsLV-mediated C3 expression induced changes in morphology of cultured HTM cells. Intracameral injection of LV-C3-GFP lowered rat IOP for at least 40 days. No significant inflammatory reactions were observed in either the LV-C3-GFP or LV-GFP groups. This study supports the possible use of C3 gene therapy for the treatment of glaucoma.

Effect of Hydrogen Sulfide Donor on Intraocular Pressure in Rats

We studied the effect of 1% sodium hydrosulfide solution (NaHS) on intraocular pressure (IOP) in intact rats and those with simulated ocular hypertension induced by prolonged systemic administration of adrenaline. A single administration of hydrogen sulfide donor as drops into the eye cavity caused the hypotensive effect, which was rather weak in the eyes of intact rats and pronounced in those with ocular hypertension. Long-term administration of NaHS by the scheme, against the background of applying adrenaline as inductor, to a large extent, prevented the IOP rise. It has been concluded that hydrogen sulfide is involved in the regulation of intraocular hydrodynamics and maintaining normal IOP levels.

Hydrogen-rich saline reduces cell death through inhibition of DNA oxidative stress and overactivation of poly (ADP-ribose) polymerase-1 in retinal ischemia-reperfusion injury.

Overactivation of poly (ADP-ribose) polymerase 1 (PARP-1), as a result of sustained DNA oxidation in ischemia-reperfusion injury, triggers programmed cell necrosis and apoptosis. The present study was conducted to demonstrate whether hydrogen-rich saline (HRS) has a neuroprotective effect on retinal ischemia reperfusion (RIR) injury through inhibition of PARP-1 activation. RIR was induced by transient elevation of intraocular pressure in rats. HRS (5 ml/kg) was administered peritoneally every day from the beginning of reperfusion in RIR rats until the rats were sacrificed. Retinal damage and cell death was determined using hematoxylin and eosin and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. DNA oxidative stress was evaluated by immunofluorescence staining of 8-hydroxy-2-deoxyguanosine. In addition, the expression of PARP-1 and caspase-3 was investigated by western blot analysis and/or immunohistochemical staining. The results demonstrated that HRS administration improved morphological alterations and reduced apoptosis following RIR injury. Furthermore, the present study found that HRS alleviated DNA oxidation and PARP-1 overactivation in RIR rats. HRS can protect RIR injury by inhibition of PARP-1, which may be involved in DNA oxidative stress and caspase-3-mediated apoptosis.

The influence of heat shock protein 27 sensibilization to retinal ganglion cells apoptosis of rats

Objective To observe the influence of heat shock protein 27 (HSP27) sensibilization to retinal ganglion cells (RGC) apoptosis of rats.Methods Thirty-five female Wistar rats were randomly divided into HSP27 sensibilization group (15 rats),borate buffer solution (BBS) control group (15 rats) and normal group (5 rats).The rats in HSP27 sensibilization group were received hypodermic injection in rear limb with 100 μg HSP27 and complete freund adjuvant,intraperitoneal injection with 1 μg pertussis toxin.The BBS control group received the same volume of BBS at the same site.The normal group received no intervention.The intraocular pressure was measured 3 days before injection and 1,2,4,6,8 weeks after injection.Four,6 and 8 weeks after injection,the retinal frozen sections was made to observe RGC apoptosis by terminal-deoxynucleoitidyl transferase mediated nick end labeling.The anti-HSP27 level in serum and cerebrospinal fluid were detected by enzyme linked immunosorbent assay.Results There was no obvious change of intraocular pressure in rats in 3 groups before injection (P＞0.05).RGC apoptosis was observed in HSP27 sensibilization group 4 weeks after injection,and increased significantly at 6 weeks after injection.There was no RGC apoptosis in BBS control group and normal group.The level of anti-HSP27 in serum and cerebrospinal fluid of HSP27 sensibilization group occurred at 4 and 6 weeks after injection respectively,decreased with prolongation of injection time.Compared with BBS control group and normal group,the RGC apoptosis rate,anti-HSP27 level in serum and cerebrospinal fluid of HSP27 sensibilization group were significantly increased (P＜0.05).There was no significant difference of the RGC apoptosis rate,anti-HSP27 level in serum and cerebrospinal fluid between BBS control group and normal group (P＞0.05).Conclusions HSP27 sensibilization could promote the RGC apoptosis.The variation trend of antiHSP27 level in cerebrospinal fluid is consistent with the RGC apoptosis. Key words: HSP27 heat-shock proteins/drug effects; Apoptosis; Animal experimentation

