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Evaluation of the modifying effect of inhalation of mainstream cigarette smoke on mouse bladder carcinogenesis.

Kato M, Wei M, Yamano S, Fujioka M, Kakehashi A, Wanibuchi H - J Toxicol Pathol (2013)

Bottom Line: The incidences of bladder tumors (papilloma and urothelial carcinoma) tended to increase in the cigarette smoke-exposed group (25.0%) compared with the controls (15.8%), albeit without a statistically significant difference.Cigarette smoke exposure did not have a significant effect on the expression of cyp1a2, cyp 1b1, cyp 2a4, cyp 2b10, cyp 2e1, or PCNA.In conclusion, limited exposure to mainstream cigarette smoke for 22 weeks, caused a significant increase in cyp1a1 expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka City, Osaka 545-0051, Japan.

ABSTRACT
Cigarette smoking is one of the major risk factors of bladder cancer in humans. To date, however, there is no experimental evidence for the effects of inhalation exposure to mainstream cigarette smoke on bladder carcinogenesis. The purpose of the present study was to evaluate the effect of inhalation of mainstream cigarette smoke on mouse bladder carcinogenesis using a cigarette smoke inhalation exposure system. Six-week-old male C57BL mice were administered 0.025% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in their drinking water for 8 weeks and then divided into 2 groups and exposed to 0 or 300 mg/m(3) wet total particulate matter mainstream cigarette smoke for 2 h per day, five times per week, for 22 weeks. The incidences of bladder tumors (papilloma and urothelial carcinoma) tended to increase in the cigarette smoke-exposed group (25.0%) compared with the controls (15.8%), albeit without a statistically significant difference. We also evaluated mRNA expression levels of cytochrome P450 (cyp) enzymes and proliferating cell nuclear antigen (PCNA) in the bladder epithelium. Expression of cyp1a1 was significantly increased in the cigarette smoke-exposed group. Cigarette smoke exposure did not have a significant effect on the expression of cyp1a2, cyp 1b1, cyp 2a4, cyp 2b10, cyp 2e1, or PCNA. In conclusion, limited exposure to mainstream cigarette smoke for 22 weeks, caused a significant increase in cyp1a1 expression. This increase coupled with the nonsignificant increase in bladder tumors suggests that a longer period of exposure is required to clarify the effects of cigarette smoke on bladder carcinogenesis.

No MeSH data available.


Related in: MedlinePlus

Gene expression of cytochrome P450 enzymes and PCNA in bladder tissue. mRNA was extracted from bladder tissues without tumor lesions in each group (n = 5) and mRNA expression was evaluated by RT-PCR followed by real-time PCR. Expression of cyp1a2 was not detected in either group. The expression level of cyp1a1 was significantly higher in the exposed group (P = 0.0286). Data are presented as means ± SD, and statistical analysis was performed using the Mann-Whitney test.
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fig_003: Gene expression of cytochrome P450 enzymes and PCNA in bladder tissue. mRNA was extracted from bladder tissues without tumor lesions in each group (n = 5) and mRNA expression was evaluated by RT-PCR followed by real-time PCR. Expression of cyp1a2 was not detected in either group. The expression level of cyp1a1 was significantly higher in the exposed group (P = 0.0286). Data are presented as means ± SD, and statistical analysis was performed using the Mann-Whitney test.

Mentions: To evaluate alterations in the mRNA expression levels of cytochrome P450 (CYP) enzymes and PCNA in mouse bladder tissue after exposure to cigarette smoke, RT-PCR followed by real-time PCR was performed using 5 bladder tissue samples without tumor lesions from each group. As shown in Fig. 3Fig. 3.


Evaluation of the modifying effect of inhalation of mainstream cigarette smoke on mouse bladder carcinogenesis.

Kato M, Wei M, Yamano S, Fujioka M, Kakehashi A, Wanibuchi H - J Toxicol Pathol (2013)

Gene expression of cytochrome P450 enzymes and PCNA in bladder tissue. mRNA was extracted from bladder tissues without tumor lesions in each group (n = 5) and mRNA expression was evaluated by RT-PCR followed by real-time PCR. Expression of cyp1a2 was not detected in either group. The expression level of cyp1a1 was significantly higher in the exposed group (P = 0.0286). Data are presented as means ± SD, and statistical analysis was performed using the Mann-Whitney test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921930&req=5

fig_003: Gene expression of cytochrome P450 enzymes and PCNA in bladder tissue. mRNA was extracted from bladder tissues without tumor lesions in each group (n = 5) and mRNA expression was evaluated by RT-PCR followed by real-time PCR. Expression of cyp1a2 was not detected in either group. The expression level of cyp1a1 was significantly higher in the exposed group (P = 0.0286). Data are presented as means ± SD, and statistical analysis was performed using the Mann-Whitney test.
Mentions: To evaluate alterations in the mRNA expression levels of cytochrome P450 (CYP) enzymes and PCNA in mouse bladder tissue after exposure to cigarette smoke, RT-PCR followed by real-time PCR was performed using 5 bladder tissue samples without tumor lesions from each group. As shown in Fig. 3Fig. 3.

Bottom Line: The incidences of bladder tumors (papilloma and urothelial carcinoma) tended to increase in the cigarette smoke-exposed group (25.0%) compared with the controls (15.8%), albeit without a statistically significant difference.Cigarette smoke exposure did not have a significant effect on the expression of cyp1a2, cyp 1b1, cyp 2a4, cyp 2b10, cyp 2e1, or PCNA.In conclusion, limited exposure to mainstream cigarette smoke for 22 weeks, caused a significant increase in cyp1a1 expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka City, Osaka 545-0051, Japan.

ABSTRACT
Cigarette smoking is one of the major risk factors of bladder cancer in humans. To date, however, there is no experimental evidence for the effects of inhalation exposure to mainstream cigarette smoke on bladder carcinogenesis. The purpose of the present study was to evaluate the effect of inhalation of mainstream cigarette smoke on mouse bladder carcinogenesis using a cigarette smoke inhalation exposure system. Six-week-old male C57BL mice were administered 0.025% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in their drinking water for 8 weeks and then divided into 2 groups and exposed to 0 or 300 mg/m(3) wet total particulate matter mainstream cigarette smoke for 2 h per day, five times per week, for 22 weeks. The incidences of bladder tumors (papilloma and urothelial carcinoma) tended to increase in the cigarette smoke-exposed group (25.0%) compared with the controls (15.8%), albeit without a statistically significant difference. We also evaluated mRNA expression levels of cytochrome P450 (cyp) enzymes and proliferating cell nuclear antigen (PCNA) in the bladder epithelium. Expression of cyp1a1 was significantly increased in the cigarette smoke-exposed group. Cigarette smoke exposure did not have a significant effect on the expression of cyp1a2, cyp 1b1, cyp 2a4, cyp 2b10, cyp 2e1, or PCNA. In conclusion, limited exposure to mainstream cigarette smoke for 22 weeks, caused a significant increase in cyp1a1 expression. This increase coupled with the nonsignificant increase in bladder tumors suggests that a longer period of exposure is required to clarify the effects of cigarette smoke on bladder carcinogenesis.

No MeSH data available.


Related in: MedlinePlus