Fig 1: A–H, Mitophagy, mediated by the PINK1–Parkin pathway, and mitochondrial biogenesis are involved in ageing and in the ageing improvement effects of acupoint catgut embedding. The hippocampus from rats of the control, model, acupoint catgut embedding, sham acupoint catgut embedding, rapamycin and 3-MA groups were prepared and analysed by Western blotting (mean ± SEM; from three independent experiments; **P < .01; *P < .05) (A) autophagy activity was measured by LC3 protein levels using an antibody against LC3B. Proteins in the PINK1–Parkin pathway were measured by PINK1, Parkin, P62, Mfn2 and Drp1 levels with relevant antibodies. Mitochondrial biogenesis was represented by PGC1-a protein levels with an antibody against PGC1-a. GAPDH was used as the loading control in all Western blots. Bar graphs show the levels of LC3 (B), PINK1 (C), Parkin (D), P62 (E), Mfn2 (F), Drp1 (G) and PGC1-a (H). In the LC3 protein, rats in model group showed suppressed in expression as compared to control group (P < .05), acupoint catgut embedding treatment on ageing rats might reverse such downtrend in ageing process (P < .01), which may be cut down by 3-MA (P < .05), while there was no statistic difference between the model rats and rats being treated by sham acupoint catgut embedding and by rapamycin (P = ns). As for Pink1 protein expression, an upward expression was seen in ageing rat model group compared to control group (P < .01), acupoint catgut embedding treatment and rapamycin on ageing rats could aggravate this upward trend (P < .01), whose effect could be inhibited by adoption of 3-MA (P < .01), no significant difference showed between model group and sham acupoint catgut embedding treatment group (P = ns). As the expression of Parkin protein, the administration of rampamycin on ageing rats might boost its expression as compared to model group (P < .05), no significant difference showed between the rest groups (P = ns). In expression of P62 protein, rats in acupoint catgut embedding treatment group represented a reduction as compared to the model group (P < .05), and comparison of the rest groups showed no significant variation (P = ns). As for expression of Mfn2 protein, hippocampus in model group estimated a down-regulation in expression when compared to the control group (P < .01), acupoint catgut embedding treatment on ageing rats might aggravate such trend (P < .05), which may be reversed by adding of 3-MA (P < .01), while comparison between the model and sham treatment, model and rapamycin showed no significant difference (P = ns). In expression of Drp1 protein, there were merely upward inclination between control and model groups (P = ns), down-regulation yet no statistic difference seen between the model group and acupoint catgut embedding treatment group and sham operation group (P = ns). In expression of PGC1-a protein, a marked decrease showed between the control and model groups (P < .05), treatment with acupoint catgut embedding and/or rapamycin on ageing rats add extra expression as compared to ageing rats (P < .01, P < .05), this increased effect mediated by acupoint catgut embedding may be blocked by 3-MA (P < .01), however, sham acupoint catgut embedding on ageing animals showed no remarkable influence in ageing rats as compared to rats in model group (P = ns)