[Comparative study of two high-efficiency methods for purifying spermatogonial stem cells].

Objective: To compare the advantages and disadvantages of the differential attachment method and immunomagnetic bead method for purification of mouse spermatogonial stem cells (mSSCs). Methods: Ten male C57BL/6 mice aged 12～15 days were selected and sacrificed by cervical dislocation. Testes were collected and the seminiferous tubule single cell suspension was obtained by enzymatic digestion. mSSCs were purified by using the differential attachment method and immunomagnetic bead method respectively. Then a detailed comparison of the two methods in terms of cell number, separation efficiency, and impact on cell proliferation and growth was conducted. Results: Both of the methods could isolate and purify stem cells from single cell suspension of mouse seminiferous tubules. mSSCs showed typical grape cluster-like clones in vitro culture, which could be continuously cultured and proliferated for over 3 months in vitro. The testes of 10 mice could obtain 3×105±0.4×105 mSSCs (n=5) by differential attachment method, cell recovery rate (the number of cells after purification/the number of cells of the single cell suspension of seminiferous tubules) was 1.5%±0.1%; 6×105±0.4×105 mSSCs (n= 5) could be obtained by immunomagnetic bead method. The recovery rate was about 3%±0.1%, and the number of stem cells obtained by the immunomagnetic bead method was higher. The stem cells obtained by the differential attachment method were more pure, because the stem cell colonies were preferentially obtained after 5 days of in vitro culture, while the stem cells obtained by the immunomagnetic bead method needed to be cultured for about 10 days before the obvious cell colonies could be observed, but the two types of purification method had no obvious effect on the long-term growth of cells in vitro. Conclusion: Both methods can get high quality mSSCs, but both methods have their own advantages and disadvantages. The differential attachment method is more economical and practical than the other, it does not require special equipment, but the stem cell number obtained is relatively lower and the time needed is longer.

[Expression of the Ces5a gene in the rat testis].

OBJECTIVE: To study the expression of the Ces5a gene in the development of the rat testis. METHODS: Using RT-PCR, Western blot, immunohistochemistry and HE staining, we determined the mRNA transcription level, protein expression and localization of the Ces5a gene in the testes of three litters of rats at different postnatal (PN) days. RESULTS: The expression of Ces5a mRNA was found in the testis tissue of the rats at 2－65 PN days, low at 2－12 days, decreased to the lowest level at 14－16 days (P < 0.05), but significantly increased at 20－35 days (P < 0.05), and elevated to the highest level at 40－65 days (P < 0.05). The expression of the Ces5a protein was also observed in the testis tissue of the rats at 2－65 PN, low at 2－12 days, with no significant change at 14－16 days (P > 0.05), but markedly increased at 20－35 days (P < 0.05), and again with no significant change at 40－65 days (P > 0.05). The Ces5a protein was expressed in the spermatogonia, spermatocytes and round sperm cells. CONCLUSIONS: The Ces5a gene may be involved in the proliferation and meiosis of rat spermatogonia and play a special role in round spermatogenesis and sperm deformation.

[Expression of the MYL2 gene in the development of rat testis tissue].

OBJECTIVE: To study the expression of the gene of myosin regulatory light chain-2 (MYL2) in the development of rat testis tissue. METHODS: Using real-time PCR and immunohistochemistry, we determined the mRNA transcription level and protein expression of MYL2 in the rat testis. RESULTS: The mRNA expression of the MYL2 gene changed in an age-dependent manner, reaching the highest value on postnatal day (PND) 2, then dropped rapidly till PND 8, increased slowly on PNDs 10 and 12, decreased on PND 14, rose slightly from PND 15 and rapidly on PNDs 20 and 25, and declined slowly from PND 65. Immunohistochemistry showed that the MYL2 protein was mainly expressed in testicular sperm cells. CONCLUSIONS: The MYL2 gene may be involved in the proliferation of spermatogonial stem cells and the process of sperm cells developing into mature sperm.

[Effect of dopamine receptor agonist apomorphine on scopolamine induced memory deficits in mice].

OBJECTIVE: To research the mechanism of dopamine (DA) controlled memory in mice. METHODS: Mice received i.p. injection of scopolamine (0.3 mg/kg, SCOP 0.3, and 3.0mg/kg, SCOP 3.0, respectively, n = 10) and saline (NS, n = 10) for 60 days in experiment 1. Memory of mice was detected by dark avoidance behavior in the 53" d and the 60"' d. Animals were sacrificed after the memory test; brain tissues were processed for Fos-ir and TH-ir by immunohistochemistry. Mice were divided into four groups according results of expri-ment 1, they received i.p. injection of apomorphine (0.1 mg/kg, APO 0.1, 0.5 mg/kg, APO 0.5, and 2.0 mg/kg, APO2.0 respectively, n = 10). RESULTS: Memory was inhibited in mice injected scopolamine 3.0 mg/kg. Latency was significantly less than in NS group, only 1/ 4 that of NS group (P > 0.05). The number of mistake of SCOP 3.0 group increased about four times than that of NS group (P > 0.05). But there was no difference of latency and number of mistake between SCOP 0.3 and NS group in expriment 1. Scopolamine-induced memory deficit was associated with decreased cellular activation, indicated by Fos immunoreactive (ir) staining, in NAcc CA1 and CA3 (P < 0.05), and also associated with decreases in the number of cells labeled for tyrosine hydroxylase (TH-ir), the rate limiting enzyme for dopamine conversion (P < 0.01) and the number of cells co-labeled for TH-ir/Fos-ir (P <0.01) in the ventral tegmental area(VTA), apomorphine lessened scopolamine-induced memory deficit in experiment 2. The number of cells co-labeled for TH-ir/Fos-ir (P <, 0.05) was increased in VTA after apomorphine treatment. CONCLUSION: Apomorphine lessened scopolamine-induced memory deficit in mice by increasing DA activities in VTA.