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An immunohistochemical study of the antinociceptive effect of calcitonin in ovariectomized rats.

Takayama B, Kikuchi S, Konno S, Sekiguchi M - BMC Musculoskelet Disord (2008)

Bottom Line: The numbers of Fos-ir neurons in the OVX-CT and sham-CT groups were significantly less than in the OVX-vehi and sham-vehi groups, respectively (p = 0.0090, p = 0.0090).The number of Fos-ir neurons in the OVX-CT-pcpa-group was significantly more than that of the OVX-CT-group (p = 0.0283), which means pcpa inhibits calcitonin induced reduction of c-Fos production.The results in this study demonstrated that 1) the increase of c-Fos might be related to hyperalgesia in OVX-rats. 2) Calcitonin has an antinociceptive effect in both OVX and sham rats. 3) The central serotonergic system is involved in the antinociceptive properties of calcitonin.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopedic Surgery, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima City, Fukushima, 960-1295, Japan. bun@fmu.ac.jp

ABSTRACT

Background: Calcitonin is used as a treatment to reduce the blood calcium concentration in hypercalcemia and to improve bone mass in osteoporosis. An analgesic effect of calcitonin has been observed and reported in clinical situations. Ovariectomized (OVX) rats exhibit the same hormonal changes as observed in humans with osteoporosis and are an animal model of postmenopausal osteoporosis. The aim of this study to investigate antinociceptive effect of calcitonin in OVX rats using the immunohistochemical study.

Methods: We assessed the antinociceptive effects of calcitonin in an ovariectomized (OVX) rat model, which exhibit osteoporosis and hyperalgesia, using the immunohistochemical method. Fifteen rats were ovariectomized bilaterally, and ten rats were received the same surgery expected for ovariectomy as a sham model. We used five groups: the OVX-CT (n = 5), the sham-CT (n = 5), and the OVX-CT-pcpa (n = 5) groups received calcitonin (CT: 4 U/kg/day), while OVX-vehi (n = 5) and the sham-vehi (n = 5) groups received vehicle subcutaneously 5 times a week for 4 weeks. The OVX-CT-pcpa-group was given traperitoneal injection of p-chlorophenylalanine (pcpa; an inhibitor of serotonin biosynthesis) (100 mg/kg/day) in the last 3 days of calcitonin injection. Two hours after 5% formalin (0.05 ml) subcutaneously into the hind paw, the L5 spinal cord were removed and the number of Fos-immunoreactive (ir) neurons were evaluated using the Mann-Whitney-U test.

Results: The numbers of Fos-ir neurons in the OVX-CT and sham-CT groups were significantly less than in the OVX-vehi and sham-vehi groups, respectively (p = 0.0090, p = 0.0090). The number of Fos-ir neurons in the OVX-CT-pcpa-group was significantly more than that of the OVX-CT-group (p = 0.0283), which means pcpa inhibits calcitonin induced reduction of c-Fos production.

Conclusion: The results in this study demonstrated that 1) the increase of c-Fos might be related to hyperalgesia in OVX-rats. 2) Calcitonin has an antinociceptive effect in both OVX and sham rats. 3) The central serotonergic system is involved in the antinociceptive properties of calcitonin.

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Related in: MedlinePlus

Ovariectomy or a sham operation was performed in each group, and from postoperative week 4 onward calcitonin or vehicle was injected 5 times a week for 4 weeks. PCPA was injected on the final 3 days of calcitonin injection. A formalin test was conducted in postoperative week 8, and two hours later, the animals in each group were perfused, and tissue was removed.
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Figure 1: Ovariectomy or a sham operation was performed in each group, and from postoperative week 4 onward calcitonin or vehicle was injected 5 times a week for 4 weeks. PCPA was injected on the final 3 days of calcitonin injection. A formalin test was conducted in postoperative week 8, and two hours later, the animals in each group were perfused, and tissue was removed.

Mentions: The rats were anesthetized by inhalation of ethyl ether (99%, Diethyl Ether, Wako Pure Chemical Industries, Ltd., Osaka, Japan). Bilateral ovariectomy was performed according to the method reported by Shibata K et al [20] to create an OVX model. Rats whose ovaries were exposed but not excised were used as a sham model. The operations and drug administrations were performed according to the schedule shown in the Figure 1. Four weeks after surgery, a synthetic derivate of eel calcitonin, ([Asu1'7]eel calcitonin) (4 U/kg/day) (Elcatonin, Asahi Kasei Co., Tokyo, Japan) was subcutaneously injected into the back of rats 5 times a week for 4 weeks. The vehicle was injected as a control. P-chlorophenylalanine (PCPA; Sigma, MO, USA), 100 mg/kg/day, an inhibitor of serotonin biosynthesis, was intraperitoneally injected on the final 3 days of calcitonin administration. Normal saline was injected as a control. The following 5 groups were established: a) a group repeatedly subcutaneously injected with calcitonin after OVX (OVX-calcitonin group, n = 5), b) a group repeatedly subcutaneously injected with vehicle after OVX (OVX-vehicle group, n = 5), c) a group intraperitoneally injected with PCPA after OVX in addition to being repeatedly subcutaneously injected with of calcitonin (OVX-calcitonin-PCPA group, n = 5), d) a group repeatedly subcutaneously injected with calcitonin after sham operation (sham-calcitonin group, n = 5), and e) a group repeatedly subcutaneously injected with vehicle after sham operation (sham-vehicle group, n = 5). After surgery and injections, the formalin test was performed as an acute noxious stimulus with subcutaneously injected with 5% formalin (0.050 ml) (Wako Pure Chemical Industries, Ltd. Osaka, Japan) into the left hind paw. All rats were perfused two hours after formalin test.