Development of a Model of Elevated Intraocular Pressure in Rats by Gene Transfer of Bone Morphogenetic Protein 2

To determine whether inducing calcification in the trabecular meshwork results in elevated IOP in living rats. To use this property to create an elevated IOP animal model by gene transfer of bone morphogenetic protein 2 (BMP2). Calcification was assessed by alizarin red staining in primary human trabecular meshwork (HTM) cells and alkaline phosphatase (ALP) activity in the angle tissue. Brown Norway (BN) and Wistar rats were intracamerally injected with Ad5BMP2 (OS) and control Ad5.CMV-Null (OD). IOPs were taken twice a week and expressed as mean integral pressures. Morphology was assessed on fixed, paraffin-embedded anterior segments. Retinal ganglion cells (RGCs) were quantified on retrograde and Brn-3a-labeled flat mounts using MetaMorph software. BMP2-treated cells displayed marked increase in calcification. Trabecular meshwork tissue showed moderate ALP activity at 13 days postinjection. Fifty-four of 55 BN and 15 of 19 Wistar rats displayed significantly elevated IOP. In a representative 29-day experiment, the integral IOP difference between treated and control eyes was 367.7 ± 83 mm Hg-days (P = 0.007). Morphological evaluation revealed a well-organized trabecular meshwork tissue, exhibiting denser matrix in the treated eyes. The Ad5BMP2-treated eye showed 34.4% ± 4.8% (P = 0.00002) loss of peripheral RGC over controls. Gene transfer of the calcification inducer BMP2 gene to the trabecular meshwork induces elevated IOP in living rats without altering the basic structure of the tissue. This strategy generates an elevated IOP model in rats that would be useful for evaluation of glaucoma drugs targeting the outflow pathway.

Development of a Model of Elevated Intraocular Pressure in Rats by Gene Transfer of Bone Morphogenetic Protein 2

Development of a Model of Elevated Intraocular Pressure in Rats by Gene Transfer of Bone Morphogenetic Protein 2

Heat shock protein 27 and its role in retinal ganglion cell apoptosis in rat high intraocular pressure model

Background Glaucoma is common blinding eye diseases characterized by chronic loss of retinal ganglion cells(RGCs).Currently glaucoma pathogenesis is not completely understood,heat shock protein 27 ( HSP27 )may be associated with the pathogenesis of glaucomatous optic neuropathy. Objective Through the establishment of a rat model of high intraocular pressure,detection of the expression of HSP27 antibody in serum and RGCs apoptosis to investigate the role of HSP27 in RGCs apoptosis. Methods Fifty-one clean Wistar rats were divided into high intraocular pressure group (34 rats)and sham operation group( 17 rats)using a random number table.An animal model of high intraocular pressure was established in the right eye by the application of bipolar underwater electrocoagulation on vein of sclera surface in the experimental group,and rats with conjunctiva incision only without electric coagulation were served as sham operation (control).The intraocular pressure of rats of the both groups including experimental and control rats was measured 1,2,4,6,8 weeks after operation and then the rats were sacrificed.1 ml serum was collected from these rats to determine the concentration of HSP27 antibody.The retinas of the rats were isolated and homogenated for the extraction and analysis of the retinal protein by Western blot.Apoptosis of RGCs were assayed by TUNEL.The use of the experimental animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by Kunming Medical Collegc. Results Intraocular pressure was elevated significantly after modeling and remained a high value during the expcrimental duration,showing a significant difference among the different groups ( F =318.502,P＜0.01 ).However,no significant change in intraocular pressure before and after operation in the sham-operation group ( F =2.076,P ＞ 0.05 ).The serum concentration of HSP27 antibody was increased significantly overtime from 1,2,4,6 to 8 weeks after the surgery applied,with a significant difference among various time points( F =154.221,P＜0.01 ),but no obvious difference was seen in the shamoperation group( F =0.422,P＞0.05 ).Importantly,Apoptosis rate of RGCs in the experimental eyes was significant higher as the time prolong after intraocular elevated(x2=856.12,P＜0.05 ).The positive rate of RGCs apoptosis in the rats with high intraocular pressure group was elevated significantly compared to the rats in the sham operation group(P＜0.05). Conclusions High intraocular pressure induces the expressions of HSP27 in retina and the accumulation of HSP27 antibody in rats serum;the elevated HSP27 is associated with the increased cell death in RGCs. Key words: Glaucoma; Heat shock protein 27 antibody; Retina ganglion cell; Apoptosis