الفهرس 
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Abstract
For many years, tobacco smoking has been linked to several morbidities. Cigarette smoking causes heart diseases, lung and esophageal cancer and chronic respiratory disease. Many epidemiological and clinical studies have shown association between tobacco and bone disease. It has been reported that smoking postmenopausal women loose significantly more cortical bone and have more spinal osteoporosis than non smoking women. The results of several studies on experimental animals are fully in accord with the epidemiological and clinical observations regarding the harmful effects of tobacco smoking on bone.
Despite the richness in the literature dealing with the relationship between tobacco smoking and several disorders, the effects of nicotine, the major alkaloid in tobacco products thought to pose the greatest risk to bone health, on bone mineral homeostasis have not been clearly defined particularly in the early stage of life with rapid bone growth and also in conditions where bone loss exceeds bone formation.
The aim of the present study was to establish the effects of chronic nicotine administration for 6 months on bone mineral homeostasis in rapidly growing young rats and ovariectomized rats in comparison with the effects in adult male and female rats. In addition, the effects of the antiosteolytic bisphosphonate alendronate were evaluated in rats treated concurrently with nicotine.
Rats were divided into 4 groups, the male, female, ovariectomized and young groups. All rats were treated subcutaneously with nicotine at doses of 3 and 4.5 mg/kg/day. Each dose was given divided into 2 equal doses administered morning and evening and the treatment was continued for 6 months. Subgroups of the adult and young rats treated with low and high doses of nicotine were treated simultaneously with alendronate in a dose of 1mg/kg/day. The daily changes in rat body weight were recorded throughout the period of the experiment.
At the end of the treatment period, the rats were sacrificed by decapitation and the blood was collected from each rat. Femurs and lumbar vertebrae were dissected free of soft tissue and used for bone measurements:
The following parameters were evaluated:-
- Daily changes in rat body weight throughout the period of the study (6 months).
- Morphological measurements of the femora (weight, length,mid-shaft total width, mid-shaft cortical width).
- Chemical composition of femoral ash (ash weight and calcium and phosphorus concentrations).
- Chemical composition of lumbar vertebral ash (ash weight and calcium and phosphorus concentrations).
- Serum concentration of calcium and phosphorus
- Serum concentration of calcitropic hormones (PTH, 1,25 dihydroxyvitamin D and calcitonin)