Systemic Toxicity Testing Research Articles

Toxicological testing of a photoactive phthalocyanine-based antimicrobial substance

The aim of the study was toxicological testing of an innovative and efficient antimicrobial agent based on photoactive phthalocyanine (Pc) derivative. A promising Aluminium phthalocyanine (AlPc) with efficient and stable antimicrobial effects was subjected to a battery of toxicological tests to avoid local and systemic toxicity hazard. In compliance with the current European legislation restricting the use of experimental animals, the methods comprised exclusively in vitro procedures based on cellular and tissue models of human origin or mimicking human tissues. The battery of toxicological tests to identify local toxicity included skin corrosion/irritation, eye irritation, and phototoxicity. The basic systemic toxicity tests included acute toxicity, skin sensitization, genotoxicity, and endocrine disruption. The results showed that AlPc induced skin and eye irritation, exhibited borderline sensitization potential and mutagenic potential in one test strain of the Ames test, which was not confirmed in the chromosome aberration test. The AlPc was found to be phototoxic. The results from the cytotoxicity test designed for acute oral toxicity estimation were not conclusive, the acute toxicity potential has to be determined by conventional tests in vivo. Regarding endocrine disruption, no agonistic activity of the AlPc on human estrogen receptor α, nor human androgen receptor was observed. The skin penetration/absorption test revealed that the AlPc has not penetrated into the dermis and receptor fluid, confirming no risk of systemic exposure via the bloodstream.

Integrating Biophysics in Toxicology.

Integration of biophysical stimulation in test systems is established in diverse branches of biomedical sciences including toxicology. This is largely motivated by the need to create novel experimental setups capable of reproducing more closely in vivo physiological conditions. Indeed, we face the need to increase predictive power and experimental output, albeit reducing the use of animals in toxicity testing. In vivo, mechanical stimulation is essential for cellular homeostasis. In vitro, diverse strategies can be used to model this crucial component. The compliance of the extracellular matrix can be tuned by modifying the stiffness or through the deformation of substrates hosting the cells via static or dynamic strain. Moreover, cells can be cultivated under shear stress deriving from the movement of the extracellular fluids. In turn, introduction of physical cues in the cell culture environment modulates differentiation, functional properties, and metabolic competence, thus influencing cellular capability to cope with toxic insults. This review summarizes the state of the art of integration of biophysical stimuli in model systems for toxicity testing, discusses future challenges, and provides perspectives for the further advancement of in vitro cytotoxicity studies.

Environmental Risk Assessment of Nanomaterials in the Light of New Obligations Under the REACH Regulation: Which Challenges Remain and How to Approach Them?

ABSTRACTWithin the European regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH, EC No 1907/2006) specific provisions for nanomaterials were included, which have become effective on 1 January 2020. Although knowledge on the peculiarities of testing and assessing fate and effects of nanomaterials in the environment strongly increased in the last years, uncertainties about how to perform a reliable and robust environmental risk assessment for nanomaterials still remain. These uncertainties are of special relevance in a regulatory context, challenging both industry and regulators. The present paper presents current challenges in regulatory hazard and exposure assessment under REACH, as well as classification of nanomaterials, and makes proposals to address them. Still, the nanospecific considerations made here are expected to also be valid for environmental risk assessment approaches in other regulations of chemical safety. Inter alia, these proposals include a way forward to account for exposure concentrations in aquatic toxicity test systems, a discussion of how to account for availability of dissolving nanomaterials in aquatic test systems, and a pragmatic proposal to deduce effect data for soil organisms. Furthermore, it specifies how to potentially deal with nanoforms under the European regulation on Classification, Labelling and Packaging of substances and mixtures (CLP) and outlines the needs for proper exposure assessments of nanomaterials from a regulatory perspective. Integr Environ Assess Manag 2020;16:706–717. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

Biocompatibility Test of Decellularized Cartilage Bovine Scaffold in Vitro and In Vivo

