An Experimental Study on the Effects of Smoking in the Perinatal Period and During Lactation on the Intervertebral Disks of Newborns

Abstract

To evaluate the histopathologic effects of smoking before, during, and after pregnancy on the intervertebral disk structure of newborns in an experimental rat model. Seven adult female Wistar albino rats were randomly allocated into 7 groups. Nicotine (2 mg/kg/d) was intraperitoneally introduced to these rats in 6 groups before, during, and after pregnancy, whereas the rat in the control group received isotonic saline intraperitoneally. Fourteen newborns delivered by each rat were euthanized at the end of 9 weeks after being breastfed for 3 weeks after birth. The vertebral columns of the euthanized rats were removed en bloc, and histopathologic evaluation was performed on the intervertebral disk specimens. Histopathologic alterations were noted and compared between groups. Ratio of proteoglycan amount exhibited a significant difference between groups (P < 0.001). Subjects in the control group had a predominantly mild amount of proteoglycans, whereas smoking before and during pregnancy and smoking before/during pregnancy and lactation resulted in deposition of a severe amount of proteoglycans in intervertebral disk tissue. Similarly, there was a statistically significant difference between groups with respect to the amount of fibrosis (P < 0.001). In the control group, fibrosis was absent in most (78.6%) subjects. Fibrosis was mild in groups with smoking before pregnancy and during lactation. A moderate degree of fibrosis was detected in groups with smoking during pregnancy, before and during pregnancy, during pregnancy and lactation, and before/during pregnancy and lactation. Results of this study imply that maternal smoking before and during pregnancy and in the lactation period may have deleterious effects on the intervertebral disk of the newborn. The duration of smoking and fertility period can influence the type and severity of these effects.