观察丙酮酸钠口服补液盐对尾吊模拟失重大鼠第5腰椎(L5)背根神经节(DRG)的保护作用。

成年雄性大鼠40只，按实验处理随机数字表法分为4组，分别为对照组(简称CON组)、悬吊组(简称SUS组)、氯化钠溶液组(简称SAL组)和丙酮酸钠氯化钠溶液组(简称PYR组)。8周后取L5腰椎双侧DRG，苏木精-伊红和甲苯胺蓝染色光镜下观察细胞和尼氏体结构形态，电镜下观测线粒体结构，Western-blot法检测胶质细胞源性神经营养因子(GDNF) 和胶质纤维酸性蛋白(GFAP)的表达；检测组织ATP含量和ATPase活性。4组样本均数的比较采用方差分析。

与SUS组和SAL组相比，PYR组DRG细胞肿胀较轻，间隙无明显增宽，尼氏体染色深。电镜下PYR组线粒体仅轻度肿胀。Western-blot结果显示，GDNF蛋白表达PYR组较SUS组和SAL组分别增加了223%和212%，GFAP蛋白表达PYR组较SUS和SAL组分别减少了28%和24%，差异均有统计学意义(P值均小于0.05)。在代谢指标中，PYR组ATP含量较SUS组和SAL组分别升高35%和38%，ATPase活性较SUS组与SAL组分别升高42%和51%，差异均有统计学意义(P值均小于0.05)。PYR组上述观察指标与CON组比较，差异均无统计学意义(P值均大于0.05)。

模拟失重可导致大鼠DRG及其细胞器、神经营养因子和能量代谢的损伤，丙酮酸钠口服补液盐可明显减轻DRG的早期失重损伤。

To study the protective effects of oral sodium pyruvate on microstructural changes of L5 dorsal root ganglion in rats subjected to simulated weightlessness.

Forty male Sprague-Dawley rats were randomly divided into groups of normal control drinking regular water (group CON), tail-suspension drinking regular water (group SUS), tail-suspension drinking normal saline (group SAL) and tail-suspension drinking pyruvate saline (group PYR). After the microgravity for 8 weeks, both sides of L5 dorsal root ganglion were taken out. Cell morphology with hematoxylin eosin staining and Nissl body shape with toluidine blue staining examined by light microscopy and mitochondria observed by electron microscopy were carried out with dorsal root ganglion. Glial cell line-derived neurotrophic factor and glial fibrillary acidic protein protein expressions were measured by Western-blot. ATP contents and ATPase activities were also detected. Four groups of samples were compared using analysis of variance.

Compared with groups SUS and SAL, dorsal root ganglion cells showed no obvious swelling and gap widened. Their Nissl bodies were staining darker and mitochondrial structure was integral in group PYR. Western-blot determinations revealed that the glial cell line-derived neurotrophic factor expression in group PYR was increased with 223% and 212%, compared with group SUS and group SAL, respectively; the glial fibrillary acidic protein level was decreased in both group SUS and group SAL by 28% and 24% in comparison with group PYR, respectively, the differences were statistically significant (with P values below 0.05). In metabolic parameters, ATP contents in group PYR were enhanced by 35% and 38%, relative to groups SUS and SAL, respectively. ATPase activities in group PYR were improved with 42% and 51%, relative to groups SUS and SAL, respectively, the differences were statistically significant (with P values below 0.05). ATP contents and ATPase activities in group PYR were all preserved. All the parameters in group PYR were not statistically significant different from those in group CON(with P values above 0.05).

The dorsal root ganglion and its organelles in both structure and function were injured in rats subjected with 8-week simulated weightlessness; oral pyruvate could alleviate damage of dorsal root ganglion in the early stage of microgravity.