Digital measuring the ocular morphological parameters of guinea pig eye in vivo with Python

AIM:To quantitatively measure ocular morphological parameters of guinea pig with Python technology.METHODS:Thirty-six eyeballs of eighteen 3-weekold guinea pigs were measured with keratometer and photographed to obtain the horizontal,coronal,and sagittal planes respectively.The corresponding photo pixels-actual length ratio was acquired by a proportional scale.The edge coordinates were identified artificially by ginput function.Circle and conic curve fitting were applied to fit the contour of the eyeball in the sagittal,coronal and horizontal view.The curvature,curvature radius,eccentricity,tilt angle,corneal diameter,and binocular separation angle were calculated according to the geometric principles.Next,the eyeballs were removed,canny edge detection was applied to identify the contour of eyeball in vitro.The results were compared between in vivo and in vitro.RESULTS:Regarding the corneal curvature and curvature radius on the horizontal and sagittal planes,no significant differences were observed among results in vivo,in vitro,and the keratometer.The horizontal and vertical binocular separation angles were 130.6°±6.39°and 129.8°±9.58°respectively.For the corneal curvature radius and eccentricity in vivo,significant differences were observed between horizontal and vertical planes.CONCLUSION:The Graphical interface window of Python makes up the deficiency of edge detection,which requires too much definition in Matlab.There are significant differences between guinea pig and human beings,such as exotropic eye position,oblique oval eyeball,and obvious discrepancy of binoculus.This study helps evaluate objectively the ocular morphological parameters of small experimental animals in emmetropization research.

Electroacupuncture alleviates ciliary muscle cell apoptosis in lens-induced myopic guinea pigs through inhibiting the mitochondrial signaling pathway

AIM:To investigate the effect of electroacupuncture(EA)on the mitochondria-dependent apoptotic signaling pathway in the ciliary muscle of guinea pigs with negative lensinduced myopia(LIM).METHODS:Guinea pigs were randomly divided into normal control(NC)group,LIM group,LIM+SHAM acupoint(LIM+SHAM)group,and LIM+EA group.Animals in the NC group received no intervention,while those in other three groups were covered with-6.0 diopter(D)lenses on right eyes.Meanwhile,animals in the LIM+EA group received EA at Hegu(LI4)combined with Taiyang(EX-HN5)acupoints,while those in the LIM+SHAM group were treated at sham points.After treatments for 1,2,and 4wk,morphological changes in ciliary muscles were observed with hematoxylin and eosin(H&E)staining and nick end labeling(TUNEL),and the expression of the mitochondrial apoptotic signaling pathway-related molecules in ciliary muscles was measured by real-time quantitative polymerase chain reaction(qPCR)and Western blot.Additionally,the adenosine triphosphate(ATP)contents were also determined in ciliary muscles.RESULTS:Axial length increased significantly in the LIM and LIM+SHAM groups and decreased in the LIM+EA group.The ciliary muscle fibers were broken and destroyed in both LIM and LIM+SHAM groups,whereas those in the LIM+EA group improved significantly.TUNEL assay showed the number of apoptotic cells increased in the LIM and LIM+SHAM groups,whereas reduced in the LIM+EA group.ATP contents showed a significant decrease in the LIM and LIM+SHAM groups,whereas increased after EA treatment.Compared with the NC group,the dynamin-related protein 1(DRP1),Caspase3,and apoptotic protease activator 1(APAF1)levels were significantly increased in the LIM group and decreased in the LIM+EA group.CONCLUSION:The results provide evidence of EA inhibiting the development of myopia by regulating the mitochondrial apoptotic signaling pathway.

Feeding Management and Disease Prevention and Control of Pet Guinea Pigs

Guinea pig is widely used in clinical drug experiments as a laboratory animal.Because of its small and lovely size,guinea pig is often kept as a pet by many families.However,there are few reports on the feeding management and disease prevention and control of pet guinea pigs.This article introduced the experience and technology of feeding management and disease prevention of pet guinea pigs,in order to provide a reference for the feeding management and disease prevention of pet guinea pigs.

