Effects of nicotine on bone mass and strength in aged female rats

Abstract

This study investigated the effects of nicotine on bone mass and biomechanical properties in aged, estrogen-replete (shamoperated) and estrogen-deplete (ovariectomized) female rats. Eight month old, retired breeder, sham-operated and ovariectomized Sprague-Dawley rats were left untreated for 12 weeks to establish cancellous osteopenia in the ovariectomized group. The animals were then administered saline, low dose nicotine (6.0 mg/kg/day) or high dose nicotine (9.0 mg/kg/day) via osmotic minipumps for 12 weeks. Vertebrae and femora were collected at necropsy for determination of bone mass and strength. As expected, ovariectomy had a negative effect on most endpoints evaluated. Vertebral body bone mineral content (BMC) and density (BMD) and the structural (ultimate load and yield load) and material (ultimate stress, yield stress, and flexural modulus of elasticity) strength properties were lower in the OVX rats than in the sham-operated rats. Femoral diaphysis BMC, BMD, ultimate load, and flexural modulus were also lower in the OVX rats than in the sham-operated rats. The nicotine doses administered resulted in serum nicotine levels that averaged 1.54.5-fold greater than those observed in heavy smokers. Despite the high doses used, nicotine had no effect on vertebral BMC, BMD, or any of the structural and material strength properties in either the OVX or the Sham rats. In addition, nicotine had no effect on femoral diaphysis BMC, BMD, ultimate load, stiffness, ultimate stress, or flexural modulus. Femoral yield load and stress were lower in low dose nicotine-treated rats than in vehicle-treated rats. However, differences were not detected between the high dose nicotine-and vehicle-treated rats for either femoral yield load or stress. The results suggest that tobacco agents other than nicotine are responsible for the decreased bone density and increased fracture risk as observed in smokers.

The influence of cigarette smoke inhalation on bone density: a radiographic study in rats

“…Despite smoking being considered one of the main risk factors to osteoporosis, most of the animal studies yet conducted have not reported a correlation between nicotine (one of the main compounds of cigarette smoke) administration and lower bone density 2,9,24,25 . A previous study of ours also reported that nicotine * did not present a negative impact on bone healing around implants inserted in tibiae of rabbits 24 .…”

“…A clinical study has already suggested that a higher incidence of poor bone quality is observed in smokers 4 . Although most of the animal studies conducted have not reported a correlation between nicotine administration and lower bone density 2,9,24,25 , nicotine is just one of the potentially toxic compounds of cigarette smoke. Still, the number of studies evaluating the effect of cigarette smoke as a whole and smoking cessation on bone is limited.…”

The Effects of Ovariectomy and Naproxen Treatment on the Strength of Femoral Midshaft and Molar Alveolar Region in Rats

“…In these studies, the reason why BMD increases with regard to baseline in femoral midshaft in all groups within 12 weeks following ovariectomy and starts to decrease after 12 weeks (Jiang et al, 1998;Jiang et al, 1997) may be the use of young (18 week) rats which skeletal development is faster. In a study, it is reported that BMD and Lmax in femoral midshaft decrease after 12 weeks following OVX in 32 week rats (Akhter et al, 2003), while no significant change is determined in femoral midshaft of 12 week rats in another research (Zhang et al). These different results may have been caused by different levels of osteopenia due to difference in the age of the animals at OVX and different post-ovariectomy periods (Patlas et al, 2000).…”

Effect of serum nicotine level on posterior spinal fusion in an in vivo rabbit model

“…The effects of nicotine alone on bone health are not conclusive (Table) [22,24,[29][30][31][32][33]. On the other hand, numerous clinical studies have consistently documented the deleterious impact of smoking on bone healing and spinal fusion [2,[34][35][36].…”