Effects of smoking cessation on serum leptin, adiponectin and other inflammatory factors in rats

Abstract

Objective To investigate the roles of leptin, adiponectin and other inflammatory factors in the inflammatory reaction of chronic obstructive pulmonary disease induced by smoking through studying the effects of smoking cessation on the levels of serum leptin,adiponectin, interleukin-6 (IL-6) and C-reactive protein (CRP). Methods Thirty male Wistar rats were randomly divided into smoking group,smoking cessation group and control group,ten rats in each group. Rats in smoking group smoked ten cigarettes every time, twice per day, six days per week, 20 weeks in total. Rats in smoking cessation group stopped smoking for ten weeks after smoking for 20 weeks. Serum leptin, adiponectin, and CRP levels were detected by enzyme-linked immunosorbent assay. Serum IL-6 level was detected by double antibody sandwich enzyme-linked immunosorbent assay. Results ① Compared with control group [(128. 00 + 13. 25) ng/L],the serum leptin levels in smoking group [(56. 23±8. 64) ng/L] and smoking cessation group [(60. 36±7. 42) ng/L] were lower (all P <0. 05). There was no statistical significance between smoking cessation group and smoking group. ②Compared with control group [(0. 369 ±0. 032) μg/L],the serum adiponectin level in smoking group [(0. 322±0. 045) μg/L] decreased ( P <0. 05). There was no statistical significance between smoking cessation group[(0. 333 ± 0. 059) μg/L] and control group and smoking group. ③Compared with control group [(23. 94 + 4. 44) ng/L].the serum IL-6 levels in smoking group [(39. 67±3. 13) ng/L] and smoking cessation group [(34. 27±7. 01) ng/L] increased (all P < 0.05). The serum IL-6 level in smoking cessation group was lower than that in smoking group ( P < 0. 05). ④Compared with control group [(494. 49 ± 124.44) μg/L],the serum CRP levels in smoking group [(809. 50± 141. 66) μg/L] and smoking cessation group [(632. 60± 182. 85) μg/L] increased (all P <0. 05). The serum CRP level in smoking cessation group was lower than that in smoking group ( P < 0. 05). ⑤Adiponectin was negatively correlated with IL-6 (y= -0.198, P <0. 05) and CRP (γ = - 0.489, P<0. 05). IL-6 was positively correlated with CRP (γ = 0.598, P <0. 05). Conclusions Smoking can decrease serum leptin and adiponectin, increase the levels of IL-6 and CRP. After smoking cessation, the levels of leptin and adiponectin show a rising trend, the levels of IL-6 and CRP decrease correspondingly. In addition,adiponectin is negatively correlated with IL-6 and CRP. These results suggest that leptin,adiponectin and other inflammatory factors may be involved in inflammatory reaction of chronic obstructive pulmonary disease induced by smoking. Key words: Chronic obstructive pulmonary diseases Smoking; Leptin; Adiponectin; Inflammatory reaction