[Exogenous CRX gene induces Müller cell-derived progenitors to differentiate into photoreceptors].

Objective: To investigate whether exogenous CRX gene would be able to induce Müller cells-derived progenitors to differentiate into photoreceptors. Methods: Experimental study. Müller cells-derived progenitors resulted from primary Müller cells isolated from KunMing mice(5-7 days old) and cultured in free-serum media. Markers of Müller cells(glutamine synthetase, GS and Vimentin) and stem cells (Nestin and Sox2) were analysed by immnocytochemical assays. The secondary passage progenitors were divided into three groups: (1)the control group; (2)the empty vector group was transfected with lentivirus GFP; (3)the treated group was transfected with lentivirus GFP-CRX. After differentiation for 7 days, 7 days after differentiation, the expression of markers of photoreceptors were analyzed by q-PCR and Western blot assay. Results: There were 96.03%±1.21% of Müllerz cells cultured in vitro were immunoreactive to both GS and Vimentin. The dedifferentiation cells expressed Nestin and Sox2. After 7 days of induction, Exogenous CRX induced Müller cell-derived progenitors to differentiate into rod-like cells showed appearance like neuron morphology. q-PCR demonstrated that mRNAs of CRX and Rhodopsin were upregulated greatly. CRX mRNA were 9 times (P<0.05) and Rhodopsin mRNA were 20 times (P<0.05). The difference between the control group and the empty vector group was not statistically significant. Western blot showed that the expression of CRX was upregulated significantly, and was 2.7 times(P<0.05). But expression of Rhodopsin was weak and was nearly not detected in the control group and empty vector group. The expression of S-opsin was not detected. Conclusion: CRX gene could induce the differentiation of Müller cell-derived progenitor into rod photoreceptors, indicating a new avenue to study müller cells as endogenous seed cells for retinal photoreceptor. (Chin J Ophthalmol, 2018, 54: 923-928).

Effects of voluntary running on plasma levels of neurotrophins, hippocampal cell proliferation and learning and memory in stressed rats.

Previous studies have shown that a 2-week treatment with 40 mg/kg corticosterone (CORT) in rats suppresses hippocampal neurogenesis and decreases hippocampal brain-derived neurotrophic factor (BDNF) levels and impairs spatial learning, all of which could be counteracted by voluntary wheel running. BDNF and insulin-like growth factor (IGF-1) have been suggested to mediate physical exercise-enhanced hippocampal neurogenesis and cognition. Here we examined whether such running-elicited benefits were accompanied by corresponding changes of peripheral BDNF and IGF-1 levels in a rat model of stress. We examined the effects of acute (5 days) and chronic (4 weeks) treatment with CORT and/or wheel running on (1) hippocampal cell proliferation, (2) spatial learning and memory and (3) plasma levels of BDNF and IGF-1. Acute CORT treatment improved spatial learning without altered cell proliferation compared to vehicle treatment. Acute CORT-treated non-runners showed an increased trend in plasma BDNF levels together with a significant increase in hippocampal BDNF levels. Acute running showed no effect on cognition, cell proliferation and peripheral BDNF and IGF-1 levels. Conversely, chronic CORT treatment in non-runners significantly impaired spatial learning and suppressed cell proliferation in association with a decreased trend in plasma BDNF level and a significant increase in hippocampal BDNF levels. Running counteracted cognitive deficit and restored hippocampal cell proliferation following chronic CORT treatment; but without corresponding changes in plasma BDNF and IGF-1 levels. The results suggest that the beneficial effects of acute stress on cognitive improvement may be mediated by BDNF-enhanced synaptic plasticity that is hippocampal cell proliferation-independent, whereas chronic stress may impair cognition by decreasing hippocampal cell proliferation and BDNF levels. Furthermore, the results indicate a trend in changes of plasma BDNF levels associated with a significant alteration in hippocampal levels, suggesting that treatment with running/CORT for 4 weeks may induce a change in central levels of hippocampal BDNF level, which may not lead to a significant change in peripheral levels.

Artificial bone of porous tricalcium phosphate ceramics and its preliminary clinical application.

The authors have prepared the artificial bone of porous tricalcium phosphate ceramics according to an appropriate formula and manufacturing technology. Physical and chemical testing shows that it possesses several distinguishing features: the communicating pores and macro/micropores; mean pore size, 380 microns (from 240 microns to 510 microns); porosity, 46.4%; and compressive strength, 97.4 kg/cm2. It consists of CaO (49.09%) and P2O5 (48.84%). The testing of its biocompatibility shows that it is devoid of systemic or local toxicity, and free of irritation or foreign body response in tissues, and it does not result in hemolysis or mutation. The new bone readily grows into its pores with direct contact to the implanted material. 11 cases of bone defects were treated with this artificial bone with satisfactory results.