Effect of NMDA and AMPA/Kainate Receptor Antagonists Against Ethambutol Induced Retinal Toxicity Using Optomotor Response (OMR) in Goldfish

Objective: Ethambutol (EMB) is known to cause ocular toxicity on prolonged use. The present studyevaluated the effect of NMDA and AMPA/Kainate receptor antagonists(memantine & trimetazidine) againstethambutol induced ocular toxicity using Optomotor response (OMR) in goldfish.Materials and Methods: Either sex of goldfishes randomized into three groups (n=8 each group) and wereexposed to daily dose of ethambutol (1 mg/ml for one hour) for 26 days. Group 1 fishes received anintravitreal injection of 1 μl of normal saline. Group 2 and 3 fishes were given intravitreal injections of 20 μgmemantine (MEM) and 10 μg trimetazidine (TMZ) respectively at 10, 15, 20th and 25th day following anesthesia.After drug exposure, fishes OMR was evaluated, and pattern velocity was recorded (on 11, 16, 21st and 26thday) at 5 rpm in different light condition (blue, green and red).Results: Upon chronic exposure (1 hr in bathing solution / day) of ethambutol, at the dose of 1 mg/ml fishesshowed statistically significant decrease in percentage relative frequency (PRF) at 7th dayupon comparison to their baseline values on day 0. Significant decrease in PRF was observed in the greencolor (550 nm, p=0.002) and red color (605 nm, p=0.001) and this effect persisted up to 21st day. BothIndian J Physiol Pharmacol 2019; 63(4) : 294–302*Corresponding author :Dr. T. Velpandian, Professor & O/I, Ocular Pharmacology and Pharmacy Division, Dr. Rajendra Prasad Centre for OphthalmicSciences, All India Institute of Medical Sciences (AIIMS), New Delhi – 110029 (India); +91-11-26593162, +91-11-26588919;E-mail: tvelpandian@hotmail.com(Received on Aug. 10, 2019) Indian J Physiol Pharmacol 2019; 63(4)NMDA Receptor and Ethambutol Induced Ocular Toxicity 295memantine and trimetazidine showed varying degrees of protection on 16th days against EMB induced oculartoxicity.Conclusion: Intravitreal administration of trimetazidine and memantine provide significant protection in thePRF-OMR, indicating the possibility of their use as a therapeutic intervention in the patients developingocular toxicity during antitubercular therapy (ATT).

Challenges in integrating component level technology and system level information from Ayurveda: Insights from NMR phytometabolomics and anti-HIV potential of select Ayurvedic medicinal plants

Background: Information from Ayurveda meeting the analytical challenges of modern technology is anarea of immense relevance. Apart from the cerebral task of bringing together two different viewpoints,the question at the pragmatic level remains ‘who benefits whom’.Objective: The aim is to highlight the challenges in integration of information (Ayurvedic) and technology using test examples of Nuclear Magnetic Resonance (NMR) metabolomics and anti-HIV-1 potential of select Ayurvedic medicinal plants. The other value added objective is implications andrelevance of such work for Ayurveda.Materials and methods: Six medicinal plants (Azadirachta indica, Tinospora cordifolia, Swertia chirata,Terminalia bellerica, Zingiber officinale and Symplocos racemosa) were studied using high resolutionproton NMR spectroscopy based metabolomics and also evaluated for anti-HIV-1 activity on threepseudoviruses (ZM53 M.PB12, ZM109F.PB4, RHPA 4259.7).Results: Of the six plants, T. bellerica and Z. officinale showed minimum cell cytotoxicity and maximumanti-HIV-1 potential. T. bellerica was effective against all the three HIV-1 pseudoviruses. Untargeted NMRprofiling and multivariate analyses demonstrated that the six plants, all of which had different Ayurvedicpharmacological properties, showed maximum differences in the aromatic region of the spectra.Conclusion: The work adds onto the list of potential plants for anti-HIV-1 drug molecules. At the sametime, it has drawn attention to the different perspectives of Ayurveda and Western medicine underscoring the inherent limitations of conceptual bilinguism between the two systems, especially in thecontext of medicinal plants. The study has also highlighted the potential of NMR metabolomics in studyof plant extracts as used in Ayurveda.© 2017 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Publishing Services byElsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Rat bone marrow stromal cell transplantation ameliorates complete spinal cord injury induced sensorimotor dysfunctions and associated neurotransmitters

Traumatic spinal cord injury (SCI) leads to sensorimotor dysfunction with significant impact on the patient and their family’s quality of life, social, and economic status. There is no complete restorative treatment so far. Bone marrow stromal cells (BMSCs) have anti-inflammatory and neuroprotective effects and recently emerged as a therapeutic candidate for SCI repair. Here, we examined the role of rat BMSCs transplantation on thoracic (T11) complete SCI induced dysfunctions, namely hyperalgesia, allodynia, locomotion, spinal reflexes, and spinal neurotransmitters in rats. Pre-labelled BMSCs were injected on day 9 after SCI locally. We observed that BMSCs transplantation facilitate locomotor recovery (week 2-8) and attenuated hyperalgesia and allodynia to varying sensory stimuli (week 6-8) after SCI. In addition, spinal reflexes and neurotransmitters were affected significantly by complete SCI, which were partially restored by BMSCs transplantation. Histological analyses also revealed the presence of BMSCs at the injury site and appear to fill the lesion cavities, thereby significantly reducing the lesion volume. Our data shows the beneficial effects of BMSCs transplantation on complete SCI-induced sensorimotor functional deficits in rats.

