Exposure to cigarette smoke via respiratory system may induce abnormal alterations of reproductive organs in female diabetic rats

Cigarette smoke (CS) has harmful effects on human fertility, reproduction, and development as well as on patients suffering from metabolic diseases such as diabetes than on healthy individuals. This study was conducted to investigate the relationship between CS exposure and histological alterations of reproductive organs in female diabetic rats. We evaluated the histology of uteruses and ovaries obtained from female rats exposed to smoke from standard cigarettes for 4 weeks (28 hours a week). After CS exposure, tissue slides were made from uterine and ovarian samples and examined after hematoxylin and eosin staining. Immunohistochemistry was used for detection of matrix metallopeptidase 9 (MMP9), C-X-C chemokine receptor type 4 (CXCR4), and estrogen receptor (ER)α in the uterus and ovary. MMP9 is an inflammatory biomarker that increases during progression to endometriosis. As a chemokine receptor, CXCR4 is involved in development of the inner wall of the uterus and cell adhesion. In the uterus, the occurrence of MMP9, CXCR4, and ERα and the number of endometrial glands were increased by CS exposure, while in the ovary, occurrence of MMP9, CXCR4, ERα, proliferating cell nuclear antigen and the number of corpus lutea or cyst follicles were increased by CS exposure. Collectively, this study indicates that CS induced abnormal development of the uterus and ovary under induced diabetes, leading to adverse effects on normal function of reproductive organs in female rats. HIGHLIGHTS: Cigarette smoke (CS) exposure adversely affected reproductive organs of diabetic female rats. In the uterus, expression of matrix metallopeptidase 9 (MMP9), C-X-C chemokine receptor type 4 (CXCR4), estrogen receptor (ER)α, and the number of endometrial glands were increased by CS exposure, In the ovary, the expression of MMP9, CXCR4, ERα, and proliferating cell nuclear antigen and the number of corpus lutea or cyst follicles were increased by CS exposure. Exposure to CS via the respiratory system exerted a harmful impact on the uterus and ovary in female rats with diabetes.