Effect of cholecystokinin and secretin on contractile activity of isolated gastric muscle strips in guinea pigs

AIM To study the effect of cholecystokinin-octapeptide（CCK-8）and secretin on contractileactivity of isolated gastric muscle strips inguinea pigs.METHODS Each isolated gastric muscle stripwas suspended in a tissue chamber containing5 mL Krebs solution constantly warmed by waterjacked at 37℃ and supplied with a mixed gas of95% O2 and 5% CO2 After incubating for lhunder 1 g tension,varied concentrations of CCK-8 and secretin were added respectively in thetissue chamber and the contractile response wasmeasured isometrically on ink-writing recorders.RESULTS CCK-8 could increase①all regionalcircular and longitudinal muscular tension at rest（fundus LM 19.7%±2.1%,P【0.01;fundus CM16.7%±2.2%,P【0.01;gastric body LM 16.8%±2.3%,P【0.01;body CM 12.7%±2.6%,P【0.01;antrum LM 12.3%±1.3%,P【0.01;antrum CM 16.7%±4.5%,P【0.01;pylous CM12.7%±5.0%,P【0.05）;②contractilefrequencies of body LM,both LM and CM ofantrum and pylorus CM（5.1/min±0.2/min to5.6/min±0.2/min,5.9/min±0.2/min to 6.6/min±0.l/min,5.4/min±0.3/min to 6.3/min±0.4/rain,1.3/min±0.2/min to 2.3/min±0.3/min,respectively,P【0.05）;③the mean contractileamplitude of antral circular muscle（58.6%±18.4%,P【0.05）and ④the motility index ofpylorus CM（145.0%±23.8%,P【0.01）,butdecrease the mean contractile amplitude ofgastric body and antral LM（-10.3%±3.3%,-10.5%±4.6%,respectively,P【0.05）.All the CCK-8 effects were not blocked by atropine orindomethacin.Secretin had no effect on gastricsmooth muscle activity.CONCLUSION CCK-8 possessed bothexcitatory and inhibitory action on contractileactivity of different regions of stomach in guineapigs.Its action was not mediated via cholinergicM receptor and endogenous prostagiandinreceptor,

Effects of rhubarb on isolated gastric muscle strips of guinea pigs

AIM: To study the effects of rhubarb (dried root of Rheum officinale Baill.) on contractile activity of isolated gastric muscle strips of guinea pigs and its possible mechanism.METHODS: A total of 48 guinea pigs were killed to remove the whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to the circular fibers, muscle strips were cut from the body. Each isolated gastric muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution, constantly warmed by water jacket at 37 ℃ and bubbled continuously with a mixed gas of 950 mL/L O2 and 50 mL/L CO2. After being incubated for 1 h with 1 g tension, rhubarb of varied concentrations (1%, 2%, 7%, 20% and 70%) was added cumulatively into the tissue chamber at intervals of 2 min. Atropine (10-6 mol/L) or isoptin (5×10-8 mol/L) orhexamethonium(10-5 mol/L) was given 2 min before the administration of rhubarb. The isometrical response was measured with an ink-writing recorder.RESULTS: Rhubarb dose dependently increased the resting tension of gastric body circular muscle(CM)(r = 0.726, P＜0.05). Atropine (r= 0.829, P＜0.05), isoptin (r = 0.764,P＜0.05) and hexamethonium (r = 0.797, P＜0.05) did notaffect its action in a dose-related manner. Atropine apparently reduced the increasing action of 1%, 3%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Isoptin inhibited the effect of 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Hexamethonium reduced the increasing action of 1%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Rhubarb increased the contractile frequency of CM of body. While atropine, isoptin and hexamethonium did not inhibit the contractile frequency of gastric body CM in comparison with rhubarb at the same concentration, rhubarb at the highest concentration (100%) decreased the meancontractile amplitude of gastric body CM. Atropine, isoptin and hexamethonium did not affect the mean contractile amplitude of gastric body CM compared to rhubarb at the same concentration.CONCLUSION: Rhubarb has exciting actions on isolated gastric smooth muscle strips of guinea pig. The exciting action of rhubarb is partly mediated via cholinergic M receptor, cholinergic N receptor and L-type calcium channel.

