Effects of Stem Cell Factor/c-Kit Signaling on In Vitro Maturation of Porcine Oocytes and Subsequent Developmental Competence After Fertilization.

Stem cell factor (SCF), also known as c-Kit ligand, plays an important role in the proliferation of primordial germ cells and the survival of oocytes during follicular development. The aim of this study was to investigate the effect of SCF/c-Kit signaling on in vitro maturation (IVM) of porcine oocytes by analyzing nuclear and cytoplasmic maturation, oocyte size, cumulus cell expansion, and developmental competence to the blastocyst stage. Moreover, mRNA expression patterns of porcine cumulus cells and oocytes were evaluated using qRT-PCR. Following 42 h of IVM, 10 and 50 ng/mL SCF-treated groups exhibited significantly (P < 0.05) increased polar body extrusion rates and intracellular glutathione levels compared with the control group. The cumulus expansion index significantly (P < 0.05) increased in all SCF-treated groups compared with the control samples. mRNA levels of the proapoptotic gene Bax and apoptosis-related cysteine peptidase Caspase3 were lower in SCF-treated cumulus cells than in the control group. Notably, the diameter of oocytes after IVM, the mRNA expression of well-known oocyte-secreted factors (GDF9 and BMP15), and an oocyte-specific protein essential for ovulation and oocyte health (YBX2) were significantly (P < 0.05) higher in SCF-treated than in non-treated oocytes. Inhibition of c-Kit during porcine IVM using ACK2, an antagonistic blocker of c-Kit, significantly (P < 0.05) decreased the polar body extrusion rate compared with the control, as well as blastocyst formation rate compared with the 10 ng/mL SCF-treated group. In conclusion, the effect of SCF/c-Kit-mediated signaling during porcine IVM could be ascribed to the reduced expression of apoptosis-related genes and higher expression of oocyte-specific/secreted factors.

The Scf/Kit pathway implements self-organized epithelial patterning.

How global patterns emerge from individual cell behaviors is poorly understood. In the Xenopus embryonic epidermis, multiciliated cells (MCCs) are born in a random pattern within an inner mesenchymal layer and subsequently intercalate at regular intervals into an outer epithelial layer. Using video microscopy and mathematical modeling, we found that regular pattern emergence involves mutual repulsion among motile immature MCCs and affinity toward outer-layer intercellular junctions. Consistently, Arp2/3-mediated actin remodeling is required for MCC patterning. Mechanistically, we show that the Kit tyrosine kinase receptor, expressed in MCCs, and its ligand Scf, expressed in outer-layer cells, are both required for regular MCC distribution. Membrane-associated Scf behaves as a potent adhesive cue for MCCs, while its soluble form promotes their mutual repulsion. Finally, Kit expression is sufficient to confer order to a disordered heterologous cell population. This work reveals how a single signaling system can implement self-organized large-scale patterning.

[Effects of Electroacupuncture on Ultrastructure of Interstitial Cells of Cajal and Stem Cell Factor-kit Signal Pathway of Gastric Antrum in Diabetic Gastroparesis Rats].

