Objective   To explore the reproductive toxicity of a periodontal sustained release drug of compound ornidazole and pefloxacin mesylate on male rats.    Methods   A total of 100 male SD rats were randomly divided into negative control

low-

medium- and high-dose groups and intervention group by random digits table

with 20 animals in each group. The rats of low-

medium- and high-dose groups were fed daily with the the sustained release drug at 1

4

and 8 g/kg respectively

and those of the negative group were fed daily distilled water

for continuously 42 d; and those of the intervention group were given cyclophosphamide (40 mg/kg) by intraperitoneal injection for continuously 5 d. During this period

general state and quality; mating and fertility

general organs

coefficient of testis and epididymis; sperm movement

count and morphology; serum T and E

2

were determined respectively. Histopathological examination of testis and epididymis

and immunohistochemistry of testis for PCNA and Bcl-2 expressions were also respectively performed.    Results   The general state of these rats was good

except one was dead in the intervention group

high-dose and negative group respectively in 2

3 and 4 weeks respectively. From the 4th week

the body weight

coefficient of testis and epididymis

and sperm mobility

counting and morphology in high-dose group were all statistically significant (P0.05); pathological testis and epididymis in high-ose group were changed

T and E

2

were also decreased

PCNA depressed

and Bcl- increased

with all these having significant difference with those of negative control (P0.05).    Conclusion   There is certainly reproductive toxicity when our periodontal sustained release drug of compound ornidazole and pefloxacin mesylate is administered in a high dose for male rats. The mechanism underlying might be the reduced serum T and E

2

decreased PCNA and increased Bax.