Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolism

OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.     

Laparoscopic Anatomy of the Abdomen and Laparoscopic Ligating Loops,Electrocoagulation, and a Novel Modified Electroligation Ovariectomy in Standing Mare

The purpose of this study was to provide a detailed laparoscopic anatomy of the caudal abdominal region of mare in a standing position and to evaluate and modify a technique for standing laparoscopic ovariectomy using combination between hand-tied ligating loop and electrocoagulation techniques, as the ligating loops, electrocoagulation, and modified electroligation laparoscopic ovariectomy were applied using nine adult mares. Laparoscopy was practical and effective for direct visual examination of internal abdominal organs in the mare. Ventral dislocation of abdominal viscera after pneumoperitoneum was established with the mare in standing position, which provided an excellent inspection of the dorsal and ventral structures in the peritoneal cavity on the right and left sides. Standing laparoscopic ovariectomy using an electroligation modified method was considered a safe and effective method for hemostasis of the mesovarium, technically easy, time saving, and economical. The mean surgical time for bilateral ovariectomy was 40 ± 7.63, 60 ± 5.25, and 85 ± 6.43 minutes for electroligation-modified technique, ligating loops technique, and electrocoagulation technique, respectively.     

“中国园艺学会十届二次理事会暨学术研讨会”预备通知

AIM:The aim of the present study is to investigate changes of five biochemical markers of bone turnover during the formation of ovariectomized rat model. METHODS:Three-month-old female SD rats were divided randomly into ovariectomized (OVX) group, sham-operated (sham) group and control group. Five biochemical markers of bone turnover levels, including serum osteocalcin (OC), total alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BALP), tartrate-resistant acid phosphatase (TRAP) and hydroxyproline (HYP) were measured before and at 1, 1.5, 2, 2.5, 3 and 4 months after surgery. The right proximal tibias of rats were excised at the same time point for histopathological observation. RESULTS:Serum OC, ALP, BALP, TRAP and HYP levels in OVX group were significantly higher than that in sham group. As regard to the time of peak level arrived, the sequence of changes was as follows: TRAP/HYP→OC→ALP/BALP. There was a significant positive correlation between five markers. The pathological changes of trabecular bone in OVX group were only observed 3 months after surgery. CONCLUSION:The results suggest that postmenopausal osteoporosis has a high bone turnover rate. During the formation of ovariectomized rat model, changes of bone resorption markers precede changes of bone formation markers. Serum OC, ALP, BALP, TRAP and HYP are sensitive to evaluate the bone loss in the earlier stage of postmenopausal osteoporosis.     

Laparoscopic Ovariectomy in Standing Mule Mares

Mules are hybrids bred from the mating of a jack donkey and a horse mare, known for their strength and resistance and still used to work in agriculture. Although they have been for long considered sterile, evidence of estrus cycle has been demonstrated together with abnormal behavior related to ovarian activity. In this study, a bilateral standing laparoscopic ovariectomy technique using the LigaSure technology was applied in 10 mare mules for treating unwanted behavioral patterns. The technique was effectively performed on these animals avoiding the risk of general anesthesia, and the use of the LigaSure technology allowed good hemostasis and reduced surgical time. Owners declared to be satisfied with the resolution of the behavior.     

Proliferation and differentiation of bone marrow mesenchymal stem cells in process of bone loss in ovariectomized rats

AIM: To study the function of proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs) for bone loss in the pathogenesis of osteoporosis (OP) in ovariectomized rats. METHODS: Animal model of OP was established by ovariectomy (OVX,bilateral ovarian resection) in 10-week-old healthy female Sprague-Dawley (SD) rats.BMSCs were isolated, cultured and purified by the combination of density gradient centrifugation, adhesion separation and limited dilution method, and cultured in vitro to the 3rd~4th passage in all experiments. The BMSCs phenotype appraisal was studied by flow cytometry. Colony-forming assay was applied to detect the BMSCs proliferation ability. The MTT method was used to analyze the growth curves of BMSCs. After adipogenic induction (ADI), lipid drops were observed by oil red O staining to compare the adipogenic potential between the 2 kinds of BMSCs. After osteogenic induction (OSI), calcium nodules were observed by alizarin red staining (ARS). The mRNA expression levels of BMSCs osteogenesis-related proteins, for instance, Runx2, osteocalcin (OCN) and osteopontin (OPN) were measured by RT-PCR. RESULTS: Compared with sham group, the colony-forming ability of BMSCs in OVX group became decreased, the proliferation capacity was declined, the osteogenic potential was decreased, and the adipogenic potential was increased(P<0.05). CONCLUSION: In ovariectomized OP rats, the proliferation and osteogenesis of BMSCs decrease, and the adipogenesis of BMSCs increases, which may cause rapid bone loss and play an important role in the pathogenesis of OP.     