Background: Incidence of cartilage defects was reported at 65.00% of the routine arthroscopy procedures. Dr.Soetomo Teaching Hospital Network Bank developed a cartilage scaffold from bovine that has been deselularized decellularized cartilage bovine scaffold (DCBS). It takes a study of biocompatibility test to prove that DCBS is not cytotoxic to cells and not generate a host response. Objective: To analyze the biocompatibility of decellularized cartilage bovine scaffold (DCBS) in vivo and in vitro. Methods and Materials: The subjects were experimental rats and experimental with in vitro and in vivo trials. The subjects were treated by toxicity test with MTT assay, irritation test using Draize Scale, acute/ pyogenic systemic toxicity test by observing changes in body weight and temperature, and implantation test by observing fibrous capsule formation and Immunoglobulin G. Data was analyzed by using Kolmogorovsmirnov, Independent T-test, Mutivariate Analysis of Variance (MANOVA), and Mann Whitney. Result: The percentage of viable DCBS (81.78%) and CBS (92.45%) was ?70% of the control; thus, it is non-toxic to the cell. Draize scale in each group was in grade 0. Changes in body weight (p = 0.981) and temperature (p >0.05) had no significant association between groups. There was a significant difference mean of the fibrous capsule (p = 0.000) thickness and no significant difference in the mean number of Immunoglobulin G which was formed at week 1 (p = 0.87) and week 4 (p = 0.63) after implantation between CCBS and DCBS. Conclusion: The biocompatibility test shows that DCBS is compatible as a biomaterial.

Interspecific Variation in Nematode Responses to Metals.

Performing toxicity testing on multiple species with differing degrees of evolutionary relatedness can provide important information on how chemical sensitivity varies among species and can help pinpoint the biological drivers of species sensitivity. Such knowledge could ultimately be used to design better multispecies predictive ecological risk assessment models and identify particularly sensitive species. However, laboratory toxicity tests involving multiple species can also be resource intensive, especially when each species has unique husbandry conditions. We performed lethality tests with 2 metals, copper chloride and zinc chloride, on 5 different nematode species, which are nested in their degree of evolutionary relatedness: Caenorhabditis briggsae, Caenorhabditis elegans, Oscheius myriophila, Oscheius tipulae, and Pristionchus pacificus. All species were successfully cultured and tested concurrently with limited resources, demonstrating that inexpensive, multispecies nematode toxicity testing systems are achievable. The results indicate that P. pacificus is the most sensitive to both metals. Conversely, C. elegans is the least sensitive species to copper, but the second most sensitive to zinc, indicating that species relationships do not necessarily predict species sensitivity. Toxicity testing with additional nematode species and types of chemicals is feasible and will help form more generalizable conclusions about relative species sensitivity. Environ Toxicol Chem 2020;39:1006-1016. © 2020 SETAC.

Papain grafted into the silica coated iron-based magnetic nanoparticles ‘IONPs@SiO2-PPN’ as a new delivery vehicle to the HeLa cells