OBJECTIVE: To observe the effects of electroacupuncture (EA) on gastrointestinal motility and the ultrastructure of interstitial cells of Cajal (ICC) and the expressions of c-kit receptor protein and stem cell factor (SCF) mRNA in diabetic gastroparesis (DGP) rats, so as to explore its mechanism. METHODS: Fifty SD rats were randomly divided into normal, model, acupoint, non-acupoint and metoclopramide groups (n＝10 rats/group). DGP model was established by intraperitoneal injection of streptozotocin (STZ, 2%), and raised with high-sugar high-fat diet irregularly. EA (sparse-dense, 10 Hz/50 Hz, 2 mA, 20 min) was applied at "Zusanli" (ST 36), "Liangmen" (ST 21) and "Sanyinjiao" (SP 6), and the corresponding non-acupoints of the 3 acupoints, daily for 15 days. The rats in metoclopramide group received intragastric administration of metoclopramide (1.7%, 1 mL/100 g) for 15 days, once a day. Blood sugar was determined with One Touch blood glucose test paper. The gastric emptying rate (GER) and the intestinal propulsion rate (IPR) were measured by intragastric phenol red. The ultrastructure of ICC was detected by transmission electron microscopy. The expression levels of c-kit receptor protein and SCF mRNA of gastric antrum were examined respectively by Western blot and RT-PCR. RESULTS: Compared with the normal group, the blood glucose significantly increased in the model group (P<0.01), while the GER, IRP and the expression level of SCF mRNA in the gastric antrum significantly decreased (P<0.01), and the ultrastructure of ICC appeared apoptosis-like changes. The blood glucose of the EA group was obviously decreased compared with that of the model group (P<0.05); the GER and IRP significantly increased(P<0.05, P<0.01); the expression level of SCF mRNA increased (P<0.01), the number of ICC increased and its ultrastructure was repaired. There was some relief on ICC ultrastructure in the acupoint group compared with that in the non-acupoint group; and SCF mRNA increased (P<0.05). There was no significant difference on c-kit receptor expression among all the modeling groups (P＞0.05). CONCLUSIONS: EA at ST 36, etc. can regulate the blood glucose and improve gastrointestinal emptying in DGP rats. The mechanism may be related to up-regulating SCF mRNA, repairing ICC ultrastructure, restoring the pacing function, and improving gastrointestinal motility.

Effects of Electroacupuncture on Ultrastructure of Interstitial Cells of Cajal and Stem Cell Factor-kit Signal Pathway of Gastric Antrum in Diabetic Gastroparesis Rats / 针刺研究

OBJECTIVE: To observe the effects of electroacupuncture (EA) on gastrointestinal motility and the ultrastructure of interstitial cells of Cajal (ICC) and the expressions of c-kit receptor protein and stem cell factor (SCF) mRNA in diabetic gastroparesis (DGP) rats, so as to explore its mechanism. METHODS: Fifty SD rats were randomly divided into normal, model, acupoint, non-acupoint and metoclopramide groups (n＝10 rats/group). DGP model was established by intraperitoneal injection of streptozotocin (STZ, 2%), and raised with high-sugar high-fat diet irregularly. EA (sparse-dense, 10 Hz/50 Hz, 2 mA, 20 min) was applied at "Zusanli" (ST 36), "Liangmen" (ST 21) and "Sanyinjiao" (SP 6), and the corresponding non-acupoints of the 3 acupoints, daily for 15 days. The rats in metoclopramide group received intragastric administration of metoclopramide (1.7%, 1 mL/100 g) for 15 days, once a day. Blood sugar was determined with One Touch blood glucose test paper. The gastric emptying rate (GER) and the intestinal propulsion rate (IPR) were measured by intragastric phenol red. The ultrastructure of ICC was detected by transmission electron microscopy. The expression levels of c-kit receptor protein and SCF mRNA of gastric antrum were examined respectively by Western blot and RT-PCR. RESULTS: Compared with the normal group, the blood glucose significantly increased in the model group (P<0.01), while the GER, IRP and the expression level of SCF mRNA in the gastric antrum significantly decreased (P<0.01), and the ultrastructure of ICC appeared apoptosis-like changes. The blood glucose of the EA group was obviously decreased compared with that of the model group (P<0.05); the GER and IRP significantly increased(P<0.05, P<0.01); the expression level of SCF mRNA increased (P<0.01), the number of ICC increased and its ultrastructure was repaired. There was some relief on ICC ultrastructure in the acupoint group compared with that in the non-acupoint group; and SCF mRNA increased (P<0.05). There was no significant difference on c-kit receptor expression among all the modeling groups (P＞0.05). CONCLUSIONS: EA at ST 36, etc. can regulate the blood glucose and improve gastrointestinal emptying in DGP rats. The mechanism may be related to up-regulating SCF mRNA, repairing ICC ultrastructure, restoring the pacing function, and improving gastrointestinal motility.