The beneficial roles of insulin and parathyroid hormones in the treatment of experimentally induced diabetic osteoporosis in female rats: bone mineral density, morphometric and histological studies.

BACKGROUND: Diabetes mellitus (DM) and osteoporosis are two frequent medical conditions with an increasing prevalence in elderly people and are responsible for large number of incurable fractures. This study is designed experimentally in female rats in order to determine whether combined treatment of insulin and parathyroid hormone (PTH) enhances the reversibility of the osteoporotic changes that occurred in streptozotocin (STZ)-induced DM. MATERIALS AND METHODS: In this study, 30 adult female rats aged 3 months were used, they were randomly divided into: control group (6 rats) and diabetes group (24 rats), in which experimental DM was induced by i.p. injection of a single dose of STZ (60 mg/kg/body weight). Diabetic group was further divided into four subgroups (6 rats each): non-treated diabetic, insulin-treated (8-12 units s.c./day of Humalin U-40), PTH-treated (6.0 µg s.c./kg/day) and combined insulin and PTH-treated subgroups. All tested groups were assessed for body weight, food and water consumptions. RESULTS: At the end of the experimental period, the bone mineral density (BMD) was measured for all rats of different groups; then the rats were sacrificed and blood samples were collected for measuring glucose, alkaline phosphatase and osteocalcin levels. Right femora were dissected out and subjected to measurement of diameter of neck and shaft, length of shaft, and weight. Then the femora specimens were processed and stained with haematoxylin and eosin for histological study. The results showed that there was a statistically significant, decrease in BMD, increase in the level of alkaline phosphate, and decrease in the level of osteocalcin in rats in diabetic group compared with other groups; these parameters improved in other groups, especially in diabetes/insulin/PTH group. The rats in diabetic group showed statistically significant decrease in neck and shaft diameters and weight of femur bone compared with other groups, while rats in diabetes/insulin/PTH group showed a significant improvement of these parameters. In diabetic group, there were different histopathological changes in cortical bone and Haversian canals, which improved in other groups, especially in rats in diabetes/insulin/PTH group. CONCLUSIONS: The untreated DM resulted in dramatic reduction in BMD and morphometric parameters. Treatment with insulin ameliorated these effects to some extent, while PTH co--treatment had a more positive effect. The combination of PTH and insulin resulted in stronger improvement of all parameters to approximately like those of control rats.

Anatomical variation of sciatic nerve division in the popliteal fossa and its implication in popliteal nerve blockade.

The sciatic nerve (SN) originates from the L4-S3 roots in the form of two nerve trunks: the tibial nerve (TN) and the common peroneal nerve (CPN). The TN and CPN are encompassed by a single epineural sheath and eventually separate (divide) in the popliteal fossa. This division of the SN occurs at a variable level above the knee and may account for frequent failures reported with the popliteal block. We studied the level of division of the SN in the popliteal fossa and its relationship to the common epineural sheath of the SN. The level of division of the SN sheath into TN and CPN above the knee was measured in 30 cadaver specimens. The SN was invariably formed of independent trunks (TN and CPN) encompassed in one common epineural sheath. The SN divided at a distance range of 50 to 180 mm above the popliteal fossa crease. The present findings suggest that the TN and CPN leave the common SN sheath at variable distances from the popliteal crease. This finding and the relationship of the TN and CPN sheaths may have significant implications for popliteal nerve block.

Vanilloid receptor type 1-immunoreactive nerves in the rat urinary bladder and primary afferent neurones: The effects of age.

The vanilloid receptor (VR1) is a molecular integrator of various painful stimuli, including capsaicin, acid and high temperature. VR1 protein functions both as a receptor for capsaicin and a transducer of noxious thermal stimuli. In addition, VR1 is well characterised at the terminals of sensory nerves involved in the pain pathway. VR1 is also expressed in a capsaicin-sensitive and peptide-containing sub-population of primary sensory nerves. Indirect immunohistochemistry was used to examine the distribution of nerves immunoreactive (ir) for VR1 in the base of the urinary bladder and in the neurones of the lumbosacral dorsal root ganglia (L1-L2 and L6-S1) of young adult (3 months) and aged (24 months) male rats. Semi-quantitative estimations of nerve densities were assessed and quantitative studies were also used to examine the effects of age on the percentage of VR1-ir dorsal root ganglion neurones. The bladder base in young adults showed dense VR1-ir fibres within the urothelium and in the subepithelium and fibres ranging from sparse to moderate in number in the muscle coat. In comparison to the young animals, the aged rats showed sparse to moderate densities of VR1-ir nerves in the subepithelium and sparse fibres in the muscle layers. In the lumbosacral dorsal root ganglia the percentage of VR1-ir neuronal profiles showed a significant reduction from (mean +/- SEM) 17.8 +/- 2% in the young adult to 12 +/- 1.6 in the aged rats. The present findings suggest that the effects of VR1 on bladder function (nociception and reflex micturition) are influenced by age and the reduction with age of VR1-ir neurones in the dorsal root ganglia could also have important implications for the micturition reflex.