Background and Aim: Laboratory mice are widely used as a research model to provide insights into toxicological studies of various xenobiotic. Acetaminophen (APAP) is an antipyretic and analgesic drug that is commonly known as paracetamol, an ideal hepatotoxicant to exhibit centrilobular necrosis in laboratory mice to resemble humans. However, assessment of histopathological changes between mouse strains is important to decide the optimal mouse model used in APAP toxicity study. Therefore, we aim to assess the histomorphological features of APAP-induced liver injury (AILI) in BALB/C and Institute of Cancer Research (ICR) mice. Materials and Methods: Twenty-five ICR mice and 20 BALB/C mice were used where five animals as control and the rest were randomly divided into four time points at 5, 10, 24 and 48 hours post-dosing (hpd). They were induced with 500 mg/kg APAP intraperitoneally. Liver sections were processed for hematoxylin-eosin staining and histopathological changes were scored based on grading methods. Results: Intense centrilobular damage was observed as early as 5 hpd in BALB/C as compared to ICR mice, which was observed at 10 hpd. The difference of liver injury between ICR and BALB/C mice is due to dissimilarity in the genetic line-up that related to different elimination pathways of APAP toxicity. However, at 24 hpd, the damage was markedly subsided and liver regeneration had taken place for both ICR and BALB/C groups with evidence of mitotic figures. This study showed that normal liver architecture was restored after the clearance of toxic insult. Conclusion: AILI was exhibited earlier in BALB/C than ICR mice but both underwent liver recovery at later time points. Keywords: acetaminophen, BALB/C, histopathology, institute of cancer research, liver injury, liver regeneration.

The present study was conducted to determine the effects of supplementing α-linolenic acid (ALA) into BioXcell(®) extender on post-cooling, post-thawed bovine spermatozoa and post thawed fatty acid composition. Twenty-four semen samples were collected from three bulls using an electro-ejaculator. Fresh semen samples were evaluated for general motility using computer assisted semen analyzer (CASA) whereas morphology and viability with eosin-nigrosin stain. Semen samples extended into BioXcell(®) were divided into five groups to which 0, 3, 5, 10 and 15 ng/ml of ALA were added, respectively. The treated samples were incubated at 37°C for 15 min for ALA uptake by sperm cells before being cooled for 2 h at 5°C. After evaluation, the cooled samples were packed into 0.25 ml straws and frozen in liquid nitrogen for 24 h before thawing and evaluation for semen quality. Evaluation of cooled and frozen-thawed semen showed that the percentages of all the sperm parameters improved with 5 ng/ml ALA supplement. ALA was higher in all treated groups than control groups than control group. In conclusion, 5 ng/ml ALA supplemented into BioXcell(®) extender improved the cooled and frozen-thawed quality of bull spermatozoa.