Wimalawansa S J, De Marco G, Gangula P, Yallampalli C
Department of Internal Medicine, University of Texas Medical Branch at Galveston, USA. swimalaw%
Bone. 1996 Apr;18(4):301-4. doi: 10.1016/8756-3282(96)00005-1.
Nitric oxide (NO) has been reported to inhibit osteoclastic bone resorption. We examined the bone-sparing effect of NO after 6 weeks of administration into estrogen-deficient rats. 30 female Sprague-Dawley rats, 12 weeks of age, underwent ovariectomy (OVX), and 5 rats were sham-operated. OVX rats were assigned to six groups (n = 5/group) treated respectively with: vehicle; 17-beta-estradiol (E2); nitroglycerine (NG, NO donor); NG-nitro-L-arginine methyl ester (L-NAME, NO synthase inhibitor); combination of E2 + NG; and a combination of E2 + L-NAME. Prior to treatment and at the end of the treatment period, bone mineral density (BMD) of rats was measured by dual-energy X-ray absorptiometry (DXA) scanning. OVX animals had significantly lower BMD and femur weights in comparison to sham operated rats (p < 0.01), and this was completely prevented by the administration of E2 (p < 0.01). Administration of NG alone prevented OVX-induced bone loss (p < 0.05). The combination of E2 + NG did not further enhance the bone mass or femur weight, and the OVX-induced bone loss was not further aggravated by L-NAME. However, in the presence of L-NAME, E2 was totally ineffective in reversing the bone loss, suggesting that the protective effect of estrogens against bone loss may be mediated through NO. In summary, the results suggest that NO counteracts the bone loss associated with OVX.
据报道，一氧化氮（NO）可抑制破骨细胞的骨吸收。我们研究了在给雌激素缺乏的大鼠给药6周后NO的保骨作用。30只12周龄的雌性Sprague-Dawley大鼠接受了卵巢切除术（OVX），5只大鼠进行了假手术。将OVX大鼠分为六组（每组n = 5），分别用以下药物治疗：赋形剂；17-β-雌二醇（E2）；硝酸甘油（NG，NO供体）；NG-硝基-L-精氨酸甲酯（L-NAME，NO合酶抑制剂）；E2 + NG组合；以及E2 + L-NAME组合。在治疗前和治疗期结束时，通过双能X线吸收法（DXA）扫描测量大鼠的骨矿物质密度（BMD）。与假手术大鼠相比，OVX动物的BMD和股骨重量显著降低（p < 0.01），而给予E2可完全预防这种情况（p < 0.01）。单独给予NG可预防OVX诱导的骨质流失（p < 0.05）。E2 + NG组合并未进一步增加骨量或股骨重量，并且L-NAME也未进一步加重OVX诱导的骨质流失。然而，在存在L-NAME的情况下，E2在逆转骨质流失方面完全无效，这表明雌激素对骨质流失的保护作用可能是通过NO介导的。总之，结果表明NO可抵消与OVX相关的骨质流失。
