The effect of leptin on adrenal glands in rats with streptozotocin-induced diabetes: an experimental study

OBJECTIVE

To determine the cross-section area of adrenal medulla and the percentage of Ki-67 (a proliferation marker) of the adrenal gland in diabetic rats after leptin injection.

STUDY DESIGN

Twenty-nine male Wistar rats were randomly divided into 3 groups: control (C) group (n = 9), diabetes mellitus (DM) group (n = 10) and leptin-injected diabetes mellitus (DM+L) group (n = 10). Experimental DM was induced by a single intraperitoneal dose of streptozotocin (40 mg/kg). After this, leptin (100 microg/kg) was injected subcutaneously for a period of 2 weeks in the diabetic group.

RESULTS

An atrophy of adrenal medulla in the DM group was observed, and this atrophy returned to normal morphology after injection of leptin. In addition, an increase in the Ki-67 percentage was demonstrated in the zona reticularis layers in the DM+L group.

CONCLUSION

Our study indicated that leptin stimulates the sympathoadrenal system and the androgen producing adrenal cortex in DM rats.

Effects of Constant Lightness, Darkness and Parachlorophenylalanine Treatment on Tail Regeneration in the Lizard Ophisops elegans macrodactylus: Macroscopic, Biochemical and Histological Changes

A better understanding of regenerative growth is very important for the development of new potential strategies. Recently, the pineal secretory product melatonin was shown to stimulate the regeneration process. In this study, we carried out an experimental investigation of tail regeneration in young adult lizards, Ophisops elegans macrodactylus Berthold, 1842, addressing the role of melatonin on the regeneration process. Lizards were divided into three groups: constant light-exposed control group (n = 13), constant dark-exposed group (n = 15) and parachlorophenylalanine (p-CPA) treatment group exposed to constant light (n = 15). Using a tail autotomy procedure, the effects of p-CPA treatment on connective tissue together with neural tissue and vascular tissue in regenerating tail in lizards were investigated. p-CPA (400 microg/kg body mass) was injected from day 0 to 30 days after autotomy. p-CPA treatment produced a significant increase in the length of the regenerated tail compared with light-exposed control and dark-exposed lizards. Total collagen content was found to be higher in p-CPA-treated animals in comparison with other groups. Histologically, a higher percentage of connective tissue and vascular tissue and a lower percentage of neural tissue were found in the regenerated tails of the p-CPA-treated lizards. Importantly, the percentage of neural tissue in lizards in the dark-exposed animals was higher than that in animals of both light-exposed and p-CPA treatment groups. Thus, it is clear that p-CPA has a stimulatory influence on fibroblast collagen production and vascularization of the regenerated tail in the lizards. Furthermore, it seems that the neural regeneration process was markedly enhanced in lizards exposed to continuous darkness. Based on the results of our study, it is suggested that melatonin may be an active factor that speeds up the rate of tail regeneration in lacertilians.

Morphometry of the sacrum for clinical use

Degenerative disease and instability in the lower lumbar spine may necessitate fusion and stabilization supplemented by instrumentation to the sacrum. However, screw placement in a reasonable position is more difficult to achieve because of the unique anatomy of the first sacral (S1) vertebra. Therefore, this study has been conducted to evaluate sacrum anatomy of the Western Anatolian population in terms of morphometric measurements and make a comparison with previous studies as well as giving a guidance to the surgeons. In this study, 60 dry adult sacrums (30 male and 30 female) were assessed for morphometric analysis. The measurement data for the sacrum and S1 vertebra revealed that there was no significant difference between both sexes except the sacral width and sacral canal width (p<0.05). In the present study, the ratio of S1 corpus' width to sacral width was lower in females compared with males. A detailed knowledge of the morphometric data about sacrum is very important for spinal surgery, as pedicle screw insertion is crucial in spinal instrumentation in order to prevent neurological injury and/or fixation failure.