The present study aims at engineering, fabrication, characterization, and qualifications of papain (PPN) conjugated SiO2-coated iron oxide nanoparticles ‘IONPs@SiO2-PPN’. Initially fabricated iron oxide nanoparticles (IONPs) were coated with silica (SiO2) using sol–gel method to hinder the aggregation and to enhance biocompatibility. Next, PPN was loaded as an anticancer agent into the silica coated IONPs (IONPs@SiO2) for the delivery of papain to the HeLa cancer cells. This fabricated silica-coated based magnetic nanoparticle is introduced as a new physiologically-compatible and stable drug delivery vehicle for delivering of PPN to the HeLa cancer cell line. The IONPs@SiO2-PPN were characterized using FT-IR, AAS, FESEM, XRD, DLS, and VSM equipment. Silica was amended on the surface of iron oxide nanoparticles (IONPs, γ-Fe2O3) to modify its biocompatibility and stability. The solvent evaporation method was used to activate PPN vectorization. The following tests were performed to highlight the compatibility of our proposed delivery vehicle: in vitro toxicity assay, in vivo acute systemic toxicity test, and the histology examination. The results demonstrated that IONPs@SiO2-PPN successfully reduced the IC50 values compared with the native PPN. Also, the structural alternations of HeLa cells exposed to IONPs@SiO2-PPN exhibited higher typical hallmarks of apoptosis compared to the cells treated with the native PPN. The in vivo acute toxicity test indicated no clinical signs of distress/discomfort or weight loss in Balb/C mice a week after the intravenous injection of IONPs@SiO2 (10 mg kg−1). Besides, the tissues architectures were not affected and the pathological inflammatory alternations detection failed. In conclusion, IONPs@SiO2-PPN can be chosen as a potent candidate for further medical applications in the future, for instance as a drug delivery vehicle or hyperthermia agent.

Use of LUCS (Light-Up Cell System) as an alternative live cell method to predict human acute oral toxicity

LUCS (Light-Up Cell System) is a new live cell test that allows assessment of a cell’s homeostasis and its alteration by a toxic agent. To evaluate the effectiveness of LUCS as an alternative test method for acute oral toxicity, we compared EC50s determined in HepG2 cells treated with 53 chemicals selected from the ACuteTox EU database with corresponding human blood LC50s derived from human acute poisoning cases. Linear regression analysis showed that LUCS results predict human data to 69 %. Rodent oral LD50s and LUCS EC50s were then correlated to human LC50s using shared data sets. Linear regression analyses comparing LUCS and animal data clearly showed that LUCS always predicts human toxicity better than animal data do.These successful prediction values prompted us to simplify the LUCS test, adapting it to regulatory and high throughput applications, resulting in a new protocol with consistent dose-response profiles and EC50s.This study demonstrates that the LUCS test method could be relevant for assessing human acute oral toxicity with a simplified protocol adapted to commercially available fluorescence readers. We suggest that this new alternative method can be used for acute systemic toxicity testing in combination with other tests under European REACH and other regulations, wherever pertinent alternative methods are still lacking.

Dose-dependent cell necrosis induced by silica nanoparticles

In recent years, much attention has been given to nanoparticles (NPs) due to their many possible applications, and as research has progressed, these NPs have become valuable tools for medical purposes. Among many different types of NPs, silica nanoparticles (SiO2NPs) have been specifically evaluated for medical purposes and have also been used in many different types of products. Although SiO2NPs have already been applied and are believed to be nontoxic, there is still a concern regarding possible adverse effects that may be triggered after SiO2NP exposure. Therefore, in the present study, we employed a recommended cell line (BALB/c 3T3) for the toxicity evaluation to investigate the cytotoxic effects of SiO2NPs produced by chemical synthesis at a laboratory scale. First, we employed OECD guideline 129 in order to evaluate cytotoxicity effects and also estimate the starting doses for acute oral systemic toxicity tests. We evaluated the cytotoxic effects of two types of SiO2NPs (nonfluorescent and fluorescent) and found that they were not significantly different (IC50 = 1986.39 ± 237 μg/mL and IC50 = 1861.13 ± 186.72 μg/mL, respectively). Then, we used the predicted LD50 of both types of SiO2NPs to suggest that they could be categorized as GHS category 4 substances. By ultrastructural evaluation, we found that SiO2NPs are internalized by 3 T3 cells and are located in vacuole-like structures with no other significant changes in cell structure. We also found that SiO2NPs lead to cell necrosis in a dose-dependent manner.

