Influence of age, gender, and race on nitric oxide release over acupuncture points-meridians

Abstract

This study examined the influence of age, gender and race on nitric oxide (NO) release over acupuncture points, meridian without acupoint, and non-meridian regions of the Pericardium (PC) and Bladder (BL) meridian as well as aging on LU meridian in 61 healthy subjects. Biocapture tubes were attached to the skin surface, and total nitrite and nitrate was biocaptured and quantified using chemiluminescence. In elder ages compared to adults, NO levels over the ventral forearm were significantly decreased over LU on radial regions but not altered over PC on medial regions. Conversely, NO content was elevated over BL regions only in overweight/obesity of elder ages. NO levels over PC regions were marginally elevated in overweight/obese males compared to females but did not alter between races. These results suggest a selective reduction of NO release over LU meridian with aging, which is consistent with a progressive decline in lung function and increase in chronic respiratory disease in elder ages. Increased NO levels along the BL meridian in older obese subjects may reflect a modified NO level along somatic-bladder pathway for counteracting bladder dysfunctions with aging. Both of them support somatic-organ connections in the meridian system associated with potential pathophysiological changes with aging.

Figure 1. Representation of a biocapture device with a semi-cylindrical molded tube taped to the skin surface over meridians.

The pericardium (PC), lung (LU), and bladder (BL) meridian lines and related acupuncture points are illustrated on the top left, top right, and bottom right panels. The region from PC 5 to PC 7 is defined as acupoint (3 acupoints), the distance between PC 3 and PC 4 is defined as meridian line without acupoint (MWOP), and non-meridian control region close to PC meridian (NMCR). The region overlapping LU 8 and LU 9 is defined as acupoint (2 acupoints), the distance between LU 6 and LU 7 represents MWOP, and NMCR as non-meridian area adjacent to the meridian. The region over BL 57 is defined as acupoint (1 acupoint), the distance between BL 55 and BL 56 represents MWOP, and NMCR as non-meridian area adjacent to the meridian. The device was adhered to the skin surface using a custom double-sided adhesive, and NO scavenging solution (100 μM PTIO) was injected into the tubing over the skin surface for 20 min in order to directly absorb NO. The PC, LU, and BL meridian lines and related acupuncture points are reproduced from J. A. Johnson, Chinese Medical Qigong Therapy: A Comprehensive Clinical Text, 2000.

Figure 2. Quantification of nitric oxide (NO) metabolites over skin acupoints/meridians in elder subjects compared to adults.

(a) Concentrations of total nitrite plus nitrate (NO_x⁻) wee compared in adults vs. elder subjects over the skin regions along the Pericardium meridian (PC, n = 14 and 10), Bladder meridian (BL, n = 12 and 7), and Lung meridian (LU, n = 14 and 8). (b) NO_x⁻ concentrations over LU regions were compared in normal weight adult vs. elder subjects (n = 10 and 16). (c) NO_x⁻ concentrations over BL regions were compared between adult and elder subjects in normal weight (n = 12 and 6) and in overweight/obesity (n = 12 and 7). (d) NO_x⁻ concentrations over PC regions were compared between adult and elder subjects in normal weight (n = 16 and 8) and in overweight/obesity (n = 12 and 10). NO_x⁻ concentrations (nmol/cm²) were obtained over acupoints, meridian lines without acupoint (MWOP), and non-meridian control region (NMCR). Each bar represents the mean values and vertical bars represent S.E.M. *p < 0.05, compared to adult; ^#p < 0.10, compared to adult.

Figure 3. Quantification of nitric oxide (NO) metabolites over skin acupoints/meridians in male compared to female subjects.

(a) Concentrations of total nitrite plus nitrate (NO_x⁻) were compared between male and female subjects over the regions along the Pericardium (PC) meridian (n = 18 and 28) and Bladder (BL) meridian (n = 14 and 23). (b) NO_x⁻ concentrations over PC regions between male and female subjects were compared in normal weight (n = 8 and 16) and overweight/obesity (n = 10 and 12). NO_x⁻ concentrations (nmol/cm²) were obtained over acupoints, meridian lines without acupoint (MWOP), and non-meridian control region (NMCR). Each bar represents the mean values and vertical bars represent S.E.M. *p = 0.05, compared to male; ^#p = 0.08, compared to male.

Figure 4. Quantification of nitric oxide (NO) metabolites over skin acupoints/meridians in Asian compared to white subjects.

Concentrations of total nitrite plus nitrate (NO_x⁻) were compared between Asian and white normal weight subjects over the regions along the Pericardium (PC) meridian (n = 16 and 6) and Bladder (BL) meridian (n = 9 and 5). NO_x⁻ concentrations (nmol/cm²) were obtained over acupoints, meridian lines without acupoint (MWOP), and non-meridian control region (NMCR). Each bar represents the mean values and vertical bars represent S.E.M.