观察右美托咪定(DEX)和水合氯醛(CHL)对体外培养新生大鼠海马神经细胞凋亡的影响。

以等渗盐水(NS)做阴性对照，药液以1：6的体积比例分别加入神经细胞培养液中。CHL组终浓度3.5 mmol/L；DEX组终浓度0.7 μmol/L；C＋D组为右美托咪定和水合氯醛混合加入培养液中，两药终浓度同CHL组和DEX组。新生SD大鼠处死取脑，显微镜下解剖分离出海马组织，消化洗涤制备细胞悬液，计数培养。原代培养7 d后加入含药培养基，再恒温孵育24 h。Western-Blot法检测激活型半胱氨酸天冬氨酸蛋白酶-3(cleaved Caspase-3)。实验重复3次。

CHL组cleaved Caspase-3条带增强，C＋D组cleaved Caspase-3条带较CHL组减轻，DEX组与NS组cleaved Caspase-3条带不明显。按灰度值计算(cleaved Caspase-3/α-tubulin)，NS组和DEX组分别为(0.15±0.12)和(0.09±0.05)，差异无统计学意义(P>0.05)，CHL组为(1.20±0.00)，较NS组增加(P<0.01)，C＋D组为0.73±0.14，较CHL组降低(P<0.01)。

水合氯醛直接接触能诱导新生大鼠海马神经细胞凋亡，右美托咪定不引起细胞凋亡，还能减轻水合氯醛引起的细胞凋亡。

To observe the effects of dexmedetomidine (DEX) and chloral hydrate (CHL) on apoptosis of hippocampal neurons in neonatal rats in vitro.

Normal saline (NS) was used as negative control, and the drug solution was added to the nerve cell culture medium at a ratio of 1∶6 volume. The CHL group was added with the final concentration of chloral hydrate (3.5 mmol/L), the DEX group was added with the final concentration of dexmedetomidine (0.7 μmol/L). Group C+ D was mixed with dexmedetomidine and chloral hydrate. The final concentration of the two drugs was the same as that of CHL group and DEX group. Newborn SD rats were killed and brain was taken. Hippocampal tissue was dissected under microscope, then were digested and washed to make cell suspension. After 7 days of primary culture, the drug containing medium was added and incubated at constant temperature for 24 hours. The active cysteine aspartate protease 3 (cleaved caspase-3) was detected using Western blot method . The experiment was repeated three times.

The results showed that cleaved caspase-3 bands in CHL group were enhanced by Western blot method, while in group C+ D they were reduced, and those in DEX group and NS group were not significant. Compared with NS group, cleaved caspase-3 expression in DEX group was no difference (0.15±0.12) vs. (0.09±0.05), but significantly increased in CHL group (1.20±0.00), (P<0.01). Compared with the group of CHL, the expression of cleaved caspase-3 in group C+ D decreased significantly (P<0.01).

Chloral hydrate can induce apoptosis of hippocampal neurons in neonatal rats in vitro. Dexmetomidine not only induce apoptosis, but also alleviate the apoptosis induced by chloral hydrate.