Adenoviral-mediated Hath1-EGFP gene transfer into guinea pig cochlea through intact round window membrane

Objective To study expression of adenoviral-mediated Hath1-EGFP gene in the guinea pig cochlea after transfer through intact round window membrane(RWM), and to assess its effects on hearing. Methods Twenty adult guinea pigs were used, of which: 12 were surgically inoculated with Ad-Hath1-EGFP in the bony groove of round window niche, and 8 with artificial perilymph. Auditory brainstem response(ABR) thresholds were determined in all animals before and 5 days after surgery. On post-surgery day 5 and day 14, animals were sacrificed and whole mounts of cochlea and frozen sections were examined. Results ABR tests showed no significant change of hearing after the surgery. Strong fluorescence staining in the cochleae was seen in Ad-Hath1-EGFP groups. The highest levels of gene expression were seen in the post-surgery day 5 group with little decrease on post-surgery day 14.The contralateral cochlea and those in the control groups were free of fluorescence staining. Conclusion The transgenic Hath1-EGFP can be effectively delivered into the inner ear through intact RWM, in an atraumatic manner.

Myopia induced by flickering light in guinea pigs: a detailed assessment on susceptibility of different frequencies

AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2 -week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n =12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured. RESULTS: A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5 ±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89 ±0.3mm, 0.69 ±0.2mm, 1.12 ±0.2mm respectively and with increase in dry weight of sclera by 0.44mg. CONCLUSION: Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could bedisrupted differently by frequency alteration.

Electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure

Objective: To investigate the electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure.Methods: Guinea pigs model of iron deficiency anemia complicated with chronic heart failure in 10 guinea pigs of the experimental group was made by feeding a low iron diet,pure water and subcutaneous injection of isoproterenol. The control group consisting of 11 guinea pigs was given normal food, normal water and injected with normal saline. The left ventricular outflow tract model specimen was also prepared. The standard microelectrode technique was used to observe electrophysiological changes of autonomic cells in the outflow tract of left ventricular heart failure complicated with iron deficiency anemia in guinea pig model. The indicators of observation were maximal diastolic potential, action potential amplitude, 0 phase maximal depolarization velocity, 4 phase automatic depolarization velocity, repolarization 50% and 90%, and spontaneous discharge frequency.Results: Compared with the control group, 4 phase automatic depolarization velocity,spontaneous discharge frequency and 0 phase maximal depolarization velocity decreased significantly(P < 0.01) and action potential amplitude reduced(P < 0.01) in model group. Moreover, repolarization 50% and 90% increased(P < 0.01).Conclusions: There are electrophysiological abnormalities of the left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with heart failure.

Expressions of cellular retinoic acid binding proteins I and retinoic acid receptor-β in the guinea pig eyes with experimental myopia

