RESUMO
BACKGROUND: Previous studies have found that polygonatum sibiricum polysaccharide (PSP) exhibits anti-osteoporosis effect, but its therapeutic effect in ovariectomized osteoporotic rats and the molecular mechanisms are poorly understood. OBJECTIVE: To investigate the effect of administration of PSP on the bone microstructure, bone mineral density as well as osteoblast- and osteoclast-related gene expression in rats. METHODS: Twenty-five infertile female Sprague-Dawley rats aged 3 months were randomly allotted into five groups (n=5 per group): sham operation (same volume normal saline), model, zoledronate (0.2 mg/kg?d), high-dose PSP (800 mg/kg?d) and medium-dose PSP (400 mg/kg?d) groups. All rats were subjected to ovariectomy except sham operation group. The administration was intragastrically given every 2 days beginning at 7 days after modeling and lasted 12 weeks. Then, the rats were sacrificed, and the uterus was weighed. The bilateral tibias were removed, one side for histomorphometric analysis by micro-CT, and the other one for RNA detection by qualified PCR. RESULTS AND CONCLUSION: Compared with the sham operation group, the rat body mass in the model group was significantly increased and the weight of uterus was significantly decreased (P < 0.05). Compared with the model group, zoledronate and high-dose PSP could significantly alleviate the excessive increase in body mass (P < 0.05). The bone mineral density in the model group was decreased by 63% compared with the sham operation group (P < 0.01), Compared with the model group, after 12-week high-dose PSP and zoledronate administration, the bone mineral density was increased by 44% and 38%, respectively (P < 0.01); the trabecular bone volume fraction and trabecular number rose significantly(P<0.05),while the trabecular separation decreased significantly(P<0.05).In vivo,PSP could significantly promote the expression levels of osteoblast-related genes (alkaline phosphatase, RUNX2, Col1a1 and osteocalcin), and significantly inhibit the expression levels of osteoblast-related genes (ACP5 and CTSK) (P < 0.05). These results imply that high-dose PSP can reduce bone loss and decrease of bone mineral density, improve the destruction of bone microstructure, as well as promote osteoblast-related genes but inhibit osteoclast-related gene mRNA expression in the ovariectomized rats.
RESUMO
This study was aimed to investigate the radioprotective effects of recombinant human interleukin-12 (rhIL-12) on monkey hematopoietic system, and to provide experimental evidence for future clinical prophylaxis and treatment for patients who suffered from acute radiation syndrome. In in vitro study, the effect of rhIL-12 in different concentrations (0, 1, 5, 25, 125 and 625 ng/ml) on colony forming capacity of human or monkey bone marrow-derived mononuclear cells was examined in methylcellulose H4434 medium. In in vivo study, the acute radiation syndrome model was established in 11 Rhesus monkeys which received lethal total body irradiation by 6 Gy (60)Co γ in single time irradiation. The irradiated monkeys were randomly divided into 3 subgroups: control group (n = 4) which received subcutaneous PBS injection, rhIL-12 single-dose group (n = 3) which received subcutaneous single injection of rhIL-12 (4 µg/kg) at 2 h after irradiation, and multiple-dose group (n = 4) which received subcutaneous injection of rhIL-12 (1 µg/kg per injection) at 2 h, day 3, 6 and 9 after irradiation respectively. Peripheral blood cells were counted before and after irradiation every other day. The survival status of animals were observed daily. In vitro test results showed that different concentrations of rhIL-12 obviously promoted human and healthy monkeys' bone marrow mononuclear cells to form various hematopoietic progenitor cell colonies, especial CFU-E and CFU-GM. All animals in control group died within 22 d after lethal total body irradiation, average survival time was (20.3 ± 1.2) d. Only one monkey in multiple-dose group died due to anemia on day 17. All monkeys in single-dose group survived. Compared with control group, rhIL-12-administrated monkeys' white blood cell count, hemoglobin level, platelet and reticulocyte counts showed faster recovery from high dose radiation. It is concluded that the rhIL-12 treatment can promote the bone marrow hematopoietic stem/progenitor cell colony formation in vitro and protect lethally-irradiated monkeys. There is an obvious therapeutic effect of rhIL-12 on monkeys suffered from bone marrow failure caused by severe acute radiation exposure.