doi: 10.1006/phrs.1999.0649, available online at http://www.idealibrary.com on Pharmacological Research, Vol. 42, No. 2, 2000 THE IMPACT OF OFLOXACIN ON RAT TESTICULAR DNA: APPLICATION OF IMAGE ANALYSIS ADEL R. A. ABD-ALLAH a , BAHAA B. GANNAM b and FARID M. A. HAMADA a,∗ a Department of Pharmacology& Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt, b Department of Pathology, Faculty of Medicine (For Girls), Al-Azhar University, Cairo, Egypt Accepted 21 December 1999 Ofloxacin induces its antibacterial action mainly by inhibition of DNA gyrase which is equivalent to topoisomerase II in mammalian cells. The present study was focused on the impact of ofloxacin on rat testicular DNA ploidy in a dose–response relationship using an image analysis technique on testicular sections following Fuelgen DNA staining. Sperm count and motility as well as sperm head abnormality tests were also investigated. Ofloxacin was given p.o. in doses of 36, 72 and 360 mg kg −1 day −1 for 15 consecutive days. The animals were then left to live safely to day 60 from starting the experiment to give them a chance to complete the cycle of spermatogenesis. Results revealed that ofloxacin significantly decreased the percentage of haploid cells in a dose-dependent manner with concomitant increase in the percentage of diploid cells. Sperm count and motility was also markedly decreased in a dose-dependent fashion. Sperm head abnormality showed no marked change following ofloxacin treatment. In conclusion, ofloxacin induced a marked disturbance in rat testicular DNA ploidy, which may be explained on the basis of cross-reactivity to topoisomerase II. c  2000 Academic Press KEY WORDS: ofloxacin, rat testicular DNA, image analysis. INTRODUCTION Ofloxacin is one of the most frequently used fluoro- quinolones in the world [1]. Its use in treatment of urinary tract infection has increased during the past decade in response to its excellent efficacy and con- cerns of increasing resistance to older agents such as trimethoprim and sulfamethoxazole [2]. Ofloxacin exhibits a good distribution pattern in low dose levels [3]. Moreover, it is being used in the treatment of several infectious diseases such as typhoid fever [4], meningococcal infection [5], and recently, multibacillary leprosy [6]. Ofloxacin is among the quinolones family that induces its antimicrobial action mainly by two mechanisms, first, inhibition of DNA gyrase [7, 8]. The latter (equivalent to topoisomerase II in mammals) is responsible for intro- ducing negative superhelical twists into double-stranded DNA, allowing its replication and synthesis, repair, recombination and transposition [9]. The second possible mechanism is delayed cell replication and production of filamentous-shaped bacteria in response to conditions which may damage DNA [10]. ∗ Corresponding author. Dr Farid M. A. Hamada, Prof. and Head of Dept. of Pharmacology & Toxicology, Faculty of Pharmacy, Al-Azhar University, Nasr-City, Cairo, Egypt. Little information is available on the impact of ofloxacin on the DNA and cell cycle of the host cells. Some reports indicated that cross-reactivity of some fluoroquinolones to mammalian topoisomerase II may result in a possible interaction with DNA-associated proteins [11,12]. Testicular DNA was previously studied by Cottry et al. [13], indicting some alterations in the DNA ploidy following administration of ofloxacin to rats by using a flowcytometric technique on testicular aspirates. Therefore, this work was designed to study the impact of ofloxacin on the testicular DNA ploidy in a dose– response relationship using an image analysis technique on testicular sections following Fuelgen DNA staining. Sperm count, motility as well as sperm head abnormality tests were also performed. MATERIALS AND METHODS Adult Wistar albino male rats weighing 180–200 g were randomized and housed in a conditioned atmosphere and kept on standard diet pellets (El-Naser Co. Abo- Zaabal, Egypt) and water ad libitum. All the animals were acclimatized in our animal facility for 7 days prior to the experiment. 1043–6618/00/020145–06/$35.00/0 c  2000 Academic Press