·AIM:All-trans retinoic acid (RA) is the only extrinsic biochemical candidate known to date that could act as a growth controller,the aim of this study was to investigate the expression cellular retinoic acid binding proteins I (CRABP-I) and retinoic acid receptor-β (RAR-β) in retina of the guinea pig eyes with experimental myopia.·METHODS:Ninety guinea pigs aged 14 days were equally and randomly divided into three groups:form deprivation (FD),-5D lens,and control.The diffusers for FD were white translucent hemispheres,and-5D lenses were used to introduce hyperopic defocus.Refraction was measured with streak retinoscopy after cycloplegia,and axial length was calculated with Cinescan A/B ultrasonography.Retina harvested at different time points were used to measure RA level with HPLC and expressions of cellular retinoic acid binding proteins I (CRABP-I) and RA receptor-β (RAR-β) were assayed with Western blot and Real-time PCR.SPSS13.0 software was used for statistical analysis.·RESULTS:Up-regulations of CRABP-I and RAR-β in ocular tissues correlated with changes in the refractive status and growth rate of the guinea pig eye (P <0.05).14 days of monocular form-deprivation led to-5.14D myopia and a 0.281mm axial elongation;14 days of monocular defocus produced-3.64D myopia and a 0.163 mm axial elongation.The level of retinal RA started to elevate in 7 days (P <0.05) after visual manipulation in both FD and-5D lens groups and became more prominent by 14 days (P <0.01).The expressions of CRABP-I and RAR-β increased by 14 days after visual manipulation (P <0.05),the mRNA level of RAR-β,however,increased by 7 days after visual manipulation (P <0.05),which suggested that changes of expressions of CRABP-I and RAR-β might lag behind the change of RA.·CONCLUSION:The levels of CRABP-I and RAR-β were elevated in retina of the guinea pig eye with experimental myopia.During the progression of experimental myopia,the retinal RA level increased rapidly,and there might be a positive feedback between the increase of RA and up-regulation of RAR-β.·

Immune Potential of a Novel Multiple-epitope Vaccine to FMDV Type Asia 1 in Guinea Pigs and Sheep

To develop a safe and efficient recombinant subunit vaccine to foot-and-mouth disease virus (FMDV) type Asia 1 in sheep, a tandem repeated multiple-epitope gene consisting of residues 137-160 and 197-211 of the VP1 gene of FMDV was designed and artificially synthesized. The biologically functional molecule, the ovine IgG heavy constant region (oIgG) as a protein carrier was introduced for design of the multiple-epitope recombinant vaccine and recombinant expression plasmids pET-30a-RE and pET-30a-RE-oIgG were successfully constructed. The recombinant proteins, RE and RE-oIgG, were expressed as a formation of inclusion bodies in E. coli. The immune potential of this vaccine regime in guinea pigs and sheep was evaluated. The results showed that IgG could significantly enhance the immune potential of antigenic epitopes. The recombinant protein RE-oIgG could not only elicit the high levels of neutralizing antibodies and lymphocytes proliferation responses in the vaccinated guinea pigs, but confer complete protection in guinea pigs against virus challenge. Although the recombinant protein RE could not confer protection in the vaccinated animals, it could delay the appearance of the clinical signs and reduce the severity of disease. Inspiringly, the titers of anti-FMDV neutralizing antibodies elicited in sheep vaccinated with RE-oIgG was significantly higher than that for the RE vaccination. Therefore, we speculated that this vaccine formulation may be a promising strategy for designing a novel vaccine against FMDV in the future.

Retinoic acid metabolic change in retina and choroid of the guinea pig with lens-induced myopia

AIM: To investigate the role of retinoic acid (RA) and retinaldehyde dehydrogenase-2 (RALDH2) of retina and choroid in the guinea pig lens-induced myopic eyes. METHODS: Totally 45 guinea pigs, at age of three weeks, were randomly assigned into three groups: the normal control, the lens-induced group and the recovering group. Out of focus was induced by the -6.00D concave lens on the left eye, and lasted for 15 days. All animals underwent biometric measurement (corneal radius of curvature, refraction and axial length). Subsequently, RA content in the retina and RPE/choriod complex was detected by reversed- phase high-performance liquid chromatography. RALDH2 protein in the retina and RPE/choriod complex was evaluated by the immunohistochemical staining and Western blotting. RESULTS: After wearing -6.00D lens for 15 days, axial length of the lens-induced eye extends and myopia was formed, with RA contents increasing in both the neural retina and RPE/choroid complex. Comparing with the lens-induced group, myopic degree significantly relieved, and its RA contents in both the neural retina and RPE/choroid complex decreased in the recovering group. In the normal control, RALDH2 protein was expressed positively in the retinal nerve fiber layer (RNFL), inner plexiform layer (IPL) and lateral border of outer nuclear layer (ONL). Retinal RALDH2 protein increased in the lens-induced group, and was also positive in the outer plexiform layer (OPL). In the recovering group, retinal RALDH2 protein attenuated the expression in the OPL turns to negative. RALDH2 protein was not expressed in the choroid of any group. CONCLUSION: RA of retina and chorid participates in the regulation of the lens-induced myopia in guinea pigs, which may be related with retinal RALDH2 protein.

