Effects of topical ketorolac tromethamine on tear parameters, meibography, goblet cell density, and conjunctival oxidative stress in healthy dogs.

OBJECTIVES: The objective of the study was to evaluate whether a twice-daily instillation of 0.45% preservative-free ketorolac tromethamine (FKT) or 0.4% benzalkonium chloride-preserved ketorolac tromethamine (BACKT), every 12 h for 30 days may affect tear film parameters and the meibography in healthy dogs. Additionally, we assessed whether the same treatments irritated the ocular surface, affected goblet cell density (GCD), and the levels of oxidative stress biomarkers (OSB) in the conjunctiva of the same dogs. PROCEDURES: Experimental and masked comparison study. In 11 healthy dogs baseline values of the lipid layer thickness, tear meniscus height, non-invasive tear breakup time (NI-TFBT), and the meibomian gland (MG) loss were assessed by OSAvet®. For each dog, one eye received 40 µL of BACKT, while the other received 40 µL FKT, every 12 h for 30 consecutive days. Tear parameters and meibography were repeated 15, 30, and 60 days post-treatments. Conjunctival hyperemia and blepharospasm were monitored at the same time points. At baseline and Day 30, a conjunctival biopsy was collected for GCD and OSB determination. RESULTS: Conjunctival hyperemia and blepharospasm were not observed. At Day 15, the MG loss increased only in FKT-treated eyes (p < .001). On Day 30, both treatment groups showed increased MG loss, shortened NI-TFBT, and reduced GCD and catalase (p < .05). At Day 30, BACKT-treated eyes showed lower levels of superoxide dismutase (SOD) (p = .006) and higher levels of malondialdehyde (MDA) (p = .02). Differences between treatments were not observed for any parameter at any time point (p > .05). 60 days after treatment, OSAvet® parameters tended to return to values assessed at baseline; however, significant differences remained for MG loss (p < .05). CONCLUSIONS: Twice-daily instillation of KT, containing or not BAC, for 30 consecutive days shortened NI-TFBT, decreased GCD, and increased the MG loss in healthy dogs. KT should be used with caution when prescribed for long periods, particularly in patients with tear film abnormalities. However, future controlled studies using KT, BAC, and other topical NSAIDs are indicated to further support this finding.

Piranhea trifoliata extracts ameliorate muscular decline in Drosophila melanogaster exposed to Paraquat.

In this study, we have demonstrated, for the first time, the muscular protective effects of Piranhea trifoliata bark extract against Paraquat (PQ)-induced oxidative stress in Drosophila melanogaster. Exposure of D. melanogaster (Canton Special) to PQ caused oxidative stress, as evidenced by protein carbonyl and elevated acetylcholinesterase (AChE) activity levels. However, a diet supplemented with the P. trifoliata extracts (0.1 mg/ml) for 10 days ameliorates protein carbonyl levels and enzymatic activities of AChE and citrate synthase to prevent PQ damage. Also, P. trifoliata bark extracts showed in phytochemical assays the presence of phenols, at 46.06 mg EAG/g extract of total phenolic compounds, and a 40% 2,2-diphenyl-1-picryl-hydrazyl scavenging effect. The study showed the muscular protective function of the P. trifoliata extracts in D. melanogaster exposed to PQ. On the basis of the results, we contemplate that the bark of P. trifoliata might prevent and ameliorate human diseases caused by oxidative stress. The muscular action of the P. trifoliata extract can be attributed to the antioxidant constituents, while the precise mechanism of its action needs further investigation.

Pre-treatment and continuous administration of simvastatin during sepsis improve metabolic parameters and prevent CNS injuries in survivor rats.

Sepsis causes overproduction of inflammatory cytokines, organ dysfunction, and cognitive impairment in survivors. In addition to inflammation, metabolic changes occur according to the stage and severity of the disease. Understanding the role and place of metabolic disturbances in the pathophysiology of sepsis is essential to evaluate the framework of septic patients, predict the syndrome progress, and define the treatment strategies. We investigated the effect of simvastatin on the disease time course and on metabolic alterations, especially with respect to their possible consequences in the CNS of surviving rats. The animals of this study were weighed daily and followed for 10 days to determine the survival rate. In the first experiment, control or cecal ligation and puncture (CLP)-animals were randomized in 24 h, 48 h, and 10 days after septic induction, for bacterial load determination and quantification of cytokines. In the second experiment, control or CLP-animals were treated or not with simvastatin and randomized in the same three time points for cytokines quantification and assessment of their body metabolism and locomotor activity (at 48 h and 10 days), as well as the evaluation of cytoarchitecture and astrogliosis (at 10 days). The CLP-rats treated with simvastatin showed a reduction in plasma cytokines and improvement in metabolic parameters and locomotor activity, followed by minor alterations compatible with apoptosis and astrogliosis in the hippocampus and prefrontal cortex. These results suggest that the anti-inflammatory effect of simvastatin plays a crucial role in restoring energy production, maintaining a hypermetabolic state necessary for the recovery and survival of these CLP-rats.

