Do cigarette smoke and vitamin E affect the development of endometrial pinopods? An animal study

OBJECTIVES

To study the effects of cigarette smoke and vitamin E on the development of endometrial pinopods.

STUDY DESIGN

Eighteen female and 12 male Swiss albino mice, 12-14 weeks old, with a mean weight of 25g (standard deviation 5g) were used in this study. Female mice were divided into three equal groups. Every day for 10 weeks, mice in Group 1 (control group) received normal saline intraperitoneally; mice in Group 2 were exposed to smoke from 20 cigarettes/day using a smoke machine; and mice in Group 3 were exposed to smoke from 20 cigarettes/day using a smoke machine and also received 50mg/kg vitamin E intraperitoneally. After 10 weeks, vaginal smears were taken from the female mice and they were copulated with the 12 male Swiss albino mice on the day of oestrus. Day 0 was defined as the day on which sperm were detected in the vagina by smear test. Mice were killed at the end of Day 5, which was considered to represent the optimal day for implantation. The uteri were removed and the effects of cigarette smoke and vitamin E on the development of endometrial pinopods were studied using an electron microscope.

RESULTS

The endometrial tissue of the control group appeared morphologically normal, with short microvilli, cytoplasm and pinopods in the form of cytoplasm and cell membrane enlargements in patches. In total, 149 pinopods were counted in the control group using a scanning electron microscope (two histologists performed the analysis and were blinded to each other's findings). In the smoke-exposed group, the cytoplasmic structure was degenerated considerably, and fewer pinopods were counted (n=11). The number of pinopods in mice who were exposed to cigarette smoke and vitamin E (n=67) was significantly higher compared with the cigarette-exposed group (p=0.002), but considerably lower compared with the control group (p=0.002).

CONCLUSION

Smoke exposure led to a significant decrease in the development of endometrial pinopods. Vitamin E, an antioxidant, partially reversed the adverse effects of cigarette smoke. This suggests that cigarettes may have a negative effect on fertility by decreasing the number of pinopods. However, this negative effect can be reduced using vitamin E. More studies should be conducted to support this finding.