Effect of green flickering light on myopia development and expression of M1 muscarinic acetylcholine receptor in guinea pigs

AIM: To investigate the effects of green flickering light on refractive development and expression of muscarinic acetylcholine receptor(mAChR) M1 in the eyes of guinea pigs.METHODS: Thirty guinea pigs(15-20 days old) were randomly divided into three groups(n=10/group). Animals in group I were raised in a completely closed carton with green flickering light illumination. Those in group II were kept in the open top closed carton under normal natural light. Guinea pigs were raised in a sight-widen cage under normal natural light in group III. The refractive status and axial length were measured before and after 8 weeks' illumination. Moreover, total RNA extracted from retinal, choroidal, and scleral tissues were determined by real-time reverse transcription polymerase chain reaction(RT-PCR). The expressions of the receptor M1 were also explored in the retina, choroid, and sclera using immunohistochemistry.RESULTS: There was a remarkable reduction in refractive error and increase in axial length after 8-weeks' green flickering light stimulation(P<0.001). The expression of M1 receptor mRNA in sclera and retina in myopia group were remarkably lower than that in group II and III(P<0.01). Significant reduced expression of M1 receptor stimulated by green flickering light in retina and sclera tissues were also observed(P<0.05). However, there was no M1 receptor expression in choroid in 3 groups.CONCLUSION: Myopia can be induced by 8 weeks' green flickering light exposure in the animal model. M1 receptor may be involved causally or protectively in myopia development.

Form-deprivation myopia induces decreased expression of bone morphogenetic protein-2, 5 in guinea pig sclera

AIM: To identify the presence of various bone morphogenetic proteins(BMPs) and their receptors in normal sclera of human, rat and guinea pigs, and to determine whether their expression changed with form-deprivation myopia(FDM) in guinea pig sclera.METHODS: The expression of BMPs and BMP receptors were detected using reverse transcription polymerase chain reaction(RT-PCR) and immunofluorescence. Two-week-old guinea pigs were monocularly form-deprived with a translucent lens. After fourteen days induction of FDM, total RNA was isolated and subjected to RT-PCR to examine the changes of BMPs and BMP receptors in tissues from the posterior sclera. Western blotting analysis was used to investigate their changes in protein levels.RESULTS: Human sclera expressed m RNAs for BMP-2,-4,-5,-7,-RIA,-RIB and BMP-RII. Conversely, rat sclera only expressed m RNA for BMP-7 and BMP-RIB,while the expression of BMPs and BMP receptors in guinea pigs were similar to that of humans. Human sclera also expresses BMP-2,-4,-5,-7 in protein level.Fourteen days after the induction of myopia, significant decreased expressions for BMP-2 and BMP-5 in the posterior sclera of FDM-affected eyes(P <0.05 vs internal control eyes).· CONCLUSION: Various BMPs were expressed in human and guinea pig sclera. In the posterior sclera,expressions of BMP-2 and BMP-5 significantly decreased in FDM eyes. This finding indicates that various BMPs as components of the scleral cytokines regulating tissue homeostasis and provide evidence that alterations in the expression of BMP-2 and BMP-5 are associated with sclera remodeling during myopia induction.