Effect of resveratrol on level of brain-derived neurotrophic factor in hippocampus of obese rats induced by ovariectomy and high-fat diet

AIM：To explore the effects of resveratrol on the level of brain-derived neurotrophic factor (BDNF) and the mRNA expression of estrogen receptor α (ERα) and estrogen receptor β (ERβ) in hippocampus of obese rats induced by ovariectomy and high-fat diet. METHODS：Fifty female Wistar rats, aged 3 months, were randomly divided into 5 groups: control (C) group, sham operation plus high-fat diet (H) group, ovariectomy plus normal diet (O) group, ovariectomy plus high-fat diet (O+H) group, and ovariectomy plus high-fat diet and treated with resveratrol (40 mg·kg-1·d-1) (O+H+R) group. Three months later, the blood was collected from the femoral artery to detect the serum concentrations of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and estradiol (E2). The mRNA expression of ERα, ERβ and BDNF in the hippocampus was determined by real-time PCR. The protein level of BDNF in hippocampal tissues was detected by ELISA and Western blotting. RESULTS：Compared with C group, the serum levels of TC and LDL-C in H group were increased, and the hippocampal level of BDNF was decreased. The rats in O group had higher concentration of serum TC, and lower levels of serum E2 and the mRNA expression of ERα, ERβ and BDNF in the hippocampus than those in C group. Compared with C,H and O groups, the level of serum TC was higher, and the level of serum E2 and the expression of BDNF in the hippocampus was lower in O+H group. The mRNA expression of ERα and ERβ in hippocampus was also reduced as compared with C group and H group. After treated with resveratrol, the rats in O+H+R group showed lower level of serum TC, and higher levels of serum E2, hippocampal BDNF and mRNA expression of ERα and ERβ than those in O+H group. CONCLUSION：Ovariectomy combined with high-fat diet decreases the mRNA expression of ERαand ERβ and the level of BDNF in the rat hippocampus. Resveratrol improves the blood lipid metabolism and up-regulates the mRNA expression of ERα/ERβ and the level of BDNF in the hippocampus in obese rats induced by ovariectomy and high-fat diet.     

Observation of estrous cycle in sexual maturation and ovariectomized female ICR mice

AIM: To observe the characteristics of estrous cycle of female ICR mice and ovariectomized mice that had reached sexual maturity stage. METHODS: ICR mice were randomly divided into 3 groups, normal group, sham operation group and ovariectomized group. After ovariectomy and sham operating, at the 8th day, the mice were taken vaginal smears twice daily (09:00 and 16:00) for 12 consecutive days. The feature of vulva in the mice and vaginal smear cytology, occurrence rate of regular estrous cycle, duration of estrous cycle and each stage duration of estrous cycle were recorded and observed. RESULTS: The characteristics of estrous cycle in normal group and sham operation group were similar. Nearly 85% of the ICR mice in sexual maturity stage showed regular estrous cycle. The majority manifested 6-day cycle (83%), and only a small number exhibited 5-day cycle (17%). Compared with 5-day group, the duration of oestrus was significantly increased in 6-day group (P<0.05). The number and kind of the cells in vaginal smear were a little different between 5-day and 6-day groups. The ovariectomized mice which showed irregular estrous cycle (76%) were characterized by continuous diestrus. CONCLUSION: Female ICR mice have the strain characteristics of estrus cycle.