Fabrication and Validation of Gyro-Dot-Optomotor Response Device using Gold Fish to Study Drugs Affecting Visual Perception.

An appropriate model to predict the effect of xenobiotics on the vision perception in neuropsychopharmacological studies is of great importance in drug development and toxicity studies. The present study evaluated the effect of CNS stimulant, depressant and therapeutic agents known to have ocular toxicity on optomotor response (OMR) using goldfish in a newly developed device. A digital light processing aided gyrating poly-chromatic dotted pattern-OMR (Gyro-dot-OMR) analyzer was developed and standardized for this study in our laboratory. Goldfishes were exposed to varying concentrations of caffeine and pentobarbitone sodium to evaluate the effect of CNS stimulation and depression on OMR in white light. Ethambutol induced ocular toxicity was evaluated by intravitreal injection into both eyes of goldfishes. They were subjected for polychromatic Gyro-dot-OMR in both clock and anticlockwise directions. At the low concentration (5, 10 and 20 ng/mL) caffeine exposed animals showed significant (p<0.05) stimulant effect and the EC50 of caffeine in goldfish was found to be 4.806 ng/mL. In contrast, pentobarbitone sodium treated fishes showed significant (p<0.05) depressant effect with increasing the concentration. Ethambutol toxicity was reflected by the color discrimination in the Gyro-dot-OMR pattern. For the first time, this model proved the possibility of running Irwin profile test on goldfish using Gyro-dot-OMR. This model successfully predicted ethambutol induced toxicity with poor discrimination of red-green color. This model can be used for predicting toxicity of drugs affecting vision perception.

Antiangiogenic and antiproliferative assessment of cyanobacteria.

Biologically active compounds with different modes of action, such as antiproliferative, antioxidant, antimicrotubule, have been isolated from algae and cyanobacteria. The present study was designed to evaluate antiangiogenic and antiproliferative potential of dichloromethane and methanol (2:1) extracts of different cyanobacteria. Further fingerprinting of the activity possessing extracts were carried out using ESI-LC-MS/MS. Extracts (25, 50 and 100 µg) were screened in the vascular endothelial growth factor (VEGF) induced angiogenesis in inovo chick chorioallontoic membrane assay (CAM) at various concentrations using thalidomide and normal saline as positive and untreated control groups respectively. The extracts were also evaluated for their antiproliferative activity by MTT assay using HeLa cancer cell line. The results obtained from the various algal extracts did not show any significant antiangiogenic activity as compared to VEGF control. Oscillatoria sp. and Lyngbya officinalis exhibited significant anti-proliferative activity at IC50 values of 220 and 260 µg/mL respectively. ESI-LC-MS/MS of L. officinalis showed the presence of lyngbyatoxin-A and that of Oscillatoria sp. reveals the presence of malyngamide-J suggesting the possibility of antiproliferative activity.

Screening of antiangiogenic potential of twenty two marine invertebrate extracts of phylum Mollusca from South East Coast of India

Objective: To evaluate the antiangiogenic potential of twenty two marine invertebrate species of Phylum Mollusca from south east coast of India.Methods:Live specimens of molluscan species were collected and their methanolic extracts were evaluated for preliminary antiangiogenic activity using the in ovo chick chorio-allantoic membrane assay. The extracts were further evaluated for in vivo antiangiogenic activity using chemical cautery induced corneal neovascularization assay in rats and oxygen induced retinopathy assay in rat pups.Results:In the chick chorio-allantoic membrane assay, four methanolic extracts of marine molluscan species viz. Meretrix meretrix, Meretrix casta, Telescopium telescopium and Bursacrumena methanolic extracts exhibited noticeable antiangiogenic activity at the tested concentration of 200 μg whereby they significantly inhibited the VEGF induced proliferation of new blood vessels. Among these four extracts, the methanolic extract of Meretrix casta exhibited relatively higher degree of antiangiogenic activity with an inhibitiory percentage (64.63%) of the VEGF induced neovascularization followed by the methanolic extracts of Telescopium telescopium (62.02%), Bursa crumena (60.48%) and Meretrix meretrix (47.01%). These four methanolic extracts were further evaluated for in vivo antiangiogenic activity whereby the methanolic extract of Telescopium telescopium exhibited most noticeable inhibition (42.58%) of the corneal neovascularization in rats in comparison to the sham treated group, and also exhibited most noticeable inhibition (31.31%) of the oxygen induced retinal neovascularization in rat pups in comparison to the hyperoxia group that was observed for considerable retinal neovascularization.Conclusions:The significant antiangiogenic activity evinced by the extract of Telescopium telescopium merits further investigation for ocular neovascular diseases.