Guinea Pig Maximization Test for Trichloroethylene and Its Metabolites

Objectives To study the contact allergenic activities of trichloroethylene (TCE) and its three metabolites trichloroacetic acid, trichloroethanol and chloral hydrate. Methods A modified guinea pig maximization test (GPMT) was adopted. The skin sensitization (edema and erythema) was observed in trichloroethylene, trichloroacetic acid, trichloroethanol, chloral hydrate and 2,4-dinitrochlorobenzene. Results The allergenic rate of TCE, trichloroacetic acid and 2,4-dinitrochlorobenzene was 71.4%, 58.3% and 100.0% respectively, and that of trichloroethanol and chloral hydrate was 0%. The mean response score of TCE, trichloroacetic acid and 2,4-dinitrochlorobenzene was 2.3, 1.1, 6.0 respectively. The histopathological analysis also showed an induction of allergenic transfomation in guinea pig skin by both TCE and trichloroacetic acid. Conclusion TCE appears to be a strong allergen while trichloroacetic acid a moderate one. On the other hand, both trichloroethanol and chloral hydrate are weak sensitization potentials. Immunologic reaction induced by TCE might be postulated as the pathological process of this illness. Consequently, it is suggested that in the mechanism of Occupational Dermatitis Medicamentose-Like (ODML) induced by TCE, the chemical itself might be the main cause of allergy. As one of its metabolic products, trichloroacetic acid might be a subordinate factor.

Effect of emodin on mobility signal transduction system of gallbladder smooth muscle in Guinea pig with cholelithiasis

Objective: To study the effect of emodin on protein and gene expressions of the massagers in mobility signal transduction system of cholecyst smooth muscle cells in guinea pig with cholesterol calculus. Methods: The guinea pigs were randomly divided into 4 groups, such as control group, gall-stone(GS) group, emodin group and ursodesoxycholic acid(UA) group. Cholesterol calculus models were induced in guinea pigs of GS, emodin and UA groups of induced models by lithogenic diet, while emodin or UA were given to the corresponding group for 7 weeks. The histomorphological and ultrastructure change of gallbladder were detected by microscope and electron microscope, the content of plasma cholecystokinin(CCK) and [Ca^(2+)]i were analyzed successively by radioimmunoassay and flow cytometry. The protein and mR NA of Gsα, Giα and Cap in cholecyst cells were determined by western blotting and real time polymerase chain reaction(RT-PCR). Results: Emodin or UA can relieve pathogenic changes in epithelial cells and muscle cells in gallbladder of guinea pig with cholesterol calculus by microscope and transmission electron microscope. In the cholecyst cells of GS group, CCK levels in plasma and [Ca^(2+)]i decreased, the protein and m RNA of GS group were downregulated,the protein and m RNA of Gi and Cap were up-regulated. Emodin significantly decreased the formative rate of gallstone, improved the pathogenic change in epithelial cells and muscle cells, increased CCK levels in plasma and [Ca^(2+)]i in cholecyst cells, enhanced the protein and mR NA of Gs in cholecyst cells, reduced the protein and mR NA of Gi and Cap in cholecyst cells in guinea pig with cholesterol calculus. Conclusion: The dysfunction of gallbladder contraction gives rise to the disorders of mobility signal transduction system in cholecyst smooth muscle cells, including low content of plasma CCK and [Ca^(2+)]i in cholecyst cells, abnormal protein and mRNA of Gs, Gi and Cap. Emodin can enhance the contractibility of gallbladder and alleviate cholestasis by regulating plasma CCK levels, [Ca2+]i in cholecyst cells and the protein and mR NA of Gs, Gi and Cap.

