Background Cigarette smoke contains a variety of carcinogens and mutagens, which may adversely affect male reproductive system. Tobacco can reduce spermatogenesis and alter sperm function by directly affecting the testis and their functions, thereby reducing male fertility. The activities of alkaline phosphatase (AKP), γ-glutamyl transpeptidase (γ-GT), β-glucuronidase (β-GD), and glucose-6-phosphate dehydrogenase (G-6-PD) in the testis are closely related to the reproductive health of male rats.
Objective The purpose of this in vivo experiment is to explore the effects of cigarette smoke on AKP, γ-GT, β-GD, and G-6-PD enzymatic activities in the testis of male rats.
Methods Two hundred males SPF SD rats were randomly divided into control group (no cigarette exposure), low dose group (10 cigarettes a day), medium dose group (20 cigarettes a day), and high dose group (30 cigarettes a day), and the administration lasted for 2, 4, 6, 8, and 12 weeks, respectively. There were a total of 20 subgroups, with 10 rats in each subgroup. The experimental groups were exposed to tobacco smoke by static inhalation in an exposure cabinet once a day, 30 min each time. The control group did not participate in the exposure, and the rest of treatment was the same as the exposure groups. On the last day of each exposure week, the rats were weighed and then sacrificed. The morphology of testis and epididymis was observed, the weights and organ coefficients of testis and epididymis were weighed and calculated, and the activities of AKP, γ-GT, β-GD, and G-6-PD in testicular tissues were measured.
Results With the increase of treatment dose, the weight growth of the rats was slower, the body weight of rats in the high dose group was significantly reduced, and there was an interaction effect between exposure dose and exposure time (P < 0.01). There were no significant changes in rat testis and epididymis weights and organ coefficients, but there was an interaction effect between exposure dose and exposure time (P < 0.01). The testicular histopathology test results showed that with the increase of exposure dose, seminiferous tubules presented different degrees of pathological damage. The activities of AKP in the medium and high dose groups were lower than that in the control group (P < 0.05), and there was no interaction effect between exposure dose and exposure time (P>0.05). The activities of γ-GT were reduced in the medium and high dose groups since week 4 (P < 0.05), and there was an interaction effect between exposure dose and exposure time (P < 0.01). The activities of β-GD of all exposed groups were lower than that of the control group of the same period from week 6 (P < 0.05), and there was an interaction effect between exposure dose and exposure time (P < 0.01); the activities of G-6-PD in the medium and high dose groups also presented the same pattern since week 4 (P < 0.05), and there was the same interaction effect between exposure dose and exposure time (P < 0.01).
Conclusion Cigarette smoke can alter the activities of AKP, γ-GT, β-GD, and G-6-PD, causing testicular tissue damage.
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