Histological Effect of Cytarabine on Liver and Buccal Mucosa in Mice

Aims : This study aimed to investigate the histopathological effect of cytarabine drug on liver and buccal mucosa in mice. Materials and Methods: Sixteen male albino mice were randomly assigned to two experimental groups and housed as eight animals /cage as a group.Control Group: was given daily I.P distilled water for 5 days. Cytarabine Group: was given daily Cytarabine at dose (100mg/kg/ I.P) for 5 days. At the end of experiment, all animals were sacrificed and liver in addition to the buccal mucosa were excised and placed in 10% buffered formalin solution for histological preparation and evaluation. Results: histopathological study of cytarabine treatment group showed multiple changes in liver like defused vacuolar swelling with abnormal hepatic cords patterns, congested sinusoids and multiple foci of apoptotic cells while in buccal mucosa sections revealed a severely shrinkaged and atrophied appearance of mucus-salivary glands, vacuolation of the stratified squamous epithelium and interstitial edema. Conclusions: this study concluded the direct cytotoxicity of cytarabine to liver and buccal mucosa. So caution should be taken when administrating the drug to patient with liver or salivary glands dysfunction.


INTRODUCTION
Cancer is considered as a serious worldwide health problem, being the second leading reason of global spontaneous mortalities after cardiovascular diseases. The reason behind developing rapidly may be mainly due to environmental carcinogens and unhealthy lifestyles (1) . The mode of treatment depends on the type, site, and grade of cancer, the step of the disease and the overall health of the patient (2) .
Chemotherapeutic agents are the compounds that used in cancer treatment and they are varying in structure and mechanism of action. Cytarabine or Cytosine arabinoside (Cytosar®) is a pyrimidine nucleoside-based chemotherapeutic agent. Cytarabine is called cytosine arabinose because it combines a cytosine base with an arabinose sugar (3) . It is a cell-phase-specific chemotherapeutic drug, primarily act during the S phase when cells are undergoing DNA synthesis (4) . It causes extensive chromosomal destruction through induction of chromatoid aberrations (5) . Thus Rapidly dividing cells, which need DNA replication for mitosis, are the mostly affected (3) . This drug, used to treat acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic myelogenous leukemia (CML), and non-Hodgkin's lymphoma (6) . Also used as an antiviral agent against herpes simplex virus and human cytomegalovirus (7) .
It is administered through continuous intravenous infusion or injection, intrathecally or subcutaneously then after three phosphorylation steps cytarabine is transformed to cytarabine triphosphate (8) . The majority of the drug is metabolized in the kidney, liver and gastrointestinal tract into its inactive metabolite and large amount of the administered dose is eliminated by renal excretion within one day (9) .
It is Common side effects include vomiting, liver function disturbances, diarrhea, bone marrow suppression, oral mucosal ulceration, rash, and bleeding (10) .

Aims of study:
This study aims to investigate the side effect of cytarabine drug on liver and buccal mucosa in mice through the histopathological examination.

MATERIALS AND METHODS
The drugs injection was done at the pharmacology laboratory of Department of dental basic sciences at college of dentistry / university of Mosul / Iraq from 1/9/2019 to 20/1/2020.

Laboratory animals
Sixteen

Experimental Design
Sixteen male albino mice were randomly assigned to two experimental groups and housed as eight animals per cage, and each group was treated as the following: Group A: served as normal control group and was given daily intraperitonial injection of distilled water at dose (5ml/kg) for 5 days. Group B: was given daily intraperitoneal injection of Cytarabine at dose (100mg/kg) (11) for five days. At the end of experiment, all animals of each groups were sacrificed and liver in addition to the buccal mucosa were excised and preserved in 10% buffered formalin for histological investigation.

Tissue preparation for histopathological study
Liver and buccal mucosa of each mice were prepared for histological study by preserving them in solution of 10% neutral buffered formalin for 24 hours in order to be fixed, after that the tissues were dehydrated by using a gradual concatenations of ethyl alcohol (70%-100%) for a period of (30minutes) for each concentration. Then the samples were cleared in 2 separated xylene changes before Passing them in 2 stages of paraffin wax at 57 degree temperature for impregnation , then embedding with paraffin in blocks for sectioning. Following that the samples were cross sectioned at 5 μm thickness, later on it stained by hematoxylin and eosin (HE) stain to examine the histological changes by means of light microscope (12) .  infiltration, periportal fibrosis, hyperplasia and many hepatocytes showed karyomegaly and pyknotic nuclei representing apoptosis (15) ‫ه‬Regarding histopathological result of current study in buccal mucosa showed severe shrinkage and atrophied appearance of mucus-  (20) . Also this result similar to result obtained by other study regarding the effect of methotrexate on parotid gland and mentioned that most of the serous acini had irregular outlines and was widely separated; ductal cells were faintly stained with variable sized vacuoles displacing the nuclei more peripherally and marked hemorrhage between acinar cells and the cytoplasm (21) . As well as in consistence with another study regarding the effect of methotrexate on rabbits submandibular salivary gland and reported that there was a glandular degeneration detected by marked vacuolations in acinar and ductal cells and complete replacement of some acinar cells by large vacuoles (22) .

CONCLUSIONS
Although cytarabine is the highly effective in treatment of cancer but it is associated with direct cytotoxicity to organs and tissues such as liver and buccal mucosa so caution should be

Dawood Gh A., Taqa Gh A., Alnema M M
taken when giving the drug to patient with liver disease or failure and salivary glands dysfunction.