Effects of hepatocyte growth factor on MMP-2 expression in scleral fibroblasts from a guinea pig myopia model

AIM:To investigate the effects of hepatocyte growth factor(HGF)on MMP-2 expression in scleral fibroblasts from guinea pig with LIM.METHODS:Sixty 1-week-old guinea pigs were chosen for the study.The right eyes were treated with-10.0 D lenses as the LIM group;the left eyes remained untreated as the control group.The refraction and axial length were measured by streak retinoscopy and A-scan ultrasonography respectively prior to and 4wk after the experiment.Four weeks later,the guinea pigs were sacrificed and primary scleral fibroblasts were taken for tissue culture.The 3rd-5th generation scleral fibroblasts were chosen for the experiments.The expression levels of HGF and MMP-2 protein in the scleral fibroblasts were analyzed by Western blotting.After HGF with different doses acted on the scleral fibroblasts of the control group,MMP-2 protein expression in the scleral fibroblasts was analyzed by Western blotting.HGF siRNA was transfected into the scleral fibroblasts of the LIM group and the protein expressions of HGF and MMP-2were analyzed by Western blotting.RESULTS:The LIM group became myopic with a significant increase in axial length(7.97±0.29 mm vs7.01±0.26 mm,P<0.05),and a significant decrease in refraction(-5.06±0.31 D vs 0.55±0.25 D,P<0.05)compared with the control group.The protein expression of HGF in the scleral fibroblasts of the LIM group was significantly higher compared with the control group(1.26±0.04 vs 0.32±0.04,P<0.05).The protein expression of MMP-2 in the scleral fibroblasts of the LIM group wassignificantly higher compared with the control group(0.89±0.06 vs 0.42±0.05,P<0.05).In the scleral fibroblasts of the control group,HGF(0,0.1,1,10 ng/mL)upregulated MMP-2 protein expression in a dose-dependent manner(0.35±0.03,0.44±0.02,0.91±0.03,1.33±0.04,all P<0.05).In the scleral fibroblasts of the LIM group transfected with HGF siRNA,MMP-2 protein expressions were significantly decreased compared with the negative control group(0.29±0.03 vs 0.81±0.05,P<0.05).CONCLUSION:HGF is a upstream mediator of MMP-2in scleral fibroblasts from guinea pig.

Dynamic changes of ocular biometric parameters:a modified form-deprivation myopia model of young guinea pigs

AIM:To evaluate the dynamic ocular biometric changes of a modified form-deprivation myopia model in young guinea pigs.METHODS:The animals were randomly assigned to two groups:the monocularly deprived facemask group(MDF,with all the right eyes covered,n =24) and the normal control group(free of facemask,n =24).Each group was then equally divided into four subgroups which were followed up for 2,4,6 and 8 weeks,respectively.Parameters measured from every eye included refraction,corneal curvature,axial length and the dry weight of sclera at the posterior pole.RESULTS:All the facemasks remained in place during the follow-up.The covered eyes developed myopia with the vitreous chamber lengthening and the dry weight of posterior sclera reduced at each time point compared with the contralateral uncovered(P <0.05 at all time points).The changes had a linear correlation with the deprivation time(P <0.05).There were no significant differences in all the parameters between the uncovered eyes of MDF group and the normal control group(P >0.05 at all time points).CONCLUSION:Monocular form deprivation with the facemask is highly effective and non-invasive in inducing axial myopia in guinea pigs.The axial myopia is mainly caused by the increased vitreous chamber length and the weakened posterior sclera rigidity.The form-deprivation eye didn't interfere with the natural development of the contralateral eye.

Protective effects of riboflavin-UVA-mediated posterior sclera collagen cross-linking in a guinea pig model of form-deprived myopia

