J Biomech.:肉毒杆菌A型毒素的最新研究进展
2008年第4期的爱思唯尔期刊《生物力学杂志》(Journal of Biomechanics)刊登了加拿大卡尔加里大学的一项最新研究。研究发现应用于神经内科的肉毒杆菌A型毒素(BTX-A)具有很强扩散作用，会很容易向临近肌肉组织扩散。
肉毒杆菌是一种形成孢子的革兰阳性需氧菌。肉毒杆菌有8型不同抗原型,其中A型肉毒杆菌毒素毒力最强。1克就能毒死数万人，但微量注入皮肤能够除皱。已有研究发现，注射肉毒杆菌毒素到肌肉处，肌肉会发生麻痹。正因为如此而被用于注射治疗眼肌痉挛、面肌痉挛等病。
最新研究中所采用的注射剂量与临床用于治疗肌肉痉挛等神经疾病所采用的剂量相当。但是结果表明，肉毒杆菌毒素会很容易向临近肌肉组织扩散，如果扩散到其它不需要麻痹的肌肉上就会引发一些并发症。
研究人员认为这项研究具有重要的意义，因为之前多数人认为当肉毒杆菌毒素注射到单一肌肉组织后，会“停留”在那里，而该研究发现它并不像想象的那样那么容易控制。鉴于目前肉毒杆菌毒素在神经内科、眼科、整形、美容外科的广泛应用，研究人员希望此项研究能够为深入研究和更好应用肉毒杆菌毒素产生一定的作用。（科学网 于乃森/编译）
生物谷推荐原始出处：
(Journal of Biomechanics)，doi:10.1016/j.jbiomech.2007.11.016，M. Yaraskavitch, Walter Herzog
Botox produces functional weakness in non-injected muscles adjacent to the target muscle
M. Yaraskavitcha, T. Leonardb and Walter Herzog
Abstract
Botulinum type-A (BTX-A) neurotoxin exerts a paralytic effect on muscles and is used increasingly to treat a variety of muscle spasticity disorders. While its pathogenesis for muscle-induced weakness has been well elucidated, the functional effects of BTX-A administration are incomplete. Specifically, weakness as a function of muscle length and stimulation frequency has only been investigated qualitatively in a few muscles and the possible effect of the toxin on non-target muscles, although considered possible based on laboratory experiments, has not been studied widely and the functional implications remain unknown. Therefore, the purpose of this study was to measure the functional implications of BTX-A on force production and possible weakness of a target muscle and a non-injected neighbouring muscle. The cat soleus was chosen as the target muscle and was injected with 3.2–3.5 U of BTX-A/kg in one hind limb, while the soleus of the other hind limb served as a non-injected control. Force–length properties within and exceeding the functional range of motion were determined at frequencies of stimulation of 10, 30 and 50 Hz. Force–length properties of the adjacent non-injected plantaris were also determined in the experimental and contralateral hind limb. Four weeks following BTX-A injections, peak soleus forces were decreased by 30% (50 Hz), 29% (30 Hz) and 29% (10 Hz) and peak plantaris forces were decreased by 11% (50 Hz), 16% (30 Hz) and 16% (10 Hz), in the experimental compared to the contralateral hind limb. Absolute BTX-associated force loss was significantly different at all frequencies of stimulation and all lengths for the soleus, while in the plantaris there was a significant force loss across long (?4 mm) but not short muscle lengths. Decreases in peak force were independent of the stimulation frequency. We concluded from the results of this study that BTX-A injection in the target muscle caused a measurable effect on force production and that force production was decreased in non-target neighbouring muscles at and near lengths of peak force production. These results are of particular importance in therapeutic procedures where isolated muscles are targeted for treatment. They should also be considered in neurophysiological studies in which BTX-A injections are used to selectively diminish muscle function.
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