Qualification of a non-animal vaginal irritation method admitted as nonclinical assessment model (NAM) in the Incubator Phase of the United States Food and Drug Administration (US FDA) Medical Devices Development Tool (MDDT)

The U.S. Food and Drug Administration (FDA) Center for Devices and Radiological Health (CDRH) classifies personal lubricants as Class II medical devices. Because of this status and the nature of body contact common to personal lubricants, CDRH reviewers routinely recommend a standard biocompatibility testing battery that includes: an in vivo rabbit vaginal irritation (RVI) test; an in vivo skin sensitization test, such as the guinea pig maximization test (GPMT); and an in vivo acute systemic toxicity test using mice or rabbits. These tests are conducted using live animals, despite the availability of in vitro and other non-animal test methods that may be suitable replacements. The only test included in the biocompatibility battery currently conducted using in vitro assay(s) is cytotoxicity. FDA's recently launched Predictive Toxicology Roadmap calls for the optimization of non-animal methods for the safety evaluation of drugs, consumer products and medical devices. In line with these goals, a Consortium comprising the Institute for In Vitro Sciences, Inc. (IIVS), industry, the Consumer Healthcare Products Association (CHPA), and the PETA International Science Consortium (PETA-ISC) is qualifying the use of an in vitro testing method as replacement for the RVI test. Participating companies include manufacturers of personal lubricants and those interested in the advancement of non-animal approaches working collaboratively with the FDA CDRH to develop an in vitro testing approach that could be used in place of the RVI in pre-market submissions. Personal lubricants and vaginal moisturizers with diverse chemical and physical properties (e.g., formulation, viscosity, pH, and osmolality) in their final undiluted form will be the focus of the program. In vitro vaginal irritation data generated using commercially available human reconstructed vaginal tissue model(s) will be paired with existing in vivo RVI data and analyzed to develop a Prediction Model for the safety assessment of these products. This research plan has been accepted into the FDA CDRH Medical Device Development Tools (MDDT) program as a potential non-clinical assessment model (NAM). The proposed NAM aligns with the goals of the recently launched FDA Roadmap to integrate predictive toxicology methods into safety and risk assessment with the potential to replace or reduce the use of animal testing.

Comparative Safety Testing (acute systemic toxicity in mice) of Two Materials Prepared from Polypropylene-Polyester (Codubix S) or Acrylate Resin (Mendec Cranio) Used for the Manufacturing of a Calvaria Prosthesis

The aim of the study was a comparison of the acute toxicity of two popular prostheses used in the reconstruction of the bones of the skull. For the tests, the following materials were used: a polypropylene-polyester knitted Codubix S cranial bone prosthesis, made by TRICOMED SA, and polymethyl methacrylate Mednec Cranio resin. The tests were carried out in accordance with the following standards – PN-EN ISO 10993-11:2009 Biological evaluation of medical devices - Part 11: Tests for systemic toxicity, and PN-EN ISO 10993-12:2012 Biological evaluation of medical devices – Part 12: Sample preparation and reference materials. During the evaluation, adult male and female Balb/c mice were used. The animals were injected intravenously using extracts of both materials in 0.9% NaCl and intraperitoneally with the same extracts in sesame oil. The tests lasted 7 days, during which the health of the animals and their behavior were assessed. Both in the control and test groups, there was no mortality of the animals, and the health and behaviour of mice were unchanged when compared with the normal. After 7 days the internal organs of the chest and abdominal cavity of the animals were subjected to macroscopic pathomorphological examination, during which no changes indicating the toxic action of Codubix S and Mednec Cranio resin were found. Before the acute systemic toxicity tests, the chemical purity of both implants was assessed. The chemical purity of a product is one of the factors determining its biological properties. A product which is characterised by a higher degree of chemical purity contains fewer substances which may have a negative impact on biological reactions. Both prostheses meet the requirements of purity for medical devices.