Protective action of Omega-3 on paraquat intoxication in Drosophila melanogaster.

Paraquat (PQ) (1,1'-dimethyl-4-4'-bipyridinium dichloride) is the second most widely used herbicide worldwide; however, in countries different sales and distribution remain restricted. Chronic exposure to PQ leads to several diseases related to oxidative stress and mitochondrial dysfunctions including myocardial failure, cancer, and neurodegeneration and subsequently death depending upon the dose level. The aim of this study was to examine if diet supplementation with eicosapentaenoic and docosahexaenoic acids (EPA and DHA, omega-3 long-chain fatty acids) serves a protective mechanism against neuromuscular dysfunctions mediated by PQ using Drosophila melanogaster as a model with focus on mitochondrial metabolism. PQ ingestion (170 mg/kg b.w. for 3 d) resulted in a decreased life span and climbing ability in D. melanogaster. In the brain, PQ increased thioflavin fluorescence and reduced either 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) nuclei staining and neuronal nuclei protein (NeuN) positive neurons, indicating amyloid formation and neurodegenetation, respectively. In the thorax, PQ ingestion lowered citrate synthase activity and respiratory functions indicating a reduction in mitochondrial content. PQ elevated Ca2+/calmodulin-dependent protein kinase II (CaMKII) mRNA expression levels, indicative of high calcium influx from cytosol to mitochondrial matrix. In brain and thorax, PQ also increased hydrogen peroxide (H2O2) production and impaired acetylcholinesterase (AChE) activity. Concomitant EPA/DHA ingestion (0.31/0.19 mg/kg b.w.) protected D. melanogaster against PQ-induced toxicity preserving neuromuscular function and slowing down the rate of aging. In brain and thorax, these omega-3 fatty acids inhibited excess H2O2 production and restored AChE activity. EPA/DHA delayed amyloid deposition in the brain, and restored low citrate synthase activity and respiratory functions in the thorax. The effects in the thorax were attributed to stimulated mRNA expression level of genes involved either in mitochondrial dynamics or biogenesis promoted by EPA/DHA: dynamin-related protein (DRP1), mitochondrial assembly regulatory factor (MARF), mitochondrial dynamin like GTPase (OPA1), and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α). In conclusion, diet supplementation with EPA/DHA appears to protect D. melanogaster muscular and neuronal tissues against PQ intoxication.

Gut microbiota: A potential therapeutic target for management of diabetic retinopathy?

Diabetic Retinopathy (DR) is one of the main complications of Diabetes Mellitus (DM), drastically impacting individuals of working age over the years, being one of the main causes of blindness in the world. The existing therapies for its treatment consist of measures that aim only to alleviate the existing clinical signs, associated with the microvasculature. These treatments are limited only to the advanced stages and not to the preclinical ones. In response to a treatment with little resolution and limited for many patients with DM, investigations of alternative therapies that make possible the improvement of the glycemic parameters and the quality of life of subjects with DR, become extremely necessary. Recent evidence has shown that deregulation of the microbiota (dysbiosis) can lead to low-grade, local and systemic inflammation, directly impacting the development of DM and its microvascular complications, including DR, in an axis called the intestine-retina. In this regard, the present review seeks to comprehensively describe the biochemical pathways involved in DR as well as the association of the modulation of these mechanisms by the intestinal microbiota, since direct changes in the microbiota can have a drastic impact on various physiological processes. Finally, emphasize the strong potential for modulation of the gut-retina axis, as therapeutic and prophylactic target for the treatment of DR.

Neuroprotective action of Eicosapentaenoic (EPA) and Docosahexaenoic (DHA) acids on Paraquat intoxication in Drosophila melanogaster.

Several studies have shown the protective effects of dietary enrichment of omega-3 (ω-3) long-chain fatty acids in several animal models of neurodegenerative diseases. Here we investigate if eicosapentaenoic (EPA) and Docosahexaenoic (DHA) acids (ω-3) protect against neurodegeneration mediated by the exposure to a widely used herbicide Paraquat (PQ) (1,1'-dimethyl-4-4'-bipyridinium dichloride), focusing on mitochondrial metabolism using Drosophila melanogaster as a model. Dietary ingestion of PQ for 3 days resulted in the loss of citrate synthase content, respiratory capacity impairment and exacerbated H2O2 production per mitochondrial unit related to complex I dysfunction, and high lactate accumulation in fly heads. PQ intoxication lead to 1) the loss of ELAV (embryonic lethal abnormal vision) and α-spectrin, essential proteins of neuronal viability and synaptic stability; 2) increased gamma-secretase activity, an enzyme related to APP release; and 3) increased the amyloid fibrils contents. All these toxic effects induced by PQ were prevented by concomitant dietary ingestion of EPA/DHA, suggesting that a neuroprotective effect of ω-3 also involves mitochondrial protection. In conclusion, concomitant EPA and DHA ingestion protects against PQ-induced neuronal and mitochondrial dysfunctions frequently found in neurodegenerative processes reinforcing its protective role against environmental neurodegenerative diseases.