Introduction: Bisphenol A (BPA), one of the environmental hormones, is plastic material that binds to the estrogen receptor in the body and acts like estrogen, which can cause endocrine and reproductive diseases. However, there are not many studies done regarding the effect of BPA on osteoporosis.
Objectives: In this study, we investigated the effect of BPA on bone mineral density (BMD) in rats.
Methodology: Six to eight week-old rats were divided into three groups: male, female, and ovariectomized rat (OVX). Nine rats were assigned to each group. Again, according to the dose of BPA, we divided them into 3 groups: control group, low dose group, and high dose group, and each group was assigned 3 rats. They orally administered BPA for 12 weeks. At the time of 6 and 12 weeks after the start of the study, BMD of tibia was measured by q-CT. Percent bone volume, trabecular separation, trabecular thickness] were measured and the changes in BMD between the two groups were compared. In addition, BPA concentration and bone formation marker procollagen type 1 amino-terminal propeptide (PINP) and bone resorption marker C-telopeptide of type 1 collagen (CTX1) were measured in the rats’ serum at the time of 12 weeks after the start of the study.
Results and Discussion: In the female and ovariectomized rat (OVX) groups, 4 BMD values all showed increasing tendency according to the dose of BPA. On the contrary, there was no correlation between the two in the male group. Serum BPA levels were 0.112ng/ml, 0.4075ng/ml, and 1.1705ng/ml, respectively in the control, low dose, and high dose groups. On the other hand, CTX1 showed significant decrease according to the dose of BPA, whose values were 11.210ng/ml, 8.524ng/ml, and 5.814ng/ml, respectively, in the three groups.
Conclusion: BPA in rats decreased bone resorption markers in serum and increased BMD in female, ovariectomized rat (OVX). However, there was no difference in bone markers and BMD in males. This is similar to the effect of selective estrogen receptor modulator (SERM), a medication for osteoporosis, and may be due to estrogen-like effects of BPA. As a result of this animal model, the effect of BPA in the human body has more variables and needs further studies.
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