An immunohistochemical study of the antinociceptive effect of calcitonin in ovariectomized rats.

Takayama B, Kikuchi S, Konno S, Sekiguchi M - BMC Musculoskelet Disord (2008)

Ovariectomy or a sham operation was performed in each group, and from postoperative week 4 onward calcitonin or vehicle was injected 5 times a week for 4 weeks. PCPA was injected on the final 3 days of calcitonin injection. A formalin test was conducted in postoperative week 8, and two hours later, the animals in each group were perfused, and tissue was removed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2654564&req=5

Figure 1: Ovariectomy or a sham operation was performed in each group, and from postoperative week 4 onward calcitonin or vehicle was injected 5 times a week for 4 weeks. PCPA was injected on the final 3 days of calcitonin injection. A formalin test was conducted in postoperative week 8, and two hours later, the animals in each group were perfused, and tissue was removed.
Mentions: The rats were anesthetized by inhalation of ethyl ether (99%, Diethyl Ether, Wako Pure Chemical Industries, Ltd., Osaka, Japan). Bilateral ovariectomy was performed according to the method reported by Shibata K et al [20] to create an OVX model. Rats whose ovaries were exposed but not excised were used as a sham model. The operations and drug administrations were performed according to the schedule shown in the Figure 1. Four weeks after surgery, a synthetic derivate of eel calcitonin, ([Asu1'7]eel calcitonin) (4 U/kg/day) (Elcatonin, Asahi Kasei Co., Tokyo, Japan) was subcutaneously injected into the back of rats 5 times a week for 4 weeks. The vehicle was injected as a control. P-chlorophenylalanine (PCPA; Sigma, MO, USA), 100 mg/kg/day, an inhibitor of serotonin biosynthesis, was intraperitoneally injected on the final 3 days of calcitonin administration. Normal saline was injected as a control. The following 5 groups were established: a) a group repeatedly subcutaneously injected with calcitonin after OVX (OVX-calcitonin group, n = 5), b) a group repeatedly subcutaneously injected with vehicle after OVX (OVX-vehicle group, n = 5), c) a group intraperitoneally injected with PCPA after OVX in addition to being repeatedly subcutaneously injected with of calcitonin (OVX-calcitonin-PCPA group, n = 5), d) a group repeatedly subcutaneously injected with calcitonin after sham operation (sham-calcitonin group, n = 5), and e) a group repeatedly subcutaneously injected with vehicle after sham operation (sham-vehicle group, n = 5). After surgery and injections, the formalin test was performed as an acute noxious stimulus with subcutaneously injected with 5% formalin (0.050 ml) (Wako Pure Chemical Industries, Ltd. Osaka, Japan) into the left hind paw. All rats were perfused two hours after formalin test.

Bottom Line: The numbers of Fos-ir neurons in the OVX-CT and sham-CT groups were significantly less than in the OVX-vehi and sham-vehi groups, respectively (p = 0.0090, p = 0.0090).The number of Fos-ir neurons in the OVX-CT-pcpa-group was significantly more than that of the OVX-CT-group (p = 0.0283), which means pcpa inhibits calcitonin induced reduction of c-Fos production.The results in this study demonstrated that 1) the increase of c-Fos might be related to hyperalgesia in OVX-rats. 2) Calcitonin has an antinociceptive effect in both OVX and sham rats. 3) The central serotonergic system is involved in the antinociceptive properties of calcitonin.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopedic Surgery, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima City, Fukushima, 960-1295, Japan. bun@fmu.ac.jp

ABSTRACT

Background: Calcitonin is used as a treatment to reduce the blood calcium concentration in hypercalcemia and to improve bone mass in osteoporosis. An analgesic effect of calcitonin has been observed and reported in clinical situations. Ovariectomized (OVX) rats exhibit the same hormonal changes as observed in humans with osteoporosis and are an animal model of postmenopausal osteoporosis. The aim of this study to investigate antinociceptive effect of calcitonin in OVX rats using the immunohistochemical study.

Methods: We assessed the antinociceptive effects of calcitonin in an ovariectomized (OVX) rat model, which exhibit osteoporosis and hyperalgesia, using the immunohistochemical method. Fifteen rats were ovariectomized bilaterally, and ten rats were received the same surgery expected for ovariectomy as a sham model. We used five groups: the OVX-CT (n = 5), the sham-CT (n = 5), and the OVX-CT-pcpa (n = 5) groups received calcitonin (CT: 4 U/kg/day), while OVX-vehi (n = 5) and the sham-vehi (n = 5) groups received vehicle subcutaneously 5 times a week for 4 weeks. The OVX-CT-pcpa-group was given traperitoneal injection of p-chlorophenylalanine (pcpa; an inhibitor of serotonin biosynthesis) (100 mg/kg/day) in the last 3 days of calcitonin injection. Two hours after 5% formalin (0.05 ml) subcutaneously into the hind paw, the L5 spinal cord were removed and the number of Fos-immunoreactive (ir) neurons were evaluated using the Mann-Whitney-U test.

Results: The numbers of Fos-ir neurons in the OVX-CT and sham-CT groups were significantly less than in the OVX-vehi and sham-vehi groups, respectively (p = 0.0090, p = 0.0090). The number of Fos-ir neurons in the OVX-CT-pcpa-group was significantly more than that of the OVX-CT-group (p = 0.0283), which means pcpa inhibits calcitonin induced reduction of c-Fos production.

Conclusion: The results in this study demonstrated that 1) the increase of c-Fos might be related to hyperalgesia in OVX-rats. 2) Calcitonin has an antinociceptive effect in both OVX and sham rats. 3) The central serotonergic system is involved in the antinociceptive properties of calcitonin.

Show MeSH
Related in: MedlinePlus