Mechanical properties, hemocompatibility, cytotoxicity and systemic toxicity of carbon fibers/poly(ether-ether-ketone) composites with different fiber lengths as orthopedic implants

Poly(ether-ether-ketone) (PEEK) has attracted more and more attention due to its chemical resistance, biocompatibility and other properties. Furthermore, carbon fibers-PEEK composite (CF-PEEK) has been considered as a novel implant because of its high mechanical strength and elastic modulus that matching with human bones. However, the length of CF has a great influence on mechanical strength and elastic modulus of the randomly distributed chopped CF-PEEK composites. In this work, CF-PEEK composites with more than 10 times length difference of fibers (length of short CF: 150–200 μm and length of long CF: 2–3 mm) were studied. As the results shown, the mechanical strength (including tensile strength, bending strength and compressive strength) of long CF-PEEK composites were more than two times of that of short CF-PEEK composites. Meanwhile, tensile modulus and bending modulus of the two kinds of composites matched well with the modulus of human cortical bone. In addition, according to the results of cytotoxicity test and hemocompatibility assessment, it indicated that the two kinds of CF-PEEK composites showed mild toxicity and no hemolytic reaction. And the histopathological section of systemic toxicity test showed that the CF-PEEK composites had no obvious acute toxicity to organisms.

In vivo systemic toxicity assessment of an oxidized dextrin-based hydrogel and its effectiveness as a carrier and stabilizer of granular synthetic bone substitutes.

The worldwide incidence of bone disorders is raising, mainly due to aging population. The lack of effective treatments is pushing the development of synthetic bone substitutes (SBSs). Most ceramic-based SBSs commercially available display limited handling properties. Attempting to solve these issues and achieve wider acceptance by the clinicians, granular ceramics have been associated with hydrogels (HGs) to produce injectable/moldable SBSs. Dextrin, a low-molecular-weight carbohydrate, was used to develop a fully resorbable and injectable HG. It was first oxidized with sodium periodate and then cross-linked with adipic acid dihydrazide. The in vivo biocompatibility and safety of the dextrin-based HG was assessed by subacute systemic toxicity and skin sensitization tests, using rodent models. The results showed that the HG did not induce any systemic toxic effect, skin reaction, or genotoxicity, neither impaired the bone repair/regeneration process. Then, the HG was successfully combined with granular bone substitute, registered as Bonelike (250-500 μm) to obtain a moldable/injectable SBS, which was implanted in tibial fractures in goats for 3 and 6 weeks. The obtained results showed that HG allowed the stabilization of the granules into the defect, ensuring effective handling, and molding properties of the formulation, as well as an efficient cohesion of the granules. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1678-1689, 2019.

Establishment of in-vitro three dimensional rat follicle culture system and validation of the applicability as an in vitro female reproductive toxicity testing system

Establishment of in-vitro three dimensional rat follicle culture system and validation of the applicability as an in vitro female reproductive toxicity testing system

Physicochemical and Biocompatibility Properties of Type I Collagen from the Skin of Nile Tilapia (Oreochromis niloticus) for Biomedical Applications.

The aim of this study is to investigate the physicochemical properties, biosafety, and biocompatibility of the collagen extract from the skin of Nile tilapia, and evaluate its use as a potential material for biomedical applications. Two extraction methods were used to obtain acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from tilapia skin. Amino acid composition, FTIR, and SDS-PAGE results showed that ASC and PSC were type I collagen. The molecular form of ASC and PSC is (α1)2α2. The FTIR spectra of ASC and PSC were similar, and the characteristic peaks corresponding to amide A, amide B, amide I, amide II, and amide III were 3323 cm−1, 2931 cm−1, 1677 cm−1, 1546 cm−1, and 1242 cm−1, respectively. Denaturation temperatures (Td) were 36.1 °C and 34.4 °C, respectively. SEM images showed the loose and porous structure of collagen, indicting its physical foundation for use in applications of biomedical materials. Negative results were obtained in an endotoxin test. Proliferation rates of osteoblastic (MC3T3E1) cells and fibroblast (L929) cells from mouse and human umbilical vein endothelial cells (HUVEC) were increased in the collagen-treated group compared with the controls. Furthermore, the acute systemic toxicity test showed no acute systemic toxicity of the ASC and PSC collagen sponges. These findings indicated that the collagen from Nile tilapia skin is highly biocompatible in nature and could be used as a suitable biomedical material.

