The effects of nail rigidity on fracture healing in rats with osteoporosis

Background and purpose Stress shielding from rigid internal fixation may lead to refracture after removal of the osteosynthesis material. We investigated the effect of a low-rigidity (Ti-24Nb-4Zr-7.9Sn) intramedullary nail regarding stress shielding and bone healing of osteoporotic fractures in the rat

Effects of a single intraperitoneal administration of cadmium on femoral bone structure in male rats

<p>Abstract</p> <p>Background</p> <p>Exposure to cadmium (Cd) is considered a risk factor for various bone diseases in humans and experimental animals. This study investigated the acute effects of Cd on femoral bone structure of adult male rats after a single intraperitoneal administration.</p> <p>Methods</p> <p>Ten 4-month-old male Wistar rats were injected intraperitoneally with a single dose of 2 mg CdCl₂/kg body weight and killed 36 h after the Cd had been injected. Ten 4-month-old males served as a control group. Differences in body weight, femoral weight, femoral length and histological structure of the femur were evaluated between the two groups of rats. The unpaired Student's t-test was used for establishment of statistical significance.</p> <p>Results</p> <p>A single intraperitoneal administration of Cd had no significant effect on the body weight, femoral weight or femoral length. On the other hand, histological changes were significant. Rats exposed to Cd had significantly higher values of area, perimeter, maximum and minimum diameters of the primary osteons' vascular canals and Haversian canals. In contrast, a significant decrease in all variables of the secondary osteons was observed in these rats.</p> <p>Conclusions</p> <p>The results indicate that, as expected, a single intraperitoneal administration of 2 mg CdCl₂/kg body weight had no impact on macroscopic structure of rat's femora; however, it affected the size of vascular canals of primary osteons, Haversian canals, and secondary osteons.</p

The role of the spleen on colonic anastomotic healing

Comelekoglu, Ulku/0000-0001-8060-6333; Nayci, Ali/0000-0002-0534-1205WOS: 000184490200007PubMed: 12893499The role of the spleen on wound healing remains unclear. This study investigates the effect of splenectomy on the healing of colonic anastomoses. Twenty-six Wistar rats were assigned into four groups: sham, splenectomy, anastomoses, and splenectomy and anastomoses. The rats underwent a standardized left colonic resection and primary anastomoses, and/or splenectomy. Bursting pressure and hydroxyproline content were used to evaluate anastomotic healing, five days postoperatively. No differences were found in the bursting pressure and hydroxyproline content between the groups. The present results indicate that splenectomy has no negative effect on the healing of colonic anastomoses in rats

Effects Of Organophosphate Insecticides On Mechanical Properties Of Rat Aorta

The present study was carried out to search whether organophosphate pesticides affect the mechanical properties of the thoracic aorta. Wistar female rats (aged 6-8 weeks) were assigned randomly to a control group and groups treated with either dichlorvos or chlorpyriphos for 90 days at a dose of 5 mg/kg/day. After that period, animals were killed and thoracic aorta strips in longitudinal direction were isolated. The stress, strain and elastic modulus were obtained from the strips. Our results showed that chronic administration of chlorpyriphos and dichlorvos caused downward shift of the stress-strain relations compared to the control curve. The elastic modulus-stress curve revealed distinct characteristics in the low and high stress regions. A power function was used to simulate the low stress region while a line was fit to the high stress region. Curve fitting procedure illustrated that both pesticides influenced mainly the high stress region, but they had diverse effects at the low stress region. The results also imply that chlorpyriphos and dichlorvos decrease the strength of the aorta and therefore might influence the response of the aorta to mechanical loading induced by blood pressure.Wo

Exposure to gamma rays induces early alterations in skin in rodents: Mechanical, biochemical and structural responses

PubMedID: 19012966In this study, the effect of gamma rays has been investigated on the normal rat skin using biomechanical, biochemical and histological techniques. Seventeen male Wistar albino rats were divided into two groups (control (n=7) and irradiated (n=10)). The irradiated group was treated with a 60Co gamma source at a dose of 10 Gy at room temperature. Skin biomechanics were measured with tensile test using biomaterial testing machine and maximum load, stiffness, energy absorption capacity, ultimate stress, ultimate strain and elastic modulus were calculated. In the irradiated group, energy, strain and toughness were significantly lower than in the control group (p&lt;0.05). However, strength, displacement, stiffness, stress and elastic modulus were similar to that of the control group (p&gt;0.05). Catalase (CAT) activities and the levels of malondialdehyde (MDA) in the skin of rats were measured using the biochemical methods. MDA levels significantly increased whereas CAT activities decreased in the irradiated group as compared with the control group (p&lt;0.05). Diameters of collagen fibers were measured by transmission electron microscopy. There was no significant difference (p&gt;0.05) between control and irradiated groups for collagen fiber diameter. Thickness of epidermis was significantly lower than the control group. There were no changes in the epidermis between the irradiated group and the control group ultrastructurally. The results of this study show that the gamma irradiation has a significant effect on normal healthy skin. © 2008 Elsevier Inc. All rights reserved.Our study was financially supported by the Grant from Mersin University Medical Faculty.Our study was financially supported by the Grant from Mersin University Medical Faculty

Sepsis induces early phrenic nerve neuropathy in rats

PubMedID: 16204602The aim of the present study was to investigate the electrophysiology of the phrenic nerve and the diaphragm muscle during sepsis. In total, 26 rats underwent either sham laparotomy or caecal ligation and puncture (CLP). Electrophysiology was evaluated via a phrenic nerve conduction study and needle electromyography of the diaphragm, prior to CLP, 6 and 24 h post-CLP and on day 7. The histopathology of the diaphragm muscle and phrenic nerve was also examined on day 7. In the sepsis group, the phrenic nerve conduction study showed decreased amplitude of compound action potential (CMAP), and prolongation in the duration and the latency of CMAP. The diaphragmatic needle electromyography showed decreased amplitude and frequency of the motor unit action potential (MUP), and prolongation in the duration of MUP, at all time points, compared with the pre-CLP values. The electrophysiological abnormalities were consistent with axonal and demyelinating phrenic nerve neuropathy. Electrophysiological abnormalities were present at 6 h with worsening at 24 h and on day 7. Histopathological examination showed normal muscular fibres and focally slight myelin degenerations of the phrenic nerve fibres. [In conclusion, sepsis induced phrenic nerve neuropathy as early as the 6th h in rats. Copyright©ERS Journals Ltd 2005

Chronic cadmiun exposure affects the antioxidant defense system in heart of ovariectomized rats

They were divided into four groups and only two groups were undergone ovariectomy operation. One of the other two groups was used for control and the other one was for Cd administration in healthy rats. Only one of the ovariectomized groups was received Cd administration ten weeks after the surgery. Cd administrations were carried out intraperitonealy for 18 weeks. At the end of this treatment period, rats were decapitated and then, heart tissues were removed. Superoxide dismutase (SOD), and catalase (CAT) activities and the levels of malondialdehyde (MDA) in the heart of rats were measured. In the ovariectomized group, MDA concentration was significantly increased whereas SOD and CAT activities were significantly decreased (p < 0.05). In the cadmium exposed rats, MDA, SOD and CAT levels were found to be significantly higher than those of the control group (p < 0.05). Similar results were obtained in the Ovx-Cd group. In conclusion, chronic cadmium exposure and ovariectomy induce the oxidative stress in the heart tissues by increasing lipid peroxidation and alter the antioxidant enzyme activities