AIM:To evaluate the effect of posterior sclera collagen cross-linking induced by riboflavin-ultraviolet A(UVA)on form-deprived myopia in guinea pigs.METHODES:Twenty-five pigmented guinea pigs of 3-week-old were randomly assigned into 4 groups that included normal control(NOR,n=7),form-deprived(FDM,n=7),normal with riboflavin-UVA cross-linking(NOR+CL,n=5)and form-deprived with cross-linking(FDM+CL,n=6).The NOR+CL group and the FDM+CL group received the riboflavin-UVA induced cross-linking at day 0.FDM was induced by monocularly deprived with facemask in the right eyes.The refraction,axial length and corneal curvature were measured by retinoscopy,A-scan and keratometer respectively in scheduled time points(day 0 and 1,2,3,4 wk after form-deprivation).At the end of 4 weeks’experiment,stress-strain tests of sclera were measured and morphological changes of sclera and retina were examined.RESULTS:After 4 wk,the interocular difference of refractive error were-0.11±0.67,-2.93±0.56,1.10±0.58,and-1.63±0.41 D in the NOR,FDM,NOR+CL,and FDM+CL groups respectively.Mixed-effect linear model revealed significant effect of FDM(P<0.01)and CL(P<0.001).Also,after 4 wk,the interocular difference of axial length were 0.01±0.04,0.29±0.07,-0.13±0.06,and 0.11±0.05 mm in the NOR,FDM,NOR+CL,and FDM+CL group.Mixedeffect linear model revealed significant effect of FDM(P<0.001)and CL(P<0.01).As for corneal curvature,significant interocular difference have not found between any of the two groups.At the end of this experiment,the ultimate stress and elastic modulus were found significantly increased in both CL groups.But no difference was found in the groups without cross-linked.There was no abnormality observed in the retina and RPE cells of the treated eyes.CONCLUSION:The posterior sclera collagen crosslinking induced by riboflavin-UVA can slow down the progress of myopia and increase the sclera biomechanical strength in the guinea pig model of form-deprived myopia.

Relaxant Effects of Matrine on Aortic Smooth Muscles of Guinea Pigs

Objective To determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects. Methods Phenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs. Results Matrine (1×10-4 mol/L -3.3×10-3 mol/L) relaxed the endothelium-denuded aortic rings pre-contracted sub-maximally with phenylephrine, in a concentration-dependent manner, and its pre-incubation (3.3×10-3 mol/L) produced a significant rightward shift in the phenylephrine dose-response curve, but had no effects on the potassium chloride-induced contraction. The anti-contractile effect of matrine was not reduced by the highly selective ATP-dependent K+ channel blocker glibenclamide (10-5 mol/L), either by the non-selective K+ channel blocker tetraethylammonium (10-3 mol/L), or by the β-antagonist propranolol (10-5 mol/L). In either "normal" or "Ca2+-free" bathing medium, the phenylephrine-induced contraction was attenuated by matrine (3.3×10-3 mol/L), indicating that the vasorelaxation was due to inhibition of intracellular and extracellular Ca2+ mobilization. Conclusion Matrine inhibits phenylephrine-induced contractions by inhibiting activation of α-adrenoceptor and interfering with the release of intracellular Ca2+ and the influx of extracellular Ca2+.

The phytoconstituents and the comparative effects of aqueous extract of Irvingia gabonensis seeds and proviron on the biochemical parameters of male guinea pigs

Objective:To investigate the phytochemical screening and the effects of the aqueous extracts of the seeds of Irvingia gabonensis on the biochemical parameters of male guinea pigs.Methods: The biochemical parameters were assayed using Randox Diagnostic kits,Phenolphthalein method and colorimetric method.The phytochemical screening was carried out using standard procedures.Results:Phytochemical investigations revealed the presence of flavonoids,tannins, carbohydrate,alkaloids,terpenoids,steroids,volatile oils,saponins and cardiac glycosides.The aqueous extract of Irvingia gabonensis seeds(SO - 400 mg/kg) caused a statistically significant(P【 0.05 ANOVA) decrease in the levels of total cholesterol,urea,uric acid,total protein,prostatic, alkaline,and acid phosphatases.The highest reduction effect was obtained with uric acid at 400 mg/kg of Irvingia gabonensis extract while the least effect was observed in total cholesterol. These effects were dose- and time- dependent.Conclusions:This shows that the seeds of Irvingia gabonensis have hepatoprotective,nephroprotective and cardio protective properties.The study therefore,supports the claims on the use of the seeds of this plant by traditional medicine practitioners as a hepatoprotective and nephroprotective agent Although further studies need to be done to isolate,identify and characterize the active principles in the seeds of this plant.