Investigating cell type specific mechanisms contributing to acute oral toxicity_suppl2

The replacement of animals in acute systemic toxicity testing remains a considerable challenge. Only animal data are currently accepted by regulators, including data generated by reduction and refinement methods. The development of integrated approaches to testing and assessment (IATA) is hampered by an insufficient understanding of the numerous toxicity pathways that lead to acute systemic toxicity. Therefore, central to our work has been the collection and evalu­ation of the mechanistic information on eight organs identified as relevant for acute systemic toxicity (nervous system, cardiovascular system, liver, kidney, lung, blood, gastrointestinal system, and immune system). While the nervous and cardiovascular systems are the most frequent targets, no clear relationship emerged between specific mechanisms of target organ toxicity and the level (category) of toxicity. From a list of 114 chemicals with acute oral in vivo and in vitro data, 97 were identified with target organ specific effects, of which 94% (91/97) were predicted as acutely toxic by the 3T3 neutral red uptake cytotoxicity assay and 6% (6/97) as non-toxic. Although specific target organ mechanisms of toxicity could in some cases explain the false negative prediction obtained with the cytotoxicity assay, in general it is difficult to explain in vitro misclassifications only on the basis of mechanistic information. This analysis will help to prioritize the development of adverse outcome pathways for acute oral toxicity, which will support the assessment of chemicals using mechanistically informed IATA.

Investigating cell type specific mechanisms contributing to acute oral toxicity_suppl1

The replacement of animals in acute systemic toxicity testing remains a considerable challenge. Only animal data are currently accepted by regulators, including data generated by reduction and refinement methods. The development of integrated approaches to testing and assessment (IATA) is hampered by an insufficient understanding of the numerous toxicity pathways that lead to acute systemic toxicity. Therefore, central to our work has been the collection and evalu­ation of the mechanistic information on eight organs identified as relevant for acute systemic toxicity (nervous system, cardiovascular system, liver, kidney, lung, blood, gastrointestinal system, and immune system). While the nervous and cardiovascular systems are the most frequent targets, no clear relationship emerged between specific mechanisms of target organ toxicity and the level (category) of toxicity. From a list of 114 chemicals with acute oral in vivo and in vitro data, 97 were identified with target organ specific effects, of which 94% (91/97) were predicted as acutely toxic by the 3T3 neutral red uptake cytotoxicity assay and 6% (6/97) as non-toxic. Although specific target organ mechanisms of toxicity could in some cases explain the false negative prediction obtained with the cytotoxicity assay, in general it is difficult to explain in vitro misclassifications only on the basis of mechanistic information. This analysis will help to prioritize the development of adverse outcome pathways for acute oral toxicity, which will support the assessment of chemicals using mechanistically informed IATA.

Microphysiological human stem cell systems for toxicity testing

Microphysiological human stem cell systems for toxicity testing

In-vitro and in-vivo, cytotoxicity evaluation of cast functionally graded biomaterials for dental implantology

