Toxicity assessment of carvacrol and its acetylated derivative in early staged zebrafish (Danio rerio): Safer alternatives to fipronil-based pesticides?

Fipronil is a broad-spectrum pesticide presenting high acute toxicity to non-target organisms, particularly to aquatic species. Natural compounds stand out as promising alternatives to the use of synthetic pesticides such as fipronil. Thus, our study aimed to compare the toxicity of carvacrol (natural), acetylcarvacrol (semisynthetic), and fipronil (synthetic) to early staged zebrafish. We conducted a series of toxicity assays at concentrations ranging from 0.01 µM to 25 µM for fipronil and 0.01 µM to 200 µM for carvacrol and acetylcarvacrol, depending on the assay, after 7-days post-fertilization (dpf). The potency (EC50) of fipronil was ∼1 µM for both deformities and mortality at 7 dpf, whereas EC50 was >50 µM for carvacrol and >70 µM for acetylcarvacrol. Fipronil at 0.1 and 1 µM caused a decrease in body length and swim bladder area of larvae at 7dpf, but no difference was observed for either carvacrol or acetylcarvacrol. Based upon the visual motor response test, fipronil induced hypoactivity in larval zebrafish at 1 µM and acetylcarvacrol induced hyperactivity at 0.1 µM. Anxiolytic-type behaviors were not affected by any of these chemicals. All chemicals increased the production of reactive oxygen species at 7 dpf, but not at 2 dpf. Genes related to swim bladder inflation, oxidative stress, lipid metabolism, and mitochondrial activity were measured; only fipronil induced upregulation of atp5f1c. There were no changes were observed in oxygen consumption rates of fish and apoptosis. Taken together, our data suggest that carvacrol and its derivative may be safer replacements for fipronil due to their lower acute toxicity.

Sulfamethoxazole (SMX) Alters Immune and Apoptotic Endpoints in Developing Zebrafish (Danio rerio).

Sulfamethoxazole (SMX) is a broad-range bacteriostatic antibiotic widely used in animal and fish farming and is also employed in human medicine. These antibiotics can ultimately end up in the aquatic ecosystem and affect non-target organisms such as fish. To discern the effect of SMX on developing zebrafish embryos and larvae, we investigated a broad range of sub-lethal toxicity endpoints. Higher concentrations of SMX affected survivability, caused hatch delay, and induced malformations including edema of the yolk sac, pericardial effusion, bent tail, and curved spine in developing embryos. Lower levels of SMX provoked an inflammatory response in larvae at seven days post fertilization (dpf), as noted by up-regulation of interferon (ifn-γ) and interleukin 1ß (il-1ß). SMX also increased the expression of genes related to apoptosis, including BCL2-Associated Agonist of Cell Death (bad) and BCL2 Associated X, Apoptosis Regulator (bax) at 50 µg/L and decreased caspase 3 (casp3) expression in a dose-dependent manner. SMX induced hyperactivity in larval fish at 500 and 2500 µg/L based upon the light/dark preference test. Collectively, this study revealed that exposure to SMX can disrupt the immune system by altering host defense mechanisms as well as transcripts related to apoptosis. These data improve understanding of antibiotic chemical toxicity in aquatic organisms and serves as a baseline for in-depth environmental risk assessment of SMX and antibiotics.

Multi-biomarkers approach to determine the toxicological impacts of sulfamethoxazole antibiotic on freshwater fish Cyprinus carpio.

Antibiotics are increasingly detected in the aquatic environment and are raising severe concerns for human and ecological health. Sulfamethoxazole being a widely recommended antibiotic in both human and veterinary medicine is consequently found in the aquatic environment. The current research was aimed to investigate the potential bioaccumulation and sub-lethal toxicity in terms of oxidative stress and histopathology of targeted antibiotic sulfamethoxazole in Cyprinus carpio at environmentally relevant concentrations over a prolonged period. Fish were exposed for 28 days to environmentally realistic concentrations (25-200 µg/L) of sulfamethoxazole. HPLC analysis revealed an inverse relationship between dosages applied and bioaccumulation in fish muscle tissues. The highest concentrations of sulfamethoxazole in the muscle tissues exposed to 25, 50, 100 and 200 µg/L were 124, 202,104.5, and 123.2 ng/g, respectively at different sampling times. Moreover, exposure to sulfamethoxazole enabled ROS (Reactive oxygen species) production in both brain and gill tissues of fish, where the increase in ROS formation was dose and time dependent. Furthermore, histopathological analysis of gills and liver revealed various alterations including pycnotic nuclei, bile stagnation, vacuolization in the liver, and partial and complete fusion of lamella and blood congestion in gills, respectively. Organ pathological index also revealed that the intensity of tissue damage increased as sulfamethoxazole dosage was increased. Quantitative evaluation of gills morphometric parameters divulged that severity of histopathological changes increased with time for all the exposed groups at the end of exposure time (28th day) indicating physio-metabolic turmoil caused by molecular and biochemical action of sulfamethoxazole. In conclusion, the assessment of bioaccumulative potential, measurement of ROS, and histopathology of Cyprinus carpio appeared to be a useful biomarker to evaluate the toxic impacts of antibiotics on the health of fish.

QUALITY OF LIFE AFTER INGUINAL HERNIA REPAIR.

OBJECTIVES: Inguinal hernias are the most commonly presented abdominal hernias with approximately 20 million people operated annually throughout the world. Severe chronic pain after hernia repair effects social life, daily activity and overall quality of life. The Short Form-36 is (SF-36) a validated indicator of overall health status. Studies have shown that the reliability of the SF-36 is exceeding 0.80. This study aims to determine the severity of pain and quality of life after open inguinal hernia repair at a tertiary care hospital using SF-36. METHODS This cross-sectional study was carried out at Indus Hospital Karachi from 1st April 2018 to 10th September 2018.88 Patients were enrolled in this study according to the inclusion and exclusion criteria. A written and informed consent was taken from all of them. After surgery they were sent home on painkillers. They were called at 4 weeks and were required to fill a pre designed questionnaire Short form -36. RESULTS Results showed that out of the 88 patients enrolled in this study 35 (39.8%) experienced mild pain, 37(42%) experience moderate pain and only 16 (18.2%) experienced severe pain. Quality of life was satisfactory in 72(81%) and unsatisfactory in 13(14.7%). CONCLUSION: Hence it is concluded that post operatively patients experienced better physical functioning and emotional role functioning whereas their perceptions about their general health and energy were satisfactory. Hernia surgery should be offered to all the patients with a clinically detectable hernia.