OBSTETRICS Nicotine, an a7 nAChR agonist, reduces lipopolysaccharide-induced inflammatory responses and protects fetuses in pregnant rats Jinying Yang, MD; Shao-Qing Shi, MD; Leili Shi, DDS; Dajun Fang, MD; Huishu Liu, MD, PhD; Robert E. Garfield, PhD OBJECTIVE: The objective of the study was to examine the effects of nicotine, an a7 nicotinic acetylcholine receptor agonist, on lipopoly- saccharide (LPS)-induced inflammatory responses in rats during pregnancy. STUDY DESIGN: Pregnant Sprague Dawley rats were randomly divided into groups (n ¼ 6 rats/group): group 1 rats each received a single intraperitoneal injection of LPS (25 mg/kg) on gestation day 16; group 2 rats were first pretreated with nicotine (1 mg/kg per day, subcuta- neously) on gestation days 14 and 15 and then were treated with single injections of LPS on gestational day 16; group 3 rats were treated with the vehicle (saline) used for groups 2 and 3 (controls). Maternal blood was collected at 6 hours and 24 hours after LPS and vehicle treatments and assayed for tumor necrosis factor (TNF)-a, interleukin-6 (IL-6), and interleukin-10 (IL-10). In addition, the number of live pups and pup weights were obtained at the time of delivery. RESULTS: LPS treatment significantly (P < .001) elevates maternal blood levels of TNF-a and IL-6 but not IL-10 (P > .05). Nicotine treatment significantly reduces LPS-induced TNF-a and IL-6 concentrations (P < .001) but does not change (P > .05) IL-10 levels. The number of live pups in the LPS group are significantly lower (P < .001) than the vehicle treated controls, and nicotine treatment significantly (P < .011) reverses this change. Similarly, fetal weights are lower following LPS (P < .016) and higher (P < .024) in the group treated with nicotine plus LPS. CONCLUSION: Nicotine reduces the LPS-induced inflammatory re- sponses and rescues the fetus in rats during pregnancy. Thus, nicotine exerts dramatic antiinflammatory effects. These observations have important implications for control of inflammatory responses during pregnancy. Key words: cytokines, inflammation, nicotine, parturition, preeclamp- sia, preterm birth, a7 nicotinic acetylcholine receptor agonist Cite this article as: Yang J, Shi S-Q, Shi L, et al. Nicotine, an a7 nAChR agonist, reduces lipopolysaccharide-induced inflammatory responses and protects fetuses in pregnant rats. Am J Obstet Gynecol 2014;211:538.e1-7. M ajor complications during preg- nancy include preterm birth (PTB) and preeclampsia. PTB affects more than 15 million babies worldwide and results in more than 1 million newborn deaths and complications of survivors. 1 Despite vast improvement in the care of preterm infants in recent decades, an effective drug for prevention and treatment of PTB has yet to be identified. PTB is a multifactorial condition with a number of risk factors including previ- ous PTB, uteroplacental ischemia, uterine overdistension, cervical disorders, and maternal stress. 2 However, intrauterine infection and inflammation have been established as major risk factors of PTB and in a number of adverse neonatal outcomes such as neonatal brain injury. 3 Cytokines and chemokines are known to be involved in both the physiological and the pathological processes of in- flammation. 4,5 Cytokines have also been shown to be involved in the physiology or pathophysiology of ovulation, im- plantation, placental function, parturi- tion, and cervical ripening. 6-14 Many studies of cytokine expression have used lipopolysaccharide (LPS), an endotoxin of Gram-negative bacterial cell walls, treatments to demonstrate inflamma- tory systems associated with preterm birth or preeclampsia. 15-29 Administration of LPS activates the maternal innate immune system by binding to pattern recognition receptors such as Toll-like receptors (TLRs). Acti- vation of TLRs by LPS increases the production of arrays of proinflamma- tory cytokines and chemokines. 27-29 These cytokines and chemokines recruit neutrophils and macrophages to the maternal-fetal interface and increase the production of downstream media- tors in the uterus, placenta, and fetal From the Department of Obstetrics and Gynecology, Guangzhou Women and Children’s Medical Center (Drs Yang, S.-Q. Shi, Fang, Liu, and Garfield) and Guangzhou Medical College (Drs Yang and Fang), Guangzhou, China; and the Departments of Obstetrics and Gynecology, St. Joseph’s Hospital and Medical Center, Phoenix, AZ (Drs Yang, S.-Q. Shi, L. Shi, Fang, and Garfield). Received Dec. 2, 2013; revised Feb. 24, 2014; accepted April 17, 2014. This study was supported by funds from the St Joseph’s Hospital Foundation (R.E.G.) and the Guangzhou Women and Children’s Medical Center (H.L.). The authors report no conflict of interest. Reprints: Robert E. Garfield, PhD, St. Joseph’s Hospital and Medical Center, Department of Obstetrics and Gynecology, 445 North 5th St., Phoenix, AZ 85004. robert.garfield@chw.edu 0002-9378/$36.00  ª 2014 Elsevier Inc. All rights reserved.  http://dx.doi.org/10.1016/j.ajog.2014.04.026 538.e1 American Journal of Obstetrics & Gynecology NOVEMBER 2014 Research ajog.org