An innovative technique of casting the titanium implant alloys and its calcium phosphate coating using centrifugal casting method was proposed in the current study. This one-step, self-coating technique results in formation of functionally graded biomaterials (FGBMs) of calcium phosphate/Titanium alloys. Two groups of samples (Group 1 and Group 2) were prepared utilizing self-coated titanium‑niobium (Ti-6Al-7Nb) and titanium- vanadium (Ti-6Al-4V) alloys respectively. The cast samples were then prepared for in-vitro cytocompatibility evaluation, in-vivo systemic toxicity and osseointegration evaluation. Cytocompatibility was examined in-vitro on human bone osteosarcoma cells (Saos-2). In-vivo surgical implantation of the samples in the mandible of the experimental dogs was correspondingly implemented. Tests for systemic toxicity, X-ray images, Dual Energy X-ray Absorptiometry (DEXA) and histopathological analysis were obtained for each dog's mandible sample. In-vitro cytocompatibility studies revealed high cytocompatibility of Group 2 in comparison to Group 1. In-vivo results proved safety of Group 2 as regards to systemic toxicity. On the other hand, results of the X-ray images, DEXA and histopathological analysis revealed comparable osseointegration potential of both groups. These results suggest the use of Group2-FGBMs in dental implant manufacturing and prove that FGBMs prepared by centrifugal casting as self-coated implants have good biocompatibility and osseointegration capability.

Predictive models for acute oral systemic toxicity: A workshop to bridge the gap from research to regulation

In early 2018, the Interagency Coordinating Committee for the Validation of Alternative Methods (ICCVAM) published the “Strategic Roadmap for Establishing New Approaches to Evaluate the Safety of Chemicals and Medical Products in the United States” [1]. Cross-agency federal workgroups have been established to implement this roadmap for various toxicological testing endpoints, with an initial focus on acute toxicity testing. The ICCVAM acute toxicity workgroup (ATWG) helped organize a global collaboration to build predictive in silico models for acute oral systemic toxicity, based on a large dataset of rodent studies and targeted towards regulatory needs identified across federal agencies. Thirty-two international groups across government, industry, and academia participated in the project, culminating in a workshop in April 2018 held at the National Institutes of Health (NIH). At the workshop, computational modelers and regulatory decision makers met to discuss the feasibility of using predictive model outputs for regulatory use in lieu of acute oral systemic toxicity testing. The models were combined to yield consensus predictions which demonstrated excellent performance when compared to the animal data, and workshop outcomes and follow-up activities to make these tools available and put them into practice are discussed here.

Investigating Organ Toxicity Profile of Tenofovir and Tenofovir Nanoparticle on the Liver and Kidney: Experimental Animal Study

Tenofovir nanoparticles are novel therapeutic intervention in human immunodeficiency virus (HIV) infection reaching the virus in their sanctuary sites. However, there has been no systemic toxicity testing of this formulation despite global concerns on the safety of nano drugs. Therefore, this study was designed to investigate the toxicity of Tenofovir nanoparticle (NTDF) on the liver and kidney using an animal model. Fifteen adult male Sprague-Dawley (SD) rats maintained at the animal house of the biomedical resources unit of the University of KwaZulu-Natal were weighed and divided into three groups. Control animals (A) were administered with normal saline (NS). The therapeutic doses of Tenofovir (TDF) and nanoparticles of Tenofovir (NTDF) were administered to group B and C and observed for signs of stress for four weeks after which animals were weighed and sacrificed. Liver and kidney were removed and fixed in formal saline, processed and stained using H/E, PAS and MT stains for light microscopy. Serum was obtained for renal function test (RFT) and liver function test (LFT). Cellular measurements and capturing were done using ImageJ and Leica software 2.0. Data were analysed using graph pad 6, p values < 0.05 were significant. We observed no signs of behavioural toxicity and no mortality during this study, however, in the kidneys, we reported mild morphological perturbations widening of Bowman’s space, and vacuolations in glomerulus and tubules of TDF and NTDF animals. Also, there was a significant elevation of glycogen deposition in NTDF and TDF animals when compared with control. In the liver, there were mild histological changes with widening of sinusoidal spaces, vacuolations in hepatocytes and elevation of glycogen deposition in TDF and NTDF administered animals. In addition to this, there were no significant differences in stereological measurements and cell count, LFT, RFT, weight changes and organo-somatic index between treatment groups and control. In conclusion, NTDF and TDF in therapeutic doses can lead to mild hepatic and renal histological damage. Further studies are needed to understand the precise genetic mechanism.