2022, Vol. 26 ›› Issue (20): 3117-3120

Effect of smoking on bone mineral density in rats

Cai Zhencun, Gao Zhenhuai, Ren Lixuan, Zhang Zelin   

Abstract: BACKGROUND: Osteoporosis is a systemic disease that causes abnormal bone metabolism and decreases bone mineral density due to various reasons. Clinical studies have found that most patients with osteoporosis have a long-term history of smoking, but whether smoking is directly related to bone mineral density reduction has not been determined yet.
OBJECTIVE: To explore the relationship between smoking and bone mineral density in rats, and to evaluate the association between smoking and osteoporosis.
METHODS: Forty Wistar rats were randomly divided into two groups (n=20 per group): non-smoking group and smoking group. Rats in the smoking group were subjected to passive cigarette smoking through a passive smoking animal exposure system that could simulate the process of human smoking. Each rat was fumigated with 20 cigarettes for 40 minutes, twice a day, for 8 weeks. Rats in the non-smoking group were used as controls and they were only raised in the passive smoking animal exposure system for 8 weeks without smoking. The natural experimental environment, feeding, water supply and other aspects of the two groups were completely the same. The bone mineral density of bilateral femurs and L5 lumbar vertebrae of rats were measured with dual-energy X-ray bone densitometer before the experiment and 4 and 8 weeks after the experiment, and the average value was taken. Body mass changes of rats were measured at the same time.
RESULTS AND CONCLUSION: There was no significant difference in bone mineral density and body mass between the two groups before the beginning of the experiment (P > 0.05). In the 4th week of the experiment, the bone mineral density of the smoking group was lower than that of the non-smoking group [(225.50±10.11) mg/cm2 vs. (238.86±11.53) mg/cm2, P=0.002]. In the 8th week of the experiment, the bone mineral density of the smoking group was further reduced, which was lower than that of the non-smoking group [(201.98±15.58) mg/cm2 vs. (240.26±13.69) mg/cm2, P=0.013]. In the 4th week of the experiment, the body mass of the rats in the smoking group was lower than that of the non-smoking group [(236.4±15.3) g vs. (258.8±19.6) g, P=0.026]. In the 8th week of the experiment, the body mass of the rats in the experimental group was still lower than that of the non-smoking group [(278.9±18.1) g vs. (339.5±13.3) g, P=0.008].The body mass gain of the experimental group in the last 4 weeks (5-8 weeks) was significantly less than that in the first 4 weeks (1-4 weeks) (P=0.006), but there was no significant difference in the body mass gain of the non-smoking group (P=0.081). Therefore, smoking can reduce bone mineral density and slow body mass growth in rats, indicating that smoking is closely related to osteoporosis. Control of smoking should be clinically concerned in patients with osteoporosis in order to achieve effective treatments.
Key words: osteoporosis, smoking, bone mineral density, fumigation, rat, body mass, experiment