Reatment protocols used by other workers, maximum treatment duration of 5 weeks was used in this study as the duration of treatment for 5 weeks is suggested to model chronic human treatment [28]. Kidneys obtained after chronic 600 mg /kg body wt. TDF treatment for 5 weeks showed proximal tubular damage and dysfunction (manifested as Fanconi Syndrome), severe morphologic abnormalities in proximal tubule mitochondria, such as giant mitochondria, disruption of cristae, mitochondrial Resiquimod site swelling, and presence of amorphous deposits in the mitochondrial matrix, the findings that were in close comparison with human kidney biopsies obtained from TDF treated HIV patients. Therefore, we carried out the studies on TDF nephrotoxicity by the administration of 600 mg/kg body wt./d (12 x clinical dose) by gavage for 5 weeks to rats.Animal treatment20 . Thereafter, serum was separated by centrifugation at 1200 g for 15 min at 4 for clinical chemistry. The serum was frozen and the analytes were measured on the third day after sacrifice of the rats. The animals were then killed by over dose of halothane anesthesia. The abdomen was opened by midline incision and both the kidneys were dissected out, cleaned off the extraneous tissue and weighed. Half of left kidney was cut in cross-section and fixed in 10 buffered formalin for light microscopy, and the remaining half was fixed in 3 glutaraldehyde for electron microscopy. Each right kidney was snap-frozen in liquid nitrogen and stored at – 70 for subsequent biochemical assays. The biochemical parameters were assayed the following day in freshly prepared homogenates PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/26080418 as described later.Morphological examination of the kidneyAfter fixating the kidney tissues in 10 buffered formalin for 24 h at room temperature, the slices were embedded in paraffin and then sectioned. Four micrometer-thick paraffin sections were stained with hematoxylin and eosin for light microscope examination using conventional protocol [29]. A minimum of 8 fields for each kidney section were examined and assigned for severity of changes by an observer blinded to the treatments of the animals. Since the tenofovir-induced morphological abnormalities in kidney are mainly localized to the proximal tubules, and the other structures of the kidney do not exhibit major histological alterations, only the renal cortex was examined in detail.Examination of the ultrastructural changes in the kidney tissues by electron microscope (EM)The rats were assigned randomly into 2 groups and were treated as follow. Group I (control): The rats in this group (n = 6) received sterile water by gavage. Group II-The rats (n = 6) in this group received 600 mg/ kg body weight Tenofovir disoproxil fumarate daily by gavage for 5 weeks. Control animals were administered sterile water by gavage on the same schedule as TDF treatment and were killed at the same time point as that of TDF treated rats.Mortality checks, clinical observations, and body weightsAnimals were checked daily for clinical signs of toxicity, morbidity, or death. Body weights were measured daily just before gavage. Twenty-four hours before sacrifice, the rats were placed individually in metabolic cages, and urine was collected for biochemical analysis. Urine samples were centrifuged to remove any suspended material, and the supernatants were used immediately for clinical chemistry. On the 36th day, after overnight fast, blood samples were collected from the rats under halothane anesthesia, by cardiac pu.