Evaluation of Phototherapy Devices Used for Neonatal Hyperbilirubinemia.

Objective: To compare phototherapy devices based on their physical and photo-biological characteristics viz spectral properties, maximum and mean irradiance, treatable percentage of body surface area, decay of irradiance over time and in vitro photoisomerisation of bilirubin. Design: In vitro experimental study. Setting: Ocular pharmacy laboratory at a tertiary care hospital. Methodology: All the characteristics were measured at a fixed distance of 35 cm from one compact fluorescent lamp (CFL) and three light emitting diode (LED) phototherapy devices in a dark room with an irradiance of <0.1μW/cm2/nm. Estimation of products of in vitro photoisomerisation was done using liquid chromatography - tandem mass spectroscopy (LC-MS/ MS). Results: The emission spectral data were comparable between the phototherapy devices. The devices, however, differed in their maximum irradiance with the spot and indigenous LED units having the highest and lowest values, respectively (56.5 and 16.8μW/cm2/nm). The mean irradiance – measured in 5x5cm grids falling within the silhouette of a term baby – of the spot and improvised LED devices were low (26.8μW/cm2/nm and 11.5μW/cm2/ nm, respectively) possibly due to unevenness in the irradiance of light falling within the silhouette. There was a significant difference in the amount of bilirubin left after exposure to light over a 2-hour time period (% reduction of bilirubin) among the four devices (P=0.001); at 120 minutes after exposure, the amount of bilirubin left was lowest for the CFL (16%) and spot LED (17%) devices and highest for the indigenous LED unit (41%). Conclusions: The four phototherapy devices differed markedly in their physical and photobiological characteristics. Since the efficacy of a device is dependent not only on the maximum irradiance but also on the mean irradiance, rate of decay of irradiance, and treatable surface area of the foot print of light, each phototherapy device should have these parameters verified and confirmed before being launched for widespread use.

Calotropis procera root extracts block VEGF-induced angiogenesis: Quantitative analysis.

Angiogenesis is controlled by number of growth factors, including vascular endothelial growth factor (VEGF). Plant derived anti-angiogenic molecules acting via VEGF are being investigated for curtailing angiogenesis dependent diseases. In this study, methanolic (CM), n-hexane (CH), ethylacetate (CE) and water (CW) extracts of the roots of Calotropis procera were tested for anti-angiogenic activity. In the chicken egg chorioallantoic membrane (CAM) assay, CM, CH and CE but not CW inhibited VEGFinduced neovascularization in a dose-dependent manner. Of all the tested extracts, CM at the dose of 10, 5 and 2.5 ng most effectively inhibited over 83, 71 and 64%, of neovascularization induced by 10ng of VEGF, respectively. Sponge implantation assay in mice further showed that at the dose of 100ng CM, CH and CE but not CW significantly inhibited neovascularization induced by VEGF (100 ng). Taken together, this study indicates that the root extracts of C.procera may possess anti-angiogenic activity.

Retinal toxicity of intravitreally injected plain and liposome formulation of fluconazole in rabbit eye.

PURPOSE: Candidal endophthalmitis is a sight-threatening ocular infection that most frequently occurs as a complication of candidemia. Fluconazole has been effective against Candida albicans in various animal models. Our objective was to evaluate retinal toxicity of plain and liposome formulation of fluconazole at various dose levels after intravitreal injection. MATERIALS AND METHODS: Twelve New Zealand albino rabbits weighing 2-2.5 kg were used. Two rabbits were used for every dose level. Liposome formulation containing 100 and 200 microg of fluconazole in sterile phosphate buffer solution and plain fluconazole at concentrations of 100, 200, 400 and 800 microg in 0.1 ml of sterile normal saline were injected intravitreally into the right eyes. The left eyes received 0.1 ml normal saline or 0.1 ml of liposome formulation without fluconazole. One week later, the animals were sacrificed, their eyes enucleated and processed for light microscopy and scanning electron microscopy. RESULTS: It showed that plain fluconazole at a concentration of 100 microg and above caused retinal changes, with disorganization of the photoreceptor outer segments. However, liposome formulation of fluconazole (200 microg/0.1 ml) did not show any significant microscopic changes of the retina. CONCLUSION: The liposome formulation decreased the retinal toxicity of fluconazole up to the studied concentration of 200 microg/0.1 ml.